Is natural better? Apparently, a lot of women think so. A survey released today by the National Institutes of Health found that 42.8 percent of American women use some form of complementary or alternative medicine, compared to 33.5 percent of men. That's similar to the gender difference in use of conventional medicine, says Richard Nahin, of the National Center for Complementary and Alternative Medicine. The most popular alternative remedies were nonvitamin and nonmineral products such as fish oil, omega-3 and glucosamine. Use of mind-body therapies such as deep breathing, meditation and yoga has also climbed since the last such poll in 2002. The report, which uses data from the 2007 National Health Interview Survey, also provides even more specific clues about the most likely consumers of these treatments: 50-somethings who have graduate degrees, are relatively well off financially, live in the West and have quit smoking.

That's a pretty desirable demographic, and marketing for natural products and supplements often aims squarely at the common ailments and anxieties of women in that target group, especially hot flashes, memory problems and arthritis. But by the time they reach a certain age, women should have learned a few things—like being wary of claims for miracle cures.

Other red flags are phrases like "no side effects," "cure-all" or "totally safe and natural." Labeling a product as natural does not automatically mean it's safe for everyone. Herbal and dietary supplements are regulated by the Food and Drug Administration as food rather than drugs, so they don't have to meet the same safety and efficacy standards as prescription drugs or over-the-counter medications. You should always tell your health-care provider about everything you are taking, because some alternative or herbal products can interfere with prescription medications. In recent years, more physicians have been encouraging their patients to use supplements when there is proof that they work. Your doctor is also likely to know the most effective dose for you.

Until relatively recently, there wasn't a whole lot of high-quality research on alternative remedies. But in the last few years, as demand for these products has grown, scientists have made a big push to find out more. Here are the results of some interesting recent studies:"

Ginkgo biloba and dementia: In many parts of the world, this herbal product is prescribed to preserve memory, but there's no solid evidence that it works. A 2007 review of existing studies by the well-respected Cochrane Collaboration found that ginkgo did not help people who were already suffering from dementia. Most recently, a study published last month in the Journal of the American Medical Association (JAMA) found that taking 120 milligrams twice a day (a standard dose) did not lower the incidence of dementia in either elderly people with no memory problems or those suffering from mild cognitive impairment. The study, which followed more than 3,000 people who were 75 and older for a median of 6.1 years, was the first clinical trial large enough to assess whether ginkgo might actually be able to prevent memory loss. The results disappointed many experts, who had been hopeful that ginkgo would work. Although the study used just one type of ginkgo extract, researchers say the results could be generalized to include all ginkgo products, which have annual U.S. sales of $249 million, according to the study's authors.

Folic acid, B vitamins and cancer risk: Another JAMA study last month found that taking supplements of folic acid along with vitamins B6 and B12 has no effect on overall cancer risk, including breast cancer, among women who are at risk for cardiovascular disease. That's worth noting, because women have been underrepresented in previous trials with B vitamins, the study's authors say. A third of American adults currently take multivitamins containing these three supplements. Since 1998, folic acid has been also been added to food in the United States as part of a policy to reduce the risk of neural-tube birth defects. The study looked at 5,442 women ages 42 and older who had either cardiovascular disease or three coronary risk factors. Although there were no reductions in cancer risk for women under 65, there was a significant decrease in invasive cancer and breast cancer in one subgroup, women who were 65 or older at the start of the study. That's important because older people are more likely to get cancer. Talk to your doctor about whether taking these supplements would be helpful for you.

Vitamin E and rheumatoid arthritis: Another study released last month found that taking vitamin E does not lower a woman's chances of getting rheumatoid arthritis. Data from some observational studies, which follow people over time without any interventions, have indicated that those on diets higher in antioxidants such as vitamin E were less likely to get the potentially crippling autoimmune disease, which affects three times more women than men. The new study, published in the journal Arthritis Care & Research, analyzed data from the Women's Health Study—39,144 women who were at least 45 were chosen to take either a dose of 600 IU of vitamin E or a placebo every other day. After 10 years, 50 women in the vitamin E group and 56 women in the placebo group developed rheumatoid arthritis, which is not a statistically significant difference given the size of the original group. The study was one of many attempts to understand the mechanism behind a wide range of autoimmune diseases, most of which are far more common in women than men for reasons scientists don't yet understand.