The Importance of Vitamin D in February 0 15

The History of the Discovery of Vitamin D

In 1650, English physician Glisson described a disease in children characterized by severe disturbances in the formation of bones and organs, which he called rickets. For centuries, doctors used various methods to treat rickets, but only two of them proved effective — cod liver oil and ultraviolet irradiation.

In the early 20th century, biochemists, while studying cod liver oil, discovered vitamin A and were pleased, believing it was the solution to the problem of rickets. However, during experiments on animals, it was found that even cod liver oil without vitamin A could cure rickets. This led to the understanding that another fat-soluble substance contained in cod liver oil was responsible for the treatment, and it was named vitamin D (while vitamins A, B, and C had already been discovered). Meanwhile, scientists continued to use sunlight to treat rickets in animals, as well as ultraviolet-irradiated feed.

On February 5, 1928, German chemist Adolf Windaus synthesized ergosterol or ergosterin — provitamin D, which under the influence of ultraviolet rays was converted into ergocalciferol. That same year, he was awarded the Nobel Prize in Chemistry for the discovery of 7-dehydrocholesterol — the precursor of vitamin D.

Today, vitamins D2 (ergocalciferol) and D3 (cholecalciferol) are known, the latter of which was discovered later. The previously existing name vitamin D1 turned out to be a mixture of ergocalciferol and other sterols.

The Importance of Vitamin D for Health

The main function of vitamin D is to maintain a proper mineral metabolism in bone tissue. It helps maintain the levels of calcium and phosphorus ions in the body by regulating their absorption in the small intestine.

A deficiency of vitamin D leads to impaired absorption of calcium and phosphorus, which can cause problems with the mineralization of bone tissue. In children, this manifests as rickets, while in adults it can lead to osteoporosis and other musculoskeletal disorders.

Additionally, vitamin D plays an important role in the functioning of the cardiovascular, nervous, digestive, immune, and endocrine systems. It may help prevent the development of diabetes, hypothyroidism, and other endocrine disorders.

Foods Rich in Vitamin D

The fat-soluble vitamin D is not destroyed during heat treatment; however, its absorption and action depend on the overall diet. A lack of proteins, essential fatty acids, vitamins A and C, as well as calcium, phosphorus, and magnesium can negatively affect the metabolism of the vitamin.

The content of vitamin D in food is low — from natural sources, significant amounts of this vitamin are found only in cod liver oil. Slightly less is found in summer butter and eggs (yolks). In plant products, vitamin D is virtually absent.

Vitamin D deficiency is most often observed at the end of winter, in February, when we experience a lack of sunlight and cannot obtain the necessary amount of the vitamin from food. This is due to the fact that the vitamin content in winter and summer products varies significantly. Therefore, it is important to consider the possibility of taking vitamin D in the form of dietary supplements.

The content of vitamin D in food (per 100 g):

Halibut liver — 100,000 IU

Cod liver — 1,500 IU

Mackerel — 500 IU

Egg yolk in summer — 300 IU

Egg yolk in winter — 120 IU

Beef liver — 100 IU

Butter in summer — 100 IU

Butter in winter — 30 IU

Cheddar — 40 IU

Milk — 5 IU