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

As the population in the industrialized world develops preference for what is perceived as a natural and holistic way of disease treatment, the popularity and the number of food supplements on the market, including herbal ones, is experiencing an unprecedented rise. However, unlike herbal medicinal products, intended for treating or preventing disease, current legislation classifies food supplements as products intended for achieving nutritional or physiological effect and to supplement the normal diet. Accordingly, most food supplements are not to be associated with specific health claims. However, either due to the subtle suggestions by the producers or the wishful thinking of the consumers, certain pharmacological effects from food supplements are often expected. Medicinal plants included in food supplements usually do not produce dramatic and instant pharmacological effects. Therefore, in order to meet the expectation of their customers, some producers have turned to the illicit and dangerous practice of adulterating their products with synthetic adulterants, including naturally occurring molecules, having the desired activity. Such practice is prevalent in, although not limited to, food supplements intended for use as weight-loss aids, as well as for sport performance and libido enhancement. The review is focusing on naturally occurring alkaloids, phenylethanolamines, and their semi-synthetic derivatives in food supplements in the European Union as reported by the Rapid Alert System for Food and Feed. Their desired and undesired pharmacological effects, as well as the methods for their detection and quantification in food supplements, will be reviewed.