Preventive care Archive

Grapefruit can mean danger when combined with some popular drugs used for high blood pressure, high cholesterol and depression

Grapefruit and grapefruit juice are healthful, providing enough vitamin C, potassium, dietary fiber, and other nutrients to earn the American Heart Association's "heart-check" mark. That's the good news. The bad news is that grapefruit juice can interact with dozens of medications, sometimes dangerously.

Doctors are not sure which of the hundreds of chemicals in grapefruit are responsible. The leading candidate is furanocoumarin. It is also found in Seville (sour) oranges and tangelos; although these fruits have not been studied in detail, the guidelines for grapefruit should apply to them as well.

The pleasure of eating a candy bar lasts but a few minutes. Burning off the calories it delivers can take nearly an hour. So this is definitely not a simple way to lose weight! 

To lose one pound by exercising, you need to burn approximately 3,500 calories. It can take days of moderate exercise to do this. A better strategy for weight loss involves a two-pronged approach: exercising and cutting calories.

Most plant-based diets emphasize foods associated with heart benefits. However, some plant foods, such as fruit juices, refined grains, processed cereals, and potatoes, can be harmful. The goal is to emphasize heart-healthy plants.

Ask the doctors

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Q. I've read that getting the flu shot annually will weaken my immune system over time. Is this true?

A. A study published in the March 1, 2017, issue of The Journal of Infectious Diseases investigated whether getting an annual vaccination against influenza (flu) can weaken your body's natural ability to protect itself from the disease. Past studies have raised similar concerns. Researchers at the University of Bergen in Norway followed 250 health care workers. Some of them got a flu vaccination every year from 2009 through 2013. The others only received the vaccine once in 2009 and not in the years from 2010 to 2013. The researchers then took blood samples before the influenza season (and before people were vaccinated that season), from the members of both groups and looked at different markers to gauge how well their immune systems would respond to the influenza virus. They found that getting an annual flu vaccination did not weaken the immune system. As a group, the people who got the flu shot annually appeared to have a better immune response to influenza than those vaccinated only once.

The shift from this condition to dementia is not necessarily inevitable.

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Will I get dementia? That common question takes on urgency if you have mild cognitive impairment (MCI), a slight but noticeable change in memory and thinking skills. But the progression from MCI to dementia is not automatic. In fact, MCI is not always permanent. "It depends on the underlying cause," says Dr. Joel Salinas, a neurologist at Harvard-affiliated Massachusetts General Hospital.

What are the causes of MCI?

MCI is not dementia (see "What is dementia?"), but it's not normal thinking, either. It often stems from disease or treatments for disease, including

Weight loss can be challenging, but there are some strategies for success.

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If you're struggling to lose weight, you probably feel like the odds are stacked against you. You're not necessarily wrong.

"There is so much great-tasting food, and it's abundant and in your face all the time. To me it's kind of a miracle that people aren't even heavier than they are," says Dr. Meir Stampfer, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. In addition to an abundance of food, most people today also have a far more sedentary lifestyle than past generations. "Even active people who exercise a lot aren't expending the calories their ancestors did," says Dr. Stampfer.

On call

Q. I have just recovered from the flu. How soon can I resume exercise again and can I go straight back to my previous routine?

A. The recommendations about when to return to exercise after respiratory infections, such as the flu, colds, or bronchitis, are vague. One major reason is that each person's response to illness is so variable. But here is my general advice.

The yoga routine "ten churnings" can be done on its own to help you get moving in the morning or to counteract stiffness after sitting for too long. In about six minutes, the routine can loosen up your joints and serve as a warm-up to a longer exercise session. To learn additional intermediate yoga exercises, visit: www.health.harvard.edu/iy

Falls can lead to pneumonia, brain injuries, or muscle breakdown. Learn the risks so you can avoid them.

It's easy to see why falls are a top cause of injury and death among older adults. Crashing to the ground with force obviously can break a bone, or worse. But are you familiar with that "worse" part? Learn about fall risks now, so you can do as much as possible to avoid injuries in the future and maintain your mobility and independence.

Fractures

In older adults, about 90% of broken bones (fractures) happen because of a fall. Breaks commonly occur in the ribs, spine, wrist, arm, ankle, or hip.