The benefits of vitamin D for prostate health may be due to the
action of the vitamin on a specific gene, suggests new research that
deepens our understanding of how nutrients and genes interact.
US researchers from the University of Rochester Medical Center report
that the active form of vitamin D in the body, 1,25-hydroxylvitamin
D3 (1,25(OH)2D), may link with a gene known as G6PD, which releases
an antioxidant enzyme and protects DNA from damage. 

According to lead researcher Yi-Fen Lee: “Many epidemiological
studies have suggested the beneficial properties of vitamin D. Our
findings reflect what we see in those studies and demonstrate that
vitamin D not only can be used as a therapy for prostate cancer it
can prevent prostate cancer from happening."

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Two sides of the vitamin
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Vitamin D refers to two biologically inactive precursors - D3, also
known as cholecalciferol, and D2, also known as ergocalciferol. Both
D3 and D2 precursors are hydroxylated in the liver and kidneys to
form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form,
and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active
form that is tightly controlled by the body.

There is growing evidence that 1,25(OH)2D has anticancer effects, but
the discovery that non-kidney cells can also hydroxylate 25(OH)D had
profound implications, implying that higher 25(OH)D levels could
protect against cancer in the local sites.

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Assessing the results
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The new study, supported by a grant from the US Department of
Defense, appears to provide further compelling evidence of the potent
anti-cancer benefits of 1,25(OH)2D. 

Normal healthy prostate cells (BPH-1 and RWPE-1) and prostate cancer
cells (CWR22R and DU 145) were subjected to oxidative stress. The
researchers found that 1,25(OH)2D induced G6PD (glucose-6-phosphate
dehydrogenase), a key antioxidant enzyme, in the healthy but not
cancer cells. G6PD scavenges reactive oxygen species (ROS) associated
with DNA damage.

Commenting on the findings Lee said: “If you reduce DNA damage, you
reduce the risk of cancer or ageing. Our study adds one more
beneficial effect of taking a vitamin D supplement. Taking a
supplement is especially important for senior citizens and others who
might have less circulation of vitamin D, and for people who live and
work areas where there is less sunshine.”

“In this study, we have demonstrated that 1,25-(OH)2D can protect
non-malignant human prostate epithelial cells against H2O2-induced
cell death through modulating the ROS defence systems, suggesting a
possible role of 1,25-(OH)2D in prostate cancer prevention”. 

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Vitamin D - bad for cancers, good for you
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Lee and his fellow researchers noted that 1,25(OH)2D may act both as
an antioxidant and a pro-oxidant, depending on the cellular
environment, with a subtle pro-oxidant activity found in cancer
cells, while it appears to behave as an antioxidant in normal healthy
cells. 

"[Our] data suggest that vitamin D might exert a subtle oxidative
stress, which could stimulate the detoxification mechanisms to
protect cells from the subsequent stress challenges; yet cancer cells
lose the 1,25-(OH)2D-induced detoxification responses, therefore,
1,25-(OH)2D acts as a pro-oxidant in cancer cells," they said. 

"Our results provide one mechanism to explain how 1,25-(OH)2D
protects non-malignant human prostate epithelial cells from oxidative
stress to attenuate the accumulation of oxidative damages during the
life. 

"Therefore, vitamin D might be beneficial for preventing the
development of age-dependent diseases," they concluded.