We know that throughout history people have lived well when their diets were rich in fruit and vegetables. There is evidence that eating fruits and vegetables helps to reduce gastric and colon cancer. All fruits and vegetables contain fiber which is helpful in preventing colon cancer. Now science has proven without a doubt that there is a relationship between intake of fruits and vegetables and health.
We now understand better why dietary fiber is protective. Fibers are fermented by bacteria in the colon which leads to short-chained fatty acids which protect against cancer causing substances. Recently, evidence shows that tomatoes may protect against esophageal and prostate cancer and carrots against cancer in the mouth and pharynx.
The reasons fruits and vegetables protect against cancer is because they contain antioxidants, increase activity of enzymes that detoxify cancer causing substances, alter estrogen metabolism, and alter the bacteria and pH in the colon. For example, onions, garlic, scallions and leeks (Allium vegetables) are rich in sulfur compounds which increase enzymes to inhibit bacteria that convert nitrates to nitrites in the stomach, and nitrites can combine with amines to form nitrosamines which can cause cancer of the stomach.
Cruciferous vegetables such as broccoli, cauliflower and cabbage have high content of organic sulfur which can stimulate enzymes in the gut to detoxify cancer-causing substances. These vegetables also contain indol-3carbinol which affects estrogen metabolism and may protect against breast and endometrial cancer.
Green vegetables such as lettuce, spinach,and mustard greens have high levels of antioxidants which block damage from free radicals within a cell. Green leafy vegetables also contain high levels of folic acid which can protect against colon cancer and heart attacks.
Red fruits and vegetables (tomatoes, red peppers, raspberries) are rich in lycopen (red pigment) which act as antioxidants and have been shown to protect against prostate cancer. Citrus fruits are rich in vitamin C, again acting as antioxidants and also preventing formation of nitrosamines.
Yellow fruits and vegetables are rich in beta carotene which is also an antioxidant and also can be metabolized to vitamin A which helps to maintain healthy cells.
Do the tomatoes in pizza may a difference? We have heard about pizza to prevent prostate cancer. Italian researchers claim that eating pizza on a regular basis may decrease a person’s chances of developing colon cancer by more than 25%. Does this sound too good to be true? Researchers asked 3,300 people who had developed cancer, how often they ate pizza. They asked the same question to 5,000 people who hadn’t developed cancer. Results showed that people who ate pizza at least once a week were less likely to develop cancer of the mouth, esophagus, or colon.
How is that possible? Well, we have data that lycopene in the tomato sauce (red color) has protective effects, It is not the pizza itself. So should we eat more pizza to prevent colon and prostate cancer? According to this study, yes, provided you pick the right kind of pizza and consume it in moderation.