Vitamin D is a group of fat-soluble substances that play a key role in the proper functioning of the body: for example, they regulate calcium and phosphate metabolism and homeostasis, supporting the physiological growth of bones and protecting them from aging but not only. Let’s find out together the properties of vitamin D and which foods are richest in it.
What is vitamin D and why is it so important?
Vitamin D refers to a group of fat-soluble substances (pro-hormones) necessary for the performance of numerous biological functions.
In humans, the best-known forms of vitamin D are:ergocalciferol (vitamin D2), which is taken in with food, and cholecalciferol (vitamin D3), which is synthesized by our bodies, both of which will then be converted to calcitriol, the hormone-active form.
These are fat-soluble substances with multiple functions: they protect the immune system, regulate calcium metabolism ensuring the well-being of our skeleton, contribute to muscle contraction, participate in the regulation of calcium and phosphorus levels in the blood, and finally intervene in the process of cell growth and differentiation.
Where does vitamin D come from?
The main source of vitamin D is endogenous production, which occurs in the skin through a chemical reaction that depends onexposure to sunlight (particularly UVB irradiation).
In fact, between May and September one should expose face, arms and legs for at least 30 minutes a day to the sun’s rays outdoors. Unfortunately, rays passing through window glass have no effect on vitamin D synthesis. However, you can also get it through diet or throughsupplementation.
What foods are rich in vitamin D?
Dietary intake ofvitamin D allows us to introduce between 10 and 20 percent of our requirements, let’s find out together which foods are the richest in vitamin D:
The main food sources are:
- Fish (such as herring, anchovies, mackerel, salmon, swordfish, mullet and sea bass, and cod liver oil);
- Cheeses, butter, and yogurt;
- Chicken egg yolk;
- Mushrooms (chiodini, shitake…);
Daily requirements can vary between 400 and 1000 international units/day, or between 10 and 25 g/day (source LARN) depending on several factors, primarily age. For example, the recommended daily intake for the adult population is 15 g/day.
Vitamin D deficiency or excess: what are the consequences?
Vitamin D deficiency can have a major impact on the health of the body, particularly the health of bones and teeth. Behaviors that can cause it to go missing include alcohol and drug use. In addition, some drugs may affect absorption.
If, after laboratory tests, a vitamin D deficiency emerges, it is a good idea to consult a specialist who can prescribe individualized supplementation therapy.
Excess vitamin D, on the other hand, can cause consequences such as vomiting, diarrhea, and muscle spasms.
Which people are most at risk for vitamin D deficiency?
People most at risk for vitamin D deficiency are pregnant women, obese people, people with autoimmune, kidney, liver, and intestinal diseases, and those taking medications that may interfere with vitamin D metabolism.