New evidence: Vitamin D supplements reduce breast cancer risk

A new study led by Canadian researchers and published in the April 14, 2010 issue of American Journal of Clicnical Nutrition suggests that taking vitamin D supplements may help reduce breast cancer risk drastically.

Anderson L.N. and colleagues from Population Studies Surveillance Cancer Care Ontario in Toronto Canada conducted the case-control study and found women taking 400 IU/day of vitamin D were at 24 percent lower risk of breast cancer compared to those who did not take supplements.

Anderson compared 3101 breast cancer patients aged 25 to 74 with 3471 controls for their intakes of vitamin D trough food and supplements to see if vitamin D has anything to do with the risk of breast cancer.  

Early evidence suggests that vitamin D deficiency boosts the risk of the disease.

Although there was an association between taking vitamin D supplements and irks of breast cancer, vitamin D in food or combined intake of vitamin D from food and supplements were not associated with the risk.

A few foods that naturally contain vitamin D include fatty fish, egg york and mushroom. A number of processed foods and beverages that are fortified with the vitamin include milk, orange juices and other solid foods.

The researchers also found calcium supplement intake was not significantly associated with reduced risk of breast cancer even though there appeared to be an inverse trend between the two.  Further they found there was no interaction between vitamin D, calcium and menopausal status in terms of their effects on the risk.

Another case-control study led by Japanese researchers and reported in the Jan 12 2010 issue of Cancer Science suggests that the protective effects of vitamin D and calcium intake against breast cancer may vary by menopausal status and receptor status.

For the study, Kawase T and colleagues from Aichi Cancer Center Research institute in Nagoya Japan compared 1803 breast cancer patients with 3606 people with cancer.

They found a significant inverse association between vitamin D and calcium intake and breast cancer risk among all subjects. Those whose intake of vitamin D and calcium were in the top quartile were 24% and 17% reduced risk of breast cancer compared to those whose intakes were in the lowest quartile.

They also observed that vitamin D may only help premenopausal women and calcium may only help postmenopausal women to reduce breast cancer risk. The associations were modified by the receptor status.

sunshine is the best source of vitamin D.  15 to 20 minutes of exposure to the sun at the hottest hour may result in enough vitamin D for the day, up to 10,000 IU at least.  Experts say those who stay indoors need to take vitamin D supplements to maintain a healthy level to prevent all kinds of diseases including  cancer, diabetes, heart disease, and many others.

Dr. John Cannell, an vitamin D expert and director of Vitamin D Council, says on his website people need to take at least 4000 to 5000 IU per day to maintain a protective level of this vitamin.  Canadian Cancer Society has already recommended taking 1000 IU per day to help prevent cancer.

By David Liu

Photo credit: wikipedia