The Essence of Vitamin D

The Essence of Vitamin D

By Dr. GeetaTrilok,
Associate Professor, Institute of Home Economics, Delhi University

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Bring Back the Sunshine

The recent interest in Vitamin D status within the clinical as well as scientific community has gained momentum. The reasons for this are many but primarily this interest has been sparked by reported prevalence of vitamin D deficiency in countries with sufficient sunshine.

The Sunshine Vitamin

Vitamin D is a fat soluble vitamin, commonly known as the ‘Sunshine Vitamin’. Since the discovery of its antirachitic effect (ability to prevent or cure Rickets) in the 1920s, the significance of Vitamin D was largely restricted to its role in maintaining the skeletal system and regulating levels of calcium in the human body. A deficiency of Vitamin D was known to cause improper mineralization of skeleton resulting in rickets in children and osteopenia in adults.

In India for example, Vitamin D deficiency is widespread with over 70% cases being reported across all age groups. Although there is no national data describing the exact extent of Vitamin D deficiency in India, studies conducted in various regions of the country indicate high levels of deficiency as being prevalent. We need to understand though, that this research is limited to one time studies conducted on small sections of people across the Indian subcontinent with limited sample sizes. The only large randomised controlled trial of vitamin D deficiency conducted in the country has showed that a weekly dose of 1400IU (i.e. 200IU per day) of Vitamin D resulted in better Vitamin D levels and increased benefits to functions of bone growth.

Historically, the main source of Vitamin D has always been via synthesis in the skin after exposure to UVB light from the sun or by consumption of Vitamin D products such as cod liver oil, wild caught salmon, other oily fish like tuna and some varieties of mushrooms, most of which are largely absent in Indian cuisines.

In any case, dietary sources of vitamin D are scarce since very few foods naturally contain Vitamin D and thus, Vitamin D intake from the diet plays a minor role in Vitamin D supply to the body, especially in the Indian scenario. Most of the Vitamin D we absorb in India is through exposure to sunlight. When the sun strikes the skin, the ultraviolet B portion of the sun spectrum enters into the skin and is absorbed by 7-dehydrocholesterol molecule present in the skin. This in turn gets converted to Vitamin D3.

India: Sunshine yet is a Vitamin D deficient country

The pertinent question here then is – Why are we facing such an increased deficiency in Vitamin D? We are a tropical country with sufficient sunlight and yet have alarmingly high levels of Vitamin D deficiency whereas people in other tropical countries like Australia, Central America,etc have reasonably adequate levels. We don’t have very dark skin with high melanin that interferes with Vitamin D synthesis like most Africans nor is the general population dressed in a way that all of their body is covered. So if most people in India are neither over covered nor excessively dark and we have lots of sunshine, why are people in India so deficient?

The answer lies in a combination of factors linked to changing lifestyles.

· Urbanization,
· Lack of sunlight exposure due to lifestyle changes or overcrowding,
· Consumption of foods not fortified with Vitamin D,
· High pollution levels and the use of sunscreen creams and skin-lightening products that block the UVB radiation
These are some of the reasons why India is Vitamin D deficient.

But why is this important to understand? The high prevalence of Vitamin D deficiency may appear to be an issue of public health concern in view of the recent role of Vitamin D in human health. Current scientific evidence indicate that the health benefits of Vitamin D go beyond its known bone functions and that it plays an important role in a variety of other physiological functions like cell differentiation, immune function, regulation of blood pressure, regulation of insulin production and many more. Vitamin D deficiency is associated with increased risk of infectious diseases like tuberculosis, with several cancers, multiple sclerosis, cardiovascular disease, Type I diabetes and other health conditions.

Given the fact that the value of Vitamin D supplementation to human health could extend beyond its well-known benefits to bone health, it is imperative then to make this Sunshine Vitamin a part of your daily health regimen in small doses. While future benefits may be a bonus, this would definitely help in maintain healthy bones for better bone health in children and better bone care in the elderly.

So bring back the sunshine to build a healthy country with happy people.

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