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Diet and Nutrition
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Vitamin
E supplements
If you’ve been taking vitamin E supplements, you’re not
alone. The positive results of early studies on the antioxidant led many
to take it in hopes of preventing or slowing everything from respiratory
infections to macular degeneration. But what proves hopeful in early,
preliminary studies doesn’t always pan out in larger research settings,
and vitamin E is a case in point.
Age- Related Macular Degeneration
Age- Related Macular Degeneration (AMD) is the breakdown of cells of
the macula, the small part of the eye that allows us to see
things sharply and in color. Little is known about what causes AMD, which
is the leading source of vision loss in people older than 55.
Early observational studies showed vitamin E might help prevent macular
degeneration. To test this theory, researchers recruited close to 1,200
participants between the ages of 55 and 80 to receive either a daily
vitamin E supplement or a placebo for four years. Participants underwent
annual eye exams to detect signs of development or progression of AMD
and changes in visual function.
The results of this study showed the incidence of AMD was similar among
participants in the two groups. In the vitamin E group 8.6% developed
AMD, whereas 8.1% in the placebo group did. Though this study clearly
indicates that vitamin E does not help prevent or slow the progression
of AMD, the study period was short, so it doesn’t prove that vitamin
E doesn’t help in the long run.
(British Journal of Medicine, July 6, 2002)
Respiratory Infections
Early studies showed that vitamins and minerals, particularly vitamin
E, may boost immune response in healthy elderly people. With this in
mind, Dutch researchers set out to investigate whether either of the
supplements lessens the rate and severity of respiratory infections in
the elderly.
The researchers enlisted 652 participants over the age of 60 and broke
them randomly into four groups. Each day, they either took a multivitamin
with minerals and a placebo, a vitamin E pill and a placebo, both a multivitamin
with minerals and vitamin E pill, or two placebos. After fifteen months
of follow-up, the researchers found that the rate of respiratory infections
did not differ among the groups. However, those who took vitamin E supplements
actually had respiratory infections that were more severe — they
were longer, caused more symptoms, and restricted more of the sufferer’s
activities.
(Journal of the American Medical Association, August 14, 2002)
February 2003 Update
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Food labels to list trans
fat
Sometime next year the Food and Drug Administration will require food
makers to list how much artery-damaging trans fat their products contain.
Trans fats, also called trans fatty acids, are found in hydrogenated
or partially hydrogenated vegetable oils. Trans fatty acids are the byproduct
of partial hydrogenation, a process that solidifies unsaturated oils.
Hydrogenation increases the shelf life of products made with these oils,
yet it also turns the relatively “safe” unsaturated fats
into trans fatty acids, which are no better (and possibly worse) than
saturated fat. Saturated fat had long been heralded as the “bad” kind
of fat until research in the 1990s showed that trans fat is actually
worse.
In a report to the FDA earlier this year, the Institute of Medicine said
Americans should cut back their intake of trans fats but there was not
enough research to recommend a safe daily level.
According to federal officials, trans fat will be labeled on a separate
line from saturated fat, telling people exactly how much of each they
are eating. Until food labels are changed, however, the only way to know
what you're eating is to read food labels carefully. If partially hydrogenated
oil is listed as one the first ingredients, the product likely has a
lot of trans fat. Deep fried foods, such as donuts and French fries,
top the list of food with high levels of trans fats.
There are also many “hidden” sources of trans fats, including
vegetable shortening and stick margarines. The rule of thumb with margarines
and spreads is the softer, the better (that is the lower in trans fats).
Trans fats also occur naturally in meat, but at much lower levels.
November 2002 Update
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Dietary
Antioxidants May Decrease Risk of Alzheimer's Disease
Alzheimer’s disease (AD) is a complex disease that spreads through
the brain. It affects some 4 million Americans, causing memory loss,
impaired thinking, and changes in personality. Scientists have suspected
that substances called antioxidants — vitamin C, vitamin E, and
beta carotene, for example — may guard against AD. However, studies
testing the relationship between antioxidant supplements and the risk
of AD have not found consistent evidence of a benefit. But now two studies
published in the Journal of the American Medical Association have
found that high intakes of antioxidants from food may reduce the risk
of developing AD.
In the first study, researchers recruited 5,395 participants with an
average age of 67.7 years, who lived independently. All participants
reported their eating habits and went through two mental state examinations
to ensure that they were free of dementia at the start of the study.
During six years of follow-up, the researchers re-screened the participants
for Alzheimer’s disease. They found that high dietary intake of
vitamin C significantly reduced the risk of developing Alzheimer’s
disease and that the reduced risk of AD from high dietary intake of vitamin
E was also borderline significant. These antioxidants were most effective
at preventing AD in current smokers, compared with current non-smokers.
Use of dietary supplements was controlled in this study, so the beneficial
effects of vitamins C and E were only from food. Vitamin C is found in
large amounts in citrus fruits, kiwi, and broccoli, and good sources
of vitamin E include nuts, milk, and egg yolk.
In the second study, participants were also free of Alzheimer’s
disease at the beginning and completed a food frequency questionnaire.
The questionnaire helped researchers keep track of the intake of certain
foods and supplements. The 815 subjects were 65 years and older, and
were followed for four years.
After adjusting for age, education, sex, race, and presence of APOE
e4 (a genetic characteristic that makes a person more likely to develop
AD), the researchers found that those with the highest dietary intake
of vitamin E were 70% less likely to develop AD than those with the lowest
dietary intake of vitamin E. However, the highest Vitamin E intake for
the study was 363.6 International Units (IU) per day, well above the
Recommended Dietary Allowance of 22 IU.
The other dietary antioxidants tested in this study, vitamin C and beta
carotene, did not reduce the risk of AD. More research will need to be
performed to find out why vitamin C proved effective in one study but
not in the other. While dietary antioxidants are proving more effective
in reducing Alzheimer's risk than antioxidant supplements, these weren't
randomized, clinical trials, so these studies won't translate into dietary
recommendations.
August 2002 Update
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Drinking Tea Benefits Heart and Bones
The health benefits of drinking tea have been well publicized lately,
and recent studies point to two newly discovered advantages to consuming
this beverage. One shows that drinking tea can help prevent death after
a heart attack. The other reports that tea may increase bone mineral
density, which helps prevent fractures and osteoporosis.
In the first study, published in Circulation, researchers questioned
1,900 patients hospitalized for heart attacks about the amount of caffeinated
tea they drank in the past year. After adjusting for age, gender, and
other variables, researchers found that those who drank 14 or more cups
of tea per week were 39% less likely to die of cardiovascular disease
in the 3.8 years following their heart attack than non-tea drinkers.
Patients who consumed 1–14 cups of tea per week were 31% less likely
to die from cardiovascular causes during that period than non-tea drinkers.
When researchers further looked into subjects' caffeine intake, they
found that caffeine from sources other than tea did not affect death
rates.
In the second study, published in the Archives of Internal Medicine,
researchers surveyed 1,037 men and women age 30 and older about their
tea consumption. Subjects who drank tea at least once a week for the
preceding six months were labeled "habitual tea drinkers." This
group was asked about their tea-drinking history, the kind of tea they
drank, how often they drank it, and how much they drank in each sitting.
Researchers then measured the bone mineral density (BMD) of the lumbar
spine, hip, neck, and total body of both the habitual tea drinkers and
the non-drinkers.
The researchers found that people who consumed tea regularly for more
than 10 years had the highest BMD scores compared to the other groups,
after they adjusted for sex, age, weight, and lifestyle variables that
may affect BMD. Those who drank tea regularly for the past 6–10
years also had significantly higher lumbar spine BMDs than the nonhabitual
tea drinkers. People who consistently drank tea for the past 1–5
years did not have any significant differences in BMD score compared
to the nonhabitual drinkers.
It didn't seem to matter what type of tea the person drank, and neither
did the amount of tea consumed each time. Only duration of habitual tea
consumption was an independent predictor of BMD score. Tea contains several
components, including fluoride and flavonoids, which may work separately
or in concert to maintain or restore bone density.
Although BMD score is often a good gauge of the risk of fracture from
osteoporosis, this study did not actually test the link between tea consumption
and bone fracture.
July 2002 Update
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New guidelines for stroke prevention
With more than 700,000 Americans having strokes each year, doctors and
patients need to focus on stroke prevention. In light of this, the American
Heart Association (AHA) has issued a statement that details how to identify
and modify risk factors. Here are the AHA's tips, along with other general
guidelines for lowering stroke risk:
Blood pressure. You should get your blood pressure checked
at least every two years because many people with high blood pressure
don't even know they have it (130–139 mm Hg systolic pressure over
85–89 diastolic pressure is considered high-normal, while anything
above 140 over 90 is considered high). If you have high blood pressure,
the following lifestyle changes can help lower it:
- Eat more fruits and vegetables. Potassium-rich foods like bananas
and oranges may be especially good.
- Pass on salt. Salt makes the body hold onto water, and the heart
has to work harder to pump the extra fluid.
- Lose weight. The heavier you are, the harder your heart has to work
to pump blood to all parts of your body.
