Research published in the British Medical Journal this week has attracted headlines in the consumer media. However, experts have questioned the validity of the study, Self-reported health without clinically measurable benefits among adult users of multivitamin and multimineral supplements: a cross-sectional study.
Several limitations in the research have been cited including by Andrea Wong, PhD, senior vice president, scientific and regulatory affairs from the US's Council for Responsible Nutrition (CRN), who called the research a "disservice to the public."
Several research shortfalls have been identified in a recent study on the multivitamins
A significant nutritional shortfall exists
Numerous studies, including the largest study in Australia to date by the CSIRO, have found that most of us do not consume enough vegetables and fruits. The Australia's Health (2018) report supports this which found that more than 99 per cent of children and 96 per cent of adults don’t eat the recommended intake of five serves of vegetables a day.
These provide multiple vitamins including A, C, D, E and K, minerals such as calcium, magnesium potassium and fibre. All of these are deficient in the Standard Australian diet.
Convenient and affordable
Over 145,000 adults were surveyed, and CSIRO found only 24 per cent of women and 15 per cent of men were consuming the recommended five vegetables and two fruits daily. Encouraging people to consume adequate vegetables and fruits is the preferred course of action. However, since a nutritional shortfall exists in most people, there is a strong justification for the valuable role of multivitamins and mineral supplements in filling these nutrient gaps.
Most multivitamin products contain many of the shortfall nutrients identified. Taking a multivitamin is a convenient and affordable way to ensure consumers get the nutrients they need. Multivitamins and minerals are not – and never have been – intended to prevent or treat disease (except in the case of folic acid in the prevention of neural tube defects in pregnancy).
- Several research shortfalls have been identified. These include:
- All measured outcomes are self-reported and therefore, less reliable.
- The results of the study are based on survey data and have not been determined individually by a clinicia.n
- The researchers did not measure the duration or frequency of multivitamin consumption.
- There is no information about the kind of products used. There is a wide variety of multivitamins and mineral supplements, including those based on age and gender. Thus, the researchers were casting an extensive net by suggesting they are a uniform product with uniform ingredients. Such a product does not exist
- The cross-sectional design of this study only provides a snapshot in time of multivitamin use and health outcomes and this prevents any determination of causality. In other words, it does not have a before or after. The only way to follow subjects is through a longitudinal study.