About Vitamin D

What is Vitamin D

Vitamin D is a fat-soluble (dissolves in fats and oil) vitamin with many positive health effects. In humans, vitamin D is unique pro hormone, the “sunshine vitamin” that is produced endogenously on the skin when in contact with ultraviolet rays of sunlight. Vitamin D is long been known to be vital for bone health. Growing evidence shows that lack of Vitamin D is linked to many diseases such as Type 1 diabetes, cardiovascular diseases, depression, rickets, schizophrenia, autoimmune diseases and infections, asthma, many cancers, rheumatoid arthritis and multiple sclerosis. Everyone needs Vitamin D but some need it more crucially such as children below 3, pregnant and lactating women, people with limited sun exposure, elderly people, people at risk for osteoporosis, dark skinned and vegans.

Vitamin D2 VS D3

There are two types of Vitamin D. Vitamin D3 (cholecalciferol) is produced by the skin through absorbing sunlight. Vitamin D2 (ergocalciferol) is produced from plants and mushrooms. Vitamin D3 is 87 per cent more effective in raising Vitamin D levels*. The sun’s rays provide ultraviolet B (UVB) energy. The sun-skin contact kicks off the process of producing pre-vitamin D and then in the liver and kidney to start making vitamin D.

Sources of Vitamin D

Most people get the vitamin D they need through sunlight exposure. 20 minutes of exposure to sunlight produces up to (10,000 to 20,000 IU) 250 µg of Vitamin D in the skin. This is equivalent to serum calcidiol (25-OH D) level of 100-200 nmol/l. It can also be obtained through the diet, but very few foods naturally contain vitamin D. These foods include fatty fish, fish liver oil, and eggs. Also meat and cheese contain small amounts. Most dietary vitamin D comes from fortified foods, such as milk, juices, yogurt, bread, and breakfast cereals. Vitamin D can also be obtained through dietary supplements.

Selected food sources of vitamin D

  • Food Vitamin D (IU*)
  • Salmon, 3.5 ounces 360
  • Mackerel, 3.5 ounces 345
  • Tuna, canned, 3.5 ounces 200
  • Orange juice, fortified, 8 ounces 100
  • Milk, fortified, 8 ounces 98
  • Breakfast cereals, fortified, 1 serving 40–100
*IU = international units Source:
Office of Dietary Supplements, National Institutes of Health