Last June 21st marked the start of summer, bringing with it the warmth and intense sunshine. The days grow longer, the long-awaited holidays arrive, along with trips to the beach, swimming pools, outdoor walks and light clothing. And even though at this time of year we spend much of the day outdoors, a significant number of people suffer from a vitamin D deficiency. So what is vitamin D? It is one of the fat-soluble vitamins -soluble in fats or oils- that plays an essential role in regulating calcium and phosphorus metabolism, both essential for the normal formation of bones and teeth, as well as enabling the absorption of calcium in the intestine. It may also play an important role in regulating the immune system. And how do we get it? Through two natural mechanisms: mostly through exposure to sunlight (short-wave UV-B rays of 290 to 320nm) and the synthesis that takes place in the skin -which can cover up to 90% of our daily needs-, and through the consumption of certain foods such as: oily fish, egg yolk, fish liver oil and some types of mushrooms, like shiitake, although all of these together provide only 20% or less of our daily requirement. So why do we have this deficiency if we get more hours of sunshine than other countries? If we stop to think about our daily routine, except for holiday periods, we spend around 90% of the rest of the year indoors, lacking natural light and therefore natural radiation. We need to spend at least 30 minutes in contact with the sun three times a week, during less intense hours, in order to produce a sufficient and healthy amount for the body. Add to this the use of sunscreen, which filters out precisely the short-wave ultraviolet rays, and a diet lacking in vitamin D, and the result is a deficiency of this vitamin.
What are the symptoms? Diffuse bone pain and joint pain, lack of energy, muscle weakness and easy fatigue when walking, muscle spasms and, in very severe cases, bone fractures. *If you experience any of these symptoms, a blood test is essential to confirm the deficiency. And what are the consequences? It reduces calcium absorption in the intestine and promotes the depletion of calcium stored in the bones, leading to bone demineralisation, osteoporosis, rickets, immune disorders, depression, and it has also been linked to respiratory illnesses such as pneumonia, tuberculosis and bronchiolitis. In short, while it is well known that excessive sun exposure can cause skin ageing or melanoma -skin cancer-, what is less well known is how much we need UV rays to synthesise this micronutrient, which is why it is recommended to expose yourself to the sun for about 10 to 15 minutes a day during the hours of lowest sun intensity, and to include vitamin D-rich foods in your diet. The sun is good for keeping us healthy!
Sources: http://www.scielo.org.co/pdf/biosa/v16n1/v16n1a08.pdf https://www.who.int/elena/nutrient/es/ http://https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
