The Potential Dangers of Supplements and Herbal Products Marketed for Improved Thyroid Function

Victor Bernet; Ana-Maria Chindris


Expert Rev Endocrinol Metab. 2012;7(3):247-249. 

In This Article

Abstract and Introduction


The trend of using natural products has increased significantly in recent decades in the USA. A national health survey by the CDC in 2007 estimated that Americans spent US $34 billion on herbal supplements, chiropractic visits, meditation and other forms of complementary and alternative medicine, similar to the amount spent on prescription drugs.[101]

Recent CDC reports indicate that over 40% of the adult US population used dietary supplements between 1988 and 1994, and the number increased to >50% between 2003 and 2006.[102] These products have not been under US FDA regulation since the introduction of the Dietary Supplement Health and Education Act in 1994. General perception is that natural products/supplements are by definition safe, when in fact reports indicate that at least some of these products can interact with and/or alter the pharmacology of various prescription drugs. Furthermore, side effects have been reported secondary either to the actual ingredients or contaminants found in these types of preparations. Manufacturers are not required to prove the safety or efficacy of a dietary supplement before it is marketed. Product labels or advertisements are permitted to claim that a particular dietary supplement addresses a nutrient deficiency, supports health or is linked to improvement of a particular body function only if there is research to support the claim. Such a claim must be followed by the words: "This statement has not been evaluated by the US Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease".[103]

A significant percentage of these products target the overweight and obese population, and represent appealing choices as weight-loss aids. As the prevalence of obesity has increased dramatically over the past few decades, popular media has promoted thin figures as desirable; the 'slimming aid' industry is seeing an unprecedented growth in sales.


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