- Exercise. Even if you don't need to lose weight, exercise can reduce
high blood pressure and may even prevent it.
- Limit your alcohol. Having more than two alcoholic drinks a day significantly
increases your risk of high blood pressure.
- Quit smoking. Smoking increases your risk of heart attack, as well
as many other diseases. And if you live with a smoker, make sure he
or she quenches his cravings outside. Exposure to secondhand smoke
can double your risk of stroke.
- Learn to relax. Various kinds of behavioral therapy, like biofeedback,
yoga, and tai chi may lower blood pressure.
These lifestyle changes can also help with other causes of stroke, like
atherosclerosis (hardening of the arteries) and high cholesterol. If
the changes don't lower your blood pressure, your doctor may prescribe
a medication such as a diuretic or beta blocker.
Other conditions. The AHA recommends that patients with
diabetes and children with sickle cell disease closely monitor their
blood pressure with screenings every six months.
Non-modifiable risk factors. Black, Hispanic, Chinese,
and Japanese people are at increased risk for stroke compared to whites.
Men and postmenopausal women are also at higher risks than others. If
one of your parents had a stroke, you are at greater risk as well, either
because of genetics or shared lifestyle traits.
While you can't do anything about non-modifiable risk factors it's helpful
to know if you fall into a high-risk group so you can carefully monitor
controllable factors.
July 2002 Update
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Healthy Diet
Eradicates Need for Trendy Supplements in Elderly
Magazine ads and television commercials tout dietary supplements that
claim to be a veritable fountain of youth for seniors. Images of grandparents
able to keep up with their grandkids convince older adults that shakes,
energy bars, and special vitamins will help boost energy and decrease
signs of aging.
Health experts, however, stress that a well-balanced diet rich in fruit
and vegetables is just as effective and probably safer. But many older
adults skip meals and eat small amounts of fruits and vegetables, citing
reasons ranging from rotten teeth to unhappiness with eating alone.
While doctors acknowledge that nutritional shakes and energy bars are
helpful for seniors who need to gain weight or have trouble chewing or
swallowing, those who eat a balanced diet or stay active do not need
them.
In spite of what the experts have said, the savvy advertisements are
convincing millions of seniors that they need these expensive supplements,
some of which have not even been proven safe.
Herbs are also a source of concern. Saw palmetto, an extracts made from
the fruit of the saw palmetto plant, is promoted as a treatment for an
enlarged prostate. Many people believe that herbs are natural and therefore
safe but this is not the case. In fact, as with most nonprescription
herbal products, the composition of the extract and the dosage have not
been standardized and the supplement is not regulated by the FDA. If
you decide to use saw palmetto, tell your doctor in order to alert him
or her to possible interactions between it and other medications you
may be taking.
People who are on strict diets — like those prescribed for kidney
disease, heart disease, or diabetes — must be especially wary of
adding any special supplements to their diet. Regardless of whether health
problems are present, you should always consult a physician before starting
any dietary regimen.
May 2002 Update
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Fish for Good Health
In April, three studies delivered powerful evidence that fish is good
for you — and could even save your life. The key is omega-3 (or
n-3) fatty acids, beneficial polyunsaturated fats provided by many kinds
of fish and certain plant foods.
Researchers in the Nurses' Health Study examined 16 years of data involving
almost 85,000 women and found an association between fish intake and
a lower risk for heart disease and death. Women who ate fish just once
a week had a heart attack risk 29% lower than those who ate it less than
once a month. Women who ate fish five times a week had nearly half the
risk of death from a heart attack.
The Harvard's Physicians' Health Study, which involves more than 22,000
male doctors who initially had no heart disease, analyzed blood levels
of omega-3 fatty acids and risk for sudden cardiac death. Researchers
found that such deaths were 81% less likely in men with the highest levels
of omega-3s. Over half of such deaths occur in people without prior symptoms
of heart disease — a compelling reason for adding more fish to
your diet.
Finally, Italian researchers reported that heart attack survivors who
took fish-oil supplements had a lower risk of sudden death. This trial
studied omega-3 fatty acids and vitamin E in 11,000 men and women who
had recently suffered heart attacks. Researchers found that 1 gram of
omega-3 fatty acids daily reduced the risk for sudden coronary death
by up to 42%. This benefit apparently reflects their calming effect on
arrhythmias, potentially fatal heartbeat irregularities. Omega-3 fatty
acids may also inhibit clotting and improve blood vessel function. The
American Heart Association recommends four servings of fish per week
but doesn't endorse supplements because of too few data on the subject.
May 2002 Update
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Asthma Education Leads to Improvement
in Children
Managing your child's asthma should include meeting with an asthma educator
a few times, according to a follow-up study. Presented at the meeting
of the American Academy of Allergy, Asthma, and Immunology, the study
reports that after attending an interactive training program three times
patients felt less worried about their asthma and had fewer asthma-induced
awakenings during the night. Both patients and their caregivers, who
also took part in the program, made better decisions about asthma care.
The 30 subjects, asthmatic children ages 6–12, underwent ACE IT!
(Asthma Care Education: Intensive Training), an interactive, small-group
education program. The sessions included a motivational talk by a teenage
athlete with asthma and a pharmacist's discussion of medications. A nurse
and asthma specialist also taught the participants about the clinical
nature of asthma, environmental controls, relaxation techniques, and
asthma action plans.
Researchers evaluated the children at the beginning and end of the training,
after six months, and again a year later. After the courses, the number
of patients reporting two or more nocturnal awakenings per month dropped
from 9 to 5, and the number of symptom-free days also improved, from
an average of 20 days per month to over 25 days per month.
The patients were more willing to use the tools available to them, such
as medications and peak flow meters, devises that asthmatics breath into
to help detect airway changes. They also worked harder to avoid things
that triggered their asthma, such as pets or dust.
The researchers plan to continue tracking these 30 children to study
the long-term effects on quality of life, morbidity, and cost of treatment.
A previous study published in the Journal of Allergy and Clinical
Immunology in 2000, found that the training program was much more
effective than simply handing out educational materials.
May 2002 Update
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New Diabetes Guidelines from the ADA
In the January 2002 supplemental issue of Diabetes Care, the
American Diabetes Association (ADA) released a compilation of all its
position statements on diabetes care, including three new ones. It includes
the first update of the ADA's nutrition guidelines since 1994.
One of the reports, Evidence-Based Nutrition Principles for the Treatment
and Prevention of Diabetes, outlines changes as to how diabetics
should approach carbohydrate intake, giving them more dietary freedom.
Previously, diabetics were advised to avoid eating simple sugars and fast-acting
carbohydrates like table sugar because these were believed to be
more rapidly absorbed than complex starches found in such foods
as potatoes, thus aggravating hyperglycemia. But there is little scientific
evidence to support this theory. In fact, the simple sugar sucrose
is no worse for a diabetic than starch, so the ADA now recommends simply
using the carbohydrate terms sugar, starch, and fiber instead.
The new guidelines also advise that it's more important for people with
diabetes to monitor and adjust their insulin requirements according to
the total amount of carbohydrates in food rather than the source or type.
They therefore dismiss the practical value of the glycemic index, which
calculates how quickly the carbohydrate content of a person's overall
diet raises blood sugar levels. Nevertheless, some carbohydrate sources
are healthier than others, so the ADA recommends diabetics get their
carbohydrates from whole grains, fruits, and vegetables because they
are also rich in fiber, vitamins, and minerals.
Diets rich in carbohydrates and low in fats used to be recommended for
all patients with diabetes but this has changed since the discovery that
diets rich in monounsaturated fatty acids lead to improvements in HDL
("good") cholesterol levels, triglyceride levels, and overall
diabetes control.
The use of fructose as an added sweetener is not recommended, but natural
fructose in fruits and other sweeteners like saccharin and aspartame
appear to be safe. The guidelines address many other important nutrition
issues, but specifically they recommend that diabetics get 60%–70%
of their caloric intake from carbohydrates and monounstaturated fats,
15%–20% from protein, and less than 10% from saturated fats. Overall,
these new options afford diabetics more choices in their diets-choices
that will provide a diet more people can adhere to.
Another of the reports, Treatment of Hypertension in Adults with
Diabetes, addresses hypertension, which occurs in up to 60% of
diabetics and substantially increases the risk of vascular problems,
such as coronary heart disease and other serious complications. The
most recent evidence supports the use of aggressive hypertension treatment
to avoid these complications. The ADA recommends people with diabetes
aim for a blood pressure (BP) of less than 130/80 mm Hg. If a diabetic's
BP is 130–139/80–89, the report suggests adopting behavioral
changes such as reducing salt intake, losing weight, and becoming more
physically active. However, if his or her BP is greater than 140/90,
drug treatment should be started. Angiotensin-converting enzyme (ACE)
inhibitors, angiotensin receptor blockers (ARBs), diuretics, and beta
blockers are recommended as first-line treatments. In many cases, patients
will need three or more drugs to control their BP.
The third report, Standards of Medical Care for Patients with Diabetes
Mellitus, is a comprehensive guide intended to provide an overview
of the components of diabetes care, treatment goals, and tools to evaluate
the quality of care. It also goes over strategies for successful guideline
implementation. For instance, successful programs give patients access
to nurses for case management services, diabetes educators, and group
visits.
