Gesundheitliche Risiken von Synephrin in Nahrungsergänzungsmitteln

Abstract

Synephrine is a sympathomimetic phenylethylamine derivative that occurs naturally in citrus fruits. It is often added to dietary supplements intended for weight loss and enhancement of sports performance, typically in the form of Citrus aurantium extracts and in many cases in combination with caffeine. The health risks of synephrine were evaluated on the basis of the available toxicological data and in accordance to the EFSA guidance on the safety assessment of botanicals and botanical preparations intended for use in food supplements. In animal studies, orally applied synephrine induced adrenergic effects on the cardiovascular system (increase of blood pressure, ventricular arrhythmias), which were enhanced by the concomitant application of caffeine as well as physical activity. Some human intervention studies investigating the acute effects of synephrine on blood pressure and heart rate of healthy, normotensive test persons indicate that synephrine can induce cardiovascular effects in humans. A series of published case reports of adverse cardiovascular effects (hypertension, cardiac arrhythmia, myocardial infarction) were associated with consumption of synephrine- and caffeine-containing dietary supplements. In conclusion, consumption of high amounts of synephrine, especially in combination with caffeine and physical exercise, is associated with an increased risk of adverse effects on the cardiovascular system. According to the assessment by the BfR (Bundesinstitut für Risikobewertung), daily intake of synephrine through dietary supplements should not exceed the median intake from conventional foods.

Suspected adverse reactions to performance enhancing dietary supplements: Spontaneous reports from the Italian phytovigilance system

“…Nevertheless, some considerations about the suspected product can be done. Some of its components, caffeine, synephrine, green tea, and thyroid hormone, can be responsible or have contributed to the reported AR (Bakhyia et al, 2017;Vargas-Uricoechea, Bonelo-Perdomo, & Sierra-Torres, 2014;Wolk, Ganetsky, & Babu, 2012). Moreover, thyroid hormones, aspirin and synephrine, are not allowed in food supplements, according to the current legislation.…”

Contaminants: a dark side of food supplements?

“…This phenylethylamine derivative with sympathomimetic action is present in weight loss and sports performance enhancement supplements prepared from bitter orange (Citrus aurantium) [165]. However, consumption of high amounts of synephrine also presents adverse cardiovascular effects concerns, especially in the common association with caffeine [166]. Therefore, the combined effects of different naturally occurring substances, illegal pharmaceutical ingredients or both, in weight loss supplements may have risks that should not be underestimated.…”

Getting More Than You Paid For: Unauthorized “Natural” Substances in Herbal Food Supplements on EU Market

“…It was demonstrated that C. aurantium and p-synephrine may increase resting metabolic rate and energy expenditure, lipolysis, and breakdown of fat during rest, as well as decrease weight when given for 6-12 weeks [68,75,76]. However, the growing use of synephrine-containing products has been accompanied by numerous reports of cardiac adverse events, such as thrombosis, coronary spasm, hypertension, tachyarrhythmia, variant angina, cardiac arrest, QT interval prolongation, ventricular fibrillation, myocardial infarction, and even sudden deaths [68,70,71,[77][78][79][80][81]. Similar to a case of an ephedrine-containing FS [82], a weight-loss FS with synephrine was suspected to be the cause of severe exercise-induced rhabdomyolysis in a young male.…”