Archive 2005 2006 2007 2008

Q: I recently read that moderate alcohol consumption (a drink a day) reduces the risk of heart disease as much as moderate daily exercise. Why not just have a drink instead of exercising?

A: Don’t give up exercise in favor of drinking if you are looking for heart benefits.

A drink a day can raise blood levels of HDL (“good”) cholesterol and can also (like aspirin) help prevent clots. This is fine, as far as it goes. But alcohol has its bad side. Drinking (especially heavy drinking) increases the risk of several cancers, as well as car crashes, injuries from falls, and other mishaps. There’s also the risk of alcoholism and birth defects. And it provides extra calories.

Aerobic exercise has many clear heart benefits. It will make your heart stronger and enable it to pump more blood with each contraction, thus lowering your resting heart rate. In addition, aerobic exercise helps control blood pressure and can also raise HDL. To benefit most, you should exercise strenuously enough to raise your heart rate and make you sweat, and do this for at least 30 minutes on most days.

The study you heard about appeared in the European Heart Journal in February. It concluded that leisure-time physical activity and moderate alcohol intake are both important ways to lower the risk of heart attacks and all-cause mortality. But the researchers also noted that there might be good reason for abstaining from alcohol. There’s rarely a good reason for abstaining from exercise.

Q: Why is some produce in the supermarket sprayed with water, and is this safe?

A: Grocers often mist certain fruits and vegetables to keep them from wilting and drying out. Leafy greens and fresh herbs, for instance, can lose a lot of water through transpiration (water exits the leaf through tiny openings, called stomata). Plain old evaporation also occurs, more so in produce with greater surface area and thin skins. Some produce—including onions, garlic, berries, and melons—should not be misted, however, because they can develop fungal growth.

Water loss also affects the nutrients in produce. According to two studies in the Journal of Food Science years ago, misted broccoli retained more vitamin C than nonmisted broccoli. And it had better color, too, which generally indicates that more phytochemicals are present.

In 1989 an outbreak of Legionnaires’ disease was linked to a grocery store’s misting machine that had a standing water reserve—a potential source of contamination. The industry has, for the most part, moved away from such a system to one connected directly to a source of tap water, which is then typically filtered. No problems have since been reported.

Q: What is prolotherapy, and does it work?

A: Prolotherapy is a non-mainstream therapy for chronic musculoskeletal pain that doesn’t improve sufficiently by conventional treatment. It involves injecting various substances, such as dextrose (sugar), into ligaments and tendons to trigger an inflammatory response that promotes healing. Proponents claim that the procedure, done repeatedly over several weeks, boosts collagen production, which strengthens the injured tissue and stabilizes joints. Others say it forms beneficial scar tissue.

There have been few good studies on prolotherapy, and the results have mostly been mixed or inconclusive. Still, several recent reviews have been somewhat positive. For instance, the Cochrane Collaboration reviewed five well-designed studies and concluded that prolotherapy might improve chronic low-back pain—though only when used in combination with exercise and other treatments.

Prolotherapy might be an option for a limited number of people with long-standing conditions, as a last resort before surgery. Few doctors and hospitals offer it, so it may be hard to find a skilled practitioner near you. It is costly, and insurance usually does not cover it. Pain at the injection site, stiffness, and bruising are common side effects; rare but serious side effects have included spinal injuries, hemorrhaging, nerve damage, and other needle-related injuries.

Q: Will calcium supplements increase calcium deposits in my arteries and thus make a heart attack more likely?

A: Very unlikely. Calcium deposits (calcification) in coronary arteries may be a sign of increased risk for heart disease, and thus some cardiologists measure these deposits via special CT scans in certain patients. But the body is very good at regulating calcium in the blood (except with a few metabolic and/or kidney conditions), and what ends up in the blood does not simply build up in artery walls.

You may be wondering about this because of a recent study from New Zealand, which found that women who took calcium supplements (1,000 milligrams a day) had more heart attacks than those taking a placebo. However, that was the first study to find this, according to Dr. Robert Heaney, a well-known calcium researcher at Creighton University in Omaha. He recently conducted a similar calcium study, which did not find an increased coronary risk. Earlier studies, including the large Women’s Health Initiative (WHI), also found that calcium supplements—along with vitamin D, which helps the body use calcium—did not affect the risk of heart disease. In fact, the WHI study suggested that calcium and vitamin D may help prevent strokes in women at high risk.

Keep taking your calcium.

Q: What is jicama, and how nutritious is it?

A: Jicama (pronounced HEE-kah-mah) is a root vegetable, native to Mexico and Central America. Also called Mexican potato, Mexican turnip, and yam bean, it’s shaped like a turnip and has a papery yellow-brown skin and a starchy white inside. It is crunchy, juicy, and mildly sweet, similar to water chestnuts.

Jicama is 90% water, which makes it low in calories (46 per cup, sliced). Nearly all the calories come from carbohydrates. It’s rich in fiber (6 grams per cup) and vitamin C (24 milligrams, about one-third the daily recommended amount), and provides some potassium (180 milligrams), too.

To prepare jicama, peel and then slice or cube it. Eat jicama raw—added to salads, or, as in Mexico, marinated with lime juice and topped with chili powder. Or cook it, as in a stir-fry with other vegetables. Raw jicama can be a refreshing, filling snack.

UC Berkeley Wellness Letter, June 2008