NEW EVIDENCE ON AN OLD VITAMIN:
VITAMIN D MAY COMBAT BREAST, COLON AND PROSTATE CANCER
From The Cancer Chronicles #32-#33
? June 1996 by Ralph W. Moss, Ph.D.
When a Western-style diet that is high in fat but low in calcium and vitamin D is fed to mice, by the eighth week the animals begin to develop precancerous growths in their colons. But if the same mice are then given two sources of calcium these changes are routinely reversed (Richter, et al., Carcinogenesis 1995;16:2685-2689).
Until now, vitamin D has been considered primarily important as a regulator of normal bodily levels (or ‘homeostasis’) of calcium. But, in addition to its role as a facilitator of calcium absorption, vitamin D now appears to have other profound effects in the body. Moderate amounts of the vitamin may help slow the growth not just colon but breast and prostate cancer, independent of its effect on calcium absorption.
"It’s becoming increasingly clear that vitamin D has a host of effects in the body, especially on the growth of tumor cells," David Feldman, MD of Stanford University told a seminar sponsored by the American Institute for Cancer Research in Washington, DC last year.
For example, intensive work is being done on the link between low vitamin D levels and prostate cancer. In fact, there is a possibility of even using the vitamin to treat the disease. The aforementioned 1,25-D form of the vitamin has induced several important responses in prostate cells, including growth inhibition.
Dr. Feldman and colleagues recently concluded that "vitamin D is anti-proliferative and promotes cellular maturation." It seems clear, they add, "that vitamin D must be viewed as an important cellular modulator of growth and differentiation....Vitamin D has the potential to have beneficial actions on various malignancies including prostate cancer."
1,25-D may prove useful in chemoprevention, they say, and/or in differentiation therapy. They maintain an "optimistic view on the possible use of vitamin D to treat prostate cancer in patients," and say that "further investigation is clearly warranted" (Adv Exp Med Biol 1995;375:53-63).
Recently, new forms (analogs) of vitamin D have been developed that have much less effect on calcium metabolism, but still retain the vitamins tumor inhibiting properties. The action of the vitamin seems to be regulated by a single receptor site, which has the same structure as certain steroid receptors (Niles, RM. Adv Exp Med Biol 1995;375:1-15).
Canadian scientists have reported that in the test tube cancer cell proliferation is "strongly inhibited" by both vitamin D and its analogs. In some systems, they say, the analogs (such as EB1089) were 10 to 100 times more potent than the original compound. This activity "predicts their potential usefulness" in animals in inhibiting squamous cancer growth (Yu. J, et al. Anticancer Drugs 1995;6:101-108)
Prostate cancer is especially prevalent and deadly among African-American men. What could prevent early prostate cancer from progressing to the malignant phase? It has been found that higher serum levels of vitamin D might do this in both Black and white men. This is so especially after the age of 57.
Scientists have concluded that vitamin D metabolism may indeed impact the risk of prostate cancer (Corder, EH, et al., Cancer Epidemiol Biomarkers Prev 1995;4:655-659).
When human prostate cancer cells were implanted into so-called "nude" mice (which are bred to lack a normal immune systems),Vitamin D slowed malig