There are surprisingly many people who take a multivitamin every morning. Satisfaction is even higher as it contains minerals. Expectations that it will prevent cancer and heart disease also play a role. But the reality is a little different.
A paper (“Multivitamin and mineral use: A rapid review of meta-analyses on health outcomes”) published online on the 24th of last month in the world-class international academic journal “Aging Research Reviews” shows that such expectations may be exaggerated. This is the result of a reanalysis of 19 meta-analyses published over a 25-year period from 2000 until recently, with a total of 5.53 million people’s data. First author Professor Weilan Wang of the National University of Singapore said, “There is no evidence that MVM (multivitamin + mineral) supplements reduce overall mortality, including cancer and heart disease.”
Cancer prevention effectiveness, mostly unproven
In conclusion, it was not effective in most cancers. In particular, there was little difference in breast and prostate cancer depending on whether or not multivitamins were taken.
The results of a large-scale cohort study conducted by the U.S. National Cancer Institute (NCI) that followed 390,000 U.S. adults for more than 20 years are the same. “Taking MVM daily did not lower the overall risk of death” (JAMA Network Open, June 26, 2024).
In this study, however, there were studies that showed that the risk of developing colon cancer was about 8% lower. However, the researchers added the caveat that “if it is only to that extent (8%), the effect is limited.” This means that the effect is minimal compared to the sincerity of taking it every day.
The effect of preventing cardiovascular diseases such as heart disease and stroke has not been confirmed. In the study of about 390,000 people mentioned above, taking multivitamins every day did not reduce the risk of death from heart disease or stroke, nor did it show any effect in extending lifespan.
Mineral supplements are not ‘all-purpose’ either.
The situation was not much different for mineral supplements taken separately for each disease. Little preventive effect was confirmed in ‘healthy’ general adults. If you are already consuming enough minerals such as calcium, magnesium, and zinc through a balanced diet, eating more will not increase your benefit.
However, results showed that it may be of some help in the elderly or those with nutritional deficiencies. In particular, in the case of eye health supplements, the results were mixed. Ordinary multivitamin or mineral supplements did not improve vision, and some analyzes showed concerning results related to macular degeneration. In fact, there are cases where it increases the risk of macular degeneration.
However, this does not mean that ‘all eye supplements are useless.’ There is ample evidence that clinical formulas (special combinations of vitamins and minerals) such as AREDS and AREDS2 for patients with macular degeneration slow the progression of the disease. This means that it is only effective when combined with a specialized prescription for the disease, rather than a general eye nutritional supplement.
Why do you feel that “taking vitamins is effective”?
Nevertheless, many people feel that their condition has improved by taking multivitamins. Researchers explain this as the ‘healthy user effect’.
People who take supplements tend to be more active in managing their health, such as diet, exercise, and regular check-ups. In these cases, the effects of MVM or individual supplements may appear larger than they actually are. It is a kind of ‘optical illusion’ phenomenon.
The United States Preventive Medicine Recommendation Organization (USPSTF) also concluded, “There is no sufficient evidence for the general adult to take multivitamins or minerals for the purpose of preventing cancer or cardiovascular disease.” This is not a recommendation to ‘not take’ the drug, but rather means to be wary of excessive expectations about the preventive effect.
In the end, you must first ask ‘Do I need it?’
In the end, multivitamins are neither a panacea nor a completely useless option. It can definitely be helpful if you are elderly or have irregular meals and may be deficient. However, if healthy people vaguely expect to prevent cancer or heart disease, it may be difficult to achieve the desired effect.
This is why Professor Andrea Maier, a world-renowned researcher in the field of aging and preventive medicine, said, “The value of multivitamins varies greatly depending on an individual’s age, health, and nutritional status.”
The core of the debate surrounding multivitamins is simple. It’s not about whether to eat or not. The first thing to consider is whether I really need multivitamin and mineral supplements.