Survey Shows Multivitamins Do Not Reduce Mortality but Does it Matter?
[Posted on: Thursday, May 31, 2018] Dietary supplements such as multivitamins are regularly consumed by more than 50% of the population in the US but they may not have much effect on the prolongation of lifespan as shown by a study published this week. A group of nutrition experts conducted a meta-analysis of data from 179 randomized clinical trials conducted over 5 years (2012-2017) selected based on their endpoints and quality of data. The meta-analysis used incidence of cardiovascular disease, stroke and all-cause mortality as surrogate endpoints for increased lifespan in consumers. It was found that regular consumption of multivitamins, vitamins C, D, β-carotene, calcium, and selenium do not have any effect on the rate of cardiovascular disease and all-cause mortality. Folic acid, with and without vitamin B complex, was found to have moderate effect, while Niacin and antioxidant mixtures were found to increase the risk of mortality. Before you stop taking vitamin supplements we should point to a few flaws in this report. First, the authors selected published reports and not the full clinical study reports. So, the analysis is highly limited by the limited data included in a publication which would make any conclusions unreliable and superfluous. Second, despite the volume of data, it is hard to assume that the trials were conducted per the standards generally reserved for randomized controlled clinical trials. Almost all clinical studies with supplements would not require regulatory approvals or even IRB supervision; the gold standards for good quality research. Most such studies are conducted for marketing purposes and without much oversight, the data could be highly flawed leading to any conclusions flawed as well. Third, although 179 study reports may seem like a large number, the authors rejected 90% of the reports (179 were selected from a pool of 1496 reports) for various reasons. The authors took care to address bias in data selection but the fact that 90% of the published reports could not be used should give us a reason for pause. Lastly, and most importantly, the effect of vitamin supplementation is greatly influenced by the overall diet of an individual. All food contains vitamins, but the overall vitamin content of our diet is low, hence the need for supplementation. It is very hard, if not impossible, to pinpoint any clinical endpoint with consumption of supplements. The use of supplements is based on generalized science that since we lack certain ingredients in our diet, supplementation could be beneficial. To make any stronger arguments would be argumentative at best and hard to prove. That is why FDA and most regulators do not allow specific disease claims for any supplement. Only general health claims can be made. And that’s how it should be. So, don’t stop taking your vitamins; just remember supplementation is but one way to improve lifespans, adequate diet and regular exercise is equally important.
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