For the complete reports, go to http://care.diabetesjournals.org/content/vol25/suppl_1/.
April 2002 Update
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New Cancer Prevention Guidelines
While some risk factors for developing cancer, such as family history,
can not be changed, there are ways for people to reduce their chances.
The American Cancer Society (ACS) recently released new dietary and physical
activity guidelines for cancer prevention.
One of the most basic tenets of a healthy diet is eating plenty of fruits
and vegetables. The ACS recommends eating no less than 5 servings of
a variety of fruits and vegetables every day. Many people have heard
of antioxidants but aren't sure exactly what they are or what they do.
Antioxidant nutrients (such as vitamin C, vitamin E, and carotenoids)
protect the body against the tissue damage that occurs as a result of
normal metabolism. Because such damage is associated with increased cancer
risk, the antioxidant nutrients are thought to protect against cancer.
Studies suggest that people who eat more vegetables and fruits, which
are rich sources of these antioxidants, have a lower risk for some types
of cancer, but studies of antioxidant supplements have not yet shown
a reduction in cancer risk.
Choosing whole grains over processed (refined) grains and sugars will
also help, so stick to whole grain rice, bread, pasta, and cereals. Also,
limit your red meat intake. When you do eat it, choose the way you cook
it carefully. While adequate cooking is necessary to kill harmful microorganisms
in meat, some research suggests that frying, broiling, or grilling it
at very high temperatures creates chemicals that might increase cancer
risk. Braising, steaming, and poaching meats cuts down on the production
of these chemicals.
Drinking too much alcohol is an established cause of cancers of the
mouth, throat, liver, and breast. Therefore, the ACS recommends limiting
alcoholic consumption to 2 drinks per day for men and 1 drink per day
for women.
The ACS also reminds people to remember that "low fat" or "fat
free" snacks like cakes and cookies are often high in calories.
High sugar intake can lead to obesity and elevated insulin levels, conditions
that increase cancer risk.
Physical activity is also an important component in the prevention of
cancer. Adults should engage in moderate-to-vigorous activity (walking,
leisurely bicycling, running, swimming) for 30 minutes or more at least
5 days a week.
Simple additions to your daily routine such as taking the stairs instead
of the elevator, taking 10-minute exercise breaks at work, and walking
to visit co-workers instead of emailing them are simple ways to increase
your activity level.
An unhealthy diet and lack of exercise can lead to weight gain and obesity,
conditions that are associated with developing cancers of the breast,
colon, endometrium, esophagus, gallbladder, pancreas, and kidney.
In addition to the general guidelines set forth by the ACS, there are
also answers to frequently asked questions about the rumored or theoretical
relationships between cancer and such substances as aspartame, beta-carotene,
calcium, coffee, fish oils, fluorides, folic acid, saccharin, and tea.
The ACS suggests that public, private, and community organizations create
environments that support the adoption and maintenance of these healthful
eating and physical activity behaviors. People should have access to
healthful foods in schools, at work sites, and when on daily outings
in their town or city.
For a copy of the complete set of guidelines, call the American Cancer
Society at 1-800-ACS-2345.
April 2002 Update
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Obesity in Children is on the Rise
A recent study published in the Journal of the American Medical Association showed
that American children are heavier now than ever before. In 1998, 12%,
21%, and 22% of Caucasion, African American, and Hispanic children, respectively,
were classified as overweight. In fact, between 1986 and 1998, the prevalence
of overweight children rose steadily among these groups.
The reason behind childhood obesity — that kids are taking in more
calories than they're expending — is easy to understand. But diagnosing
obesity is more complicated. It cannot be diagnosed simply by looking
at someone because ideal body images differ among individuals, and different
body shapes carry weight differently.
And changing lifestyles that create obesity may be even harder. Children
are spending more time than ever watching television, playing video games,
and surfing the Internet instead of being active. Their parents are busier
than ever, too, making it harder to cook nutritious meals.
This is all problematic, as obesity is a risk factor for many health
problems, both in childhood and later in life. Children who are overweight
are more likely to develop high blood pressure, high cholesterol, and
heart disease as adults than kids of normal weight. Long-term obesity
also increases the risk of arthritis, heart disease, diabetes, and certain
kinds of cancer.
So what can you do? First, talk with your child's doctor. Objective standards
have been developed for defining and measuring obesity. He or she will
use the body mass index (BMI), calculated from your child's weight and
height, and compare it with national growth charts.
There are also tangible things parents can do to help prevent (and treat)
obesity in their children as well as in themselves. Begin by establishing
healthier eating habits and promoting a more active lifestyle. For example,
you can plan daily family activities that involve exercise; limit television,
computer, and video game use; eat meals together as a family whenever
possible; and when eating out, choose lower fat items on the menu.
March 2002 Update
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Advanced Macular Degeneration and Nutritional
Supplements
Nutritional supplements may help slow the progression of advanced macular
degeneration (AMD), the most common cause of vision loss in people over
age 55, a new study suggests.
The Age-Related Eye Disease Study (AREDS), reported in the October 2001 Archives
of Ophthalmology, is the largest clinical trial to have tested the
impact of nutritional supplements on AMD and cataracts. AREDS involved
nearly 5,000 women and men, ages 55-80, at 11 clinical centers nationwide.
Participants in the macular degeneration portion of the study were divided
into groups depending upon the severity of their condition. They received
one of the following daily regimens: 1) antioxidants (500 mg vitamin
C, 400 IU vitamin E, 15 mg beta-carotene), 2) zinc (80 mg, plus 2 mg
copper to prevent anemia), 3) a combination of the antioxidants and zinc,
or 4) a placebo. Participants were evaluated every six months for vision
loss and annually for retinal changes.
Over the seven-year study, combined antioxidants and zinc reduced the
risk for progression to advanced AMD by 25%, compared with placebo, among
those who already had extensive intermediate or large drusen or advanced
AMD in one eye. This treatment also reduced the AMD-related loss of visual
acuity by about 19%. Antioxidants or zinc alone reduced the risk, but
to a lesser extent. AREDS subjects with early or no AMD got no measurable
benefit from the supplements. In the companion study of cataract development,
antioxidants and zinc (separately or in combination) had no beneficial
effect.
Though participants reported no major side effects, the long-term consequences
of taking these nutrients at levels above the Recommended Dietary Allowance
(RDA), as AREDS participants did, are unknown.
January 2002 Update
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Salt Restriction More Potent Than Exercise
Physicians often give patients with hypertension a daunting list of
lifestyle changes to help lower their blood pressure: lose weight, exercise
more, eat less salt, drink less alcohol, eat more foods rich in calcium,
potassium, and magnesium. Of course, these changes do work — people
who follow them can reduce their need for medications or even do without
blood pressure-lowering drugs. But which of these lifestyle changes gives
you the biggest bang for your buck?
University of Colorado researchers recently compared the impact of exercise
or moderate salt restriction in 35 healthy older women with high-normal
blood pressure or mild hypertension (systolic blood pressure 130–159
mm Hg), none of whom were using drugs to lower their blood pressure.
Half the women exercised for three months — starting at 30 minutes
a day three or four times a week and working up to 45 minutes a day every
day, if possible. The other half tried to reduce their daily salt intake
to less than 2.4 grams of sodium (the amount in a level teaspoon of table
salt) without otherwise changing their diets. All were asked to try to
avoid gaining or losing weight.
The clear winner, reported in the American Journal of Cardiology,
was sodium restriction. Among the women who ate less salt, average systolic
blood pressures fell 16 mm Hg, compared with a still-respectable 5 mm
Hg in the exercise group. By the study's end of the study, systolic blood
pressure was lower in 88% of the women who ate less salt and in 55% of
the exercisers.
So if you're trying to lower your blood pressure, should you just forget
about exercise and work harder at eating less salt? No. Exercise has
other benefits besides lowering blood pressure — it can help control
weight, improve the cholesterol profile, stave off diabetes, and keep
bones strong. The real message from this study is that everyone should
exercise, but that people who are trying to control blood pressure should
lower their sodium intake, too.
December 2001 Update
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Diet and Exercise Dramatically Delay Type 2 Diabetes
Americans at high risk for type 2 diabetes can sharply lower their chances
of getting the disease with diet and exercise, according to the results
of a major clinical trial. The same study also found the oral diabetes
drug metformin (Glucophage) reduces diabetes risk, though less dramatically.
The findings came from the Diabetes Prevention Program (DPP), a major
clinical trial comparing diet and exercise to metformin in 3,234 people
with impaired glucose tolerance, a condition that often precedes diabetes.
Smaller studies in China and Finland had previously shown diet and exercise
can delay type 2 diabetes in at-risk people. But the DPP, conducted at
27 centers nationwide, is the first major trial to show diet and exercise
can effectively delay diabetes in a diverse American population of overweight
people with impaired glucose tolerance (IGT). IGT is a condition in which
blood glucose levels are higher than normal but not yet diabetic.
