Curated by Maria Rita Insolera, Naturopath
Vitamin D is a fat-soluble vitamin (which dissolves in fats) conveyed in the body through fatty substances. Useful as an anticancer and to regulate the absorption of calcium, phosphorus and vitamin A. Let's look better.
Milk, source of vitamin D
The chemistry of vitamin D
The term Vitamin D refers to a group of liposoluble pro-hormones composed of vitamin D1, D2, D3, D4 and D5.
There are two most common and important forms, especially for the biological value:
- ergocalciferol, or vitamin D2, of vegetable origin;
- colecalciferol, or vitamin D3, derived from cholesterol and of animal origin
Vitamin D in general is found in an inactive form and, before becoming calcitrol (a biologically active form of vitamin D) it must undergo two hydroxylation reactions.
Properties of vitamin D
Our body is able to produce vitamin D on its own thanks to the action of the sunlight it receives and is useful for:
- to regulate the levels of calcium and phosphorus, participating indirectly in the formation of bones and teeth, and helping to preserve their health;
- regulates vitamin A absorption
- it is useful against rickets, a childhood disease with serious consequences for growth;
- carries out an anti-tumor action;
- stimulates the immune system.
Vitamin D food supplements
Vitamin D is found in foods of animal origin, such as liver, eggs, butter, milk, salmon, tuna, herring, and in those of vegetable origin, such as mushrooms and some green leafy vegetables.
Vitamin D keeps its properties unchanged even in contact with light and heat.
You can learn more about the properties of vitamin D and the foods that contain it
Vitamin D herbal supplements
A good remedy offered by nature is cod liver oil . The cod obtains vitamin D by feeding on the plankton that lives near the surface and which in turn synthesizes it by exploiting the sunlight that filters through the water.
Cod liver oil was, and in some cases still used, in the presence of hypovitaminosis due to vitamin A and D deficiency.
Cod liver oil, one of the major food sources of vitamin D, has an antirachitic action able to improve the absorption of calcium and phosphorus, also strengthening teeth and bones. For this reason it is useful for the prevention and treatment of osteomalacia and osteoporosis .
Vitamin D supplements on the market
Commercially available vitamin D supplements are mainly vitamin D3 supplements . In fact, studies identify vitamin D3 (or cholecalciferol, of animal origin) - and not vitamin D2 (or ergocalciferol, vegetable) or others, the most effective form of vitamin D to ensure correct concentrations of this nutrient in the blood.
Being one of the fat-soluble vitamins, to maximize absorption it is good to take supplements for lunch or dinner, along with fatty foods.
Daily requirement of vitamin D
The daily requirement of vitamin D in a healthy adult is 10 µg / day . This quantity, when you have a regular life that allows you to live even outside the home, is naturally stored with exposure to sunlight.
For children up to 3 years, pregnant women and the elderly, 10 µg / day of viamine D are sufficient.
For children from 3 years of age and throughout adolescence, the need for vitamin D slightly increases up to 15 µg / day.
In any case, dietary supplements of this vitamin are not necessary when exposure to sunlight is adequate. Otherwise, it is advisable to consult a specialist doctor who will assess the need to take natural vitamin D supplements.
They may need vitamin D supplements:
- Individuals who expose themselves little to sunlight and who live in highly polluted places (smog absorbs the ultraviolet rays necessary to activate vitamin D).
- Women who use oral contraceptives, as these drugs interfere with the absorption of this vitamin.
- Women during pregnancy and lactation, for which a quota of vitamin D equal to 10 mcg is required.
Its deficiency can cause various bone problems, such as fragility, osteoporosis, pain in the pelvis and legs, but also muscle spasms.