In mice models of breast cancer, researchers at the Georgetown Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center, found that vitamin D significantly reduced development of estrogen receptor-positive (ER+) breast cancer both in lean and obese mice, but had no beneficial effect in estrogen receptor-negative (ER-) cancer. In fact, obese mice destined to develop ER- breast cancer were clearly worse off than lean ER- mice if they were given vitamin D in their diet.
The researchers also found that vitamin D reversed insulin resistance in obese mice, no matter which breast cancer subtype they later developed. In lean mice, however, there was no evidence that vitamin D increased insulin sensitivity. “Use of vitamin D supplementation is clearly tricky. In the many studies that have been done studying the effect of vitamin D in different cancer types, there is no straight link between use and benefit,” says the study’s lead investigator, Leena Hilakivi-Clarke, Ph.D., a professor in the Department of Oncology. For example, in the colon, vitamin D seems to reduce the risk of cancer development, but it may not have any effect on later stage colon cancer.
There is also concern that vitamin D may increase the risk of prostate, esophagus and pancreatic cancer. In work she has conducted in endometrial cancer, Hilakivi-Clarke found that although vitamin D was not beneficial in lean mice, in obese animals it reverses both early and advanced stages of the cancer. “This is not a vitamin that should be taken lightly,” she cautions. “People need sufficient amounts because it has beneficial effects for overall health that have nothing to do with preventing cancer. But for those who want to boost their use of vitamin D, it is important that they have their individual levels tested by a physician, and that they discuss their desire to use supplements.”
– Georgetown University Medical Center
Comments by Dr. Keith & Laurie Nemec on Vitamin D
What this study shows is that more is not always better. There is an ideal physiological dosage for every vital nutrient and that dosage can be attained without harmful effects when it comes from a food source or from the sun exposure. Vitamin D can be beneficial as part of an alternative cancer treatment program if it comes from the sun or vitamin rich foods. If it is taken in supplemental form then it needs to be monitored with vitamin D blood testing. The best way to live the God directed and God designed life is to live the 7 Basics Steps to Total Health Lifestyle each day.
