Nutrition Archive

Can curbing your usual daily calorie intake by 10% improve health and longevity?

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There is a saying: "The less you eat, the longer you live." The rising rates of obesity have shown that Americans consume more than necessary, and cutting back on calories may be a smart move.

"People naturally gain about a pound a year, on average, beginning in middle age, so healthy weight needs to be a goal for older men," says Vasanti Malik, a research scientist in the Department of Nutrition at Harvard's T.H. Chan School of Public Health. "That is why being mindful of how many calories you really need — and perhaps cutting back some, an approach called calorie restriction — may help some men stay healthy and maybe even live longer."

Research we're watching

Gluten, a storage protein in wheat, rye, and barley, triggers inflammation and intestinal damage in people with celiac disease. Due to concern that gluten may also increase the risk of obesity, diabetes, and cardiovascular disease among healthy people, the number of people without celiac disease who have adopted a gluten-free diet grew more than threefold from 2009 to 2014.

A team led by researchers from Harvard T.H. Chan School of Public Health used 20 to 30 years of data from the 64,714 women in the Nurses' Health Study and the 45,305 men in the Health Professionals Follow-up Study to examine the relationship of dietary gluten to the risk of chronic conditions such as coronary artery disease in people without celiac disease or heart disease. All the participants had completed questionnaires on their diet and health every four years from 1986 through 2010.

New phrases showing up on packaging don't always tell you if the food is better for your health.

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You're not alone if you don't know the meaning of certain terms on food labels lately. A new language has developed to describe healthy ways to produce meat, vegetables, fruit, and other products in the grocery store. "It's not just the terms that are confusing, but also various associated health claims," says Vasanti Malik, a nutrition researcher at the Harvard T.H. Chan School of Public Health.

Organic vs. natural

Some food is labeled "organic" or "natural." What's the difference? The FDA doesn't have a definition for "natural," although it doesn't object to the term if a food does not contain added color, artificial flavors, or synthetic substances.

Some aspects of diet may diminish or heighten the effect of prescription drugs or cause harmful side effects.

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You take your pills on time each day and get your prescriptions refilled before they run out. But all that hard work to stick to your medication plan can be scuttled if your diet is undermining the drugs' effects. "I see a lot of people who don't believe in the importance of following dietary recommendations for medications. That's a concern," says Dr. Randall Zusman, a cardiologist and Harvard Medical School associate professor.

Dietary risks

The following foods, drinks, or ingredients can interfere with specific drugs.

Do a little research, follow a few rules, and make polite requests.

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Going out for dinner can be a nice way to unwind with family or friends. But if you're watching your salt intake, restaurants aren't always so relaxing. Much of their fare is loaded with sodium, a main component of salt. In fact, some entrees at popular chains contain far more than 2,300 milligrams (mg) of sodium — the recommended limit for an entire day's worth of food (see "Super-salty entree examples").

Limiting sodium is especially important for people with high blood pressure, because excess salt worsens this common condition, leaving you more prone to heart attack and stroke. If you eat out only once a month, you probably needn't worry too much. But Americans tend to eat out far more frequently — about five times a week, on average. So it's worth learning some strategies for staying within your salt budget when you eat away from home.

Research we're watching

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If you're craving a crunchy snack, a handful of cashews is a heart-healthy choice, a small study suggests.

Although they're a popular pick in nut mixes, cashews have a bit of a bad rap. Because cashews contain about 20% saturated fat, the FDA omitted them from the qualified health claim suggesting that nuts may lower heart disease risk when eaten as part of a diet low in saturated fats and cholesterol.

In the journals

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Omega-3 fish oil supplements can help prevent death from heart disease in patients who've had a heart attack, but a science advisory published March 28, 2017, in Circulation found there is no research to support their use to prevent heart disease in the general population.

Researchers reviewed all randomized clinical trials that evaluated the potential role for fish oil supplements to prevent cardiovascular disease, including two studies published before 2002 and 13 published since then. The studies assessed the clinical impact of fish oil treatment on cardiovascular outcomes, such as heart attacks, strokes, and atrial fibrillation (a heart rhythm disorder).

Mounting evidence suggests that eating nuts and seeds daily can lower your risk of diabetes and heart disease and may even lengthen your life.

If your idea of healthy eating was formed a few decades ago, it may be hard to shake the notion that you should avoid nuts, which are high in calories and fat. But new evidence has overturned that assumption. In fact, a recent analysis of the nation's eating habits and health outcomes suggests that eating too few nuts and seeds is associated with an increased risk of dying from cardiovascular disease or diabetes.

For that study, in the March 7, 2017, Journal of the American Medical Association, researchers from the Tufts Friedman School of Nutrition Science and Policy relied on a model that used data from scores of observational studies on diet and health, including the National Health and Nutrition Examination Surveys, which provided detailed information on Americans' eating habits over the decade ending in 2012. They estimated that in 2012, over 300,000 deaths from heart disease, stroke, or type 2 diabetes — about 45% of all deaths from those conditions — were associated with eating either too much or too little of 10 nutrients.