by Eileen Eva

Created on: October 04, 2010   Last Updated: March 25, 2011

The sunlight has many twists; your ophthalmologist says that you need to use sunglasses with UV protection. The dermatologist cautions you against overstaying under the sun and not using enough sunscreen. The nutritionist says you are not getting sufficient Vitamin D and advices to should stay under natural sunlight more. After listening to them, you are left wondering who to pay attention to.

What is Vitamin D and who needs it?

Vitamin D forms a group of secosteroids that are fat-soluble and grouped in 5 different classes, D1 to D5. We only need ergocalciferol and cholecalciferol or D2 and D3 respectively. When grouped, the two can be referred to as Vitamin D.

Daily functions of Vitamin D include regulation of phosphate and calcium levels in the bloodstream, leading to proper mineralization and development of bones. Lack of enough Vitamin D will result to rickets and osteoporosis in children and adults respectively. Vitamin D is also responsible for modulation of neuromuscular functions in the body.

Vitamin D also helps strengthen our immunity, reduce risks of peripheral artery disease, cancer and fighting the flu. It is believed that, lack of enough exposure to sunlight during the winter reduces synthesis of Vitamin D and results to higher cases of influenza.

The relationship between natural sunlight and Vitamin D

The human skin and the skin of vertebrates in general, can synthesize Vitamin D3 through the reaction of 7-dehydrocholesterol and ultraviolet light at wavelengths between 270-300nm. This wavelength is attainable under the midday sun and exposure of about 10-15 minutes. 7-dehydrocholesterol is found in large concentrates in the epidermal layer of our skin. The synthesis of Vitamin D by our skins through UVB gives the vitamin the nickname “sunshine vitamin”.

What is the required daily intake of Vitamin D?

Depending on your geographical location, season, skin type and exposure to the sun, you could be getting insufficient Vitamin D from natural sunlight. To address this, the following Vitamin D intake other than the sun is recommended.

Pregnant and lactating mothers should consume 600 IU daily. People aged 71 and above regardless of sex should take at least 800 IU a day. Those aged 1 to 70 years should consume 600 IU every day. Aged people are encouraged to ensure they get enough Vitamin D to help prevent osteoporosis, a condition common in old age.

Other sources of Vitamin D

It is believed that fatty fish and fish liver oils have the highest amounts of Vitamin D. Fish like Tuna, Salmon, Mackerel, Catfish and Eel will provide sufficient amounts of the vitamin. Fortified cereals and milk also qualify as sources of Vitamin D. For vegans, mushrooms and yeast exposed to UV will provide enough amounts of Vitamin D.

There is no danger of the skin over synthesizing Vitamin D but you can overdose when ingesting it. Pregnant women should be careful with Vitamin D supplements as an overdose can result in mental retardation and facial deformation of their infants.

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