9/22/2007 - Nutrition and Lifestyle -- Vitamin D in the News - an Update - Vicki Saunders, MS, RD

Recently, numerous studies about the association between vitamin D levels and cancer risk have been in the news. And the message continues to be that an optimal level of Vitamin D, higher than many had previously thought, is critical to many aspects of good health – and disease prevention. One such study, from Creighton University in Omaha Nebraska, involved almost 1200 women – some of whom were given calcium supplements; others were given calcium plus 1000 iu of vitamin D; and another group was given a placebo. Researchers were focused on Vitamin D’s effect on bone health, but its effect on cancer prevention stood out as a significant side benefit.

The group of women taking 1000 iu of vitamin D reported a 3% cancer rate over the four years of the study. The group of women taking a placebo, reported a 7% rate. The vitamin D group had an astonishing 60% lower rate of cancer – and when the researchers corrected for those who already had cancer at the beginning of the study, the rate was actually 77% lower.

In February of this year, two meta-analyses were published by Dr. Edward Gorham and Dr. Cedric Garland in the American Journal of Preventive Medicine. The first study looked at colorectal cancer risk correlated with serum levels of 25 hydroxyvitamin D. Results showed that a 50% lower risk of colorectal cancer was associated with a vitamin D level of 34 ng/ml compared with a level of 12 or less. A daily dose of 2000 iu would raise the serum level to about 46 ng/ml, which, according to Dr. Gorham, would lead to a two-thirds reduction in the risk of colorectal cancer for the whole population. For breast cancer, a serum level of 52 ng/ml was associated with a 50% lower risk than 13 ng/ml or less.

“The data are very clear,” said Dr. Cedric Garland. “Individuals in the group with the lowest blood levels of Vitamin D had the highest rates of breast cancer – and the breast cancer rates dropped as the blood levels of 25-hydroxyvitamin D increased.” The level of vitamin D3 required to reach those blood levels are about 4000 iu per day or 2000iu and 10-15 minutes a day in the sun.

And finally, the July issue of American Journal of Clinical Nutrition reported that slightly over half of otherwise healthy children from the Northeast have low levels of vitamin D (defined as below 30 ng/ml). Further studies need to be done to determine whether this level for adults is equally applicable to children and to determine the potential consequences of insufficient vitamin D.

What may not have been a vitamin we are used to making an effort to consume, or at least pay close attention to, has turned out to be ever so critical. We can easily test this level at the Center for Health and help you reach your optimal levels.