Ratings:

*Has shown promise in early clinical trials, but needs more study to verify its safety and efficacy

**Has undergone serious scrutiny, yet many doctors in this country remain skeptical

***Has an accepted role in mainstream medicine

Calcium

Rating: ***

The claim: Calcium builds stronger bones and helps prevent osteoporosis, which can lead to crippling fractures.

The evidence: Scientists know that calcium is critical for healthy bones; the recommended daily intake is 1,000mg. A study in The New England Journal of Medicine found that taking 1,000 milligrams of supplemental calcium a day slowed bone loss in post-menopausal women by 43 percent.

The caveat: Exceeding the recommended daily intake could block the absorption of other minerals.

Evening Primrose Oil

Rating: *

The claim: Herbalists recommend supplements made from this plant for many inflammatory conditions, especially rheumatoid arthritis.

The evidence: Evening primrose oil contains several essential fatty acids, including gammalinolenic acid, or GLA. In a few small studies, some people with rheumatoid arthritis who took supplements containing GLA had less joint pain, swelling and stiffness. Evening primrose oil probably cannot replace anti-inflammatory drugs, which are standard therapy for rheumatoid arthritis. But some arthritis sufferers who use the herb are able to reduce their drug dosage.

The caveats: Evening primrose oil appears to be nontoxic, but the safety of using it for extended periods has not been studied. Side effects include nausea and headaches.

Feverfew

Rating: *

The claim: Prevents migraine headaches, which afflict about 28 million Americans (75 percent of whom are women).

The evidence: British researchers have found that migraine sufferers who took a daily capsule containing the equivalent of two feverfew leaves (roughly 80 milligrams per capsule) had 24 percent fewer attacks than patients given a placebo. Several other small studies have found similar benefits. Lab research suggests that chemicals in feverfew thwart production of hormone-like molecules called prostaglandins, believed to be a factor In many migraine attacks.

The caveats: Larger studies would clarify feverfew's role in treating migraines. It does not appear to diminish the duration of migraine attacks. Quitting this herb may cause rebound headaches, as well as nervousness, insomnia and other symptoms. Feverfew may also interact with drugs used to prevent blood clotting and with iron supplements.

Fish Oil

Rating: **

The claim: It reduces the risk of heart disease and eases symptoms related to some forms of arthritis and depression.

The evidence: One study found that people who eat fish at least once a week are half as likely to suffer sudden cardiac death. Fish oil appears to prevent blood clots and, at doses up to six grams per day, may also reduce levels of triglycerides, blood fats associated with an increased risk of heart disease. A few small studies suggest that taking fish-oil pills may allow patients with rheumatoid arthritis to decrease drug dosage. Preliminary research hints that the supplements may also help control bipolar disorder (manic depression).

The caveats: There is little evidence that taking these supplements offers benefits you would not get from eating salmon or other fatty varieties of fish a few times a week. People who take blood-thinning drugs should not use fish-oil pills.

Folic Acid

Rating: ***

The claim: Taken before and during pregnancy, this B vitamin prevents birth defects that can result in diseases of the skull and spine, such as spina bifida.

The evidence: Two large studies published in the early 1990's found that women who took folic-acid supplements were up to 72 percent less likely to have babies with neural tube defects. Based on these studies, the U.S. Public Health Service recommends that women who may become pregnant should consume 400 micrograms of folic acid a day - preferably from foods such as chickpeas, spinach, and oranges but by supplement if necessary. Some evidence suggests that folic acid and other B vitamins could also reduce the risk of heart disease, but more study is needed.

The caveat: Very high doses of folic acid may mask a vitamin B-12 deficiency.

Educate yourself strictly on the type of diet you've decided on. Learn how to cook foods that are diet friendly, what foods you should avoid, etc. Think of a manner of exercise you feel you can "live with" right now. Even walking your dog for ten minutes a day is better than nothing is.

Ginger

Rating: *

The claim: Ginger is often taken in supplement form to prevent motion sickness and relieve nausea, particularly among pregnant women.

The evidence: A study published this year found that 90 percent of expectant mothers who took four 250-milligram capsules of ginger experienced less nausea and vomiting than pregnant women who took placebos. At least two studies suggest that taking ginger will reduce the risk of seasickness. In one, ginger was more effective than Dramamine.

The caveats: Other studies suggest that ginger may not prevent nausea and vomiting related to surgery and anesthesia. High doses might interfere with blood-thinning drugs such as warfarin, as well as medications that control blood sugar in diabetics. Some experts also question ginger's effect on fetal development.

Glucosamine and Chondroitin

Rating: **

The claim: These natural compounds (which are sometimes combined in one pill) are said to ease joint pain and stiffness caused by osteoarthritis, the most common form of arthritis.

The evidence: A scientific review for the National Institutes of Health analyzed 15 studies involving glucosamine and chondroitin - taken separately or together, in various dosages.

Caveats: Uncertain

Five Supplements to Avoid

Some dietary supplements have no proven value; others may be harmful. For either of these reasons and sometimes both, these potions are best left on the shelf.

Bee pollen: There is no proof that these exotic-sounding pills increase physical vigor and energy, as is often claimed.

Billberry: Extract of these berries supposedly improves night vision. But in a pair of studies published in the late 1990's, the men who took these supplements remained in the dark.

Ephedra: A review in The New England Journal of Medicine in 2000 found that this herb, widely used for losing weight and increasing energy, raises the risk of heart attacks and strokes.

Kelp: There is no scientific evidence to support the use of seaweed-based pills and powders. And because of their potentially high iodine content, they could cause thyroid problems.

Shark Cartilage: A book called Sharks Don't Get Cancer (Avery, 1992) promoted these supplements as a miracle cure. But sharks do get cancer, and there is no evidence that these pills fight the disease.