Food and cancer

In general, vegetable products reduce the risk of cancer, since they contain substances with antioxidant effects that prevent carcinomas. It is not a matter of excluding all meat intake, but of making room for a greater quantity and variety of vegetable foods. Vegetables reduce the risk of cancers of the mouth and pharynx, esophagus, lung, stomach, colon and rectum, larynx, pancreas, liver, ovary and endometrium. Fruits, on the other hand, minimize the risk of mouth and pharynx, esophagus, lung and stomach cancers. Consequently, it is recommended to consume at least five servings of fruits and vegetables every day.

However, each type of carcinoma should be considered individually. 

First, we must mention colon and rectal cancer (CRC), the second leading cause of death from cancer in Spain and the first in the non-smoking population (among smokers, lung cancer is the leading cause). There are diseases that predispose to CRC, such as polyps, which can grow and become malignant, and inflammatory bowel diseases such as Crohn's disease or ulcerative colitis. Sometimes there are genetic roots: 25% of patients have an affected relative.

Foods with a high fiber content play a protective role against CRC: fiber accelerates the intestinal transit time and the exposure of the colonic mucosa to carcinogens, as well as contributing to a higher acidity in the colon. Although all vegetables are recommended, the efficacy of cruciferous vegetables such as broccoli, cabbage or cauliflower stands out. Other foods with a protective effect are fish (containing omega 3), olive oil, milk (for its calcium), and those containing vitamin D, folates, flavonoids, antioxidant vitamins (A, C and E) and selenium. White meat (chicken, beef, turkey) have a neutral effect.

On the other hand, red meat (beef, veal, pork) or processed meat (cold cuts, sausages) is an increased risk. Their cooking at high temperatures leads to the formation of substances (fecapentanes, 3-ketosteroids) capable of producing mutations in the cells and, in the presence of a relative scarcity of protective substances and an adequate genetic basis, of favoring the malignant transformation of polyps. More generally, they are also associated with overall mortality of non-cancerous origin. Nitrites contained in smoked foods and processed and salted meat products are also implicated in CRC. 

Lifestyle conditions the appearance and development of the various carcinomas. There are three determining factors. Tobacco increases the risk of CRC, even with reduced consumption, and has a direct relationship with other cancers such as lung, larynx and bladder cancers. Alcohol (in any amount) is another risk factor. Finally, physical exercise represents an ideal preventive measure, as well as benefiting other aspects of health.

In relation to prostate cancer, it appears that prostate cancer cells are present in this organ in almost all men over 50 years of age. Fortunately, they only progress to clinical disease in some cases, possibly depending on environmental and dietary factors. Soy intake, omega-3 fat and tomatoes, thanks to their lycopene content, a powerful antioxidant, reduce the risk. On the other hand, calcium intake increases the risk (it is four times higher in men who consume 2,000 mg of calcium per day compared to those who consume only 500 mg per day, equivalent to two glasses of milk).

Pancreatic cancer has been associated with high glycemic index diets, that is, diets very rich in sugars or rapidly absorbed starches (excess potatoes, rice, bread). And breast cancer tends to respond more to genetic and hormonal factors, although it has a positive association with alcohol consumption, obesity and lack of physical exercise.

In summary, from a nutritional point of view, to prevent cancer, it is advisable to avoid excess calories and to reduce certain forms of cooking such as barbecue, smoked, salted foods, etc. On the other hand, fiber, vitamins and certain minerals and antioxidant substances have a protective effect against tumors.