Of the 3,234 participants enrolled in the DPP, 45 percent are from groups
that suffer disproportionately from type 2 diabetes: African Americans,
Hispanic Americans, Asian Americans and Pacific Islanders, and American
Indians. The trial also recruited others known to be at higher risk for
type 2 diabetes, including people age 60 and older, women with a history
of gestational diabetes, and people with a first-degree relative with
type 2 diabetes.
Participants ranged from age 25 to 85, with an average age of 51. All
had impaired glucose tolerance as measured by an oral glucose tolerance
test, and all were overweight, with an average body mass index (BMI)
of 34. They were randomly assigned to one of the following groups: intensive
lifestyle changes with the aim of reducing weight by 7 percent through
a low-fat diet and exercising for 150 minutes a week; treatment with
the drug metformin (850 mg twice a day), approved in 1995 to treat type
2 diabetes; and a standard group taking placebo pills in place of metformin.The
latter two groups also received information on diet and exercise.
During an average follow up of about 3 years, about 29 percent of the
group receiving standard treatment developed diabetes. In contrast, 14
percent of the diet and exercise, and 22 percent of the metformin arms
developed diabetes. Volunteers in the diet and exercise arm achieved
the study goal, on average a 7 percent — or 15-pound — weight
loss, in the first year and generally sustained a 5 percent total loss
for the study's duration. Participants in the lifestyle intervention
arm received training in diet, exercise (most chose walking), and behavior
modification skills.
In all, participants in the random intensive lifestyle intervention reduced
their risk of type 2 diabetes by 58 percent, and those who received metformin
reduced their risk of getting type 2 diabetes by 31 percent.
September 2001 Update
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More Encouraging Data on Alcohol and the Heart
Having a drink or two per day lowers your risk heart disease and stroke.
Little surprise then that two new studies report people who drink alcohol
also have lower risk of developing heart failure and better outcomes
if they have heart attacks. The studies were reported in a recent issue
of the Journal of the American Medical Association.
The first study involved 1913 adults who were admitted to 45 different
U.S. hospitals between August 1989 and September 1994 for heart attacks.
The researchers, who were based at Harvard Medical School and Harvard
School of Public Health, interviewed the patients an average of 4 days
after their heart attacks, inquiring about a range of issues including
their alcohol consumption.
About half (47%) reported they didn't drink alcohol during the year before
their heart attacks. Another 36% said they drank fewer than 7 drinks
per week. The remainder (17%) said they had 7 or more drinks per week.
Those who drank the most were younger, and more likely to be male, current
or former cigarette smokers, and have physically active life styles.
Survival rates were lowest for those who did not drink at all before
their heart attacks and best for those who drank 7 or more drinks per
week. For every 100 people, 6.3 of the abstainers died each year, compared
with 3.4 of those who drink 1-6 drinks per week and 2.4 of those drank
7 or more drinks.
Heart failure
The second study was based on 2,235 elderly people (average age 74 years)
who participated in a long-term epidemiological survey in New Haven,
CT. None of the subjects had heart failure at the time of enrollment
in the study in 1982. And the researchers excluded heavy drinkers (those
drinking more than four drinks per day).
Half of the subjects reported no alcohol consumption in the month before
enrollment, while 40% reported consumption of 1-20 ounces (up to 1 or
1.5 drinks per day), and 10% reported drinking 21 to 70 ounces (about
1.5 to 4 drinks per day).
During the next 14 years, 281 people developed heart failure, including
28 fatalities. The rates of heart failure for every 1000 people per year
were 16.1 for abstainers; 12.2 for those who drank 1-1.5 drinks per day;
and 9.2 for those who drank more heavily. Statistical analyses that adjusted
for other differences among these groups concluded that light drinking
reduced one's risk for heart failure by 19%, and moderate or heavy drinking
reduced the risk by 53%.
Because moderate drinking can easily progress to problem drinking, no
experts feel comfortable in encouraging nondrinkers to take up alcohol
for medical reasons. However, researchers are debating whether some people
who have given up alcohol might be encouraged to resume it. Future research
may also define certain subgroups who can benefit most from alcohol,
perhaps by raising their HDL cholesterol.
September 2001 Update
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New Vitamin A Recommendations
You can never get too much of a good thing or is it too much of a good
thing is just that? Regardless of which saying you prefer, it appears
that when it comes to vitamin A, it's possible to overdo it. In fact,
the National Academies' Institute of Medicine recently lowered the recommended
daily allowance (RDA) for this vital nutrient and warned people not to
take megadoses of vitamin A supplements.
Vitamin A is important for normal vision, immune function, growth, and
other bodily processes. To ensure adequate stores in the body, men are
now being told to consume 900 micrograms (mg) daily and women 700 mg
daily. However, nobody should ingest more than 3 milligrams (or 3,000
mg) per day. Recent research shows excess vitamin A intake may increase
the risk of liver problems and birth defects if taken during pregnancy.
Vitamin A deficiencies, which cause vision impairment, are rare in North
America. Daily requirements can be met without taking supplements if
you eat a balanced diet that includes darkly colored fruits and vegetables
like oranges, carrots and broccoli. However, new research found these
fruits and vegetables actually yield half as much vitamin A as previously
thought. So those who don't eat meats, fish, eggs or vitamin-fortified
cereals need to make sure they're getting enough vitamin A. However,
if you take vitamin supplements, even a regular multivitamin, you could
be consuming more than what's safe. The megadoses sold in health stores
can be particularly dangerous. They are often measured in "international
units" and 10,000 international units is the same as 3,000 mg.
August 2001 Update
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Take Low-Dose Aspirin and Skip Vitamin E to Prevent
Cardiovascular Disease
For more than 100 years aspirin has helped relieve headaches and other
pain, and now new evidence from the Primary Prevention Project backs
the claim it also helps prevent heart attacks and other cardiovascular
events. The same study also found the antioxidant vitamin E didn't help.
The theory that anti-platelet/anti-inflammatory drugs like aspirin and
antioxidant nutrients like vitamin E might interfere with atherosclerosis
and prevent cardiovascular disease is not new. But previous research
on both possibilities has come up with mixed results. In an attempt to
resolve the debates, Italian researchers randomized 4,495 people (2583
females and 1912 men) with an average age of 64.4 to receive low-dose
aspirin (100mg/day) or no aspirin and vitamin E supplements (300mg/day)
or no vitamin E. They limited their investigation to people over 50 with
one or more of the major cardiovascular risk factors: hypertension, high
blood cholesterol, diabetes, obesity, family history of early heart attacks
or individuals who were elderly.
Aspirin proved to be beneficial with respect to all of the criteria measured.
It reduced the risk of a cardiovascular death by 44% and the risk of
cardiovascular events or disease by 23%. However, severe gastrointestinal
bleeding was more frequent in the aspirin group than in the non-aspirin
group (1.1% vs 0.3%). Consistent with the negative results of other large
published trials, vitamin E provided no significant improvements in any
of the criteria.
The study was stopped prematurely after a mean follow-up of 3.6 years
because evidence from two other studies involving a total of 24,289 patients
concurred that aspirin is beneficial in primary prevention.
August 2001 Update
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Garlic’s Effects on Cholesterol Are Modest
Garlic preparations, available in most health food stores, are sold
with the promise of numerous health benefits. Lower cholesterol levels
are among the most touted of these benefits. Unfortunately, data from
only a few small research trials support the claim that garlic preparations
can lower LDL cholesterol.
A "meta-analysis" of rigorous published trials involving garlic
preparations offers a better gauge of garlic’s value in reducing
cholesterol. A meta-analysis mathematically pools data from several studies
to better estimate the effects of an intervention — for example,
a drug, dietary supplement, operation, or lifestyle change — than
one could do with the data from a single, smaller study. This report,
published in the Annals of Internal Medicine, reviewed 45 controlled
studies involving 796 subjects (In contrast, most studies of cholesterol-reducing
medications involve much larger numbers of patients). Overall, the researchers
found that, on average, garlic supplements decreased total cholesterol
by 16 mg/dL. But the six most rigorous studies, which also controlled
for the volunteers’ diets, failed to show a significant difference
in cholesterol reductions between garlic and placebo groups. (Annals
of Internal Medicine, Vol. 133, No. 6, pp. 420–29.)
These results are all the more disappointing because, in general, studies
that show a positive effect are most likely to be published. Thus, meta-analyses
may offer an overly optimistic assessment of a drug or other intervention.
In other words, "negative" studies may have simply never been
published (and thus could not be included in this meta-analysis) because
researchers found no difference between garlic and a placebo. If so,
the value of garlic would be even less than that described here.
If you’re taking a garlic supplement, the good news is that the
meta-analysis found no evidence of dangerous side effects. It simply
suggests the benefits are small. But for those of you only considering
these preparations, the study doesn’t offer much encouragement.
Perhaps its central message is that garlic is no substitute for the highly
effective, safe medications that are proven to control cholesterol and
lower heart disease risk. Garlic may or may not belong in your medicine
cabinet, but it has proven itself to be a vital component to any well-stocked
pantry.
