Dietary supplement use does not cause development of eating disorders (ED), and the vast majority of studies attempting to link supplements and ED are poorly designed and conflate dietary supplements with laxatives, illegal drugs, and other harmful products, according to a review published in Nutrients.

The review was written by Susan Hewlings, PhD, RD, a science consultant in the dietary supplement, CBD, and cannabis industries who serves as vice president of research at Radicle Science, and co-founder of Substantiation Sciences.

This review comes at a time when a wave of state bills have been introduced in the legislative branches of mostly Democrat-controlled states including New Jersey, Rhode Island, New York, California, Colorado, Missouri, Maryland, and Massachusetts. Bills this year in Maryland and Colorado were unsuccessful, while proposals in California and New York are still pending. No states have yet passed legislation to restrict the sale of either weight loss or muscle-building products.

Each of these states has introduced legislation modeled after recommendations by STRIPED (Strategic Training Initiative for the Prevention of Eating Disorders), an organization associated with Harvard University which has sought for years to ban the sale of “over-the-counter diet pills” and “muscle supplements” to children, per its advocacy playbook.

Risk Factors

Hewlings’ review discussed the risk factors for clinically-diagnosable eating disorders which had the strongest statistical power. Psychological, genetic, biochemical, environmental, and sociocultural factors outweigh all others, and more often than not, eating disorders manifest alongside other comorbidities such as depression, anxiety, and obsessive compulsive disorder.

According to the review, behaviors which have the most significant risk factor for disordered eating do not include the use of dietary supplements. Risky behaviors may include the use/abuse of laxatives and prescription diuretics, the use of nicotine, exercise fixation, self-induced vomiting after eating, the maintenance of unrealistic beauty standards, irrational and maladaptive beliefs about body fat, and harsh self-criticism, Hewlings wrote.

“To point to any one factor, whether it’s access to dietary supplements or anything else, is completely remiss,” Hewlings told Nutraceuticals World. “The etiology and risk factors for eating disorders are complex and multi-dimensional. Decades of research, including that which is supported by STRIPED and other activist organizations, goes against the notion that any one factor is directly causative of eating disorders. So that’s the first issue that comes to my mind when it comes to these claims.”

Most of the studies cited by STRIPED are retrospective surveys. Based on the methodology, these studies cannot establish causality, Hewlings noted. Since participants in these studies were already diagnosed with ED at baseline, a study can confuse a symptom, which occurs as a result of ED, with a risk factor, which occurs before ED. “It is reasonable to state that the abuse, not use, of some supplements may be a sign or symptom of an eating disorder, but not a risk factor,” Hewlings wrote.

She noted that the evidence supporting a therapeutic role dietary supplements in the treatment of ED is substantial. “The use of supplements is supported by the Academy of Nutrition and Dietetics’ protocol for eating disorder treatment, and in practice, meal replacements, protein shakes, and other products are very helpful for patients who still have a lot of negative experiences with eating,” Hewlings said. 

What’s a ‘Diet Pill?’

Multiple studies cited by STRIPED, and age restriction bills, consistently use the term “diet pill.” When definitions are provided, this is a reference to dietary supplements, laxatives, diuretics, stimulants, anabolic steroids, and other types of illegal products purchased from disreputable online vendors.

This definition, when used in clinical studies, makes it impossible to quantify the use of supplements, versus other aforementioned ‘diet pills.’ “I can only speculate as to why this is being done, as Bryn Austin [director of STRIPED] and others know the difference,” Hewlings said.

“These researchers surveyed participants already diagnosed with eating disorders, and asked them if they’ve ever used a ‘diet pill,’ without being specific to dietary supplements,” Hewlings said.

She noted that in her years of experience as a dietitian working with clients suffering from eating disorders, the abuse of diuretics, laxatives, and ipecac is a major problem for practitioners treating ED. However, dietary supplements are a completely separate category of products from over-the-counter drugs, with completely different safety profiles.

“This is the faulty way in which they’re attempting to create a causative relationship,” Hewlings said. “If you’re genuinely looking to establish a cause and effect relationship when it comes to lifestyle-disease relationships, you need serious statistical power, as seen in studies such as the Nurses’ Health Study. It’s important not to oversimplify extremely complicated relationships […] With that said, it’s interesting that Harvard University, which is reputed for strong, credible research, continues its affiliation with STRIPED.”

This conflation is occurring with muscle-building products as well, Hewlings noted. In claims made by Austin and others regarding teens with muscle dysmorphia, whey protein, amino acids, and other supplements are characterized as being part of a category that includes anabolic steroids, stimulants, selective androgen receptor modulators (SARMs), and other experimental drugs. 

Evidence is Outdated

Hewlings noted that studies cited by STRIPED in its advocacy for age restriction bills are at least 20 years old. “When they’re making claims about what teens are doing using this old research, they’re referring to an entirely different generation. Current surveys show that ‘diet pill’ usage is consistently going down.”

In 2022, high school students reported using “diet pills” at the lowest levels ever recorded (1.6%, within the past 12 months) compared to highs of 21% reported in 1982. The National Health and Nutrition Examination Survey (NHANES) found that one third of adolescents used a dietary supplement, with the most common being multivitamin/mineral (17.3%), vitamin D (5.4%), and vitamin C (4.2%). No weight loss or weight gain supplements were identified as used most often by adolescents.

Another study mentioned in Hewlings’ review, which utilized NHANES data spanning 1999-2016, found that of all non-vitamin and non-mineral supplements, the most common were omega-3s and probiotics. In this study, the two most common motivations for use were “to maintain health” and “to improve overall health,” with no reporting by this cohort that use was motivated by weight loss.

“While, according to Johns Hopkins Medicine, around one in 100 people have body dysmorphia, per the CDC, one in five children are affected by obesity. So it’s hard to see why we would want to put age restrictions on products that, if used as directed, in consultation with parents and healthcare providers, promote health and wellness,” said Steve Mister, president and CEO of the Council for Responsible Nutrition (CRN), which funded the review with a restricted grant to Nutrasource.

“Nobody is proposing we impose age restrictions on potato chips and soda, which we know are contributing to the much bigger problem of childhood obesity. The solutions to either of these complex issues is, unfortunately, not so simple,” he noted. 

Is Age Restriction the Best Use of Resources?

Enforcing an age restriction on dietary supplements, which would be a major personnel and financial burden for state agencies, isn’t supported as a priority by the clinical evidence on ED risk factors, Hewlings said.

STRIPED hasn’t been receptive to feedback from critics, Hewlings noted. But based on her discussions with state legislators, Hewlings said she is optimistic that there is room for negotiation with bill sponsors. For example, she had a recent discussion with New Jersey Assemblyman Herb Conaway Jr., who sponsored an age-restriction bill but eventually removed it from the docket in order to rework the language.

The lack of enforceability of these state bills also seems to be slowing them down. For instance, following feedback from trade associations, sponsors of the most recent age-restriction bill in California amended language to require the state’s department of health to create a list of supplements that would be subject to age restriction. Shortly after, Governor Gavin Newsom vetoed the bill, citing concerns about the lack of resources to collect evidence and identify a litany of banned products. Hewlings also noted that teens are most likely to shop online rather than at the brick-and-mortar retail locations these age restriction bills have been targeting.

“At any age, someone can develop an eating disorder, or body dysmorphia. We should direct the conversation away from age bans and toward the resources that we can provide people with before they develop an eating disorder. There is more effective research to use which has established the risk factors and etiology that would be valuable for screening and prevention programs,” Hewlings said.