Vitamin D: Brazilians are deficient even in full summer sun – 03/07/2023

It was to be expected that, in countries with a milder climate, people could even lack vitamin D. But here, in sunny Brazil, guided by what the medical books say, who could imagine something like that happening in a large proportion of young, healthy individuals?

Well then: the surprise is that, according to a new study, more than half of Brazilians between 18 and 45 years old, or 50.7%, have vitamin D levels that are a bit to be desired, while 15.3% are deficient for real, being able to pay the price of this lack with health.

Unlike other substances that deserve the nickname of vitamin and designated by different letters, which the human body is in no way able to produce alone, “D” can be synthesized by the skin under the effects of solar radiation. In fact, most of what our organism has comes from this production and not from the plate.

Knowing this since it was discovered in 1916 — when it was noticed that the sun helped to treat rickets and that this, in fact, happened because it would make the levels of this molecule return to plumb — has always been a kind of safe conduct for Brazilians . It was thought that, in terms of vitamin D, they would have nothing to worry about in a land that, well, well, is just as hot.

But this is not what the work published in the Journal of the Endocrine Society tells us. Signed by researchers from four institutions in the country — the Paulista School of Medicine of Unifesp (Federal University of São Paulo), UFPR (Federal University of Paraná), the Gonçalo Moniz Research Center of Fiocruz Bahia and the Irmã Dulce Foundation —, it analyzed the dosages of vitamin D in the blood of no less than 1,029 adults, residents of São Paulo, Curitiba and the scalding Salvador.

Could the situation be even worse?

That’s what I ask myself when endocrinologist Marise Lazaretti Castro, a professor at Unifesp, talks about the research, of which she is one of the authors.

Considered one of the greatest specialists in osteometabolic diseases in the country — and we know that strong bones depend on vitamin D —, she confesses to being in love with this substance that, in the body, acts like a hormone.

“Until about 15 years ago, we didn’t even have a method to measure it in the country. Once again, because it was thought that, as we have a lot of sun, it would not be common to find cases of deficiency in Brazil”, explains the doctor, who attributes the result of the recent investigation to a major change in behavior.

“People spend more and more time indoors,” he notes. And, of course, she recalls that the period of confinement due to the pandemic may have aggravated the situation.

The fact is that Marise and her colleagues, including epidemiologist Edson Duarte Moreira Júnior, from Fiocruz in Bahia, decided to check the situation, without settling into the old confidence in the sun over our heads. For this, they took a series of precautions. One of them was to choose cities in different regions — one in the South, another in the Southeast and yet another in the Northeast.

“It’s just that latitude makes a difference in solar radiation”, he clarifies. “The exposure and consequently the levels of vitamin D tend to be higher the closer we are to the Equator.”

Another zeal was to select healthy people, so that no one would say that the proportion of people with disabilities had something to do with an illness. Therefore, the idea was to look for participants in blood banks. It makes sense. In principle, people who donate blood are doing very well, they go through a questionnaire to assess their general condition and even undergo tests to rule out the existence of diseases.

Finally, one of the most important details: the researchers made a point of carrying out the measurements right in the middle of summer. “It’s when vitamin D is higher in the bloodstream”, justifies Professor Marise. That is, cloudy days are not an excuse for the numbers that the study ended up finding. They reveal the best-case picture.

“To our astonishment, even in the middle of summer, one fifth of São Paulo residents had vitamin D concentrations below 20 nanograms per milliliter of blood, which is the minimum limit of what we consider healthy”, she says.

In more than half of São Paulo residents, or 52%, vitamin D was suboptimal, that is, there were less than 30 nanograms per milliliter of blood — a condition of insufficiency, not as bad as the deficiency itself, but that already draws attention.

In Curitiba, the insufficiency rate remained at the same 52% and the disability rate was 12%, a little lower. “Probably, in São Paulo people are walking even less outdoors”, ponders the teacher. In Salvador, with all that sun illuminating the Baía de Todos os Santos and making Carnival boil, an unbelievable 12% of the population is also disabled, which is more serious, while 47% have insufficiency.

Deep down, between us, the numbers are similar. And in the winter, the researchers calculate, it should get worse by about 10%. That is, the scenario is more nebulous for health according to the season.

Note that the research did not consider elderly people, whose bodies produce less vitamin D by nature. Hence, real life, outside its select sample, can be much darker.

Who needs supplementation?

There is another inevitable question, seeing these results. “You don’t feel anything when vitamin D is below the desired level, unless it is very low, increasing the risk of fractures, reducing muscle strength and eventually even harming the immune system”, teaches the professor. So, it’s good to be smart.

Food sources to revert a situation of deficiency, in the words of the endocrinologist, are very scarce. “We cannot depend on food to guarantee vitamin D and that is a fact”, she says.

However, according to her, if someone plays football every weekend shirtless, goes to the beach or the pool, walks to work for more than 20 minutes — to give some everyday situations as an example — he will not need to take a supplement. of vitamin D. Point. From the top, after all, solar radiation is not weaker, quite the contrary.

“Who needs supplementation is that person who stays more indoors or in other closed environments, who is barely outdoors”, believes the teacher. “Or, even, those who have some contraindication to sunbathing, such as a higher risk of skin cancer, and who live with sunscreen because of that.”

The doctor makes a point of including individuals over 60, 70 years old on the list: “If we find 20% of young adults with vitamin D deficiency, this happens to 56% of the elderly, according to other studies”.

In general, it’s worth noting, women are at greater risk of vitamin D insufficiency or deficiency because they don’t go around shirtless in the first place. The exposed skin area, especially if the sunbath is not the most prolonged, makes a difference.

People with obesity also deserve attention. There is evidence that the levels of vitamin D found in your circulation tend to be lower than those of normal weight people. Partly for cultural reasons: those who accumulate fat are victims of gordophobia and cover their bodies more in front of other people’s eyes. “Not to mention that vitamin D is fat-soluble and, therefore, the adipose tissue can sequester it from the blood”, adds Marise.

Finally, another work by the professor that has not yet been published, although it was presented at a congress, evaluated more than 400,000 doses of vitamin D in children and adolescents. “The conclusion is that, nowadays, adolescence becomes another risk range for the deficiency of this substance.” Bad news, since this is a crucial phase for the formation of bone mass, a process that depends on vitamin D.

without overdosing

Even in cases where supplementation is advisable, no exaggeration. “The big problem is that people take too much vitamin D, which is also not good. And, unfortunately, it is sold without a prescription”, says Marise.

For people who don’t get a little sun every day, especially if they belong to the groups at risk of deficiency mentioned above, the right thing would be to replace them with an adequate dose of the vitamin, the one that the skin would produce well if it was exposed to the rays . “This is usually something between 800 and 1,000 IU (international units) daily, no more than that”, informs the endocrinologist, to give an idea.

The best thing would be for you to go to the doctor to measure your vitamin D and receive proper guidance, before going out buying capsules on your own. And, speaking of going out, you already know: enjoy and feel the sun on your skin for a few moments.

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