Prostate Cancer: The Smoking Guns of Milk Consumption

Scientist prove milk-drinking men are more susceptible to prostate cancer, but continue trying to figure out why. There are three smoking guns: the suspicion that milk increases testosterone, milk seems to increase IGF-I, and milk tends to disrupt vitamin D balance. The first explanation for why milk might be associated with higher risk of prostate cancer in men is that the more fat consumed, the more the body is likely to make testosterone. A higher fat diet promotes testosterone production, which tends to increase the risk of prostate cancer.

 IGF-I (Insulin-Like Growth Factor I) plays a role in the increase risk of prostate cancer. Its name comes from the fact of taking cancer cells, putting them in a test tube, and adding IGF-I to them, they grow and start multiplying. "Insulin-like" means it acts like insulin, moving sugar from the blood stream into the cells. Everyone has IGF-I, although the serum concentration in adults varies dramatically from one person to another. IGF-I hastens cancer cell growth in-vitro (in the test tube), which is the key factor in IGF-I role in the increase risk of prostate cancer.

  

The vitamin D phenomenon is quite interesting. When the sun hits your skin it makes vitamin D. It's made right in your skin, but it's not active yet. It's a preliminary form of vitamin D. The vitamin D goes to the liver where the first step of activation occurs and a hydroxl group (-OH) is added. Then it goes to the kidney where another one is added in the second step of activation. You now have the active form of vitamin D which goes to the digestive tract to help your body absorb calcium. That is vitamin D's function.  

Vitamin D has another function important to you--vitamin D protects the prostate. Vitamin D helps protect the maturity of prostate cells. If you have too much calcium in your diet, from milk or other source, your body stops activating all that vitamin D. The Vitamin D activation pathway is blocked.  Your body says “I don't need any more vitamin D." The problem is, the prostate loses out. The prostate was depending on that vitamin D to maintain its maturity. Now it's lost it because the body has too much calcium in the blood.

Ironically, even though you drink vitamin D-fortified milk, the increased calcium intake reduces the amount of active vitamin D in the bloodstream. This is due to the fact that vitamin D in milk is a precursor. It is not yet the active form. For example, men in a Harvard Physicians’ Health Study who consequently got prostate cancer had a higher IGF-I level and a lower vitamin D level. The more calcium they consumed, the more misfortune they were in. These are the things we learn as researchers seek to explain the effects of milk and dairy consumption.