Recent review does not find causal link between dietary supplements and eating disorders

A recent review investigated the relationship between dietary supplements and eating disorders, finding no causal relationship between dietary supplement usage and the development of eating disorders. Certain groups such as the Harvard T.H. Chan School of Public Health’s Strategic Training Initiative for the Prevention of Eating Disorders (STRIPED) have attempted to link eating disorders with the usage of dietary supplements marketed for weight management. As a result, they have lobbied for legislation throughout the country that would restrict minors from purchasing weight management dietary supplements. The review was written by Susan J. Hewlings, PhD, who was director of scientific affairs of the contract research organization Nutrasource at the time, with funding from the Council for Responsible Nutrition (CRN; Washington, D.C.). The review addressed the flaws in the evidence used to justify the conclusion that dietary supplement usage can lead to eating disorders.

For example, many of the studies lump dietary supplements in with other over-the-counter drugs and adulterated products as “diet pills,” without providing a definition for what they mean by “diet pill.” One study cited by the review investigated the connection between “ergogenic supplement use and disordered eating attitudes and behaviors,” among 1633 university undergraduate students from 10 top-ranked National College Athletics Association (NCAA) Division I colleges. In the study, subjects completed a non-validated online survey on supplement use, athletic activities, and eating attitudes and behaviors.

“A major design flaw in this study is that illegal substances and prescription drugs such as anabolic steroids, human growth hormone, and androstenedione were grouped together with dietary supplements. These are not dietary supplements and are not sold under this regulatory classification,” wrote Hewling. And while the study found that “supplement use was associated with higher Eating Disorders Examination-Questionnaire (EDE-Q) Global, Shape Concern, and Restraint scores in both males and females,” Hewling points out that this does not represent a causal relationship, and studies such as this do not prove that supplements cause eating disorders but that dietary supplements may be abused by those with eating disorders. She acknowledges that the DSM-V states that “dependence on enteral feeding or nutritional supplements taken orally is a symptom or warning sign of an eating disorder, specifically Avoidant/Restrictive Food Intake Disorder,” but emphasizes that a warning sign is not a “risk factor,” which occurs before the associated outcome, increasing its likelihood.

“The key issue is not supplements, or specific ingredients, but the intent or behavioral drivers,” explained Hewling to Nutritional Outlook. “Dietary supplements could be compared to exercise. For example, if we looked only at time spent exercising, we could say any professional athlete engages in excessive exercise to compete at the top level. However, most engage in well-designed programs with plans for recovery and nutrition to support their endeavors. When one engages in the exercise with a focus on thinness or achieving a body ideal as opposed to achieving optimal health or performance that’s when a problem is likely. It is a fine line but there are some warning signs that separate eating disorder behaviors from health or performance behaviors.”

The fact is that eating disorders are highly complex, as are its triggers. However, Hewling pointed out in an interview that a well-documented aspect of eating disorders are cultural ideals of body image. This was once portrayed in advertising campaigns for clothing and beauty products but has since been exacerbated by social media that now finds people digitally manipulating the way the look via filters. There is also the issue of bullying that happens through online forums that can be intense and traumatic. It shouldn’t be ignored that dietary supplements have made their way into the discussion about eating disorders, in part, because teens on social media are seeing influencers market weight management products in ways that may set unrealistic expectations and trigger unhealthy behaviors. But, are dietary supplements the real problem here?

“This is a comprehensive cultural issue we are dealing with, so merely blocking access to some supplements to those under 18 isn’t based on the science as we know it,” said Hewling.