In early 2007, however, this theory was abandoned. Compelling evidence from a number of studies suggested that people who lived in sunnier regions built up levels of vitamin D that protected them from a number of cancers. Conversely, those who lived further north, where the sun’s rays are weak, failed to build up these levelsduring the course of daily living.

As a result of these findings, the Canadian Cancer Society has recommended increasing daily intake of vitamin D during the fall and winter months, to reduce the risk for colorectal, breast and prostate cancers. Vitamin D deficiency has also been linked to cardiovascular disease, osteoporosis, juvenile diabetes, multiple sclerosis, and even influenza.

Vitamin D and cell Health

Often referred to as the sunshine vitamin, vitamin D is
manufactured when ultraviolet (UV) light penetrates the upper layers of unprotected skin. The vitamin D is then converted by the liver and kidneys into a form that can  be utilized by the body for cellular repair and other vital functions. It is the ability to repair damage to cells that helps prevent cancers from developing. The genes that respond to vitamin D’s metabolites within the cells play a crucial role in keeping the cell healthy.

Vitamin D and Canadians

In the summer months, when the sun’s rays are stronger, Canadians who expose their skin to sunshine for a brief time period every day, generally manufacture enough vitamin D to provide adequate protection from disease. For full body exposure, this time period is
estimated to be 15 minutes, and for half body exposure, two 15 minute periods daily. (People with darker skins require considerably longer exposure—some say 10 times as much— as their natural pigmentation filters out more of the rays responsible for the production of vitamin D.)

The problem occurs during the fall and winter, when the sun’s rays are weak and do not produce significant levels of vitamin D in the skin. During this time, our bodies use stores of vitamin D produced in the summer and whatever is supplied in the food, but this appears to fall short of the amount required for optimum protection against disease.