Ephedra-free dietary supplements could lead to potential health risks

12/09/05 Two common weight loss supplements promoted as ephedra-free and safe for dieters caused increased heart rate among healthy people, and could have harmful health effects in some people, according to a study by UCSF scientists. Their placebo-controlled clinical study is the first to examine the pharmacological effects of these re-formulated dietary supplements.

The research examined the effects on blood pressure and heart rate of two dietary supplements containing bitter orange extract- a substance that has rapidly replaced ephedra in weight-loss products since it was banned by the FDA in 2004 because of concerns about serious health effects.

The study involved 10 healthy adults given single doses of one of the two supplements or a placebo. The two supplements tested were Advantra Z and Xenadrine EFX. Single doses of both products increased heart rate by an average of 11 to 16 beats per minute over baseline, the scientists found. This would be the equivalent of an 18 percent increase if baseline rate is 80 beats per minute.

In addition, Xenadrine EFX also significantly increased blood pressure by 7 to 12 percent (9-10 mm Hg), the researchers reported. Xenadrine EFX appears to have similar acute cardiovascular stimulant actions as banned ephedra products, according to their report.

The scientists call for further research on the safety and effectiveness of bitter orange- containing supplements.

The research is published in the September issue of The American Journal of Medicine, available September 9.

Bitter orange extract, or Citrus aurantium, is extracted from the dried fruit peel of bitter orange. Known in Chinese herbal medicine as Zhi shi, it is a traditional remedy for gastrointestinal ailments, the scientists said.

The research is funded by grants from the National Institutes of Health.

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