Using Herbal Supplements? Use Caution, Too

Herbal supplements have grown into a $19-billion-a-year industry used by 60 million Americans. If you're one of them, how can you find out if your supplement works, or if it's safe?

Under the Dietary Supplement Health and Education Act of 1994, the FDA treats supplements as food. Unlike prescription and over-the-counter drugs, they can make it to market without proving purity, composition, effectiveness, or even safety. And they can stay there until the FDA proves them unsafe after reviewing complaints filed by doctors and consumers. This can—and does—take years.

Although 10 years after the supplement act was enacted, the FDA said it planned to adopt new policies on monitoring product and ingredient safety, it has not yet done so.

The National Institutes of Health is doing dozens of studies on supplements from magnesium to mistletoe to look at whether they really work. Supplements with proven value include ginger for nausea, saw palmetto for enlarged prostates, and St. John's wort for mild depression. But they share the shelves with products that have doubtful or "zero benefits," says Sheldon S. Hendler, M.D., an internal medicine specialist in San Diego and author of the Physicians' Desk Reference for Nutritional Supplements. Breast and penis enlargers fall in the worthless category, he says.

Mixed results

Other supplements show mixed results. Case in point: echinacea, the best-selling herb used to ward off colds. A blinded, placebo-controlled 2005 study in the New England Journal of Medicine reported that echinacea was of no value in preventing or treating colds. Studies of garlic, taken to lower cholesterol, have also had varied outcomes.

One reason is lack of standardization. A study may use different parts of an herb, or even different species, and that may affect outcomes. Some supplements may not offer the same herb or nutrient used in the study. The concentration of an herb in a supplement can vary, too, and a product may not even provide enough to make a difference. In a recent lab report that checked supplements of the antioxidant coenzyme Q10, one product didn't contain a drop of the substance.

While the government works to tighten the rules and gather evidence, consumers should be "open-minded skeptics," says Shawn Talbot, Ph.D., a nutrition expert and author of The Health Professional's Guide to Dietary Supplements. Here is his advice:

• Do your homework to see if a supplement is right for you based on your health status. Tell your doctor about all supplements you take. Talk with your doctor first if you're pregnant or nursing, take other medications, or have an illness such as heart disease, diabetes, or cancer.

• Don't fall for drivel and hype. Supplements can't claim to treat or cure with no proof. But they can use confusing "structure/function" claims like "supports the immune system" without a shred of evidence. Ask the maker for backup studies. Don't be fooled by a supplement touting a "breakthrough" or "instant results," Dr. Talbot says. Just because a supplement is labeled "natural" doesn't mean it's safe or effective.

• Look for a quality control seal. Supplements marked USP, NSF, or Consumer Labs guarantee that the contents match the label.

• Keep in mind that the active ingredients in many supplements aren't known, says the National Center for Complementary and Alternative Medicine. The contents of a supplement may differ from what's on the label, so you may be taking less or more of the supplement than what the label says.

Adding to supplement risks  

Supplements rarely come with package inserts that list side effects, contraindications, and interactions, so here are a few to ponder:

• St. John's wort may prompt sunburn and hinder birth control pills, heart drugs, and a host of other medications. It also may cause rejection of transplanted organ.

• Echinacea, a potential immune booster, could be risky if you're allergy-prone or have an autoimmune disease such as lupus.

• Iron supplements can lead to iron overload and possible cirrhosis, liver cancer, and heart disease in men and postmenopausal women.

• Ginger, gingko, garlic, fish oil, and coenzyme Q10 thin the blood and could reduce clotting in surgery, especially if you also take vitamin E, aspirin, or other blood thinners.

• Vitamin E, in excess, may actually increase cardiovascular risk, heart failure, and hospital admission for heart disease, in people with existing cardiovascular disease.