Vitamin CVitamin C is a antioxidant, meaning it helps prevent cell damage. Vitamin C has been shown to reduce cancer growth in some types of cells grown in laboratories, but this effect has only been seen at high doses over long periods of time. Studies in humans have not shown a reduced risk of prostate cancer with vitamin C.
Vitamin DVitamin D is a vitamin that is found in food and is also produced by the body and activated after exposure to ultraviolet light from the sun. Studies suggest that activated vitamin D may be broken down in the prostate, where it may play a role in preventing cancer. Research also suggests there may be a link between increased exposure to sunlight and decreased risk of prostate cancer.
While low levels of vitamin D seem to increase the risk of prostate cancer, large supplementary doses of vitamin D increase the level of calcium in the blood which in turn can cause other problems such as kidney stones and hardening of the arteries. Synthetic forms of vitamin D have been created to try to produce an anti-tumour effect without impacting on blood calcium levels.
In late 2004, researchers at the University of Toronto reported the results of a trial in 15 men with advanced prostate cancer. The patients all received 2,000 units/day of cholecalciferol (a form of vitamin D) for up to 21 months. Fourteen of the 15 men showed evidence of a clinical response and none had any side effects. While the trial was small, these are the most positive results for a vitamin D compound to date in human cancer.
Good dietary sources of vitamin D include:
Milk fortified with vitamin D
Fatty fish (such as salmon and mackerel)
Cod liver oil / fish liver oil
Some breads and cereals
Some egg yolks