June 2001 Update
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National Cholesterol Education Program Releases
New Guidelines for Treating and Preventing High Cholesterol
On May 15, 2001, the National Cholesterol Education Program (NCEP) — coordinated
by the National Heart, Lung, and Blood Institute (NHLBI) — released
the first major revision of its recommendations for detecting and lowering
high cholesterol in adults since 1993.
One of the fundamental features of the new guidelines is the accurate
assessment of heart disease risk using a new "global risk assessment
tool" that combines multiple risk factors into a measure of a person's
absolute risk of developing coronary heart disease within the next 10
years. According to the guidelines, patients who have a risk of 20% or
higher should receive aggressive therapy to control cholesterol levels.
In addition to aggressive treatment of high LDL cholesterol, as laid
out in the 1993 report, the revised guidelines also recommend a more
assertive treatment approach for diabetes, low HDL levels, and high triglyceride
levels.
Specific changes include:
- Treating high cholesterol more aggressively for those with diabetes,
even if they do not have heart disease.
- A full lipid profile (which measures total cholesterol, LDL,
HDL, and triglycerides) as the first test for high cholesterol (rather
than simply testing total cholesterol and HDL and performing a full
lipid profile only if total cholesterol is high).
- A new level at which low HDL becomes a major risk factor for heart
disease. The 1993 guidelines defined a low HDL as less than 35 mg/dL;
now it is less than 40 mg/dL.
- More aggressive treatment of high triglyceride levels.
- Advising against the hormone replacement therapy (HRT) as an alternative
to cholesterol-lowering drugs for post-menopausal women.
Another key change in the guidelines is intensified lifestyle recommendations
regarding nutrition, exercise, and weight control to treat high cholesterol.
The updated diet advises that less than 7% of daily calories come from
saturated fat and limits dietary cholesterol to less than 200 mg per
day. It also allows up to 35% of daily calories from total fat, provided
most come from unsaturated or monounsaturated fat, which doesn't raise
cholesterol levels. Additionally, the guidelines strongly underscore
the need for weight control and physical activity, both of which improve
various heart disease risk factors.
The revised recommendations also emphasize careful attention to the metabolic
syndrome, a particular cluster of cardiovascular risk factors that
is becoming increasingly common in the United States. Characteristics
of metabolic syndrome include too much abdominal fat, high blood pressure,
high blood sugar, elevated triglycerides, and low HDL.
For more information, see the "Live Healthier, Live Longer" Web
site by going to the NHLBI home page at www.nhlbi.nih.gov and
clicking on ATP III Cholesterol Guidelines under Highlights.
| 2001 Cholesterol Guidelines |
| Total Cholesterol Level |
Total Cholesterol Category |
| Less than 200 mg/dL |
Desirable |
| 200-239 mg/dL |
Borderline High |
| 240 mg/dL and above |
High |
| LDL Cholesterol Level |
LDL-Cholesterol Category |
Less than 100 mg/dL
|
Optimal |
| 100-129 mg/dL |
Near optimal/above optimal |
| 130-159 mg/dL |
Borderline high |
| 160-189 mg/dL |
High |
| 190 mg/dL and above |
Very high |
Trigylceride Level
|
Triglyceride Category |
| Less than 150 mg/dL |
Normal |
| 150-199 mg/dL |
Borderline high |
| 200-499 |
High |
| Greater than or equal to 500 |
Very high |
| HDL Cholesterol Level |
HDL-Cholesterol Category |
| Less than 40 mg/dL |
Low (representing increased risk) |
| 60 mg/dL and above |
High (heart protective) |
|
Three Categories of Risk that Modify
LDL Cholesterol Goals |
| Risk Category |
LDL Goal (mg/dL) |
| Coronary Heart Disease (CHD) and CHD equivalents |
Less than 100 |
| Multiple (2+) risk factors |
Less than 130 |
| 0-1 risk factor |
Less than 160 |
|
| Risk factors (exclusive of LDL cholesterol):
cigarette smoking; blood pressure greater than or equal to 140/90
mm Hg or on antihypertensive medication; HDL cholesterol less than
40 mg/dL; a family history of coronary heart disease before age
55 in a father or brother or age 65 in a mother or sister; age
above 45 for men and 55 for women |
May 2001 Update
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Study Shows Fish Consumption Protects Against Stroke,
But FDA Suggests Pregnant Women Should Take Caution
A large study in the Journal of the American Medical Association (JAMA)
recently showed that regularly eating fish might protect against ischemic
stroke, which is the most common type of stroke. Numerous studies have
already shown an association between fish consumption and a reduced risk
of heart disease. But there is a caveat. The Food and Drug Administration
(FDA) recently warned that pregnant women and women who are of childbearing
age who may become pregnant, should avoid certain types of fish that
contain high levels of mercury, which may be harmful to their unborn
children.
Results of the Nurses' Health Study, published in the JAMA article,
involved nearly 80,000 women. It showed that women who ate fish two to
four times a week had a 48% lower risk of ischemic stroke — the
kind caused by blood clots — than women who ate fish less than once
per month. Even women who ate fish only once a week or less had a risk
reduction, but it was not statistically significant. These results held
true primarily among women who did not regularly take aspirin, which
prevents the formation of blood clots. Omega-3 fatty acids, the protective
substances found in fish, reduce levels of fats related to cardiovascular
disease and help prevent blood clotting. Dark, oily fish such as mackerel,
salmon, and sardines are a good source of omega-3 fatty acids.
Although pregnant women need not give up fish — and its beneficial
health effects — altogether, they should be careful about what types
of fish they eat. The FDA has advised that pregnant women and those who
may become pregnant stop eating shark, swordfish, king mackerel, and
tilefish. These large, long-living fish contain hazardous levels of methyl
mercury, a form of mercury that can accumulate in a woman's body
and affect the developing central nervous system of an unborn child.
This can lead to babies with slower cognitive development. As an extra
precaution, the FDA advised that nursing mothers and young children also
avoid these fish. Mercury gets into both fresh and salt water through
industrial pollution.
Some critics feel the FDA's mercury warnings are not strong enough. A
report by the National Academy of Sciences suggested the exposure limits
for mercury should be four times stricter.
While this controversy remains unresolved, the FDA encouraged pregnant
women to continue to eat a variety of other fish, containing very low
levels of mercury, as part of a balanced diet. Among other health benefits,
the fatty acids in fish enhance brain development. According to the FDA,
women can safely eat up to 12 ounces of fish per week. Fish that contain
low levels of mercury include shellfish, canned fish, smaller ocean fish,
and farm-raised fish. Women who eat fish caught by family or friends
should contact their local health department for advice on the safety
of fish from local waters.
May 2001 Update
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Children and Peanut Allergies
Children usually outgrow allergies to milk and eggs, but not to peanuts.
In a recent study, researchers found that the majority of children with
peanut allergies will have adverse reactions to accidental peanut exposure
within five years. In addition, allergic reactions are likely to worsen
over the years.
Researchers followed 83 children who were diagnosed with a peanut allergy
before their 4th birthday. Of these children, 61 had initial non-life-threatening
reactions, while 22 had potentially life-threatening reactions. After
5.9 years, they found that 50 of the 83 children had experienced a total
of 115 adverse reactions to peanuts.
Most of the reactions increased in severity after the initial reaction.
Of the children with initial non-life-threatening reactions who had additional
reactions, 44% had at least one potentially life-threatening subsequent
reaction. And of the 22 children who had initial life-threatening reactions
followed by additional reactions, 71% had at least one additional life-threatening
reaction.
In 12 of the original 83 children, the initial reaction occurred after
touching, (not eating) peanuts, and they experienced only skin symptoms.
Eight of these 12 had subsequent reactions, and all eight had at least
one occurrence of respiratory or gastrointestinal symptoms. Children
with only skin symptoms had significantly lower serum peanut-specific
antibodies than those with other initial symptoms, but there was no "safe" antibody
level below which subsequent reactions were only skin-specific.
Most children with peanut allergies accidentally ingest peanuts and this
study showed that allergic reactions are likely to get progressively
worse with each exposure. Children must be educated to avoid peanuts
and foods containing peanuts. In addition, children should always have
access to a self-injectable epinephrine kit that both parents and children
should know how to use if the need arises.
February 2001 Update
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Low-Sodium DASH Diet Lowers Blood Pressure
The effect of reducing dietary salt on controlling hypertension, or
high blood pressure, has been surprisingly controversial. But in a recent
study, a collaboration of scientists, including researchers from Harvard
Medical School and the National Heart, Lung, and Blood Institute of the
National Institutes of Health, suggest that reducing salt intake may
dramatically lower blood pressure in people with or without hypertension,
regardless of age, race, or gender.
The trial, known as the Low-Sodium DASH Diet study, tested the effects
on blood pressure of lower levels of sodium intake combined with the
Dietary Approaches to Stop Hypertension (DASH) diet, which is low in
fat and rich in fruits, vegetables, whole grains, and low-fat dairy products.
More than 400 subjects were assigned either a typical American diet or
the DASH diet for 12 weeks. The salt content of every participant's diet
was randomly changed every four weeks to one of three sodium levels:
high (3,300 mg), intermediate (2,400 mg), or low (1,500 mg).
