It is well known: during the coldest months, the sun’s rays are not strong enough in Belgium for the human body to naturally synthesize vitamin D by exposing the skin to light. As a result, a large part of the population is deficient. The EG-Strada group figures the percentage of Belgians in this case at 45%, or even 67% in winter. For dietician Clément Godart, these figures even rise to 70% and 90% respectively. To fill this gap, many are turning to food supplements. Problem: these are increasingly criticized (risk of overdose, absence of clear benefits in studies, etc.).
However, there is an alternative: simply adapt your lifestyle, especially through diet. An initiative to which the Belgians are clearly reluctant. According to Sciensano, their eating habits only cover a third of the recommended daily amount of vitamin D. Here’s how to fix it.
Limited choices
Unfortunately for us, few foods are rich in vitamin D. Harvard University listed them and it is clear that this one is short. Some are of animal origin and contain vitamin D3, while those of plant origin have vitamin D2. There is an ongoing debate as to whether the D3 would be better than the D2, but it is not settled. In both cases, the result is more or less the same: both forms are converted by the body into calcitriol, the active form of vitamin D.
As for vitamin D3, the richest food is not very popular, since it is cod liver oil. If the idea of consuming it revolts you, rest assured, it’s not just that! In second place, we find a much more popular product: salmon. More broadly, oily fish are renowned for their amounts of vitamin D. Harvard University also cites swordfish, tuna and sardines. “Smaller quantities [de vitamine D3] are found in egg yolks, cheese and beef liver“, she adds.
Obviously, if you are vegetarian, your possibilities of sources of vitamin D3 are reduced to a trickle. For vegans, it is not even possible to turn to eggs and cheese. We must therefore turn to vitamin D2. The concern is that here, the list of foods naturally containing this nutrient comes down to a single product: mushrooms, and not just any mushrooms! For this, we must turn to those who have been able to synthesize vitamin D2 “due to intentional exposure to large amounts of ultraviolet light“(just like human skin synthesizes vitamin D3 with UVB rays), specifies Harvard University.
Get in the sun and/or eat foods fortified with vitamin D
Given the low number of foods rich in vitamin D, the frequency of deficiencies is not surprising. If these products are not enough and the UVB rays of the Sun are strong enough (which is generally the case from April to September), it is possible to remedy this by exposing yourself to them. “It appears from several studies and reports that spending a quarter to half an hour outdoors is enough to synthesize vitamin D“, informs the Cancer Foundation (dark-skinned people need to expose themselves a little longer than light-skinned people). No need therefore to risk a sunburn by basking in the pill for hours!
Without this contribution linked to UVB rays, it is easy to lack vitamin D, especially in winter. The study therefore suggests that people with an insufficient intake turn to foods enriched with vitamin D. It thus joins Harvard University, which lists a few of them: enriched orange juice, fortified milks (of animal or plant origin), or fortified cereals.
Scientology is promoted Moreover “fortification of foods with vitamin D at the national level“, Who “is considered an effective strategy to improve the vitamin D level of a population“. The health institute notes, however, that “this enrichment strategy requires careful selection of food carriers“so as not to compromise the safety of the Belgian population.”Considering technological and regulatory aspects and the safety of food carriers, the fortification of bread and milk was considered the most optimal.“.
Supplementation or not? Depending on the case
If people do not have enough vitamin D from food (enriched or not), there is only one option: supplements. The Sciensano study notes that these are even more important for certain parts of the population. This is the case with young children, “for whom direct exposure to the sun is strongly discouraged“and who therefore lack vitamin D. Ditto for pregnant women because if it turns out that they suffer from a deficiency, that “can cause growth retardation and skeletal malformations in children“.
Be careful, however: if food supplements are sometimes recommended, they arouse in parallel the mistrust of the scientific community. Sciensano, for example, warns those who give it to babies. “Among infants who receive vitamin D supplements, we find that 26% take too much“, warns the author of the study, Isabelle Moyersoen.
More generally, the entire population must avoid overdose. The Belgian Ministry of Health recommends a total daily vitamin D intake of at least 20 µg, i.e. 800 IU per day. But Harvard University notes, however, that care must be taken not to exceed 4,000 IU (or 100 µg) for children aged 9 and over. The institution clarifies that it is very unlikely to reach this level with diet or sun exposure alone, but it can be the case with supplements, hence the recommendation to be supervised by doctor. Without these precautions, an excessive and toxic intake of vitamin D can cause a “hardening of blood vessels and tissues due to increased blood calcium levels, which can lead to heart and kidney damage“.
Supplements to have better bones? Watch out for shortcuts!
So yes, vitamin D deficiency can cause rickets in children and osteomalacia (weakening of the bones) in adults, as vitamin D helps calcium bind to the bones. However, it is not yet entirely certain that vitamin D supplementation by food supplements makes it possible to completely avoid these pathologies.
The CNRS thus notes that “recent studies have demonstrated the absence of clinical benefit from the administration of vitamin D, including on the reduction of the risk of bone fracturesIt’s even possible that these supplements can cause kidney stones, notes a study by the French research center. That “therefore raises the question of the merits of routine administration of vitamin D supplements“, he concludes.
This analysis was confirmed by a meta-analysis published in 2022which also shows a “lack of benefits in terms of bone density“. She clarifies that if “correction of severe vitamin D deficiency remains essential“, vitamin D supplements have not been shown”no effect on incidence of cancer, cardiovascular events or type 2 diabetes mellitus“. Their only visible positive effect is a “slight decrease in cancer mortality“.
