The Council for Responsible Nutrition (CRN) recently denounced a study published in the British Medical Journal called “Self-reported health without clinically measurable benefits among adult users of multivitamin and multimineral supplements: a cross-sectional study.” The trade association, which represents the dietary supplements industry, believes that because of the study’s limitations, the conclusions its authors reached are providing a “disservice to the public.”
 
The study’s objective was to determine why multivitamin and mineral (MVM) supplement users continued to use the products, in light of some clinical trials which have failed to achieve clinical significance in the health benefits being assessed. The researchers surveyed 4,933 adult MVM users and non-users alike who participated in the National Health Interview Survey in 2012, in an effort to determine their self-reported health outcomes as well as potential disease outcomes they had. The survey included a self-rated health status, whether the participants needed help with routine needs, reporting on history of 10 chronic diseases, reporting on the presence of 19 health conditions in the past 12 months, and the Kessler 6-item Psychological Distress Scale to measure psychological distress in the past month.
 
The researchers found that MVM users self-reported 30% better overall health than non-users, despite there being no significant differences between MVM users and non-users in the following survey measurements of diseases and psychological distress.
 
“Our finding that MVM users and non-users do not differ in various psychological, physical, and functional outcomes corroborates previous reports that MVMs do not improve overall health in the general adult population,” the authors of the study concluded. “The results here suggest two potential explanations underlying widespread MVM consumption in the absence of clinically measurable benefits: MVM users believe in the efficacy of MVMs by harboring a positive expectation regarding the health benefits of MVMs; and MVM users intrinsically harbor a more positive outlook on their personal health regardless of MVM usage. A growing body of evidence suggests that positive expectation influences treatment outcomes for diseases including heart disease, cancer, musculoskeletal disorders, injuries, and obesity.”
 
CRN Reacts
Andrea Wong, PhD, senior vice president of scientific and regulatory affairs at CRN, discounted the study, based on both the unreliability of self-reported health measurements and the fact that the trials cited by the authors which failed to show clinical significance far from reflect the overall body of research on dietary supplements; and the survey didn’t reflect the types of supplements participants used, nor did it measure the frequency or duration of usage.
 
“The multivitamin continues to be one of the most popular dietary supplements among Americans and plays an important role in promoting and preserving good health, and for good reason. CRN stresses that these findings of the recent study in no way discount the multivitamin’s many benefits in combatting insufficient nutrient levels and promoting optimum health, nor does it provide basis for consumers to reconsider their decision to take a multivitamin or to take one in the future,” Wong said.
 
“The many limitations and shortcomings that hinder this study must be taken into account, only some of which are acknowledged by the study’s own authors. For instance, the results of the study are based on survey data, so rather than being determined by a clinician, all measured outcomes are self-reported and therefore less reliable. The study also does not capture the composition of the multivitamin or multimineral products reported by respondents, or the duration or frequency of consumption. It is impossible to know which products were taken or how often respondents took them over the 12-month period covered by this survey, or even how long the subjects had previously been on their regimens. Additionally, the cross-sectional design of this study only provides a snapshot in time of multivitamin use and health outcomes, preventing any determination of causality.”
 
CRN pointed to U.S. data from regulatory agencies which demonstrates nutritional deficiencies which are prevalent among Americans, such as the 2020 Dietary Guidelines Advisory Committee report – these deficiencies include vitamins A, C, D, E, and K, calcium, magnesium, dietary fiber, choline, and potassium as under-consumed to varying extents across demographics.
 
“To identify recommended levels of these nutrients to avoid deficiency, and then to acknowledge these shortfalls in many Americans’ diets, should alone be a strong justification for the valuable role that multivitamins and minerals can play to help meet those recommended levels when they are not met by diet alone,” Wong continued. “The conclusions of the study are a disservice to the public and should not influence consumers’ decision to take a multivitamin or other dietary supplement product. As data continues to show that Americans, particularly low-income populations, do not get the essential nutrients needed from diet alone, taking a multivitamin is a convenient and affordable way to ensure consumers get the nutrients they need.”