Industry Rebuts Bitter Orange Review

Industry Rebuts Bitter Orange Review

WASHINGTON--Members of the herbal industry are challenging thefindings of a research review published in Experimental Biology and Medicine(www.ebmonline.org), which questions thesafety and efficacy of Citrus aurantium (bitter orange). The ingredientis currently used in many dietary supplements as a substitute for ephedra.According to the researchers, from Georgetown University, use of C. aurantium,due to its synephrine content, has the potential to increase blood pressure andcardiovascular events, despite the lack of adverse event reports.

"The public and medical community should be concerned about the growinguse of C. aurantium without adequate data on safety and efficacy,"wrote one of the researchers, Adam Myers, Ph.D., in a news release about thestudy. Myers singled out possible adverse interaction of the ingredient'sflavonoids on the body's drug metabolizing mechanisms, which could increaseserum levels of some pharmaceuticals.

However, the American Herbal Products Association (AHPA), noted there iscontradictory research regarding the effect of C. aurantium on drugmetabolism. "This review mistakenly implies that bitter orange supplementsare likely to affect drug metabolism," said Steven Dentali, Ph.D., vicepresident of scientific and technical affairs with AHPA (www.ahpa.org)."The authors cite references for this effect from bitter orange juice,which is not relevant to the plant parts used in dietary supplements."

Dentali and Mark Blumenthal, founder and executive director of the AmericanBotanical Council (ABC) (www.herbalgram.org),also questioned the applicability of research on intravenous administration ofbitter orange or synthetic synephrine. Blumenthal noted injected synephrine andbitter orange have shown an increase in blood pressure, but oral dosage studieshave not. He added that while there is a need for scientific review of C.aurantium, the conclusions from this review are largely speculative.

Dentali agreed with Blumenthal's assessment. "There is one point onwhich we may all agree, and that is that more research on this herb would bewelcome," he said. "But critical interdisciplinary thinking--espousedby these authors--should begin with consideration of the ingredient thatconsumers are actually taking."