Ephedra and Caffeine: A Dangerous Combination
]]>Ephedra]]> ...a few years ago, not many people knew much about this supplement, but now it seems to be making headlines frequently. Ephedra is touted as a weight-loss aid, in part because it raises a person’s rate of metabolism. Unfortunately, as products containing ephedra have grown in popularity, so has the controversy surrounding it.
The Food and Drug Administration (FDA) has accumulated reports of 155 deaths associated with ephedra use as well as more than 16,500 complaints about the supplement. In addition, several studies have called the safety of ephedra into question. In December 2003, the FDA decided to act and announced that it was banning ephedra—the first time the FDA has ever banned a dietary supplement.
The best selling ephedra-containing dietary supplement is Metabolife 356 (DESC), which contains ephedra and caffeine. A study published in the January 14, 2004 issue of The Journal of the American Medical Association looked at the metabolic effects of DESC on the cardiovascular system, including heart rhythm and blood pressure.
About the study
The study involved 15 healthy volunteers, all approximately 27 years of age, who were randomized to receive one dose of DESC or placebo. The study was double blind, meaning that neither the study participants nor the researchers knew who received DESC and who received placebo. Seven days after the initial dose, study participants returned for the second part of the trial and received the opposite treatment. Researchers measured systolic blood pressure and took electrocardiograms (ECG) before and one, three, and five hours after taking either the DESC or placebo.
The researchers were most interested in the part of the ECG called the maximum QTc interval, which measures the time between certain electrical impulses in the heart. Average QTc interval is about 380 milliseconds (ms). A longer QTc interval can increase the risk of arrhythmias, or abnormal heart rhythms, and interrupting the heart’s normal rhythm can be dangerous, even deadly.
Systolic blood pressure (SBP), the top number in the blood pressure reading fraction, is the pressure generated in the heart when it contracts. Most experts agree that a SBP less than 120 mmHg (millimeters of mercury) is most desirable.
On average, the group who took DSEC had significantly longer QTc intervals than the placebo group at every point after dosing. The average increases were 27.20 ms for the DESC group and 2.63 ms for the placebo group. Both the FDA and the European Center for Proprietary Medicinal Products have identified increases in QTc interval of as low as 30 ms as increasing the risk of arrhythmias.
The maximum SBP measurement was 4.8% greater in the DESC group than the placebo group. In addition, all patients taking the DESC reported nonspecific symptoms like jitteriness, queasiness, and “not quite feeling right.” None of the patients died or suffered serious complications.
In light of the increases in QTc interval and SBP caused by a single dose of DESC, the authors concluded that people should be advised to avoid dietary supplements that contain ephedra and caffeine.
How does this affect you?
While ephedra coupled with caffeine increased systolic blood pressure, the most significant finding of this study is that taking it can increase the risk of a heart rhythm irregularity. Now that the FDA has banned ephedra, it should be more difficult to locate ephedra-containing supplements. However, it will not be impossible. This study’s findings should make you think twice before trying ephedra in any supplement.
Another important point to draw from the study is that just because a product is made from natural ingredients like herbs, doesn't mean it's safe. Some of the most poisonous substances on earth, after all, are derived from plants. And the safety of even benign plant products cannot be guaranteed unless an agency like the FDA rigorously monitors and assesses its potential for harmful effects in humans. The FDA can make no such guarantees regarding any dietary supplement, including ephedra.
With few over-the-counter alternatives for weight loss, the public appeal of ephedra is understandable. At this point, however, most experts agree…it’s just not worth the risk.
Food and Drug Administration
National Library of Medicine: PubMed
American Heart Association (AHA). What are arrhythmias? AHA Web site. Available at: http://www.americanheart.org/presenter.jhtml?identifier=560 . Accessed on: January 13, 2004.
Marieb E. Human Anatomy and Physiology . 6th edition. San Francisco, CA: Pearson Benjamin Cummings; 2004.
McBride B, et al. Electrocardiographic and hemodynamic effects of a multicomponent dietary supplement containing ephedra and caffeine. JAMA. 2004;291(2):216-221.
Richwine L. US announces ban on ephedra supplement. Reuter Health Information. Available at: http://www.nlm.nih.gov/medlineplus/print/news/fullstory_15357.html . Accessed on: January 12, 2004.
Last reviewed Jan 16, 2004 by ]]>Richard Glickman-Simon, MD]]>
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