Editor’s Note: The following is an overview of the research provided by study author C. Michael White, professor of pharmaceutical practice at the University of Connecticut.
(The Conversation) — Many over-the-counter dietary supplements — especially those used for sexual enhancement and weight loss — are tainted with undisclosed pharmaceutical ingredients. This is the main conclusion of my recently published review in the Journal of Clinical Pharmacology.
My assessment of the Food and Drug Administration Healthcare Fraud Products Database 1,068 unique dietary supplement products marketed between 2007 and 2021 containing active ingredients found in prescription drugs or deemed too dangerous for use in humans. Of the contaminated dietary supplements my study identified, 54% were for sexual dysfunction and 35% for weight loss. While many such products are removed from the market once detected by the FDA, other contaminated dietary supplements may end up on the market in their place.
why is it important
Food supplements are used by 58% of American adults. And according to recent surveys by the Council for Responsible Nutrition, American consumers have a moderate level of confidence in the quality and safety of food supplements. However, my study suggests that this confidence is misplaced, as many dietary supplements contain unlabeled synthetic active ingredients.
So what are these hidden substances and why are they important?
The active ingredient sibutramine, which the The FDA has recommended removing from the US market in 2010 after research has shown that it increased the risk of heart attacks and strokes. And phenolphthalein, also commonly found in weight loss dietary supplements in the FDA database, was removed from over-the-counter laxative products in 1999. when the FDA reclassified it as “not generally recognized as safe and effective”. The FDA Warning came after studying showed that the ingredient can damage people’s DNA and increase the risk of cancer.
My study also identified the presence of ingredients approved only for use in prescription drugs. These include sildenafil and tadalafil, which are used in FDA-approved erectile dysfunction drugs like Viagra and Cialis. Such inadvertent uses can be dangerous because the active ingredients in these drugs come with risks such as loss of vision or priapism, or prolonged erection of the penis. My study also documented frequent cases in which more than one active ingredient found in erectile dysfunction drugs were combined in a way that had never been studied for safety.
Another reason hidden active ingredients are problematic is that they pose a risk of serious drug interactions. When the active ingredients found in erectile dysfunction drugs are used with high blood pressure or prostate drugs such as nitrates and alpha-blockers, life-threatening drops in blood pressure can occur.
Similarly, two of the dietary supplements identified in my study contained flibanserin, the active ingredient in Addyi prescription drug, which is used to treat female sexual dysfunction. Flibanserin is generally safe, but can significantly lower blood pressure if used with alcohol.
Pharmacists check for these types of drug interactions before dispensing prescription drugs. However, if undisclosed ingredients are hidden in dietary supplements, it is impossible to prevent adverse drug interactions.
What is not yet known
Dietary supplement manufacturers do not provide the FDA with evidence of good manufacturing practice before selling them in the United States, and these manufacturers may change their products without notice. The FDA must prove a dietary supplement product is unsafe before it can take action, but this is difficult to enforce when there are more 29,000 food supplements to be sold in the United States
FDA evaluations are laborious and expensive because these evaluations also seek to detect other dietary supplement issues such as the presence of heavy metals or bacterial or mold contamination. The agency’s process for evaluating these supplements is also deeply underfunded. FDA Alerts Consumers to Newly Detected Contaminated Dietary Supplements through its Healthcare Fraud Products Database while trying to remove these products from the market.
If the product you plan to use is on this list, avoid it. However, if your product is not included in the database, it may simply mean that it has not yet been reviewed.