It's fairly clear that Vitamin D is good for you. You need vitamin D to absorb calcium, regulate phosphorus levels, and maintain cell and bone growth, to name a few reasons. While you can get enough vitamin D from about ten to fifteen minutes in the sun, or through foods and supplements, that is not the same amount needed to reduce cancer risk.

The American Institute for Cancer Research (AICR) recently held a conference on food, nutrition, physical activity and cancer. At the conference, researchers shared a new finding: confirmation that certain proteins responsible for tumor growth and development can be activated by vitamin D, making it a key vitamin in reducing cancer risk.

One thing the researchers had not determined was how much vitamin D was needed daily to reduce the risk of cancer. They were almost certain the current daily recommended amount of 400 international units would not be enough. Another issue they were presented with was determining how much vitamin D a person is getting. While it is easy to count supplement grams and the amount of vitamin D in foods, it is not easy to determine how much vitamin D someone is producing in response to sun exposure. Environmental pollution, skin color, and age play a part in determining the amount of vitamin production from sunlight. There are no accurate methods of vitamin D measurement. Blood tests for vitamin D measurement are not very dependable or precise, and even if they were the levels of vitamin D needed in the blood are unclear.

While it is encouraging to hear that vitamin D can potentially decrease the risk of cancer, the details still need to be worked out. How much vitamin D? And once we know how much, the next question is, 'How do I know how much I am producing?'

Some researchers are saying 'go ahead and boost your intake now, because the new numbers are going to show a vitamin D deficiency in most Americans', but others are saying to wait. And still other researchers have conducted studies that counter the results offered at the American Institute for Cancer Research conference - some studies show that vitamin D does not help protect against cancer risk. The jury is still out on a solidified medical agreement.