The most substantial evidence to the role of diet in development of prostate cancer is the higher prevalence of prostate cancer among the people of Japanese and Chinese descent in the United States than among their ascendants. Studies conducted have found out that increased consumption of fat is associated with higher prevalence of prostate cancer and higher mortality. However, there are also studies suggesting that increased consumption of fat has no effect on development of prostate cancer.

Prostate cancer rates go higher as the body mass index increases. In obese people, Psa levels drop and more aggressive and deadly forms of prostate cancers may develop.

Lycopene is a strong antioxidant found in plenty amounts in tomato and its products. It is suggested that lycopene reduces the risk of prostate cancer. Studies carried out have found that people who consume higher amounts of tomatoes have 11% lower risk of developing prostate cancer than people who consume the least.

Lycopene is a strong antioxidant found in plenty amounts in tomato and its products. It is suggested that lycopene reduces the risk of prostate cancer. Studies carried out have found that people who consume higher amounts of tomatoes have 11% lower risk of developing prostate cancer than people who consume the least.

Soy beans contain high amounts of phytoestrogen, a plant-based estrogen. Phytoestrogen inhibits alpha reductase enzyme and prevents activity of male hormones (androgen). Men who consume higher amounts of soy have reduced risk of prostate cancer. The lower prevalence of prostate cancer among Asian men is attributed to high consumption of soy.

In experimental studies conducted, catechin found in green tea has been shown to destroy prostate cancer cells and stop development of cancer cells. Lower rates of prostate cancer among Asian people is attributed to consumption of green tea in high amounts.

Vitamin D is produced in the body through diet and sunlight activating the inactive Vitamin D in the skin. There are several observations and studies on the effect of Vitamin D on prostate cancer:

1. People in Northern European countries are exposed to less sunlight; and rate of mortality from prostate cancer is high is those countries.
2. Prostate cancer is more common in old age. Vitamin D levels drop with increasing age.
3. The melanin pigment in the skin of dark-colored people block the ultraviolet light, preventing activation of Vitamin D in the skin. Colored people have the highest prevalence and mortality of prostate cancer in the world.
4. It has been found that people who eat calcium-rich diets have reduced levels of Vitamin D in their blood and increased risk of prostate cancer.
5. Since Japanese people have a fish-rich diet, their intake of Vitamin D is high. Japanese men have relatively low rate of prostate cancer.
6. Studies conducted show that prostate cancer cells have Vitamin D receptors and Vitamin D inhibits development of prostate cancer cells and prevents them from spreading.