Individuals with high blood pressure or heart disease should avoid ephedra-free weight-loss products.

Scientists at the University of California, San Francisco, tested two products, Advantra Z and Xenadrine EFX, and found they increased the heart rates of healthy adult users by an average of 11 to 16 beats per minute -- an 18 percent jump over the normal 80 beats per minute.

In addition, Xenadrine EFX, which also contains high doses of caffeine, increased blood pressure by 7 to 12 percent (between 9-10 mm Hg), the researchers reported in the September issue of the American Journal of Medicine.

Same Adverse Effects?

"These findings indicate that ephedra-free dietary supplements could have some of the same adverse health effects associated with previously available ephedra products, such as Metabolife 356 and Ripped Fuel," lead researcher Dr. Christine Haller, an assistant professor of medicine at UCSF, said in a prepared statement.

According to the researchers, bitter orange extract has quickly replaced ephedra as a prime ingredient in weight-loss products since the latter was banned by the FDA in 2004 after its use was linked to health problems.

However, "consumers should be aware that ephedra-free dietary supplements have not been extensively tested for safety and the health effects are not well known," Haller said.

Synephrine, Zhi Shi

Bitter orange extract's main active ingredient is synephrine, which is used in drug formulations to treat low blood pressure and nasal congestion. Bitter orange is also known as the Chinese herbal medicine Zhi shi, used to treat gastrointestinal troubles.

Based on their findings, the UCSF team advise that individuals with high blood pressure, heart disease or any other pre-existing conditions that might be exacerbated by the supplements avoid ephedra-free weight-loss products.

More information: For more on maintaining a healthy weight, head to the Harvard School of Public Health.

(c) HealthSCOUT
(c) 2005 Daily News Central. All rights reserved.