in whom it should be measured and when to supplement

There is no doubt that vitamin D plays an important role in health. In recent decades, findings have been added to the well-known role it plays on the musculoskeletal system that link it to less classic actions on general health.

But still there are discrepancies in the recommendations on who to evaluate it, when to supplement, what the optimal levels are according to each objective (a young and healthy person is not the same as someone undergoing cancer treatment or an older adult who faces risk of fractures).

In pursuit of settling these controversies, guidelines and consensuses have been drafted in the last 15 years, arising from the review of the scientific evidence available to date, which is extensive and growing: interest in the extraskeletal effects of vitamin D has led to conducting clinical trials on its role in cancer, cardiovascular risk, respiratory infections (especially during the COVID pandemic), autoimmune diseases, diabetes.

The problem is that many times the methodology used in these investigations differs greatly from each other, as well as the populations studied. A no less minor aspect is the overall variation in the concentrations of vitamin D, known as “the sunshine vitamin”: the countries further away from the Ecuador (as is the case of Argentina) tend to have a greater deficit. But even within our country, living in Jujuy is not the same as living in Ushuaia. Nor measure it in winter or summer.

Video

Known as the sunshine vitamin, vitamin D acts on bones, muscles and the nervous system.

“Optimal levels of 25-hydroxyvitamin D (25 OHD) remain the subject of debate“, recognize the authors of the Consensus statement on assessment of vitamin D status and supplementation: why, when and howpublished in April in Endocrine Reviews.

This document, emerging from the VI international conference “Controversies in Vitamin D”, highlights that the lack of standardization of clinical trials carried out worldwide poses challenges in the interpretation of the data and points out that the initial negative results are probably due to the fact that Individuals with good levels of vitamin D were studied, which made it difficult to observe benefits from increasing their intake.

“However, subsequent analyzes have suggested potential benefits in reducing the incidence of cancer, autoimmune diseases, cardiovascular events and diabetes,” state the authors of the consensus and maintain that “more studies are needed to investigate the effects of vitamin D in relation to different recommended levels of 25 OHD and the effectiveness of different supplemental formulations.”

Meanwhile, a clinical practice guideline from the Endocrine Society (ES) of the United States published this month agrees that more research is needed, suggests not taking supplements in doses higher than the dietary reference intakes in healthy adults under 75 years of age, nor perform routine tests to evaluate vitamin D levels. In return, he recommends a “empirical” supplementation in risk groups (under 18 years of age, pregnant women, adults with prediabetes, and over 75 years of age).

“Although a causal relationship between 25OHD concentrations and many disorders has not been clearly established, these associations have led to a widespread vitamin D supplementation and an increase in laboratory tests in the general population,” question the authors of the ES guide.

According to the object, the risk-benefit relationship of increasing intake and the role of evaluating its levels for the prevention of diseases “remain uncertain”.

“This is a guide unlike any other, intended for healthy population only and focused on a cost-effectiveness analysis”, he considered in dialogue with Clarion the endocrinologist specialist in osteology Beatriz Oliveri, one of the country’s leading experts in the study of vitamin D.

For Oliveri, this guide arises in response to the fact that in recent years “has gone to an extreme to measure the levels of 25OHD, this nutritional marker of vitamin D, in the entire population”, something that he considers unjustified.

However, he says he does not fully agree with empirically supplementing (without previously measuring levels) to specific groups. “If there are populations at risk, they must be evaluated: having a deficiency is not the same as having an insufficiency. The cost-effective aspect should not be the only one that matters,” he emphasizes.

“Guides are guides, they are not lawand the universe of people who need supplementation is very large,” emphasizes Oliveri, who is part of the Mautalen Health and Research staff and is an independent researcher. ad honorem in the Laboratory of Osteoporosis and Metabolic Bone Diseases INIGEM (Hospital de Clínicas/UBA-CONICET) and former president of the AAOMM (Argentine Association of Osteology and Mineral Metabolism).

It is estimated that vitamin D deficiency affects around 1 billion people of all ages around the world.

Vitamin D is obtained through diet and mainly from sun exposure. But it is a difficult figure. Oliveri explains it: “It is formed in the skin – it is a hormone, it is not a vitamin – due to exposure to ultraviolet radiation. As we move away from the equator there is less UV radiation. And in the autumn-winter months, even less.”

Changing habits contributes to hypovitaminosis D.”People take better care of themselves due to photoaging and the possibility of skin cancer. He also spends less time outdoors, especially in cities with high pollution. In cultures like Muslims, where women are fully covered, the deficiency is enormous,” she warns.

To make matters worse, the “ideal” hours for the formation of vitamin D are between 10 and 15 (the peak of UV radiation is between 12 and 14): precisely the period in which extreme care must be taken to prevent skin cancer. It is even more difficult for dark skin to synthesize the vitamin.

