Vitamin D deficiency is now being recognised as one of the most common medical conditions worldwide
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OK article There’s much more to the sunshine vitamin in India Express Aug 20, 2011
Vitamin D deficiency is now being recognised as one of the most common medical conditions worldwide. The consequences of its deficiency include poor bone development and health as well as increased risk of many chronic diseases, including Type I and Type 2 diabetes, rheumatoid arthritis, Crohn’s disease, multiple sclerosis, heart disease, stroke, high blood pressure, infectious diseases, tuberculosis, asthma, psoriasis, depression as well as increased risk of dying of many deadly cancers including colon, prostate, and breast.
Vitamin D’s role in skeletal growth and maintenance and in the formation of teeth and the bones is well-known. Severe deficiency of this vitamin leads to soft bones that bend and break easily — referred to as rickets in children and osteomalacia in adults.
The major source of vitamin D for most humans is exposure to sunlight. There is, however, much more to the ‘sunshine vitamin’ when it comes to what it does for us.
Though this vitamin is naturally present in very few foods, it is added to foods through fortification in developed countries. A long-held assumption that the vitamin D content of the food supply is sufficient to maintain healthy circulating levels when adequate sun exposure is compromised is a fallacy worldwide. Even in country like ours with plenty of sunshine, this deficiency is being recognised.
Rich food sources include fish, oils, ghee, butter and egg yolk. Compared to fish-liver oil, which is the best dietary source of vitamin D, other foods are quite low in this vitamin. Ideally, a diet that includes dairy, fish and egg yolk coupled with adequate exposure to sunshine should prevent vitamin D deficiency.
However strangely, deficiency of this vitamin appears to be widespread.
An exposure of half an hour a day, around mid-day (11 a.m. to 3 p.m.), is recommended. However, despite abundant sunshine, Indians are particularly prone to vitamin D deficiency. Some of the reasons could be inadequate exposure to sunlight, particularly for those who remain indoors during the day (inside office) or home-bound elderly and an increased use of sunscreens, which is recommended for prevention of skin cancer.
Research has also shown that Indian skin pigmentation needs several times more exposure to sunlight, as compared to fair-skinned, in order to generate the same amount of this vitamin.
In general, the greater the skin pigmentation, the lesser vitamin D is produced. In India, vitamin D deficiency is more common in pregnant women, school going children, young adults and elderly. Vitamin D deficiency can occur without any symptoms but when symptoms occur it indicates severe deficiency.
Vigilance of one’s vitamin D status by the yearly measurement of 25-hydroxyvitamin D, the storage form of this vitamin which correlates best with deficiency symptoms, is suggested to be a part of an annual physical examination. A significant role of this hormone is as an immune enhancer. The hormone stimulates white blood cells which regulate the immune system.
Studies suggest a link between vitamin D and Tuberculosis. In one study, one third of the total subjects suffering from tuberculosis were found to have vitamin D deficiency and supplementation with vitamin D significantly enhanced recovery from tuberculosis. There is some evidence for a role of vitamin D reducing the risk of pneumonia.
Studies have also found a relationship between vitamin D and multiple sclerosis. Vitamin D deficiency also increases the risk of respiratory infections as well. High intake of vitamin D by pregnant mothers reduces the risk of asthma by as much as 40 per cent in children in the age group between 3 and 5 years.