The following information is a list of the most promising supplements, the reasons they show promise and the rating they receieved for effectiveness.
- 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
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
The claim: Herbalists recommend supplements made from the evening primrose 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.
The claim: Feverfew 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 (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 headache 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.
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: Studies continue to see if taking these supplements offers the same benefits you get from eating salmon or other fatty varieties of fish a few times a week. Results thus far are encouraging but some health professionals remain skeptical. IMPORTANT: People who take blood-thinning drugs should not use fish-oil pills. See also: Fat Content in Fish
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.
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.
Glucosamine and Chondroitin
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.
Five Supplements Under Consideration
Some dietary supplements have no value for some while not for others and further studies/proof may be underway; 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.
- Bilberry: Extract of these berries is said to improve your night vision. Studies published in the late 1990's say the men who took these supplements received little to no benefits.
- 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. The U.S. has since banned its use.
- 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.
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