Vitamin D (3) (Cholecalciferol)

In 1992, Edward Mellanby discovered vitamin D while researching the bone disease rickets. Nicknamed the “sunshine vitamin” because it can be produced by the exposure of the skin to the sun, as well as to full-spectrum ultraviolet rays, vitamin D is needed by our bodies to absorb calcium and phosphorus. It is also vital to healthy bones and teeth. Research has revealed that a shocking 40 percent of the general population is lacking in adequate levels of vitamin D. However, there is only a small margin between safe and toxic levels of this vitamin, and excess can cause kidney damage.

Vitamin D is currently known as a pro-hormone involved in mineral metabolism and bone growth. Its most dramatic effect is to facilitate intestinal absorption of calcium, although it also stimulates absorption of phosphate and magnesium. In the absence of vitamin D, dietary calcium is not absorbed efficiently. Vitamin D stimulates the expression of a number of proteins involved in transporting calcium from the lumen of the intestine across the epithelial cells and into blood.

The term vitamin D (synthetic) actually refers to a group of steroid molecules. Naturally occurring vitamin D3, also known as cholecalciferol, is generated in the skin of humans and animals when light energy is absorbed by a precursor molecule 7-dehydrocholesterol. Those with adequate exposure to sunlight, who are generally healthy, do not normally require dietary supplementation of vitamin D.

Vitamin D is called the “sunshine vitamin” because the body will produce sufficient vitamin D when the skin is exposed to the sun two or three times weekly for as little as 15 minutes. Vitamin D is essential for the absorption and use of calcium in our bodies and for maintenance of strong bonds; it is also known as the most important nutrient in preventing osteoporosis and in reversing depression vitamin D is a fat-soluble vitamin that is stored in the body fat and released as required.

The yeast form of vitamin D, called vitamin D2 or ergosterol, is made by artificially irradiating fungus in an exposure process. Vitamin D from ergosterol is not a naturally occurring form of vitamin D. It is manmade for consumption as a vitamin D supplement. Ergosterol is often used as the vitamin D source in fortified foods and food supplements.

Naturally occurring vitamin D in foods is scarce. Fresh-water algae, sea vegetables, shitake mushrooms, and edible weeds are the vegetable sources highest in naturally occurring vitamin D. In years past it was common, although undesirable and unhealthy, for mothers to give their children cod liver oil daily to avert a concern over rickets. Vitamin D deficiency was such a problem among many children that governments mandated that all milk be fortified with synthetic vitamin D. The best naturally occurring source of vitamin D is still made by the body in response to sunshine and full-spectrum lighting.

Adequate vitamin D is necessary for health, our consuming large quantities of synthetic vitamin D is dangerous. The immediate effect of an overdose of vitamin D is abdominal cramps, nausea, and vomiting. Toxic doses of vitamin D taken with time may result in a buildup of irreversible deposits of calcium crystals in the soft tissues of the body that damage the heart, lungs, and kidneys.