A team led by nutritionist Michael Ristow of the University of Jena in Germany asked a group of young men to exercise after giving half of them moderate doses of vitamins C and E. In the pill-takers, exercise failed to improve insulin sensitivity, which is believed to be one of the important benefits of activity. (The more sensitive the body is to insulin, the better able it is to convert glucose into energy, keeping blood sugar levels on an even keel.) Antioxidant takers also failed to experience a boost in their body’s natural defense mechanism against oxidative damage.

Quoted in The New York Times, Dr. Ristow didn’t beat around the bush. “If you exercise to promote health, you shouldn’t take large amounts of antioxidants,” he said. As he points out, the study results suggest that taking antioxidant vitamins may short-circuit the body’s own natural antioxidant system.

The researchers were quick to say that antioxidant-rich fruits and vegetables are fine, since they contain many substances that are known to be healthy.

This isn’t the first study to point to potential risks from taking high doses of antioxidants. But then other findings continue to suggest that there may be real benefits. In people with early signs of macular degeneration, for instance, a mix of antioxidants seems to slow the progression of the vision-robbing disease. And there’s provocative evidence from early trials that a mix of antioxidants may prevent or slow noise-induced hearing loss.

For now, it’s probably wise to go easy on antioxidants unless your doctor says you need a supplement. And, of course, to help yourself to an extra serving or two of fruit or vegetables.

© 2009 PDQhealth

A new report finds that a combination of several antioxidant vitamins–including beta carotene and vitamins C and E–may protect against noise-induced hearing loss. The findings were reported today at the annual conference of the Association for Research in Otolaryngology. In one study, researchers at the University of Michigan gave guinea pigs an antioxidant supplement and then exposed them for four hours to sounds at 110 decibels, the equivalent of a loud rock-and-roll concert. The treatment prevented temporary noise-induced hearing loss. A second study found that antioxidant vitamins can prevent permanent damage to cells in the inner ear after a single very loud noise exposure.

Other research has linked damage from free radical oxygen molecules to noise-induced hearing loss. And previous investigations have shown that antioxidants given after animals are exposed to loud noise may protect their ears from subsequent damage.

“I am very encouraged by these results that we may be able to find a way to diminish permanent threshold shift with noise exposure,” said Debara Tucci, MD, a hearing expert at Duke University Medical Center. An estimated 26 million Americans suffer noise-induced hearing loss, according to the National Institute on Deafness and Other Communication Disorders, which funded the two studies.

Multivitamins typically include a healthy dose of antioxidant vitamins. But even if supplements prove to be helpful in protecting ears, the best prevention will remain avoiding loud noises, keeping the volume level down on MP3 players, and wearing earplugs in settings like rock concerts and around noisy machinery.

For more information about hearing protection, check out H.E.A.R. (Hearing Education and Awareness for Rockers).

2009 PDQhealth

Danish and Swedish scientists tracked 1,409 middle-aged volunteers for 21 years. During that time, 61 developed age-related dementia, 48 with Alzheimer’s. Reviewing diet surveys conducted at the beginning of the study, the research team found that devoted coffee drinkers—those downing three to five cups a day—were 65 percent less likely to develop dementia than those who averaged only two cups or less.

There are plenty of potential explanations. Previous studies have shown that coffee may lower the risk of type 2 diabetes, a disease that damages blood vessels. A Swedish study published in 2004, for instance, which followed 1361 women over 18 years, found that the more coffee the women drank, the lower their odds of developing diabetes. In a study of 17,111 men and women published in the British medical journal The Lancet in 2002, Dutch researchers reported that people who drank seven cups of coffee were half as likely as non-coffee-drinkers to develop diabetes. Lower risk of diabetes might in turn protect blood circulation in the brain and reduce the danger of dementia.

Coffee is also rich in antioxidants, which are believed to protect the circulatory system. A 2004 study conducted by University of Glasgow researchers found that coffee contains levels of antioxidants as high as those in black tea—and that coffee’s antioxidants are actually more easily absorbed into the bloodstream. Indeed, when researchers analyzed the diets of 2,672 Norwegians—among the world’s most avid coffee drinkers—coffee contributed more antioxidants than anything else on the menu.

And in animal studies, caffeine has been shown to protect against the brain plaques that are a hallmark of Alzheimer’s.

“Coffee has two virtues,” an old Dutch proverb says. “It is wet and warm.” If you’re a true coffee lover, you know wet and warm is just the beginning. There’s the nose-filling roasted aroma of fresh-ground beans, the intense yet smooth taste of a fine French roast, the frothy surface of a perfectly made cappuccino, the bittersweet richness of a perfectly balanced mocha. And then, of course, there’s the reviving buzz of caffeine, which can lift the spirit and jumpstart the most sluggish morning.

And now, the evidence shows, coffee possesses an even more important virtue: it can help keep us healthy. It’s good, as the old ad slogan said, to the last drop.

