Many people are deficient in vitamin D.

Many people are deficient in vitamin D. A glass of milk, for example, has only 100 IU. Other foods, such as orange juice, yogurt and cheese, are now beginning to be fortified, but you have to work fairly hard to reach 1,000 IU a day.

Many people are deficient in vitamin D. The easiest and most reliable way of getting the appropriate amount is from food and a daily supplement.

A preponderance of evidence, from the best observational studies the medical world has to offer, gathered over 25 years, has led to the conclusion that public health action is needed.

Primary prevention of these cancers has largely been neglected, but we now have proof that the incidence of colon, breast, and ovarian cancer can be reduced dramatically by increasing the public's intake of vitamin D.

The higher the level of vitamin D, the lower the risk of breast cancer.