Multiple Dosing of Ephedra-Free Dietary Supplements: Hemodynamic, Electrocardiographic, and Bacterial Contamination Effects

Department of Dietetics and Nutrition, College of Health Professions University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
Clinical Pharmacology &#38 Therapeutics (Impact Factor: 7.39). 12/2012; 93(3). DOI: 10.1038/clpt.2012.241
Source: PubMed

ABSTRACT Four popular ephedra-free dietary supplements were evaluated for their effects on heart rate (HR), blood pressure (BP), and electrocardiographic (ECG) parameters. Twelve healthy men participated in a study randomized for product sequence, with a 21-day washout period between supplement-administration phases. Throughout the study, Holter monitors were used to assess ECG and HR activity. BP was assessed automatically on multiple occasions. The supplements were ingested three times daily for 3 days. Caffeine content, microbial load, and serum caffeine concentrations were determined. Mean systolic (SBP) and diastolic BP (DBP) readings showed significant increases relative to baseline (10.8 ± 2.5 and 5.3 ± 3.1 mm Hg, respectively; P < 0.05). All supplements significantly increased HR and decreased bradycardia runs; abnormal atrial/ventricular events were frequently noted. Gastrointestinal and sympathomimetic symptoms were also common. Two supplements were heavily contaminated with Bacillus species. In light of these findings, the use of ephedra-free dietary supplements should be discouraged in individuals with hypertension, diabetes, or other cardiovascular diseases.Clinical Pharmacology & Therapeutics (2013); advance online publication 30 January 2013. doi:10.1038/clpt.2012.241.

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    ABSTRACT: The findings regarding cardiovascular actions of dietary supplements labeled as "ephedra free" reported by Foster et al. in the March issue reaffirm decades of research that began in the 1920s with K.K. Chen's study of naturally occurring adrenergic chemicals. Although the study by Foster et al. provides scientifically sound data needed by the US Food and Drug Administration (FDA) as it evaluates the safety of these products, we should ask, "Why was it necessary that these chemicals be studied again for their cardiovascular actions in humans?"
    Clinical Pharmacology &#38 Therapeutics 04/2013; 93(4):297-9. DOI:10.1038/clpt.2013.15 · 7.39 Impact Factor

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