Multivitamins and minerals took a blow recently, when the Annals of Internal Medicine published a seemingly definitive suite of articles, capped off with a controversial editorial declaring that multivitamins were ineffective in the prevention of chronic disease.
The three articles in the journal followed various populations. The first was a meta analysis that incorporated over 450000 people who had taken part in various studies. This research determined that multivitamin use did nothing to prevent heart disease or cancer, and that use of beta carotene supplements by smokers may, in fact, elevate the lung cancer risk.
The second article was a controlled study that followed 1700 people for five years, who had already had a heart attack, examining the rate of further cardiac episodes, and the influence of multivitamin supplementation on this statistic. The third was the result of a twelve year controlled study in men over 65 years of age, and it assessed the effect of multivitamins on cognitive decline.
In a climate where more than half of all adults in the United States (and likely other western populations) use multivitamins, these articles challenged the status quo, attracted a lot of attention, and a fair amount of criticism, a lot of it questioning the experimental design and the choice of population that were studied in these trials.
It has also opened a dialogue on the issue of multivitamin supplementation within the scientific community, and articles are now appearing that refute the claims made in the Annals of Internal Medicine. One of these is a rebuttal, published in the Nutrition Journal, which points out some of the issues overlooked by the Annals of Internal Medicine studies.
The author points out that while the trio studies looked at three of the major killers, it failed to collect data on many chronic conditions and quality of life issues that are more directly related to vitamin and micronutrient deficiencies. Just as the original studies collected data over many years, much of this research is still in progress, including promising investigations into different areas of cancer prevention, cognitive decline, and cataract formation.
The author points out that the average American diet may not necessarily resemble the diets eaten by the study participants, in terms of fruits, vegtables and whole grains, important sources of vitamins and minerals in the food. Study participants included cardiac patients, many of whom were using nutrition to mitigate their ongoing conditions, and medical professionals, who presumably possess the knowledge and financial ability to make healthier food choices.
For many people, it is argued, a multivitamin supplement is very useful. It is a simple and cheap way to ensure an adequate intake of micronutrients, where the diet is equivocal or lacking, or where there is uncertainty. While individual supplements can be used to prevent specific deficiencies, high multivitamin use in the population is thought to be very effective in the treatment and prevention of some of the more common and obvious vitamin and mineral deficiencies, incuding anaemia, osteoporosis, and neural tube disorders in pregnancy. It is possible that the instances of these conditions may increase if multivitamin use fell out of favour.
The trio of articles published by Annals of Internal Medicine represent a solid body of research conducted into some of the most serious and common diseases plaguing western medicine. Obviously, this generated a great deal of attention from the press, where this surprising finding was widely disseminated and potentially taken out of context. This rebuttal does not directly disagree, or outwardly reject the findings of the original researchers, rather, it points out that in many situations not within the scope of the trio of high profile studies, multivitamin use can be very beneficial. Vitamins and minerals are known to help with recovery from exercise, maximising muscle performance, bone and joint health, and immune function. This is further, valuable food for thought when considering whether or not you wish to take a multivitamin supplement.
Ward E. Addressing nutritional gaps with multivitamin and mineral supplements. Nutr J. 2014 Jul 15;13(1):72.