Washington, D.C.—A study published in BMJ Open came to the conclusion that multivitamins and multimineral (MVM) products result, not in improved health, but in the perception of improved health. The Council for Responsible Nutrition released a statement decrying the “many limitations and shortcomings that hinder this study,” noting that MVMs are intended to fill gaps in nutritional intake.
The study was a cross-sectional analysis performed on 21,603 participants in the 2012 National Health Interview Survey. It found that among 4,933 adult MVM users and 16,670 people who did not take MVMs, those who took MVMs self-reported 30% better overall health than non-users. The researchers measured rates of 10 chronic diseases, the number of present health conditions, severity of psychological distress, and need for help with daily activities, and found no difference between those who took MVMs and those who did not.
The study concluded: “These results suggest that widespread use of multivitamins in adults may be a result of individuals’ positive expectation that multivitamin use leads to better health outcomes or a self-selection bias in which MVM users intrinsically harbour more positive views regarding their health.”
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In CRN’s statement, Andrea Wong, Ph.D., SVP, Scientific & Regulatory Affairs, CRN, stated: “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 the survey, or even how long the subjects had previously been on their regiments. 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.”
Dr. Wong went on to note that the purpose of an MVM is not, in fact, to treat or prevent chronic disease, but to fill in what is missed in the diet. “The primary role of a multivitamin is to fill nutrient gaps and to ensure the public gets the recommended levels of nutrients essential to everyday life. Government data repeatedly demonstrates that Americans fall short in getting the appropriate amount of essential nutrients they need. For example, the 2020 Scientific Report from the Dietary Guidelines Advisory Committee identified vitamins A, C, D, E, and K, calcium, magnesium, dietary fiber, choline, and potassium as under-consumed nutrients. 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.”
Dr. Wong pointed out that many of the nutrients in which Americans are deficient can be found in most multivitamin products. She concluded: “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.”