According to the findings of a group of Canadian scientists from the University of Toronto and St. Michel's Hospital, published in the Journal of the American College of Cardiology, daily use of vitamin and mineral supplements has little or no expected benefit.
The deficiency of certain nutrients obtained from food (vitamins, minerals and antioxidants) is often attempted to be replenished with the help of dietary supplements. Such additives do not undergo clinical trials, which is why they are not considered a drug, and their circulation is practically unregulated.
In a systematic review of more than a hundred previous studies conducted from January 2012 to October 2017, the researchers found that most popular multivitamin supplements containing vitamins C and D, as well as calcium, do not have any practical health benefits. In addition, the scientists note that they have not found any evidence that the use of vitamin supplements actually reduces the risk of developing cardiovascular disease, heart attacks, strokes or early death.
The only exception was folic acid, and to a lesser extent the complex of B vitamins, which have shown their usefulness in preventing the occurrence of diseases of the cardiovascular system, in particular stroke.
"We were surprised to find only a few of the beneficial effects of popular vitamin and mineral supplements," said Dr. David Jenkins, lead author of the study.
"Our research has shown that if you want to use a multivitamin, vitamin D, calcium or vitamin C, there will be no harm, but it turns out that there will be no benefit either."
Meanwhile, research has shown that excess levels of niacin (vitamin B3) and antioxidants in the body, in turn, may be associated with an increased risk of death. This is because niacin may have a negative effect on blood sugar levels. Antioxidants ("free radicals") are naturally produced by our body in sufficient quantities. And their overabundance can lead, for example, to disruption of the natural anticancer mechanisms in the body.
According to researchers, most often an excess of vitamins and minerals in the body occurs as a result of a person exceeding the norms prescribed by doctors.
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“This study suggests that people should be more careful in their choice of supplements and use only the amount of vitamins and minerals that are prescribed by their doctor in each case,” says Jenkins.
The scientists used vitamins A, B1, B2, B3 (niacin), B6, B9 (folic acid), as well as the minerals carotene, calcium, iron, zinc, magnesium and selenium as objects of research.
Researchers have also found that some substances are more effective than others. For example, there has been an association between the use of zinc supplements and a reduction in the onset of cold effects. Despite popular belief in the effectiveness of vitamin C, it has not shown any practical benefit in this.
“With no significant benefits other than folate, which lowers the potential risk of heart disease, it’s safer to rely on healthy foods to provide you with the vitamins and minerals you need,” Jenkins says.
"There is not a single study that proves that supplements can be more beneficial than a healthy diet that contains fresh vegetables and fruits, as well as nuts."
Canadian scientists suggest that a possible reason for the lack of a positive effect of taking dietary supplements on human health may be the peculiarities of the composition of the supplements. And in some cases, dietary supplements can be completely hazardous to health. So, the magazine Consumer Reports two years ago analyzed the composition of some popular dietary supplements and found in them substances dangerous to human health that can cause damage to the digestive system, arrhythmia, dizziness and the development of cancer.
Nikolay Khizhnyak
