Suspected adverse reactions associated with herbal products used for weight loss: spontaneous reports from the Italian Phytovigilance System

Overweight and obesity represent worldwide a rising health problem. In this context, dietary supplements and herbal preparations are often used as self-medication for weight loss. The aim of this study was to describe the safety profile of dietary supplements for weight control by analyzing spontaneous reports of suspected adverse reactions (ARs) received by the Italian Phytovigilance System, from July 2010 to October 2017. The suspected ARs were collected using an ad hoc reporting form, registered in a database at the National Institute of Health and evaluated by a multidisciplinary group of experts. The causality assessment was performed using the WHO-UMC system or the CIOMS/RUCAM score. In case of serious adverse reactions, a feedback is provided to the reporter by e-mail. Sixty-six spontaneous reports were collected. ARs involved cardiovascular system (26%), liver (14%), central nervous system (12%), skin (9%), gastrointestinal system (17%), thyroid (8%), kidney (4%), and other organs/systems (10%). In 64% of cases, the reaction was serious. Dechallenge was positive in 46 cases; three cases of positive rechallenge were reported. After the causality assessment, the association between the product intake and the adverse reaction was judged as possible in the majority of the cases (n = 43; 65%). The data collected confirmed the existence of safety concerns on herbal dietary supplements used for body weight control, mainly related to quality of products and their use as self-medication. In this scenario, spontaneous reports represent the only tools available to monitor safety of these products.