The researchers found that with either diet, the lower the salt intake,
the lower the blood pressure. But at each sodium level, blood pressure
was consistently lower for those on the DASH diet. Moreover, the largest
reductions in blood pressure were found among those who followed the
DASH diet while consuming 1,500 mg of salt per day, well below the government's
recommended daily intake of 2,400 mg, or 1 1/4 teaspoons. This combination
worked best for all participants, but particularly for patients with
hypertension, whose systolic blood pressure was 11.5 millimeters of mercury
(mm Hg) lower than hypertensive participants on the control diet with
a high sodium level. The beneficial effect of a lower sodium diet was
also more pronounced in women than men and in blacks than people of other
races.
Controlling blood pressure reduces the risk of developing complications
associated with hypertension, which include heart disease and stroke.
New dietary guidelines from the American Heart Association recommend
that everyone adopt an eating plan similar to the DASH diet and limit
their sodium intake to less than 2,400 mg per day. Other things you can
do to keep blood pressure in check include maintaining a healthy body
weight, cutting down on dietary fat, and staying active.
January 2001 Update
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High-Fiber Diet Doesn't Lower Colon Cancer Risk
Observational studies have suggested a link between diet and the risk
of developing colon cancer. Consuming lots of red meat and fatty foods
has been associated with a higher risk of this disease, while a diet
high in fiber and fruits and vegetables seemed to lower that risk. Two
recent studies in the New England Journal of Medicine suggest
otherwise. In these clinical trials, researchers examined the role diet
might play in the development of adenomatous polyps in the colon. (These
growths are the precursors of most colon cancers.)
The first study followed 2,079 men and women who had had such polyps
removed within the previous six months. These volunteers were assigned
to one of two groups. The first group ate a diet that was low in fat
(20% of total calories), high in fiber (18 grams of fiber per 1,000 calories
of food consumed), and included 3.5 servings of fruits and vegetables
per 1,000 calories of food eaten. Researchers provided the second group
with a pamphlet on healthy eating and told these patients to follow their
normal diets. Both groups were followed for roughly four years and had
a colonoscopy (examination of the colon) once a year during this period.
Surprisingly, the rate of recurrence of large polyps did not differ significantly
between the two groups, leading study investigators to conclude that
a low-fat, high-fiber diet rich in fruits and vegetables did not help
prevent recurrence of these precancerous polyps.
The second study focused on cereal fiber, specifically wheat bran. Again,
study participants included only patients who had had adenomatous polyps
removed within three months of the trial's start. Of the 1,303 people
who completed the study, investigators assigned 719 to a high-fiber diet
(13.5 grams per day) and 584 to a low-fiber diet (2 grams per day). At
the end of three years, the polyp recurrence rate was 47% in the high-fiber
group and 51.2% in the low-fiber group. Again, not a significant difference.
Does this discouraging news about fiber mean people should abandon whole
grains and fruits and vegetables? No. First, it is important to remember
that these studies looked at whether or not the polyps returned within
four years, but couldn't really assess whether diet may or may not play
a role in preventing those polyps from turning into cancer. Observational
studies do show that people who eat diets higher in fiber and fruits
and vegetables have a lower risk of colon cancer and that when their
diets change, so does their level of risk. But researchers are not yet
sure why. Second, these dietary elements are important for general health
and have been shown to reduce the risk of heart disease and diabetes.
So make sure you eat enough fruits and vegetables and whole grains.
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Disappointing Look at Vitamin E and Heart Disease
Over the years, observational and experimental studies have suggested
that regular intake of vitamin E (from supplements and food sources)
can help reduce heart disease risk. The scientific theory is that the
antioxidant properties of this vitamin interfere with the oxidation of
low-density lipoproteins, which slow the progression of atherosclerosis.
The problem with experimental studies is that these data cannot tell
us exactly how a given treatment or medication will act in real human
beings. And the problem with observational, or prospective studies, (which
follow a group of people over time to see which among them may develop
a disease or condition) is that they are not really helpful in pinpointing
the reasons those people develop that disease or condition.
Randomized controlled trials are considered the gold standard for evaluating
a medical or preventive treatment. Here, study subjects are matched for
a set of characteristics to "level the playing field." Then
researchers randomly assign some patients to get the treatment or medication
and another group to get a "fake" treatment or medication.
Even when applying this research method to assess the value of vitamin
E in preventing heart disease, results have been mixed. One study conducted
in China showed that study volunteers taking a vitamin cocktail of vitamin
E, beta carotene, and selenium had a lower rate of death from heart disease,
although these supplements didn't seem to lower the rate of cardiovascular
incidents (heart attack or stroke). Another study looked at 29,000 older,
male smokers. These volunteers took 50 mg of vitamin E per day, plus
beta-carotene for five to eight years, yet the death rate from coronary
heart disease remained unaffected. Men in the study who had a history
of heart attack were actually more at risk for death due to heart disease.
The Cambridge Heart Study was far more encouraging. This research looked
at roughly 2,000 patients assigned either to vitamin E or placebo. After
less than two years of follow-up, the number of non-fatal heart attacks
fell significantly, but deaths due to cardiovascular problems remained
the same. Some problems in the study design suggest that these results
could have occurred as easily due to chance as to the vitamin E. Yet
another study conducted in Italy showed that 300 mg of vitamin E per
day slightly increased the number of non-fatal heart attacks, but slightly
lowered the death rate due to heart disease.
The most recent study was published in the New
England Journal of Medicine. As part of the Heart Outcomes Prevention
Evaluation (HOPE) study, investigators assigned 772 patients to take
400 IU of vitamin E each day, and 739 patients to placebo. All the study
volunteers were at high risk for cardiovascular problems because they
either already had evidence of heart disease or had diabetes plus one
additional risk factor. After 4.5 years, there was no hint that the vitamin
E helped reduce heart problems. The death rate due to cardiovascular
disease was about the same in both groups, as were the rates for heart
failure, unstable angina, and bypass or angioplasty. The vitamin E hypothesis
is not completely dead, however. For example, some researchers believe
vitamin E might be helpful in preventing new atherosclerotic plaques
or that it may be effective only if used with other antioxidant vitamins.
The researchers from this study will continue monitoring patients to
determine whether vitamin E helps reduce risk for cancer.
So what to do? All these studies show that vitamin E is safe and very
low in side effects, so it may not be time just yet to toss it from your
health regimen. But right now, the chances are low that vitamin E offers
major health benefits.
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Is It Butter . . . or Medicine?
Not only can you find this product in the grocery store, but in television
advertisements as well — a margarine-like spread that can help reduce
cholesterol levels? Not as crazy as it sounds, Benecol is a margarine-like
spread made with compounds called plant stanol esters, which have been
shown to help lower cholesterol levels.
Plant stanol esters are a type of phytochemical (a chemical compound
derived from plants, such as pine trees, soy, corn, and wheat) which
block the LDL "bad" cholesterol from entering the micelles,
the cellular structures that transfer cholesterol from the small intestine
into the bloodstream. Sitostanol is particularly good at blocking intestinal
absorption of cholesterol, and in its soluble form, it has an even more
effective cholesterol-lowering effect.
Benecol has been available in Finland for four years, and studies there
show that substituting Benecol for margarine or butter reduced cholesterol
levels. In 1995, the New England Journal of Medicine published
a study that evaluated the cholesterol-lowering effect of this butter
substitute. This research found regular use of Benecol resulted in a
14% reduction in serum cholesterol levels (for example, a person with
a cholesterol level of 240 mg/dl could get that level down to 207 mg/dl).
While this is a promising product, particularly for people who enjoy
a pat of margarine on their toast or baked potato, consumers need to
realize that this item is merely a supplement and no more. It is not
a "magic bullet" but rather can be a useful addition to a heart-healthy
diet — one that is low in saturated fats, trans fats, cholesterol,
and refined carbohydrates and rich in fruits, vegetables, and whole grains.
For more information on high cholesterol levels and how to reduce them,
see page 669 of the Family Health Guide.
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Update on Fen-Phen and Heart-Valve Problems
Two recent studies are adding to the data concerning fen-phen and heart-valve
problems. These studies should offer some reassurance to patients who
took this combination of weight-loss drugs.
Researchers from Harvard Medical School evaluated echocardiograms performed
on 226 people who took fen-phen as part of a long-term study from September
1994 to September 1997. Shortly after the manufacturer’s voluntary
withdrawal of fen-phen, the medications were stopped and the patients
underwent testing to determine if any heart-valve problems had developed.
The echocardiograms showed that not one patient had severe valvular disease.
Mild leaking of the aortic valve was detected in 12 patients, and three
patients exhibited moderate aortic-valve leaking — a total of 15
(6.6%) patients. Three subjects (1.3%) had moderate leaking of the mitral
valve. To compare the rate of heart-valve problems in these patients
to the rate one might expect to see in the general population, investigators
turned to data collected as part of the Framingham Heart Study (the long-term
epidemiological study being conducted in a Boston suburb). They found
nearly the same rates of aortic- and mitral-valve leaking in the Framingham
volunteers as in the diet-drug study participants.
