Opinion – Drauzio Varella: Vitamins give the false sensation that we are taking good care of our health

There is a lack of evidence to justify the indication of vitamins for healthy adults, I have repeated in this column for years. I do not forget to mention that pregnant women can benefit from some of them, such as folic acid, which is important for the development of the fetal nervous system.

Every time I write this, I get an avalanche of uncivilized criticism, many of which come from doctors who claim to be witnesses to the health benefits of vitamins, minerals, and antioxidants in their already healthy patients.

I make this preamble, dear reader, in a vain attempt to avoid the usual offenses. The text that follows brings a series of recommendations enunciated, not by me, but by the respected United States Preventive Services Task Force, the USPSTF, which has just updated the analysis of the impact of vitamin supplements on the risk of cardiovascular diseases, cancer and mortality. of the adult population, as well as its harmful effects.

The review focused on studies of healthy adults, 18 years of age and older, without nutritional deficiencies, cardiovascular disease, cancer or other chronic illnesses — with the exception of high blood pressure, overweight and obesity.

Studies with beta carotene and vitamin A. Six randomized, double-blind clinical trials on beta carotene supplementation were evaluated. When compared to the placebo group, those who received daily beta-carotene had no reduction in mortality or in the incidence of cardiovascular disease or cancer, the two leading causes of death among us.

In two randomized trials among adults at risk for lung cancer — smokers and workers exposed to asbestos — the group that took beta-carotene or beta-carotene plus vitamin A had an increased incidence of lung cancer of 18% and 28%, respectively. .

A study conducted to assess the role of vitamin A in overall mortality showed no significant difference compared to the placebo group.

Vitamin E. In nine randomized studies, the daily administration of vitamin E, for a period of three to ten years, was not able to reduce overall mortality or cardiovascular events. Cancer incidence and mortality were the same as in the placebo group.

Multivitamins. The review analyzed nine randomized trials. It was not possible to demonstrate benefits in overall mortality from cardiovascular disease or cancer.

Of the nine, three specifically studied mortality from cancer and cardiovascular disease: two used multivitamin supplements while the third associated an antioxidant with multivitamins. There was no benefit.

Vitamin D with or without calcium. In 32 randomized trials in which vitamin D was administered alone or in combination with calcium, there was no decrease in overall mortality or mortality from cardiovascular disease or cancer. The incidence of infarctions and strokes was the same as in the placebo group.

Vitamin C. Despite the popularity and widespread consumption, there are only two randomized trials. Result: no effect on overall mortality, incidence of cardiovascular events, and cancer mortality.

Selenium. There is no demonstration of a beneficial effect on overall mortality, cancer or cardiovascular disease.

harm. Most supplements do not cause major side effects. Beta-carotene should not be given to smokers and people exposed to asbestos. Vitamin E in daily doses between 111 and 200 units increases the risk of hemorrhagic stroke. Vitamin D —in doses over 1,000 units— and vitamin C increase the risk of kidney stones.

You will ask, dear reader: if there is no demonstration of effectiveness, where does so much popularity of vitamins come from?

First, from the dream of the fountain of youth that has soothed humanity since the beginning. Second, our lack of willingness for physical activities and to get up from the table before devouring everything we were offered. Vitamin pills give us the feeling that we are taking good care of our health, without any effort.

This illusion is responsible for a world market that moves US$ 110 billion a year. In the United States it is US$ 10 billion; in Brazil, R$ 6.6 billion annually.

So much money invested in pills that are almost always useless that end up in the toilet. It makes sense?