Vitamin D: Do You Really Need to Take It as a Supplement?

Emil Lahr
Emil Lahr
Nov 2 · 6 min read

The vitamin D requirement is not met during the winter. This is confirmed by a study funded by the Swiss National Science Foundation. This is due to the lack of sunshine, which varies greatly depending on the season. In spring and summer, the body stores vitamin D in the fatty tissues to build up reserves. Then, in autumn and winter, these reserves are used. Consequently, according to the Federal Office for Food and Veterinary Safety (FVO), about 60% of the population is not sufficiently nourished during the months with less sunlight.

Vitamin-D

This is a problem of some concern. It should be noted that the sun plays an important role in the amount of vitamin D in the blood. Under the action of UV rays, a form of pre-vitamin D, present in the skin of each of us, becomes an active form. An essential mechanism for our bone health. Otherwise, children may suffer from rickets (delayed bone growth). In adults, an acute deficiency sometimes leads to osteomalacia, i.e. softening of the bones.

This problem is well known in the medical world. Vitamin D supplements, for example in the form of supplements, are therefore recommended for people in at-risk groups. These include infants (with little exposure to the sun to protect their skin), pregnant women, infants and the elderly. “The skin’s ability to transform pre-vitamin D diminishes after the age of 65,” explains Professor Olivier Lamy, director of the Centre hospitalier universitaire vaudois (CHUV). Even if these people are exposed to the sun, the mechanism is difficult to activate.

A model discussed

However, according to the FNSF study, the problem affects a larger part of the population. In winter, many people, including healthy young people, are below the WHO recommended standard of 30 nanograms per milliliter. “This low rate does not lead to immediate disease,” notes Professor David Vernez, specialist in risk assessment at Unisanté and author of the study. But in the long run, it can increase the risk of osteoporosis, with young and healthy individuals who are the most susceptible.

These conclusions make some members of the medical profession skeptical. “When 60% of people are out of norm, we can still define it as a norm”, asked Professor Omar Kherad, medical director of the Department of Internal Medicine of La Tour Hospital and master in public health. In medicine, when there are more sick than healthy people in a population, it is always surprising. Doubts shared by Professor Lamy: “This type of standard does not take into account individual variability. It would be more logical to use a number that changes, for example, depending on the gender and age of a person.

It is therefore difficult to conclude that all those who do not take vitamin D in winter are really at risk. “The WHO standards on which we have based this study are relatively high. We might think that some people are not in danger at lower rates,” admits Professor Vernez.

Risk of overdose

The specialists are qualified, but this figure of 60% below the norm does not fall on deaf ears. This topic is widely used by the pharmaceutical industry to promote the need for supplements. However, “no benefit of these products for healthy young people has been scientifically proven,” says Professor Kherad. More seriously, an overdose of supplements can lead to serious side effects, such as heart rhythm disorders, weakness, headaches, nausea, vomiting and disturbances of consciousness, according to the OSAV. In addition, “while vitamin D is useful for older people who do not get much, it has been observed that too high a dose can cause multiple problems,” warns Professor Lamy. For all these reasons, the introduction of vitamin D supplements should be discussed with a doctor and reserved for groups at risk (infants, pregnant women, lactating women and the elderly).

However, the industry does not hesitate to target its advertising campaigns at healthy people. In 2018, at the Lausanne Marathon, Labatec distributed vitamin D vials to runners in the form of drops. When asked about their motives, the company replied that “Vitamin D has many virtues in adult athletes: it increases physical performance, improves recovery after exercise and strengthens immunity. In support of its claims, Labatec refers to observational studies (i.e. studies of low scientific value) conducted more than seven years ago. In the absence of concrete evidence, the company responded: “There are enough studies that demonstrate a link between muscle health and vitamin D, but we cannot go further. It is not one of the main objectives of our communication. However, the commercial operation carried out during the marathon was aimed at athletes. “This is a great marketing movement,” says Professor Kherad. Does this kind of free distribution make everyone want to benefit from it? And here we are for months of useless treatment.

An opaque market

It must be said that large sums of money are at stake because the market for vitamin D supplements is growing by leaps and bounds. Between 2013 and 2018, the costs of all medicines charged to basic insurance in Switzerland rose from 5,623 million to 7,027 million, an increase of 25%. In the same period, sales of drugs for the prevention and treatment of vitamin D deficiency increased from 6 million Swiss francs to 22 million Swiss francs. A significant increase of more than 360%. Proof that marketing works. However, it is not possible to have an overview of the market: this type of product is available at the counter and most companies active in this sector do not want to communicate their turnover.

Wrong messages

This is the case with Cerascreen, based in Germany. For some time now, the company has been marketing vitamin D testers in Swiss pharmacies. It assures us, without providing further details, that it is “experiencing rapid growth”.

It must be said that his concept is simple: just prick your finger with a small kit, then send the blood sample to the company, which will analyze it and, if necessary, give advice on supplementation. A process that avoids going to the doctor for a vitamin D test. “Although the Federal Commission on Nutrition does not recommend screening , we think it is preferable for people to know their values and needs and be able to influence them specifically,” Cerascreen explains. This message is openly contrary to the Swiss guidelines and clearly aimed at a much wider public than the groups at risk. According to their website, which was consulted in August, women in general are among those at risk. “In fact, we made a mistake that we have now corrected,” says Cerascreen. It should not be the word “women”, but “pregnant women”.

Advertising messages that are often approximate or even wrong in this case, encourage as many people as possible to take the doses. “I’m fed up,” says Professor Lamy. Scientific data are misused and exploited by unscrupulous people. In fact, since, depending on the season, more than 60% of the people performing this type of test would have been informed of the “insufficient intake”, millions of potential customers are at the mercy of the sellers of vitamin D supplements. While, as the OSAV points out, the possible protective functions conferred on vitamin D in the context of cancer, cardiovascular or neurological diseases remain controversial, a definitive conclusion is not possible for the time being.

Doctors are not always informed

Every year, doctors prescribe thousands of doses of vitamin D. Already in 2011 in France, a report by the High Health Authority showed that the costs of testing amounted to 92 million euros. However, according to the report, the evaluation of vitamin D levels in the blood hardly ever provides “useful information for health professionals”. In the 2000s,” explains Professor Olivier Lamy, director of the CHUV Centre for Bone Diseases, “there was some kind of euphoria about vitamin D. Many medical journals have shown positive associations between this and protection against certain diseases. Probably there was a selection of works in the publications. It is easier to publish a study with a positive result. But when these studies were conducted using a more appropriate methodology, these results could not be confirmed.

However, many doctors are still affected by these messages, which are now obsolete. “There is some kind of prejudice in action”, says Professor Omar Kherad, medical director of the Department of general internal medicine of La Tour Hospital. It is increasingly easier for a doctor to offer something to his patient than to explain that it is better to abstain.

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch
Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore
Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade