Raising Vitamin D levels could cut down the number of people who develop colon or breast cancer by tens-of-thousands each year

September 10, 2007

In lab experiments Vitamin D helps prevent cancer cells from growing and spreading. In published clinical trials people who were supplemented with high dosages of Vitamin D had fewer cancers.

In this new study scientists from the University of California, San Diego, compared the average-wintertime blood levels and the rates of both colon and breast cancer in 15 countries. The rates of the cancers fell as the blood levels of Vitamin D increased. The average late-winter Vitamin D level among Americans was 15 to 18 ng/ml. The protective effect against colon cancer appeared to begin when blood levels reached 22 ng/ml. For breast cancer the protective effect started when blood levels reached 32 ng/ml. Based on the data the researchers argue that if Americans were able to maintain a Vitamin D level of at least 55 ng/ml, there would be 60,000 fewer cases of colon cancer (number of new cases estimated each year in the USA is 107,300), and 85,000 fewer cases of breast cancer (out of an estimated 180,000 new cases each year). Therefore about 56% of all cases of colon cancer and 47% of all cases of breast cancer in the USA would be totally prevented simply by raising the blood level of this inexpensive and safe Vitamin (and that is just in one year). Worldwide the number of colon cancer cases would drop by 250,000 and the number of cases of breast cancer would drop by 350,000. The researchers estimate that besides modest sun exposure people should consume 2000 IU of Vitamin D every day. The study is published in the August 2007 issue of the journal Nutrition Reviews.

Commentary by Jerry Hickey, R.Ph.; my recent lab test shows that the level of active Vitamin D in my blood as measured by the active form (1,25,Dihydroxycholecalciferol) is 42.5 ng/ml. The normal level according to the lab (BioReference Laboratories) ranges from 25.1 to 66.1 ng/ml. A year ago I would have been very happy with this level, but now I have increased my daily intake to 2,200 IU of Vitamin D3; D3 converts to the active form better than D2. Many people are deficient in Vitamin D and they depend on dairy as a source but a glass of milk typically supplies only 100 IU of Vitamin D and many multiple vitamins also supply as little as 100 IU. According to many studies Vitamin D decreases the risk of colon, breast, prostate, ovarian, rectal (in some populations), and pancreatic, and other cancers and adequate Vitamin D levels are needed to cut cancer incidence.