"The most important implication for the general public is that serious adverse events do occur (with) over-the-counter dietary supplements," Dr. Susan Smolinske, one of the study authors, told Reuters Health.

The side effects, if any, naturally vary with the supplement, added Smolinske, of Wayne State University in Detroit, Michigan.

In this study, she said, some of the supplements "more likely to be a problem" included ma huang, guarana, ginseng and St. John's wort, as well as products containing multiple active ingredients.

Ma huang, also known as ephedra, is an ingredient of some supplements touted for weight loss. The herb affects the cardiovascular and central nervous systems, and has already been linked to the risk of seizure, heart attack and sudden death, even in healthy people. The US Food and Drug Administration has issued an alert warning consumers against its use, particularly along with caffeine.

Guarana is another herbal stimulant used in some products sold as energy boosters and diet aids. Potential side effects include nausea, anxiety and irregular heartbeat. Both ginseng and St. John's wort can interact with certain prescription drugs. And heavy overdoses of ginseng have been reported to cause sleeplessness, muscle tension and swelling. Dietary supplement refers to a broad category of products that includes herbs, vitamins, minerals, amino acids and various traditional "remedies." Unlike drugs, these products are not evaluated by the US Food and Drug Administration for safety and effectiveness before hitting the market.

According to Smolinske and her colleagues, their findings suggest that dietary supplements require better surveillance--"particularly mandatory reporting of adverse events." In addition, they call for a comprehensive registry of dietary supplements so that information on their intended effects and side effects is easily accessible to poison control centers and others. Only about a third of the supplements reported to the centers were listed on the main commercial database that poison-control staff use.

The findings also "warrant concern" about the lack of child-resistant packaging on supplements, the study authors add. Among the reports of adverse symptoms were 48 cases involving children who accidentally took a supplement.

Ed. Note: Please remember, we do not endorse any treatments and strongly advise you to check with your doctor before using, stopping or changing any treatment

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