Wisdom Wednesday: Vitamin D May Decrease Breast Cancer Risk

The merits of vitamin D when it comes to cancer prevention have long been at the heart of medical debates. Where some studies have revealed that overall cancer risk is lower in people with higher levels of this vitamin, others have suggested that vitamin D has no impact on a person’s vulnerability to the disease.

Still, the case for ensuring that you get enough vitamin D is fairly strong, as low blood levels of this nutrient have been associated with raised risk of bladder cancer and, in a study that was published earlier this year, an elevated risk of bowel cancer. Previous research has also suggested a link between high vitamin D levels and better survival rates in people going through breast cancer treatment.

In a pooled analysis of a prospective cohort study and two randomized clinical trials, researchers at the University of California, San Diego School of Medicine have now investigated whether and to what extent high levels of vitamin D in the blood were associated with a lower risk of developing breast cancer.

Their analysis – which was conducted in collaboration with specialists from Creighton University in Omaha, ND, the Medical University of South Carolina in Columbia, and the nonprofit organization GrassrootsHealth in Encinitas, CA – suggests that certain levels of vitamin D correlate with a “markedly lower” risk of breast cancer. These results are now published in the journal PLOS ONE.

“We found that participants with blood levels of 25(OH)D that were above 60 nanograms per milliliter (ng/ml) had one-fifth the risk of breast cancer compared to those with less than 20 ng/ml.” – Cedric F. Garland.



Moreover, the higher the levels of vitamin D in the system, the lower the breast cancer risk, explain the scientists. Garland and his team estimated that the minimum healthy level of 25(OH)D in blood should be about 60 ng/ml, which is a lot more than the 20 ng/ml concentration recommended by the National Academy of Medicine.

My Take:
Vitamin D3 taken as a supplement, in food, or converted from cholesterol in the skin from exposure to sunlight is all converted to 25(OH)D by the liver and released into the blood stream. This is the inactive, but stable form of vitamin D. It is then converted by the kidneys or by each individual cell into 1,25(OH)D, the active form. The inactive form is what is commonly measured on blood testing.
The studies that suggest that vitamin D has no impact on health risks have all been conducted on elderly residents of retirement communities. See my blog “Seniors Don’t Need Calcium, Vitamin D Supplements” posted January 5, 2018.

The Bottom Line:
The normal range for 25(OH)D in the blood is 30-100 ng/ml. Levels below 20 are deemed low while 20-30 is considered “insufficient” rather than low? I have been using 42-80 as my healthy range, but will consider raising the minimal healthy level to 60 ng/ml based on this study.

Source: June 18, 2018 National Institutes of Health