Age also influences: “older adults, even if they are exposed to the same UV radiation, produce 60% less vitamin D“.

And acquiring it through food is very complex: “it is very poorly distributed in food: in salmon – which must not be farmed -, herring, eggs, some mushrooms, fortified milk, and on and on.”

In Buenos Aires, according to a study carried out in 2013, the intake of vitamin D in children from 2 to 4 years old reached 260 IU/d (daily units) and between 4 and 90 years old it was even lower (150 to 90 IU/d). d).

The recommended doses range, depending on age, between 600 and 800 IU/d (according to the United States Institute of Medicine) and 600 and 2000 IU/d (for SSc). Vitamin D deficiency levels are considered to be less than 20 ng/ml, although many experts believe that optimal levels of 25OHD are greater than 30 ng/ml, which is why between 20 and 30 is considered insufficient.

—In whom should vitamin D be evaluated?

—This is my personal position: basically, I measure vitamin D for those who are at risk to see what levels they have and to be able to supplement them appropriately. I would not test hydroxyvitamin D in the entire population. But I would suggest as public health measures for the entire population those that contribute to having good levels of vitamin D: adequate intake and sun exposure.

What should that exhibition be like? In an interview with Clarín, Michael Holick, the world’s leading expert in vitamin D research (who has carried out several works with Oliveri), recommended exposing oneself without protection. half the time it takes for everyone’s skin to turn red (15 minutes if one turns red after half an hour).

“The ideal is to uncover the abdomen, the back and protect the face, which is always what is most exposed, most damaged by the sun and does not produce too much vitamin,” he pointed out. And, to the relief of dermatologists, he clarified: “After the exposure necessary to generate the recommended values, you do have to put on a good protector.”

Oliveri’s “recipe” is: in the summer, 15 to 20 minutes outside the hours of maximum solar radiation. In autumn and winter, at midday, two or three times a week, protecting the face, ears and scalp with sunscreen.

—Who are in the groups at risk for vitamin D deficiency?

—There is a lot of consensus on this —says the doctor—. Older adults at risk of falls due to sarcopenia (will have a greater chance of falling and fractures). Those who undergo treatment for osteoporosis will have better results if they have a good level of vitamin D. Institutionalized patients, those who are in nursing homes, not only because of their age but because they go out less.

Pregnant women are also a risk group. Vitamin D reduces the risk of preeclampsia (high blood pressure), gestational diabetes, premature fetal death, and low birth weight. There are studies on the importance of having good levels in the first trimester of pregnancy. And others that show that more pregnancies are achieved through in vitro fertilization if you have good levels of vitamin D.

Also the entire population not exposed to the sun (those who had skin cancer, for example). People with obesity, those who take medications that alter the metabolism of vitamin D and diseases that cause poor absorption (such as celiac disease). Those who have undergone bariatric surgery, who have had a transplant, are undergoing oncological treatments or have rheumatic diseases (rheumatoid arthritis, lupus, multiple sclerosis), among others.

—Should it be supplemented in them?

—The universe of people in whom it should be evaluated and supplemented is very large. It’s not just anyone who comes to the office. I think we have to find a middle ground and I think that in one or two years, perhaps we will find it.

It would be good for the general population to receive the recommended dietary doses and when there are more risks of deficiency (the groups mentioned above), to supplement. But not to everyone.

—And how is vitamin D supplemented?

—Supplementation should be done only if indicated and depends on whether the person has a deficiency or if it is administered as a form of prevention.

There are different forms of vitamin D, but the most important thing to supplement is D3 or cholecalciferol. It can be given in daily or weekly drops. There are also single doses that can be given every 15 days, once a month, or every two months. These intermittent doses (in capsules or liquid) have the advantage that patients adhere more.

And, I insist, although very high doses are needed to become intoxicated, supplementation must be prescribed by doctors, who must indicate how to take it.

Oliveri has been dedicated to vitamin D research for more than 40 years. During the talk, she discusses data from various studies that show multiple effects of vitamin D on the body throughout life. “Sorry I talk so much, but I love vitamin D“, apologizes.

—Because vitamin D is a hormone of life. It accompanies you from pregnancy, from when you are a fetus, to adulthood. Not only is it essential for musculoskeletal health, but it has been shown to have anti-inflammatory action. By reducing cellular oxidation, it reduces DNA damage, reduces the excessive proliferation of low-differentiated cells (which is why it has been seen to be beneficial in some cancers or diseases such as psoriasis), which is why it also has an impact on immune level (there were many studies during the pandemic).

It accompanies different life processes with positive action, but it is not a panacea. I am not going to treat a person with hypertension or cancer with vitamin D alone, but having a good level will be beneficial for some diseases and improves the response to some treatments.

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