An analysis of supplement adverse events found that less than 1% of them were serious in nature. The research, which was sponsored by an industry trade group, comes despite a 2015 study that found more than 20,000 emergency visits each year are due to supplement adverse events and indications the true number of events are under-reported.
Researchers examined 41,000 adverse event reports related to supplements made by two manufacturers. The study was conducted by Supplement Safety Solutions, a safety consulting firm to the supplement industry, and the Council for Responsible Nutrition. The latter is a trade association and lobbying group for supplement manufacturers.
Results, published in the Journal of Dietary Supplements, found 0.48% of the adverse events were considered serious. More than two-thirds of those serious adverse events were in supplements marketed for weight loss. About 20% were for products purporting to help with glycemic (sugar) control.
The most common symptoms associated with the serious adverse events were dehydration, dizziness, headache, nausea and vomiting.
A 2018 study analyzing adverse events from supplements reported to the FDA over a 10-year period found serious outcomes included deaths, hospitalizations, life-threatening conditions and birth defects. It also estimated that the dietary supplement adverse event reporting rate is only about 2%.