Milk-drinking men have a higher risk of prostate cancer

Prostate Cancer - How Foods Fight Cancer

Large studies have shown that milk-drinking men have a higher risk of
prostate cancer. However, milk’s ability to boost IGF-1 is not the only
mechanism by which this occurs. Milk is also high in fat and has no fiber
at all. As a result, it may increase the body’s production of testosterone,
which is linked to prostate cancer risk.

In addition, milk appears to interfere with the activation of vitamin
D in the body. Vitamin D is actually a hormone that helps your body
absorb calcium from the digestive tract. It also protects the prostate
against cancer. Vitamin D is normally produced by sunlight’s action on
the skin. Although it can also come from the diet, edible forms of the vitamin
are inactive precursors. In order to function as full-fledged vitamin D,
the substance must pass first to the liver and then to the kidneys for slight
changes to its molecular structure. This is where dairy products become a
problem. As the load of calcium from ingested dairy products floods into
the bloodstream, it apparently signals the body that, since there is plenty
of calcium in the system already, the body does not need to activate vitamin
D to try to absorb any more. That is, the body reduces its vitamin D
activation so that it does not absorb too much calcium, since calcium
overdoses can be toxic.

The result: High-calcium foods can cause a substantial drop in the
amount of activated vitamin D in the blood. And since vitamin D is essential
for maintaining a healthy prostate, less vitamin D in the blood may
mean that the risk of prostate cancer climbs. Researchers have found that
less vitamin D in the blood is indeed associated with higher cancer risk.

Milk often contains added vitamin D, but it is in the inactive precursor
form, and dairy consumption suppresses vitamin D activation in the body.1
At least twenty research reports in diverse populations, including the
Harvard studies mentioned above, have linked milk drinking to prostate
cancer. In addition, two recent meta-analyses that evaluated the combined
results of twelve prospective studies and eleven case-control studies found
a consistent positive association with both dairy intake and calcium intake
on prostate cancer risk.7,8