Vitamins are vital organic substances necessary for the normal functioning of the human body. According to the Russian Ministry of Health, 40-50% of people aged 50 and older regularly take vitamin supplements. In 2009, total sales of food additives in the United States totaled approximately $ 27 billion. In 2010, despite the economic downturn, this number increased by 4.4%.
Do healthy people really need multivitamin preparations and minerals? The results of large-scale studies over the past 2 decades have been able to answer this question.
How useful are vitamins and minerals to healthy people?
The combination of selenium, α-tocopherol and β-carotene, as previously believed, reduces overall mortality by about 10%. However, studies were conducted in areas where micronutrient intake was quite low.
Until 2018, several reviews were published on the use of vitamins in the prevention of diseases in healthy people. Almost everyone came to the disappointing conclusion: "Vitamins are useless."
A JAMA scientific review concluded that folates, contrary to misconceptions, did not have a significant impact on overall mortality.
Paradox: are vitamins harmful?
A scientific analysis of American university research concluded that vitamins are not only useless to healthy people, but also harmful. Calcium with vitamin D increases the risk of cardiovascular disasters, especially myocardial infarction.
The World Cancer Research Foundation recommends no nutritional supplements.
A study of alpha-tocopherol and beta-carotene showed the first convincing evidence of the harmful effects of vitamins in 1994. Scientists have found that β-carotene increases the incidence of lung cancer by 18%. Total mortality increases by 8%, mainly due to an increase in mortality from coronary heart disease. α-tocopherol did not significantly change the risk of developing lung cancer.
Treatment with β-carotene, vitamin A, and vitamin E may increase overall mortality. The potential role of ascorbic acid and selenium in increasing mortality requires further research.
Despite a good research methodology and large sample size, the results were met with strong skepticism. They were considered incompatible with some previously published experiments, on the basis of which vitamins were started to be prescribed uncontrollably.
Several accompanying letters from scientists pointed to potential research flaws. However, the results of subsequent tests using other vitamins have not confirmed any benefit.
The most recent reviews by scientists have shown that vitamin E can increase the risk of developing prostate cancer among healthy men.
Are vitamins harmful to everyone?
Scientists emphasized that these findings relate to a healthy population and the prevention of chronic diseases. In special cases, patients may need vitamins or supplements.
Folic acid supplementation during pregnancy significantly reduces the risk of neural tube defects in the fetus.
Iron-containing foods can significantly reduce the risk of anemia and maternal complications. Also, these findings do not deny the potential health benefits of eating fresh fruits and vegetables.
Why do people use vitamins and believe in their effectiveness?
The significant beneficial effects of vitamins on the prevention of pellagra, rickets and scurvy have played a role in their distribution. Until the 1990s, some prominent scientists strongly advocated the use of vitamins. Linus Pauling, a two-time Nobel Prize winner in chemistry, recommended taking multivitamin supplements to cancer patients.
Despite the negative research results, a positive opinion about vitamins remained in the media.
In the long run, vitamins can slightly increase the risk of cancer and cardiovascular disease. However, in the short term, they do no harm.
The main benefits of vitamins are pharmaceutical companies that regularly release commercials about their benefits.
