Vitamin D and Calcium Act Jointly to Prevent Cancer

Monday Sept 28, 2009 (foodconsumer.org) -- An article published in the Sept 2009 issue of Anticancer Research suggests that vitamin D supplements may better be used together with calcium supplements to prevent cancer.

Low, insufficient or deficient vitamin D is now considered as a risk factor by many researchers for various types of cancer.  For example, scientists suggest that maintaining high levels of vitamin D can reduce risk of breast cancer by up to 70 percent.

Ecological studies using UV-B exposure as an index of vitamin D3 photo production in the skin found a highly significant inverse relationship between UV-B and mortality of fifteen types of cancer, according to Peterlik M and colleagues, authors of the article from Medical University Vienna in Austria.

For colon, rectal, breast, gastric, endometrial, renal and ovarian cancer, a similar inverse association between incident cancer cases and intake of calcium has also been established.

Already known is that lung and endometrial cancer, as well as multiple myeloma, are sensitive to both vitamin D and calcium.

Physiological studies have found that locally produced 1,25 dihydroxyvitamin D3 and extracellular Ca2+ act jointly as key regulators of cellular proliferation, differentiation and function.

The authors listed three ways 1,25-dihydroxyvitamin D3 and calcium interact to modulate cell growth:

(i) Signaling pathways from the VDR and the CaR converge on the same downstream elements, e.g. of the canonical Wnt pathway;

(ii) high extracellular calcium modulates extrarenal vitamin D metabolism in favor of higher local steady-state concentrations of 1,25(OH)2D3;

(iii) 1,25(OH)2D3 may up-regulate expression of the CaR and thus augment CaR-mediated antiproliferative responses to high extracellular Ca2+.

In conclusion, Peterlik et al. suggests that combined supplementation is required for optimal chemoprevention of cancer by calcium and vitamin D.

Vitamin D is naturally synthesized in the skin when exposed to the sun. Vitamin D supplements can be a cost-effective way to acquire the vital nutrient.  Calcium can be obtained from both animal-based foods and plant-based foods.

High concentrations of calcium are found in both animal-based foods such as milk, yogurt and cheddar cheese and plant-based foods such as pinto beans, red beans, white beans, tofu, bok choy, kale, Chinese cabbage, broccoli, rhubarb and spinach.

The calcium in plant-based foods is more easily absorbed than that in milk. The foods that contain high levels of absorbable calcium include rhubarb, spinach, Chinese cabbage, tofu, red beans, and pinto beans.

By David Liu, edited by Rachel Stockton