Vitamin D in your child's nutrition - sources and supplementation

Phosphorus, calcium, and vitamins D and K are indispensable nutrients that should be present in our diets to ensure the proper functioning of the bone system. The primary function of vitamin D in the body is to increase the absorption of calcium and phosphorous in the lower parts of the digestive tract, which can then be incorporated into the bones and strengthen their structure. As a result, vitamin D prevents osteomalacia, i.e. bone dislocation, osteoporosis and curvature, also affecting the mineralization of bone tissue and supporting the proper development of the body. It has also been shown that vitamin D affects the functioning of the immune system, by regulating the activity of antigen-presenting cells and T-lymphocytes. Cholecalciferol is also involved in the differentiation of various cells of the body, not only bone cells, but also steroid hormones. Furthermore, vitamin D is the subject of numerous studies aimed at demonstrating its preventive effect on the development of cancers such as bone marrow, breast, prostate, colon, breast, and melanoma.

The skeleton of a child and a young person under the age of 25 is in a constant phase of rebuilding and storing minerals such as calcium and phosphorus. A condition for the proper functioning of the organism and the strengthening of bones is the provision of adequate amounts of substances necessary for this process, such as vitamin D, calcium, phosphorus, and vitamin K, together with the diet (selected supplements). After 25 years, bone-dependent processes, or weakening skeletal structures, begin to take place in the body. To delay the onset of osteoporosis in later years, it is important to ensure an adequate amount of vitamin D in a child's diet. A deficiency of this vitamin can be dangerous for the proper development of a child and may lead to diseases such as rickets. It is also important to note that the role of vitamin D does not only concern the regulation of processes of mineralization of bone tissue. Vitamin D also supports the proper development of the immune system and reproductive system in children and prevents the occurrence of cancer. The Institute of Food and Nutrition recommends providing 5 µg of cholecalciferol in the daily diet of infants, children, and adolescents up to the age of 18.

Approximately 80 to 90 percent of vitamin D is produced endogenously in the skin after UV radiation. Only 10 to 20 percent of cholecalciferol is provided through diet. The remaining sources are listed in the table below. Fatty fish such as cod, salmon, mackerel, herring, and eel are rich in vitamin D. Egg yolk, cereal gruel, infant formula, and modified milk are also good sources of vitamin D. Learn more about vitamin D supplementation!

The skin synthesis of Vitamin D is a natural source for our body. It is recommended to spend time outdoors, especially during warm, summer and sunny days. However, excessive use of sunscreen filters and covering large parts of the body can hinder the synthesis of cholecalciferol in the skin. Furthermore, the body's ability to produce Vitamin D decreases with age, which can lead to deficiencies. Additionally, the climate in Poland, with its low number of sunny days per year, poses a challenge for sufficient Vitamin D intake. For these reasons, as well as based on studies confirming low Vitamin D concentrations in the blood of Poles, supplementation of Vitamin D is recommended for all population groups. Recommended doses, according to Polish guidelines for the prevention of Vitamin D deficiency, are as follows (refer to the total sum of Vitamin D from food and supplements): Preterm infants – 10–20 µg/d from the first days of life until the corrected age of 40 weeks, followed by the same recommendation as for full-term infants, full-term infants – 10 µg/d from the first days of life, breastfed infants – 10 µg/d, infants fed with formula – 10 µg/d (total from diet and supplements), infants fed both breastmilk and formula – the dose is determined by a physician, children and adolescents aged 2–18 years – 10 µg/d in the months from October to March or year-round if sun exposure or sun radiation is lacking, children and adolescents aged 2–18 years with overweight and obesity – 20–25 µg/d should be considered. Vitamin D is an extremely important component of the diet, as it not only ensures proper mineralization of the skeleton but also contributes to the development of the immune and reproductive systems, participates in cell division and differentiation, and prevents cancer.