A second study published in the November 23, 1999, issue of the American
Heart Association journal, Circulation, suggests that heart-valve
abnormalities in individuals who took dexfenfluramine (Redux) may dissipate.
Although study findings did link the drug to mild aortic-valve disease
and moderate mitral-valve problems, it also noted that valve problems
might eventually go away after drug use is stopped.
Using echocardiograms to spot heart-valve abnormalities, investigators
evaluated 223 patients who had taken dexfenfluramine for an average of
seven months. The tests were performed an average of 8.5 months after
the participants stopped taking the drug. None of the former dexfenfluramine
users was found to have severe mitral valve disease or moderate (or worse)
aortic-valve disease, but 7.6% had either mild aortic-valve disease or
moderate mitral-valve problems. People who had stopped treatment less
than eight months before the echocardiogram were twice as likely to have
valve problems than those who had been off dexfenfluramine for longer,
suggesting the problem regresses.
Could it be that these diet pills are safe after all? An editorial in
the Journal of the American College of Cardiology accompanied
publication of the Harvard study and asked whether there was adequate
proof of any increase in risk from fen-phen. No one is ready to go so
far as to suggest that these drugs should return to the market, but a
reasonable conclusion at this point is that there is an increased risk
of heart-valve problems, though the risk is probably quite small.
Regardless of the relative risks and merits of fen-phen — and of
diet drugs in general — weight loss remains a problem that cannot
be solved by any "magic bullet." Medications may help a little
in some patients, and surgical solutions might be considered for severely
overweight individuals. However, for most of us, regular exercise and
careful attention to how many calories we eat remain the best strategies
for successful and lasting weight loss.
Journal of the American College of Cardiology, Vol. 34, No. 4,
pp. 1153–58.
Circulation, Vol. 100, No. 21, pp. 2161–67.
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Vitamin C: How Much Is Enough?
Vitamin C is touted as a potential weapon in combating a range of illnesses,
from the common cold to cancer and heart disease.
No one believes that taking vitamin C supplements in moderate doses presents
any danger, and foods rich in vitamin C (fruits and vegetables) offer
real health benefits. But could consuming large amounts of vitamin C
supplements be too much of a good thing?
Despite some theoretical dangers, vitamin C appears to have very few
toxic effects. However, at very high doses, vitamin C can indeed cause
problems. Diarrhea and abdominal bloating can result from taking several
grams at once — a tactic that has been advocated by some for preventing
and treating the common cold.
Studies show that high doses of vitamin C could lead to over-absorption
of iron, which could potentially damage the heart, liver, and other organs.
Too much vitamin C may also contribute to kidney stones or give false-positive
readings on blood-stool tests. Such events occur rarely if ever, so these
really are minor concerns. But, even if people are not endangering themselves
much by taking large amounts of vitamin C, research suggests that they
are not helping themselves either. Studies of dietary patterns show that
people who get an average of 200 mg of vitamin C per day from fruits
and vegetables have a lower risk of cancer — especially cancers
of the mouth, esophagus, stomach, colon, and lung. Five servings of fruits
and vegetables a day are enough to provide this much vitamin C. In research
trials, consuming more vitamin C has not led to a detectable increase
in health benefits. As for heart disease, there is evidence that marked
vitamin C deficiency is associated with an increased risk of cardiovascular
problems, but there is no proof that taking supplements offers additional
benefits over those offered by a diet that includes the recommended amounts
of fruits and vegetables.
Experts from the National Institutes of Health recently reviewed the
evidence on this topic and concluded that, ideally, people should try
to get their vitamin C from eating five servings of fruits and vegetables
daily. Taking more than one gram (1,000 milligrams) of vitamin C per
day should be discouraged because of the small, yet real, possibility
of adverse effects. These recommendations do not mean that people who
are taking vitamin C supplements or a multivitamin pill should stop,
particularly if they just can't manage to eat enough fruits and vegetables.
However, there is no reason to take high doses of vitamin C, and there
may even be a small possibility of harm. For more information on vitamins
and minerals, see page 43 of the Family Health Guide.
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Fish Oil Supplements Valuable for Heart Disease
Sufferers
Eating like an Eskimo is believed to prevent cardiovascular disease.
Now, a new Italian study has found that polyunsaturated fatty acid (fish
oil) supplements significantly reduced the risk of recurrent heart troubles
and related mortality in patients who had a history of heart disease.
The study involved 11,000 subjects who had survived heart attacks in
the preceding three months. Researchers then monitored their progress
for three-and-a-half years as they took daily doses of polyunsaturated
fatty acid and vitamin E. Vitamin E, prevalent in leafy greens, is also
touted for its antioxidant properties. Subjects received one of four
treatments: polyunsaturated fat supplements, vitamin E supplements, both,
or neither. Polyunsaturated fat supplements reduced patient mortality
by nearly 20% and decreased chances of another heart attack by 10%-15%.
Vitamin E, however, failed to improve survival significantly nor was
there any additive effect when the two supplements were taken together.
Neither supplement caused side effects.
The study might even underestimate the potential of polyunsaturated fatty
acids, according to an accompanying editorial. Italians are already thought
more resistant to coronary disease because of their Mediterranean diet.
Results in less healthy populations might be amplified, and this could
also explain vitamin E's lackluster performance. For more information
on dietary fats and oils, see page 40 of the Family Health Guide.
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The Health Burden of a Few Extra Pounds
According to an extensive study conducted by the American Cancer Society,
even being moderately overweight adds a significant burden to your health.
This research looked at the relationship between body-mass index and
the risk of death. It also examined the influence of smoking, disease,
race, and age on the weight-related risk.
Body-mass index (BMI) combines height and weight measures to gauge body
mass. It is calculated by dividing your weight in kilograms by the square
of your height in meters. The simplest way to calculate your BMI is to
use a table that lists the BMI for various weights and heights.
The study investigators followed more than one million adults between
1982 and 1996 and found that being moderately to severely overweight
greatly increases a person’s chance of early death from cancer,
cardiovascular disease, and other illnesses. Smoking and the presence
of disease exacerbated this risk.
The lowest risk of death was associated with BMIs of 23.5 to 24.9 in
men and 22.0 to 23.4 in women. Death rates then increased as BMI increased.
Even exceeding the upper end of the ideal range by just a point or two
appeared hazardous. The risk of death from cardiovascular disease increased
significantly in men after a BMI of 26.5 and in women after 25.0 in men.
And the most obese white men and women (35+ BMI) were at least twice
as likely to die than their healthy cohorts. For instance, a 5 ft. 9
in. male weighing 150 pounds has a BMI of 22. Add just 30 lbs. to this
person, and the BMI increases to 27, already raising his health risks.
At a 35 BMI, our 5 ft. 9 in. male would weigh 240 pounds, and have increased
his risk of dying from cancer by 40% and cardiovascular disease by almost
100%. Smoking and the presence of disease decreased the chance of survival
regardless of the subject’s BMI.
Black Women proved the exception. Even the heaviest black women saw only
a 20 –30% increase in their risk of death — opposed to the
nearly 100% increase in risk for similarly overweight white women. This
confirms the findings of previous studies, and could be related to differences
in how the two groups of women store and process fat.
The study’s conclusion regarding the health effects of extreme leanness
is more controversial. While subjects with BMIs under 18.0 experienced
a moderately higher risk of death, researchers believe this was more
likely a function of an unrecognized disease which resulted in lower
body weight, rather that being underweight itself.
Debating the consequences of extreme leanness is academic. Only 7.7%
of the US population have BMIs lower than 20. Obesity, however, is a
public health threat. Nearly one- third of Americans are moderately overweight
(25.0 to 29.9 BMI) and almost one-quarter are significantly overweight
(30+ BMI). For more information on obesity and approaches to weight loss,
see page 853 of the Family Health Guide.
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Cereal Fiber Reduces Heart Disease Risk for
Women Too
Several studies have demonstrated that, for men, a high-fiber diet reduces
the risk of coronary heart disease. Recently, data from the Nurses' Health
Study suggests that the same is true for women.
Study investigators looked at the typical daily diet of 68,782 women.
None of these women had known cardiovascular disease, cancer, high cholesterol,
or diabetes at the time the study began. Researchers followed the women
to see how many experienced a heart attack or died of heart disease.
After adjusting for age differences among the groups, the women who ate
the most fiber had a 59% lower risk of dying from coronary disease over
the next 10 years when compared with women who ate the least amount of
fiber. Statistical analysis indicated that each 10-gram per day increment
in long-term total fiber intake was associated with a 19% reduction in
coronary heart disease risk.
Researchers also found that the women with the highest long-term intake
of cereal fiber had a 34% lower risk of coronary heart disease when compared
with the women with the lowest consumption of cereal. Yet, the amount
of fruit and vegetable fiber had little effect on heart disease risk.
In fact, the benefits of cereal fiber appear to be particularly potent.
An increase of five grams per day of cereal fiber was associated with
a 37% reduction in heart disease risk.
The information from this report presents a particularly strong case
for eating more whole grain products as a way to add fiber to your diet.
