Some of the most exciting studies on tomatoes have focused on their ability to protect against cancer, especially prostate cancer. Dr Edward Giovannucci of the Harvard Medical School has published two interesting studies that investigated the effects of foods, particularly tomatoes, on cancer risk. In his 1995 study, Dr Giovannucci found that of the 48,000 men surveyed, those who ate ten or more servings of tomatoes a week reduced their risk of prostate cancer by 35 per cent and their risk of aggressive prostate tumours by almost 50 per cent. Indeed, it seemed the higher the tomato intake, the lower the cancer risk. Interestingly, lycopene is the most abundant carotenoid in the prostate gland.
Dr Giovannucci’s subsequent study in 1999 showed that, of all tomato products, tomato sauce consumption at just two servings a week was by far the most reliable indicatOr of reduced risk for prostate cancer.
Two important points emerge from these studies. The first, which I mentioned earlier, is that processed tomatoes sauce and paste are more effective than raw tomatoes in reducing cancer risk. In the raw tomato, the lycopene is bound into the cell walls and fibre. Processing breaks down these cell walls and frees the lycopene to be absorbed by the body. Ounce for ounce, processed tomato products and cooked tomatoes contain two to eight times the available lycopene of raw tomatoes. While processing does diminish the levels of vitamin C in the tomatoes, it elevates the total antioxidant activity, thus ultimately pro. viding an enhanced benefit.
The second important point, which Dr Giovannucci mentions in his article, once again highlights the importance of whole foods. While he notes the associationbetween tomato consumption and reduced cancer risk, particularly lung, stomach and prostate cancers, he makes it clear that ‘a direct benefit of lchpene has not been proven and other compounds in tomatoes alone or interacting with lycopene may be important’. Given the rich array of nutrients in tomatoes it wouldn’t be surprising if, once again, the synergy of those nutrients were the reason for the positive effects.
Prostate cancer isn’t the only type of cancer that toma~ toes seem to help protect against. A growing body of evidence suggests that lyCOpene provides some degree of protection against cancers of the br cervix, bladder and lung.
Lycopene seems to reduce the risk of cancer in several ways. As a particularly powerful antioxidant, it helps block the ongoing destructive effects of the free radicals in the body Its especially effective in this mission when sufficient vitamin E is present. Lycopene also seems to interfere with the growth factors that stimulate cancer cells to grow and proliferate. And finally it seems to stimulate the body to mount a more effective immune defence against cancer.“
As mentioned, lycopene, which is fat-soluble, needs a bit of dietary fat to transport it into the bloodstream. A Whole, fresh tomato, eaten out of the hand, is not a good source of this nutrient. The top-ranked tomato-based foods that seem to be the most cancer-protective are all prepared with some oil. A salad of tomatoes with some extra-Virgin olive oil is really a health-promoting food. The green colour of olive oil indicates the presence of polyphenols. Those polyphenols combined with the powerful nutrients in ,tomatoes are a healthy treat on spaghetti sauce, as a pizza topping. or in tomato-based soups. ”