You Use That Stuff, Too?

One challenge to studying garlic is the many forms in which it's available -- cooked, raw, mashed and in supplements. Christopher Gardner, director of nutrition studies at the Stanford Prevention Research Center, is trying to allow for possible differences in effectiveness by giving 200 people with moderately elevated cholesterol either fresh garlic, one of two types of garlic supplements or a placebo every day for six months. A previous Gardner study found at least one garlic supplement did not lower cholesterol, but he's not finished exploring the possibility that some form of garlic has a cardiovascular benefit.

"It's biologically plausible that [herbs like garlic, ginkgo and ginseng] can help people," he said, "but . . . it doesn't mean that it works. When you do these clinical trials, it takes dozens of them to show something."

Deep Breathing

Deep breathing is an integral part of meditation and yoga, but some alternative practitioners teach deep breathing alone to calm the mind and body. Plenty of people are trying it -- 11 percent of respondents to the NCCAM survey reported trying it for health reasons in the past year -- more than any of the other "mind-body therapies" in the survey except prayer.

David Spiegel, medical director of the Center for Integrative Medicine at Stanford Medical Center, said his center uses deep breathing therapy mainly to help patients with stress and anxiety disorders.

"The problem with modern humans is that our stress response is a physical one," Spiegel said. "When we prepare our bodies to fight or flee, we tend to get hyper-aroused." Deep breathing, he said, can help people regulate their stress levels and heart rate.

A few small studies in Israel have found that sessions of slow, deep breathing can lower blood pressure in people with high blood pressure. But large, randomized, controlled studies on the health effects of deep breathing are rare. On the other hand, no studies appear to report negative side effects.

Meditation

People have sought mental calm and physical relaxation through meditation for thousands of years, but only recently have researchers begun to study meditation's effect on the brain. The NCCAM survey found that 7.6 percent of respondents had tried meditation in the past year.

Andrew Newberg, a neuroscientist involved in studies of the practice at the University of Pennsylvania Medical School, says meditation may improve immune system function and affect dopamine and serotonin levels, which affect feelings of well-being.

A few studies have shown meditation may help reduce blood pressure and relieve pain from arthritis and other conditions, but because study participants also received biofeedback and other alternative therapies, it's hard to say how much of the effect was due to meditation. A meta-analysis published last year in the Journal of the American Board of Family Practice similarly reported that fibromyalgia patients may benefit from a combination of meditation and other therapies.

While the link between meditation and disease prevention or treatment is still tentative, some practitioners use meditation in clinical settings. The program for stress management at the University of Pennsylvania, for example, teaches meditation in hospitals, schools and violence prevention programs.

NCCAM is funding clinical trials on the use of meditation and other alternative therapies to treat rheumatoid arthritis, binge eating disorder and cardiovascular disease. In addition, the center is partnering with the National Heart, Lung, and Blood Institute and the National Institute on Aging to study the effect of meditation and health education on heart disease in African American women age 60 and over.