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Initiated in the 1960s, vitamin D supplementation before the age of 1 helped fight rickets. But beyond this age and for the general population, the recommendations are sometimes contradictory. The national college of general teaching practitioners has issued a surprising opinion.
Essential for the proper functioning of our bones, muscles and immune system, vitamin D is important in children. And this, from birth to prevent the risk of rickets. Vitamin D intake is therefore generally recommended to support the needs of children and their overall good health.
Supplementation initiated to combat rickets
In France, the introduction of vitamin D supplementation in the 1960s and the marketing of artificial milks enriched with vitamin D since 1992 were followed by a drastic reduction in the incidence of deficiency rickets. From now on, this disease is almost exceptional, and only affects breastfed children who have not received vitamin supplementation before the age of 5 and to a lesser extent those with risk factors for deficiency (obesity, black skin , lack of exposure to the sun, reduced intake).
According to the French association of ambulatory pediatrics, new recommendations for 2022 have made it possible to “smooth out” the recommendations with now a single recommended intake of 400 to 800 IU per day for 0-18 year olds, without distinction of age, except in special cases (obesity, black skin, lack of sun exposure, diet vegan for which the recommended intakes increase to 800 to 1600 IU per day of vitamin D2 or D3). Doses of 200,000 IU should be avoided.
But the national college of teaching general practitioners wanted to know if, beyond the first year to prevent rickets, vitamin D supplementation was still relevant. Faced with the multitude of opinions on the subject, doctors have scoured the medical literature to give their opinion.
Supplementation before 1 year must be subject to a medical prescription
Experts specify that in infants: “supplementation of 400 IU/d was sufficient to achieve serum vitamin D concentrations considered “normal”. Higher doses did not improve bone density, but an increased risk of hypercalcemia could be observed. In the absence of risk factors for rickets, the level of evidence was insufficient to conclude that it was clinically effective.“.
Experts add that overdose errors with sometimes serious situations (linked to hypercalcemia or hyperphosphatemia) have been described and favored by access without a prescription to solutions with a high concentration of vitamin D. A campaign of the Anses had reminded that these supplements remain medications that must be prescribed by doctors or midwives.
Beyond a year, the usefulness of supplementation is less obvious
Beyond this age and the prevention of rickets, doctors admit that the scientific literature has little evidence on the usefulness of supplementation. They write thus:
- “In children aged 1 to 5 years, no randomized controlled trials (RCTs) of sufficient methodological quality assessing the risk of rickets or bone fragility have been identified.
- In those aged 5 to 13 years, trials have not shown convincing results in reducing the risk of rickets. A double-blind RCT conducted in 8,851 children aged 6 to 13 years old showed no difference between the group supplemented with vitamin D for 3 years and the control group, neither in the risk of fracture, nor in adverse effects. .
- In adolescents between puberty and up to age 18, supplementation increased serum vitamin D levels, with conflicting results on bone density benefits.“.
Beyond extra-osseous effectiveness (growth, pubertal development, ENT infections, etc.), the influence of vitamin D has not been proven by quality studies. The data collected by these doctors recognize at most a slight reduction in the severity of asthma in childhood, in the event of an initial serum vitamin D level < 10 ng/L and with a low level of evidence.
In conclusion, the authors state that “It is reasonable to maintain systematic supplementation of 400 to 800 IU/day in infants, particularly before the age of 1 year, in the case of breastfeeding, or in the presence of deficiency risk factors.” but that “for other clinical situations, current data do not allow us to conclude that there is a favorable benefit/risk balance for vitamin D supplementation“.
And yet, a French population is largely deficient…
This opinion could seem to go against the general recommendations and the observation of a generalized vitamin D deficiency among the French. A Inserm study had thus shown that 58% of the population had an insufficient concentration of vitamin D (less than 20 ng/ml) and around 15% a true deficiency (<10 ng/ml).
Faced with these same figures, the High Council of Public Health recommended in June 2022 :
- to ensure moderate but sufficient solar exposure;
- to consume foods rich in vitamin D consistent with nutritional recommendations (mainly fatty fish, but up to one serving per week, cod liver oils, eggs, cheese and dairy products (2 per day));
- to avoid self-prescribing food supplements rich in vitamin D.
In conclusion, by exposing yourself moderately to the sun and adopting a varied diet, the risks of deficiencies are limited. Vitamin D supplementation may be considered by your doctor in the event of a proven deficiency.
Details from Dr. Gérald Kierzek, emergency physician and medical director of Doctissimo
Vitamin D is not only involved in bone metabolism but participates in the immune and inflammatory response, regulates cell proliferation and differentiation, but also the secretion of hormones such as insulin and renin. In France, our dietary lifestyles and low exposure to the sun often do not allow the nutritional need for vitamin D to be covered, causing vitamin D deficiency or deficiency, which is common and underdiagnosed. Apart from, some accidental overdoses by misuse of food supplements, the risks of systematic supplementation seem limited compared to the benefits.