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Mini: Which types of supplements lead the pack for serious adverse events in the U.S.?

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One of the main ways to gather data about nutritional supplement safety is to monitor supplements after they come to market. In the U.S., the Dietary Supplement and Non-Prescription Consumer Protection Act requires that supplement manufacturers report any serious adverse events (SAEs) to the FDA within 15 days of finding out from customers or health care professionals. An SAE is technically defined in the Food, Drug, & Cosmetic Act as an event that “(r)esults in death, a life-threatening experience, inpatient hospitalization, a persistent or significant disability or incapacity, or a congenital anomaly or birth defect; or requires, based on a reasonable medical judgement, a medical or surgical intervention to prevent an outcome described above”. In short — SAEs are indeed serious!

A team of researchers took advantage of the requirement for supplement manufacturers to systematically collect and report SAEs by monitoring the SAEs reported to two large supplement manufacturers based in the U.S. over 2.5 years. They did this in order to determine which supplements caused the most problems, what kinds of problems were caused, and to get an estimate of how many of the problems supplements caused were major ones. Their findings were published[1] in December of 2018.

Around 41,000 adverse events were reported over the 2.5 years monitored by the researchers, and around 0.5% of these were SAEs. Since we don’t know how many people took the supplements, it’s hard to say how common adverse effects were overall. However, this study does allow an estimation of what types of supplements are most linked to serious adverse effects, and how those effects usually manifest. In the table below, we summarize the main findings for the top three supplements linked to SAEs.


This study can’t tell exactly which ingredients were the main culprits, in part because many of these supplements are combinations of several ingredients. However, one clear take-home message is that weight and fat loss supplements are the biggest offenders as a class, accounting for around 70% of all serious problems.

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See other articles in Issue #50 (December 2018) of Study Deep Dives.

Other Articles in Issue #50 (December 2018)