Evidence of the Benefits of Vitamin D

Posted on by Margo Gladding

Two meta-analysis studies have been published online demonstrating the benefits of vitamin D on breast cancer and colorectal cancer.

What are meta-analysis studies? Meta-analysis combines the results of several studies that address a set of related research hypotheses – in this case, the outcome of vitamin D on breast cancer and colorectal cancer. The studies were conducted by a team of cancer prevention specialists at the Moores Cancer Center at the University of California, San Diego, as well as by colleagues on both coasts.

The findings showed that taking 2,000 IU of vitamin D3 daily increased blood levels of vitamin D and reduced instances of colorectal cancer by about two-thirds and breast cancer incidents by half.

Breast cancer research
For the breast cancer meta-analysis, published online in the Journal of Steroid Biochemistry and Molecular Biology, the data from two previous studies involving 1,760 people were divided into five equal groups, from the lowest blood levels of vitamin D (less than 13 nanograms per millilitre) to the highest (about 52 ng/ml). The data showed conclusively that the higher the amount of vitamin D in the blood, the lower the rate of breast cancer.

Colorectal cancer research
Similarly, the colorectal cancer meta-analysis, published online in the American Journal of Preventive Medicine, pooled data from five studies involving 1,448 people and found that when individuals took 2,000 IU of vitamin D daily (about 46 ng/ml), the rate of colorectal cancer dropped by two-thirds.

Recommended intake of vitamin D
One of the coauthors recommends 2000 IU per day, saying that 400 IU (the current RDA) is not enough to make a difference in cancer prevention. It is currently set at 400 IU to prevent rickets and decrease bone fractures. Research by Reinhold Vieth, director of the Bone and Mineral Laboratory at Mount Sinai Hospital in Toronto, has shown that daily vitamin D dosages of up to 10,000 IU are safe.