Vitamin D was found in plant life going back more than 750 million years. It's one of the oldest hormones on Earth, says a 2008 review in Nutrition Reviews. Only recently has it become becoming apparent that vitamin D3 reacts with other micronutrients. Although it's not yet known what vitamins need vitamin D3 to function, it is known that several minerals react with vitamin D3.
The Making of Vitamin D3
When your skin is exposed to sunlight, ultraviolet B radiation stimulates a cholesterol-like substance found just under your skin in the epidermis to react. A chemical process takes place, and previtamin D3 is formed, says Nutrition Reviews. From there, the previtamin D3 goes into the bloodstream, where it's transported to the liver. There, another chemical process occurs to form 25-hydroxyvitamin D. From there, it speeds to the kidneys by way of the bloodstream and is converted again, this time to its active form -- called 1,25-dihydroxyvitamin D.
Calcium and Vitamin D
Technically, calcium is a mineral. Its effectiveness in your body is crucial to the amount of vitamin D3 available. Calcium is necessary for strong bones and teeth. If there isn't enough serum calcium in your body, calcium is leached from your bones, which may cause problems such as osteoporosis, rickets and bone density issues. To ensure complete utilization of your dietary calcium, vitamin D3 needs to be available for the chemical process to be completed. In a 2006 study in the "New England Journal of Medicine," more than 36,000 postmenopausal women were given calcium and a vitamin D3 supplement. Half of them received a placebo. The placebo group experienced 1.06 less calcium density as a result of not using vitamin D3. The vitamin D3 group showed a significant improvement in hip bone density.
Phosphorus and Vitamin D
Once vitamin D3 reaches the kidneys, the amount produced is dependent on the amount of phosphorus in your bloodstream. Every cell of your body requires phosphorus to function normally. Most of the phosphorus -- about 85 percent, according to the Linus Pauling Institute -- is in your bones. You need phosphorus, along with calcium, for the mineralization of your bones. Vitamin D3 plays a vital role in regulating adequate serum phosphorus levels.
Sources of Vitamin D
There are few natural dietary sources of vitamin D. They include mackerel, sardines, pink salmon and egg yolks. Some foods in the United States are fortified with vitamin D to ensure adequate intake, especially during the winter when people often don't get enough sunshine. Fortified foods include milk, formula, some breads and cereals, and sometimes orange juice. There is some controversy around how much vitamin D is needed daily. The recommended dietary allowance is 600IU per day. The 2008 review in "Nutrition Reviews" recommends the dietary allowance needs to be raised to 1,000IU per day.
References
- "Nutrition Reviews": Vitamin D: a D-Lightful Health Perspective; Michael F Holick; Sept.2008
- "New England Journal of Medicine": Calcium plus Vitamin D Supplementation and the Risk of Fractures; Rebecca D. Jackson, et al.; Feb.2006
- "Linus Pauling Institute": Minerals
- "National Acadamies Press": Calcium and Related Nutrients: Overview and Methods
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