2023-10-19 08:22:16
by Anna Fregonara
Vitamin D is actually an important hormone for bones, muscles and the immune system. Part of our needs come from food, but part comes from exposure to the sun without protective creams. The summer reserve is not enough: here’s how to do it
So important because it is a hormone although it is called vitamin D. And it is famous as the sunshine vitamin. In fact, it is synthesized in the skin after exposure to ultraviolet B rays, those that reach the subcutaneous tissue. a fat-soluble hormone and for this reason it needs a little (not too much) cholesterol to develop, explains Maria Luisa Brandi, endocrinologist, president of the Observatory on Fragility Fractures (Off) and of the Italian Research Foundation on Bone Diseases ( I sign).
Its main role is to regulate the intestinal absorption of calcium and phosphorus, promoting normal bone formation and mineralization. It also guarantees normal muscle contractility and interacts with the immune system, exerting an immunomodulatory effect. It comes in two important forms for humans: vitamin D2 (ergocalciferol), which is taken with food of plant origin, and D3 (cholecalciferol) which is synthesized by the body when we expose ourselves to the sun or eat foods of plant origin animals that contain it.
How do you get enough in the winter?
The summer supply is not enough to guarantee needs for the whole year. Even from November to March it is good to expose at least your face, neck, arms and hands to the sun for 30 minutes a day. Only for this half hour without sunscreen, which prevents UVB rays from working (for the rest of the time it is always essential to spread it, with protection 30 or 50 depending on the more or less pale skin, on all exposed parts of the body because there protects itself from the risk of melanoma). The other natural source of vitamin D is food, which provides 10-20% of the requirement. The foods that are richest in it are: fatty fish (such as snapper, cod, sea bream, dogfish, sole), milk, dairy products and cheeses, pork, beef liver, cod liver oil, egg yolk and mushrooms .
What factors affect absorption?
In addition to sun exposure and diet, advanced age, smoking, obesity, excess alcohol, some drugs, pathologies such as celiac disease, Crohn’s disease, osteoporosis, hyperparathyroidism count. It is not possible to suggest a general recommendation for everyone because it changes, in everyone, how much is ingested and absorbed, how much is metabolised and how, how much becomes accessible. The signs that patients report that can make the doctor suspicious of a possible deficiency are muscle weakness and pain in the muscles and bones.
How can you estimate your vitamin D reserve?
The most accurate method is the dosage of vitamin D metabolised by the liver in its serum form with a blood sample: we speak of deficiency when blood levels are less than 30 ng/L (nanograms per litre). The results of the analyzes must be evaluated by the doctor, the only one who can indicate if necessary to prescribe a supplement or recommend foods fortified with D. By instead analyzing calcium and phosphate at plasma and urinary levels we understand how efficient we are in vitamin D, says the professor Maria Luisa Brandi. Is it true that people with dark skin need to expose themselves to the sun for longer periods because melanin slows down the absorption of vitamin D? Melanin reduces its synthesis in the skin. also confirmed by the fact that dark-skinned North American people have lower levels of vitamin D than white-skinned people, even if habits and customs are the same.
October 19, 2023 (modified October 19, 2023 | 08:21)
© ALL RIGHTS RESERVED
#hour #sun #face #arms #time.news