Prostate cancer rates are much higher in Western countries such as the United States and United Kingdom, when compared to Asian countries. This is thought to stem from the protective effect of genistein, an isoflavone found in soya beans. Asian countries eat fermented soya products such as tofu and miso, and this is thought to decrease the risk of sex hormone related cancers. However, countries in South America also have lower prostate cancer risk, but they do not eat soya.
South American Prostate Protection
Some other factor must therefore explain the lower risk of prostate cancer in the South American countries when compared to the West, as they do not eat soya beans. Researchers have addressed this problem and concluded that tomato might be the protective factor. Countries that eat high concentrations of tomatoes including those in South America, and possibly Spain and Italy, appear to have significantly lower risk of prostate cancer.
What Is Special About Tomatoes?
Tomatoes are a rich source of carotenoids, and are particularly rich in lycopene. Unlike many carotenoids, lycopene cannot be converted in humans to vitamin A. However, lycopene does have antioxidant functions and in this regard may decrease the levels of oxidative stress in the body. In particular, lycopene accumulates in the prostate tissue, and this may make the antioxidant activity of the carotenoid particularly effective at preventing cancer initiation.
How Else Might Lycopene Work?
Although lycopene is considered a potent scavenger of free radicals, the ability of lycopene to reduce oxidative stress may not be the way it prevents cancer. This is because although free radicals may be implicated in cancer, their role is not fully understood. However, lycopene is also thought to function by enhancing gap cell communication between cells, and this might increase the likelihood that cancerous cells die through apoptosis.
Some Like It Hot
The lycopene in tomatoes may therefore be beneficial to the health. However, as with all plant phytonutrients, the lycopene is trapped inside tough cell walls that cannot be broken down by human enzymes. Chewing releases the lycopene, but the amount released is not high unless food is chewed for long periods. Therefore cooking is the best way to release the lycopene from the tomato and make it bioavailable. Because lycopene is fat soluble, consuming cooked tomatoes with fat may be even better.