In winter you spend less time in the sun and you are more at risk of a vitamin D deficiency. Let’s see how you can fix it
In winter it is very common to have the low vitamin D: The levels of this nutrient drop when there is less exposure to the sun. This is because vitamin D, compared to other vitamins, is more difficult to take through food: it is found only in a limited number of foods and even with a varied and balanced diet we are often deficient. The alternative source to recover sufficient doses of vitamin D is thedirect exposure to sunlight. In fact, this nutrient is also synthesized in the skin: 15-20 minutes a day of sun exposure without sunscreen are enough to have adequate levels of vitamin D, even without a special diet. Not surprisingly, she is called “sun vitamin”. In the cold months, when you spend a lot of time indoors and you stay covered, there is no possibility of using this natural source of vitamin D and it can happen that you have a low level.
Vitamin D in foods: which ones to choose
As an alternative to the sun, a diet rich in vitamin D includes the consumption of certain foods. The pesce it is the richest food source of this nutrient, which being fat-soluble, is found in greater quantities in fatty fish such as salmon, herring, eel, oily fish and, for molluscs, in oysters. Among plant foods, i mushrooms they can contain significant amounts of vitamin D: their content depends a lot on the period of exposure to sunlight. In the case of mushrooms grown in the dark, such as the classic white mushrooms, the vitamin intake is almost negligible, while in the case of mushrooms grown in the sun, the level of vitamin D can increase up to 40 times. This also happens after harvesting: to increase the vitamin level, just leave the mushrooms to dry in the sun for at least 40 minutes. That’s why the wording “dried in the sun”, in the case of packaged dried mushrooms, it makes all the difference. Other foods with a good supply of vitamin D are egg yolk, which contains about 4.5 µg per 100 g, and some of the fattest cheeses. On the other hand, milk and plant foods have almost no vitamin D content.
Vitamin D deficiency, symptoms
To understand how vitamin D deficiency manifests itself, it is important to first understand how it works. Its function is essential to regulate theabsorption of calcium and phosphorus, therefore for the mineralization of the skeleton. Vitamin D also regulates the expression of genes involved in the regulation of immune system and in cellular differentiation. It is therefore easy to understand the importance of its contribution to our body. Vitamin D deficiency is asymptomatic and presents symptoms only when the deficiency is very severe. The main symptoms are: bone pain, muscle pain, joint pain, muscle weakness and brittle bones. In the most severe cases, neurological symptoms, mental confusion and persistent tiredness may also occur. THE risk factors that can lead to a vitamin D deficiency are advanced age, smoking, obesity, celiac disease and renal and hepatic insufficiency. The subjects most exposed to a serious lack of this nutrient are those who suffer from osteoporosis, hyperparathyroidism (a disease caused by an excess of parathyroid hormone) and lymphomas.
Low vitamin D when supplements are needed
The only way to get a diagnosis of vitamin D deficiency is through the 25-OH-D dosage test, which is carried out with blood sampling: we speak of vitamin D deficiency or hypovitaminosis D when blood levels are less than 30 ng/L. The results of the analyzes must then be evaluated by a doctor, who will prescribe if necessary amount of vitamin D supplement to take. In all other cases, it is sufficient to expose yourself to the sun without protection for at least 15 minutes a day. Even when taking supplements it is good to pay attention to possible side effects of vitamin D poisoning: the most common are vomiting, diarrhea, constipation and mental confusion. In these cases it is advisable to consult your doctor.