In the great family of vitamins, D is a bit exceptional. Unlike vitamins B or C for example, it is not a vitamin itself. From a scientific perspective, it is similar advantage to a pre-hormone because of its metabolic role. The protective properties of vitamin D
In fact, its main role is to maximize the absorption of calcium, which will subsequently bone mineralization. But according to several scientific studies, his interest is not limited to bone growth, far from it. Doctors signatories of the appeal on vitamin D emphasize preventive virtues. Small non-exhaustive review of its beneficial effects on health (1):
Prevention of falls and risk of fractures in the elderly
Vitamin DC'est effect as naturally linked to the primary role of vitamin D. According to a recent meta-analysis (1), a vitamin D combined with calcium in people aged over 50 years could significantly reduce the risk of fracture. This effect is more pronounced among people aged over 70 years. Other studies have shown a reduced risk of falls (and therefore fewer fractures) and improved muscle performance, always among the elderly;
- Against hypertension and cardiovascular disease. If the action of vitamin D on bone is directly related to its role (in combination with calcium), it is surprising that she would also have profound effects on cardiovascular health. The subjects deficient in vitamin D 25 (OH) (blood levels below 15 ng / mL) had twice the risk of developing myocardial infarction compared with those whose vitamin D levels 25 (OH) was sufficient (higher 30 ng / mL). (2) and (3)
- Against cancers. Vitamin D is inversely related to risk of developing certain cancers, including breast and colon. For example, a team of researchers followed over 4 years postmenopausal women who received either a placebo or calcium alone or calcium combined with vitamin D. Women in the latter group showed a reduction in cancer risk by 60% compared to other groups. Furthermore, it has also been shown that the risk of breast cancer is reduced 58% in women whose blood levels of vitamin D is high compared to others with low rates. (4), colorectal cancer also seems directly linked to vitamin D levels in the blood over the latter, the higher the cancer risk is low.
For Professor Serge Hercberg, research director at Inserm and professor of nutrition at the Medical University Paris 13 and forerunner of the famous National Health and Nutrition Program (PNNS), "these studies provide evidence of research interesting and encouraging. Nevertheless It still lacks the data to be able to decide on a firm and final on the preventive role of vitamin D for cancer or cardiovascular disease. For example, the fund international research on cancer (WCRF in English) refers to relationships causal links between vitamin D and colorectal cancer, but data are so far insufficient to make recommendations. The sun, indispensable ally of vitamin D
But after studying SUVIMAX, 75% of the French have lower levels of vitamin D 25 (OH) below 31 ng / mL. Women over age 45 seem particularly prone to this lack of vitamin D because they are almost 90% to be in this case. The situation is similar to the United States where, in 2004, 77% of the population was deficient.
Currently, the French Agency for Food Safety (AFSSA) recommends a daily intake of vitamin D than 400 units per day for children under 3 years old, pregnant women and seniors and 200 units for children over 4 years and adults. "Recent studies suggest that vitamin D intakes above would be necessary in adults, about 1 000 to 2000 units per day to achieve levels of vitamin D 25 (OH) 30 ng / mL, note signatories of the appeal. A supplementation would be particularly important during the months of autumn and winter.
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