September 2005

‘Ephedra-free’ dietary supplements may pose risks

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 scientists from the University of California at San Francisco. 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. One of the study supplements contains only bitter orange extract, while the other supplement contains several other ingredients, including caffeine. 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 were 80 beats per minute.

In addition, the bitter-orange-extract supplement also significantly increased blood pressure by 7 to 12 percent (9–10 mm Hg), the researchers reported. The caffeine-containing supplement 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 — particularly among those most likely to take them: overweight people who may have other health conditions.

Source: University of San Francisco, www.ucsf.edu

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