If you’ve been diagnosed with breast cancer, or you’re at risk for it, have your blood levels of vitamin D checked right away. A new study found that women with low blood levels of vitamin D at the time of breast cancer diagnosis were almost twice as likely to have their cancer spread, and 73% more likely to die over the next 10 years compared to women with adequate vitamin D levels. Risk factors include being age 55 or older,  having an abnormal biopsy, especially proliferative lesions with atypia, a family history or genetic predisposition, having used hormone replacement therapy, DES exposure, chest radiation exposure for another cancer, inactivity and obesity.

Only about one quarter of the women had adequate blood levels of vitamin D at the time of diagnosis.

Breast cancer cells have vitamin D receptors, and when the receptors are activated by vitamin D, it triggers a series of molecular changes that can slow down  cell growth, cause cells to die and make the cancer less aggressive, says head researcher Pamela Goodwin, M.D., professor of medicine at the University of Toronto.  Obesity can reduce blood levels of vitamin D, because fat traps the vitamin.

Monitoring blood levels is important because you don’t want to overdo it, either. An optimum level mid-range is 30-60 ng/ml, according to leading vitamin D researcher, Michael Holick, M.D. If your doctor doesn’t know anything about this, or doesn’t think it’s important, he’s got his head in the sand. Find someone who does.

The Anti-Aging Bottom Line: If you have low levels of vitamin D, it’s almost impossible to raise your blood levels enough without supplemental vitamin D, and you may need high doses initially to get back to normal. Once you’re at normal, experts are now recommending 1,000-2,000 IU a day (from both food and supplements) of vitamin D3, the most active form, to stay in a normal range.

QUICK TIP: According to Jean Carper, vitamin D supplements are safe up to a daily dose of 10,000 IU. Learn More

RELATED PRODUCTS: Our Original, PLUS and GOLD Multi Nutrient Formulas contain 1,000 IU of vitamin D3. In 2007, we increased the amount in our formulas from 600 IU to 1,000 IU, in response to research indicating that the RDA for vitamin D is far too low for most adults.

Written exclusively for Stop Aging Now, the authority on anti-aging research, anti-aging nutrition, and anti-aging supplements.