Although the dietary intake is often deficient, especially in strict vegetarians, it is not usually necessary to resort to specific vitamin D supplements.
This micronutrient can in fact be synthesized in the skin starting from cholesterol, following exposure to UVB rays; the possibilities of synthesis are however reduced by atmospheric dust and above all by sun creams, which when they have a protection factor greater than eight can even stop it completely.
It must be said, however, that generally not all the skin is sprinkled with the cream, which moreover is not generally reapplied with the required regularity.
By virtue of all these factors, and of course the latitude, it is difficult to establish what is the time of sun exposure necessary to cover the daily requirement of vitamin D.
It is generally suggested that an exposure of 5-30 minutes a day, on at least a couple of occasions a week and in the hottest hours, is sufficient in this sense; it is not necessary to expose the whole body, it is enough to uncover the arms, the face, legs or back.
Frequency appears to be more important than quantity, given that excessive and unprotected sun exposure, in addition to being a known risk factor for melanoma, does not involve additional benefits on the synthesis of vitamin D.
It should also be specified that the organism is able to keep the accumulated quota to make it available when needed, for example during the winter.
fortified, vitamin D can be present in two different forms, D2 (ergocalciferol, of fungal and vegetable origin) and D3 (cholecalciferol, of animal origin). The latter has been shown to be more bioavailable, even if there are conflicting opinions about it; regardless of its origin, in order to become biologically active, vitamin D must undergo double hydroxylation, first in the liver and then in the kidneys. Once activated, it therefore behaves like a real hormone, acting above all in the intestine to enhance the active absorption of dietary calcium. It therefore contributes to the "homeostasis of calcemia and" adequate bone mineralization.
Vitamin D deficiencies can occur due to one or more of these factors: insufficient food intake, reduced intestinal absorption capacity (malabsorption diseases), chronic kidney diseases (due to inability to activate vitamin D) and insufficient sun exposure. Severe vitamin D deficiencies cause rickets in children and osteomalacia in adults (reduced bone mineralization, with or without skeletal malformations, respectively). Among the factors that expose individuals to a greater risk of vitamin D deficiency, we remember:
- dark complexion (melanin hinders skin synthesis, even if those with darker skin run a lower risk of osteoporosis);
- milk allergy, vegan diet or lactose intolerance (deficiency of foods rich in vitamin D), age over 50;
- obesity (adipose tissue sequesteres vitamin D in proportion to its mass, however it is a protective factor against osteoporosis);
- reduced sun exposure and intestinal fat absorption problems (biliary diseases, cystic fibrosis, Crohn's disease, Orlistat, Cholestyramine, chronic laxative abuse, etc.).
Vitamin D supplements, in combination with calcium supplements, are mainly recommended for postmenopausal women as a preventive strategy against the onset of osteoporosis. This practice is opposed to estrogen replacement therapy, since the deficiency of these hormones contributes significantly to the onset of the disease; however, since it is an endocrine therapy, with potential side effects, in most cases doctors prefer to rely on the simple supplementation of calcium and vitamin D.
The joint use of these supplements can also be combined with prolonged treatment with corticosteroids, in order to prevent osteopenia induced by these drugs (reduction in bone mass).
Other conditions that justify the use of vitamin D supplements: osteomalacia, rickets, familial hypophosphataemia, Fanconi syndrome, secondary hyperparathyroidism due to low levels of vitamin D, hypocalcemia from hypoparathyroidism, psoriasis, muscle pain and weakness, bone problems from chronic renal failure.
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Vitamin D supplementation
soft gel: one tablet a day allows you to take a quantity of Vitamin D3, which is useful for bone health but also for the immune system. Easy to swallow, the capsules are made in the UK, with quality ingredients and to high manufacturing standards.
Dr. Giorgini Vitamin D Food Supplement
The Dr. Giorgini Vitamin D supplement, on the other hand, is available in the form of tablets. Useful for those who have little exposure to the sun but also for those who want to promote the well-being of bones and teeth, thanks to a better absorption of calcium, the tablets contain maltodextrin from corn or rice, microcrystalline cellulose, gum arabic, vitamin D3, silicon dioxide and magnesium stearate of vegetable origin. We recommend taking 1 tablet once a day, at any time of the day.
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