Deficiency of Vitamin D
It is estimated that 76.5% of the population of Sa?o Paulo and 50% of world’s population have a deficit of vitamin D. The new recommendation of the “American Society of Endocrinology” is that the reference level of this vitamin should be above 50ng/mL and its deficiency only can be detected by blood test.
Besides regulating the phosphorus and calcium metabolism, ensuring, among other functions, normal bone mineralization and avoiding rickets, new evidence relates insufficient levels of vitamin D to an increased risk of developing other non-bone pathologies such as cardiovascular diseases, hypertension, neoplasms, dementia, infectious diseases and autoimmune diseases as insulin-dependent diabetes, multiple sclerosis, rheumatoid arthritis, lupus and inflammatory bowel disease.
In pregnant women, it could cause preeclampsia and multiple abortions. Vitamin D acts as a potent hormonal precursor regulating the proliferation, maturation and apoptosis of cells. The richest foods in vitamin D are fatty fishes as salmon, sardines, tuna, anchovies and mackerel, but even the daily intake of these foods only accounts for 6.85% of daily necessities. The highest absorption of vitamin D occurs by exposure to the sun through UVB rays.
This is where the controversy begins, since sunscreen impairs the absorption of vitamin D. A sun protector factors (SPF) equals to 8, for example, inhibits vitamin D absorption in 95%. The excess vitamin D occurs only through supplementation, since obtaining it through the sun is regulated by the skin. For being a fat-soluble vitamin, it is not excreted and its excess by bad administered supplementation can be very risky. An elevation of calcium concentration in the blood may occur and cause calcification of various tissues, including the kidney, leading to renal failure. *Do not take supplements without the advice of a nutritionist!