You can do this by eating whole wheat bread, brown rice, and whole grain
pastas, instead of the refined versions, and opting for a high-fiber
breakfast cereal. Although the fiber in fruits and vegetables does not
appear to lower heart disease risk, eating plenty of fruits and vegetables
offers other health benefits, so these food groups should not get short
shrift in anyone's diet. For more information on diet and nutrition,
see page 39 of the Family Health Guide.
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Carbonated Beverages and the Risk of Bone Fractures
in Teenaged Girls
Osteoporosis, or the loss of bone density, is usually thought of as
a geriatric condition. But the disease may have its roots in adolescence
as bone mass reaches its peak level. Factors that affect the accumulation
of bone mass during this time can increase the risk of bone fractures
and osteoporosis. In this context, teenaged girls may be jeopardizing
their current and future health by drinking too many carbonated beverages.
Past results indicate that consumption of carbonated beverages is associated
with bone fractures among teenaged girls. A recent cross-sectional study
involving 460 9th- and 10th-grade girls confirmed these findings. The
teenagers completed a questionnaire describing their physical activities
and personal and behavioral habits. Researchers analyzed the results
to determine an association between consumption of carbonated beverages
and bone fractures.
Of the girls surveyed, 80% drank carbonated beverages, and nearly two-thirds
of the girls drank cola. One-fifth of the girls reported having had bone
fractures. Analysis showed that the risk of bone fracture in girls who
drink carbonated beverages is three times that of girls who do not. The
risk is highest, seven times greater, among
physically active girls who drink both cola and noncola.
The results suggest a strong association between consumption of carbonated
beverages and bone fractures in teenaged girls, but the researchers caution
that a cause and effect relationship cannot be assumed. Despite that,
they have a few theories that may explain the association. Laboratory
research has shown that the high phosphorous concentration in cola can
cause bone loss that may lead to a greater risk of bone fractures. Another
plausible theory is that the consumption of carbonated beverages takes
the place of consumption of milk, an important source of calcium. Low
calcium intake can increase the risk of osteoporosis. Between 1970 and
1997, the consumption of carbonated beverages increased by 118% per capita
in the United States, while milk consumption declined 23%.
The study, however, did not include questions concerning the amounts
of milk and carbonated beverages consumed. Long-term studies that include
these factors may help to assess the effect of milk and carbonated beverage
consumption. Also, the use of bone density measurements may demonstrate
a cause and effect relationship between carbonated beverage consumption
and bone fractures. Research is necessary to determine how carbonated
beverages may lead to bone fractures among physically active girls. Despite
the need for further studies, the current body of evidence suggests that
education on the health impact of carbonated beverage consumption may
be a possible way to promote optimal bone development in teenaged girls
and prevent osteoporosis.
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Caution Always Key in Using Herbal Medicines
A recent study published in the New England Journal of Medicine offers
another important reminder on careful use of herbal remedies. This caution
is rooted in the absence of strict pharmaceutical controls in the manufacture
of such products and how the lack of these requirements can leave room
for tragic errors.
In the mid-1990s, doctors at a clinic in Belgium treated 43 patients
with end-stage kidney failure, requiring dialysis or transplant. Not
surprisingly, these individuals had something in common in their medical
histories. Between 1990 and 1992, each had used a Chinese herbal remedy
in combination with two other drugs for weight loss. The herbal preparation
supposedly contained Stephania tetrandra and Magnolia officinalis.
But the sudden appearance of kidney failure in these patients, caused
their doctors to suspect that the herb Aristolochia fangchi, which
is poisonous to the kidneys, had unintentionally been substituted for S.
tetrandra. The Chinese names for A. fangchi and S. tetrandra sound
similar and the two are often confused. Analysis showed that the herbal
remedy did, in fact, contain aristolochic acids, which are derived from
A. fangchi. Aristolochic acids cause cancer in rats and mutations in
bacteria and mammals.
Reports of patients who had developed urothelial carcinoma (cancer of
the tissues lining the bladder, ureter, and part of the kidney), as well
as kidney failure related to the Chinese herbs, drew concern among the
Belgian doctors. When one of their patients also developed this cancer,
the doctors decided that all patients with end-stage kidney failure related
to the use of Chinese herbs should be checked for cancer of these organs.
By removing these organs, the doctors hoped to prevent cancer from developing
in their patients. Thirty-nine of the 43 patients agreed to undergo the
preventive surgery. Of these patients, 46% of them already had cancerous
growths in the removed tissues. In addition, 19 of the remaining 21 patients
had abnormal growths in the urinary system. The investigators also analyzed
DNA samples taken from the kidneys and ureters of each patient. The DNA
samples for every patient showed changes typically found after exposure
to aristolochic acid. The researchers compared these results to analysis
of DNA samples taken from eight patients with end-stage kidney failure
unrelated to Chinese herbs. None of these control samples showed DNA
changes formed by aristolochic acid.
The doctors calculated the cumulative dose of the implicated herb and
other treatments for each patient. They found that the risk of cancer
was related to the cumulative dose of A. fangchi. Because many
of the patients had also taken appetite suppressants as well as a diuretic,
the doctors noted that these drugs might enhance the toxicity of aristolochic
acid.
This case study provides strong evidence suggesting a relationship between
the Chinese herb A. fangchi and urothelial carcinoma. While a
manufacturing mistake led to the introduction of this herb into an herbal
preparation for weight loss, this study highlights the risks involved
in taking herbal remedies. There is little control over the quality of
herbal medicines. This means that the label on an herbal medicine may
not accurately represent what is actually in the container, as was the
case with S. tetrandra. Several countries have banned the use
of herbs that contain aristolochic acid, yet Aristolochia is readily
available in the United States in capsule form.
In the United States, the FDA does not have the authority to assess the
safety and efficacy of a dietary supplement before it reaches the shelves
of stores. The agency is allowed to restrict a supplement only after
it proves the substance is harmful as commonly consumed, but there is
no adequate system for reporting serious side effects associated with
these products. Furthermore, the FDA does not have any way of knowing
which herbal remedies contain harmful substances such as aristolochic
acid. The case of the Chinese herbal diet pill and its association with
urothelial cancer is just one of a number of cases that demonstrate the
need for greater oversight of dietary supplements and caution in the
use of supplements on the part of consumers.
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Healthful Diet Connected to Lower Mortality in Women
We are constantly told to eat a healthful diet — to increase fruit,
vegetable, and grain intake while decreasing fat consumption. But for
many of us, incorporating five fruits and vegetables into our daily routines
seems impossible: they cost too much, they take too long to prepare,
they contain harmful pesticides, they spoil easily. The latest study
makes it easy to see the connection between a healthful diet and our
own mortality — and the need to stop making the same old excuses.
Simply increasing your weekly intake of 23 recommended foods could really
make a difference.
Researchers from the National Cancer Institute and the City University
of New York sent a food-frequency questionnaire to women who had participated
in an earlier cancer study. About 50,000 women responded, but 18% were
excluded because of incomplete information or answers that were deemed
unreliable. The researchers were left with 42,254 participants, nearly
90% of whom were white and had 12 or more years of education. The questionnaire
asked the women to indicate which of the following 23 food items they
ate at least weekly: apples or pears; oranges; cantaloupe; orange or
grapefruit juice; grapefruit; other fruit juices; dried beans; tomatoes;
broccoli; spinach; mustard, turnip, or collard greens; carrots or mixed
vegetables with carrots; green salad; sweet potatoes or yams; other potatoes;
baked or stewed chicken or turkey; baked or broiled fish; dark breads
like whole wheat, rye, or pumpernickel; cornbread, tortillas, and grits;
high-fiber cereals, such as bran, granola, or shredded wheat; cooked
cereals; 2% milk and beverages with 2% milk; and 1% or skim milk. The
researchers calculated each of the women’s recommended foods score
(RFS) by adding the number of items each woman checked off. The women
were then divided into four groups: those who ate 0–8 of the recommended
foods per week; those who ate 9–11, those who ate 12–13, and
those who ate 14–23.
The women were followed up about five and a half years later, when their
average age was 66. At that point, the researchers determined the number
and cause of deaths within each group. After adjusting for other lifestyle
factors — such as smoking status, physical inactivity, alcohol consumption,
vitamin supplement use, and education — they found an inverse association
between RFS and mortality from various diseases. Women who ate the most
recommended foods were at 30% lower risk from dying of cancer, coronary
heart disease, or stroke than those who ate the least. Even those who
ate modest amounts of the recommended foods (9-11) had a decreased risk
of dying from these diseases and stroke.
The study's results serve as a reminder to incorporate as many fruits,
vegetables, and whole grains into our diets as possible. For nutrition
strategies and an outline of the government’s Dietary Guidelines,
see page 39 of the Family Health Guide.
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Calcium Carbonate's Effect on the Absorption of
Levothyroxine
A recent study has revealed that calcium carbonate may reduce the body's
ability to absorb the thyroid medication levothyroxine. The people who
are probably most affected by this discovery are postmenopausal women,
since they often end taking both levothyroxine and calcium carbonate.
However, anyone taking |
