Vitamin D and cancer

Vitamin D is an essential micronutrient and an endocrine messenger that regulates cellular growth and differentiation.

There are two types of vitamin D – vitamin D3 and vitamin D2. Vitamin D3, or cholecaliferol, is formed in the skin upon UV exposure.The other, vitamin D2, or ergocalciferol, is derived from food or supplements. Low levels of D3 have been associated with increased incidence of breast, colon and prostate cancer.

Vitamin D is both a fat-soluble vitamin and hormone. Vitamin D causes the inhibition of cell proliferation, stimulation of apoptosis, suppression of inflammation and inhibition of tumour angiogenesis, invasion and metastasis.

It is interesting to note that many prostate cancer cells have lost the ability to synthesise D3 but still possess D3 receptors, suggesting the hypothesis that existing prostate tumours might
require treatment with D3.

In a study of 620 healthy volunteers, the risk of developing colon cancer decreased threefold in subjects with moderate D3 plasma concentrations as opposed to those with low concentrations. In addition, low vitamin D3 concentrations have been implicated as a risk factor in cancers of the breast, colon and prostate.

In fact, vitamin D3 has been shown to specifically decrease the expression of aromatase, the enzyme that catalyses oestrogen synthesis selectively in breast cancer by exerting direct and indirect effect. It directly represses the aromatase transcription and decreases inflammation.

A trial demonstrating the potency of both vitamin D3 and D2 has proved that D3 is approximately 87% more effective at raising and maintaining serum 25(OH) D concentrations and produces two- to three-fold greater storage of vitamin D than does D2.