Facts & Recommendations
Vitamin D, the sunshine vitamin, includes two different types: the vitamin D2 (Ergocalciferol) and the vitamin D3 (Cholecalciferol). The latest is taken as dietary supplement.
It is interesting to note that this fat-soluble vitamin, unlike others, can be provided by two different ways: it can be ingested through diet and it can be synthesized by the body when the skin is exposed to light (UVB exposure).
Mainly self-production by the skin (80-90% of the supply).
The main food sources are cod liver oil, oily fish (salmon, sardines, herring and mackerel), red meat, liver, egg yolks as well as shiitake mushrooms.
Vitamin D3 functions like a hormone. It is converted to calcitriol which helps your body managing the calcium metabolism, promoting its intestinal absorption and bone mineralization.
It helps regulate the amount of phosphorus too.
Both calcium and phosphorus support a healthy bone and teeth development.
Furthermore, it has been proven that vitamin D contributes to the maintenance of normal muscle function, supports the immune system plays a role in the cell division and participates in the process of insulin secretion
During pregnancy and lactation, vitamin D3 maintains proper skeletal development of the foetus and prevents low birth weight; during lactation, it promots increased production of breast milk.
At term, infants are born with a store of vitamin D reflecting the mother’s vitamin D status.
Vitamin D3 deficiency
According to the WHO, Vitamin D deficiency is thought to be a widespread public health problem. The prevalence of vitamin D3 deficiency is estimated at 13% in Europe (2016 – ODIN).
The main risk factors given are:
- lower intensity of sunlight to which skin is exposed (less outdoor activities, regular use of high factor sunscreen, clothing covering a large part of the body)
- decreased absorption through diet resulting from age, obesity or malabsorption.
Consequences of a vitamin D3 deficiency
Low levels of vitamin D3 are associated with a poor bone health (which can lead to osteoporosis).
Maternal vitamin D3 deficiency is associated with an increased risk of pre-eclampsia and gestational diabetes as well as risk of impairment in bones quality of the offspring and low birth weight.
Most countries have their own recommendations for vitamin D intake based on the sun exposure in specific groups of the population.
The German Federal Institute of Risk Assessment (BfR) recommends as highest vitamin D3 concentration to be used in dietary supplements 20 µg (800 IU).