© 2009 PDQhealth

Bradley Willcox, MD, co-principal investigator of the Okinawa Centenarians Study, has been working to uncover the secret of the islanders’ exceptional longevity. When we asked him by email what he’d discovered, part of his answer took us by surprise. ”Sweet potatoes,” he wrote.

It turns out that sweet potatoes are an important staple in the Okinawan diet, along with bitter melon (a tropical fruit often used in stir fries) and sanpin tea (a blend of green tea and jasmine flowers.) What do they have in common? Antioxidants, and plenty of them. One theory of aging holds that unstable oxygen molecules, called free radicals, which are normally generated by the body’s biochemical processes, keep chipping away at healthy cells, damaging and ultimately destroying them. Antixoidants neutralize these unstable molecules and protect against cellular wear and tear.

Fruits and nuts
Blueberries are especially rich in antioxidants, which may explain results from a study by researchers at the Jean Mayer Human Nutrition Research Center, who laboratory mice blueberry extract over a period of time equivalent in mouse lives to ten human years. When the blueberry mice reached old age, they outperformed a control group of mice fed regular chow on tests of balance and coordination. Antioxidants in blueberries, scientists speculate, may block oxidative damage to brain cells and blood vessels.

The antioxidant theory may help explain the remarkable longevity of another group, the Seventh Day Adventists, who typically outlive their neighbors by 4 to 7 years. Their religious denomination, founded in the U.S. in the 1840s, emphasizes healthy living and a vegetarian diet. And fruits and vegetables, of course, are the most abundant source of antioxidants in the diet. Their longevity may also be partly due to the fact that they eat little or no read meat, thus avoiding artery-clogging saturated fat, according to Joan Sabate, PhD, chairman of nutrition at Loma Linda University in California, where the Adventist studies have been conducted.

Sabate offered another more surprising explanation. Nuts. “Among Adventists, the more frequently people eat nuts, the longer they live on average. Our numbers suggest that nuts alone may account for an extra two and a half years of life.” What’s so good about nuts? First off, they are rich sources of unsaturated oils, so they offer benefits similar to those associated with olive oil. Nuts are also concentrated sources of vitamins, minerals, and other phytochemicals, including antioxidants.

Long live chocolate!
An even more surprising secret of longevity shows up in studies of the residents of the San Blas islands, off the coast of Panama. Here, people called the Kuna remain remarkably free of signs and symptoms of high blood pressure, which plagues most Americans as they get older, increasing the risk of heart disease and stroke. A study published last year showed that the Kuna’s rate of heart disease is only 9 per 100,000 people, compared to 83 per 100,000 among nearby mainland Panamanians.

The reason? Chocolate, says Harvard University professor Norman Hollenberg, MD, who has been studying the Kuna for more than two decades. The Kuna imbibe a drink made with cocoa in generous proportions—five or more glasses a day. And cocoa turns out to be unusually rich in flavonols, which help preserve the healthy function of blood vessels, especially their ability to widen or constrict as needed. Maintaining youthful blood vessels lowers risk not only of high blood pressure but other life-threatening chronic conditions, including type 2 diabetes, kidney disease, and even dementia.

Wine or other alcoholic beverages deserve a place at the table; they are consistently associated with lower mortality, as long as they’re consumed in moderation.

More important than specific foods, however, are overall eating patterns. Consider evidence from the Baltimore Longitudinal Study of Aging, which was begun in 1958 and is now the longest-running study of aging in the world, with more than 1,500 participants. A recent analysis of 501 men from the study found that those who helped themselves to lots of fruits and vegetables were less likely to develop heart disease and more likely to be alive at the end of 18 years of study. Each serving of fruits and vegetables led to a 6 percent reduction in risk of total mortality. Men who limited their saturated fat also reduced the risk of heart disease. But far and away the most impressive benefits fell to men who did both. Those who served up fruits and vegetables and cut back on saturated fat slashed their risk of dying of heart disease by 76 percent and of any cause by 31 percent during the study period.

Hara hachi bu
Because so many variables are involved, scientists can’t say exactly how many extra years of life you or I will gain by eating well and staying active. But Harvard School of Public Health epidemiologist Meir Stampfer, PhD, one of the country’s leading experts on health and nutrition, estimates that women in the Nurses Health Study who followed all the best health and diet advice might be adding an additional 14 years to their lives. Joan Sabate of Loma Linda University believes the Seventh Day Adventists add an extra ten years to their lives thanks to five lifestyle factors: being vegetarian, not smoking, exercising frequently, maintaining a healthy weight and, of course, eating lots of nuts.

According to Bradley Willcox, the Okinawans have traditionally followed hara hachi bu, a custom of eating until they are just 80 percent full. The practice allows them to consume fewer calories without bothering to read nutrition labels—and it means they don’t have to obsess about what to eat and not eat but can go about enjoying themselves.

That may be even more crucial to their longevity than, well, sweet potatoes or sanpin tea. Finding delight in family and friends, having something to look forward to every day: studies of centenarians around the world suggest that these intangibles, even more than the specifics of diet, may be the most powerful secret to longevity. The Okinawans call it ikigai, or “finding your reason to live.”