It is logical to think that multivitamins could be beneficial. After all, vitamins and minerals are essential to life and experts always point out that everyone should take multivitamins irrespective of age. However, In December, two studies in Annals of Internal Medicine failed to find benefits from such supplemental pills. The first trial, part of Physician's Health Study II from Harvard, involved nearly 6000 men over 65 years of age who were given a standard daily dose of Centrum Silver or placebo for more than a decade. Periodic cognitive testing found that the multivitamins did not slow age related declines.
The second study, involved 1700 people across U.S and Canada who previously had a heart attack. They were randomized into two groups and were given multivitamins and placebo. Over an average of five years, the risk of second heart attack or other cardiovascular events was the same in both groups. However, many subjects did not stick to the regimen and withdrew early.
In 2012 another clinical trial which was also a part of Physician's Health Study II, involving 14,600 men over 50, found that multivitamin supplements if given for 11 years will reduce cancer risk. There was no positive effect observed on cardiovascular diseases. Similarly another study used a 5-ingredient multivitamin trial showed small reduction in cancer risk in men. None of these results were statistically significant.
In conclusion, the general public should not routinely take a multivitamin supplement. Vitamins should be used to treat a diagnosed vitamin deficiency (scurvy, beriberi) or to prevent a deficiency in a pregnant or breast feeding woman or someone on a strict diet eg for weight loss or is vegetarian. Certain vitamins, especially in high doses or in combination with other drugs may actually be harmful instead of helpful.
Posted by: Kamaldeep Kainth, PharmD candidate 2015