Nutrition in cancer prevention - fruits and vegetables

There are various studies that show that high intake of vegetables and fruits lowers the risk of cancer. This effect is observed in epidemiological studies, where the high consumption of these foods produces a decrease in lung, stomach and colon and rectal cancers. In other studies, it has been observed that diets poor in fruits and vegetables increase the incidence of cancers of the lung, larynx, oropharynx, esophagus, stomach, colon, rectum and pancreas.

However, it should also be noted that other studies have not shown any protective effect of fruits and vegetables against cancer. In any case, although the abundant consumption (at least five servings a day) of fruits and vegetables did not reduce the incidence of cancer, it would help reduce the risk of other diseases such as cardiovascular diseases.

Rich in anticarcinogens

Research studies have shown the existence of anticarcinogens in these foods that can act by blocking the action of a carcinogen, or by preventing the neoplasia from progressing.

Some of these anticarcinogens are:

• Isothiocyanates and indoles, present in cabbage, broccoli, pumpkin and cauliflower
• Folic acid
• Vitamins C, E and A
• Selenium
• Polyphenols
• Flavonoids
• The alysulfides of garlic and onions
• Protease inhibitors present in legumes and corn.

How do they work?

Although the exact mechanisms through which they act are not known, it is thought that their antioxidant capacity would be one of the mechanisms of prevention of cancer development; other effects are the prevention of alterations in the synthesis of genetic material, the enhancement of cellular immunity against tumor cells, or the decrease in the proliferation of tumor cells.

However, the isolated administration of these anticarcinogenic substances (in the form of supplements) does not have the protective effect demonstrated by whole foods.

What about fiber?

: dilutes carcinogenic substances that are in the digestive tract; decreases the contact time of carcinogens with the intestinal mucosa; eliminates the metabolites of carcinogens that the liver produces through the circulation between the liver and the digestive tract; and prevents or hinders the contact time of the bacteria with the food bolus (preventing the bacteria, by acting on this bolus, from producing free radicals that damage the genetic material of the cells of the intestinal wall and cause cancer cells to appear).

One aspect to highlight, and many times forgotten, is that we must carefully wash all fruits and vegetables before eating them to eliminate residues of pesticides and artificial herbicides, which are potentially carcinogenic.