Diet in cancer prevention

Cancer is a set of complex diseases characterized by abnormal cell growth, practically autonomous. It can begin locally and spread to other surrounding tissues, leading to death if the patient does not receive adequate treatment.

Cancer is the second leading cause of death in developed countries, surpassed only by cardiovascular diseases, and is a public health problem in all countries of the world.

Cancer is caused by the complex interrelation of internal factors (genetic and metabolic alterations) and environmental factors, such as smoking, radiation, viruses, bacteria and eating habits, among others.

Although certain foods or eating habits cannot be considered direct causes of malignant tumors, there is scientific evidence that establishes a close relationship between some types of cancer and certain foods or forms of preparation and consumption that should be taken into account to prevent and treat the disease.

Main environmental factors that increase cancer risks

• Smoking, considered the main factor.

• Eating habits.

• Consumption of alcoholic beverages.

• Sedentary lifestyle and obesity.

• Infectious diseases.

• Radiation, among others.

Possible influences of diet on the development of cancer

Cancers of the oral cavity, pharynx and esophagus: in developed countries the main risk factors are:

• Smoking.

• Consumption of alcoholic beverages.

• Overweight and obesity.

• Micronutrient deficiencies related to very poor diets.

• Consumption of food at very high temperatures.

• Chinese-style salted fish intake.

Stomach cancer: infection by the bacterium helicobacter pylori is a confirmed risk factor. However, it is not a sufficient cause for cancer, it is believed that a diet containing a lot of salted foods, especially meats and pickles, increases the risk. Also, high consumption of fruits and vegetables, rich in vitamin C, is associated with a decreased risk.

Colorectal cancer: colorectal cancer incidence rates are about ten times higher in developed countries than in developing countries. It is estimated that diet may be responsible for this marked difference.

The main risk factors are:

• Overweight and obesity.

• Regular consumption of canned meats.

Factors that possibly reduce the risk of colorectal cancer:

• The intake of fruits and vegetables.

• High folate intake, either in the diet or through vitamin supplements.

• High calcium intake.

Lung cancer: smoking increases the risk of lung cancer by about 30%, causing more than 80% of lung cancers in developed countries. Opinions are divided as to the effect of the consumption of fruits, vegetables and the nutrients contained in them. So far, the main priority in the prevention of lung cancer is to eliminate smoking.

Breast cancer: Breast cancer is the most common cancer among women. It has been shown that the only dietary factors that increase the risk of breast cancer are:

• Obesity, it is estimated that this can increase the risk of breast cancer by approximately 50%.

• Consumption of alcoholic beverages.

Endometrial cancer: the risk of endometrial cancer is three times higher in obese women than in lean women. Unconfirmed case-control studies seem to indicate that diets rich in fruits and vegetables would reduce the risk and diets rich in saturated fats or total fat would increase it.

Prostate cancer: the incidence of prostate cancer is about ten times more common in North America and Europe than in Asia. The data obtained in prospective studies have not found any relationship between specific dietary factors and the appearance of this type of cancer, but they do point to a certain relationship with the Westernized diet.

Kidney cancer: overweight and obesity are considered to be responsible for up to 30% of kidney cancers in both men and women.

Substances contained in some foods related to the origin and progression of cancer

Mycotoxins: these are compounds produced by fungi. The best known are aflatoxins, which proliferate mainly in grain stores (corn, sorghum, millet, rice and wheat), oilseeds (olive, soybean, sunflower, cotton) and spices (chili and black pepper), at high temperatures and humidity. They are the most potent liver carcinogens currently known.

Nitrosamides and nitrosamines: they do not occur naturally in food. They are formed as a result of the reaction between amines in food and sodium nitrite, a sodium salt that is added to meat foods as a preservative and color fixative in meats and their derivatives. These compounds are found mainly in processed meats and sausages.

Smoked foods: the method used to produce smoked foods is considered carcinogenic. Its effect comes from the polycyclic aromatic hydrocarbons produced in the process.

Fats: the consumption of foods rich in saturated fats, from butter, cream and red meat, seems to be related to the origin of breast, endometrial, colon and rectal cancer.

Food components that reduce the risk of developing cancer

Dietary fiber: the dietary fiber present in fruits, vegetables, whole grains and legumes, accelerates the intestinal transit, reducing the time that the possible toxic components remain in contact with the digestive tract, reducing the chances that they cross the barrier of the intestinal tissue and pass to other organs and tissues. Likewise, fiber "captures" certain harmful elements, leaving them unable to pass through the intestine to the rest of the organism. A diet rich in dietary fiber is believed to reduce the risk of colon cancer.

Vitamin a (retinol, carotenes (provitamin a)):

• Vitamin a, due to its trophic and epithelial protective effect, collaborates in the defensive-immunological barrier of the skin and mucosal structures. On the other hand, beta-carotenes act as antioxidants, trapping free radicals and free oxygen molecules that constitute toxic and carcinogenic elements.

• However, although the protective effect of consuming a diet rich in vitamin A has been confirmed, it is recommended to avoid vitamin A supplements. So far, supplements have not been shown to reduce the risk of cancer; on the contrary, high-dose intakes of vitamin A have been associated with an increased risk of developing lung cancer in smokers.

Foods containing vitamin a (retinol, carotenes (provitamin a)):

• Foods of animal origin: dairy products, egg yolks, fish and animal livers, blue fish and pates.

• Foods of vegetable origin: tomatoes, watermelon, cherries, chard, spinach, green celery, carrots and in some fruits.

Vitamin c (ascorbic acid): It is a powerful antioxidant. It traps free radicals and free oxygen molecules that constitute toxic and carcinogenic elements. It inhibits the formation of nitrosamines, a group of substances with proven carcinogenic effects.

Foods containing vitamin C (ascorbic acid):

• Fresh fruits. Examples: kiwi, lemon, tangerine, orange, grapefruit and guava.

• Vegetables. Examples: lettuce, spinach, broccoli, tomatoes, peppers, carrots, cauliflower and cabbage.

• Vitamin c suffers considerable losses during cooking and prolonged storage; therefore, to ensure adequate levels in the body, fresh fruits and vegetables should be ingested naturally on a daily basis.

Vitamin e (tocopherols): It is a potent antioxidant that protects lipids and other cell components from oxidative damage. It has been associated with selenium in the prevention of fibrocystic disease and breast cancer. Its action is favored by the unsaturated fatty acids contained in the diet.

The combined action of vitamin e (tocopherols), vitamin c, beta-carotene and selenium, strengthen the immune system, act by neutralizing free radicals, reducing the risk of lung, pancreatic and neck cancer. Foods containing vitamin e:

• They are mainly found in foods of vegetable origin, such as nuts, virgin olive oil, sunflower seed and corn oils, as well as in olives.

• They are also found in eggs.

• Vitamin E can be easily destroyed by the action of heat and oxygen in the air.

Selenium: Together with vitamin E, it is an antioxidant that delays the aging of tissues and prevents the appearance of certain types of cancer. However, it is not recommended to ingest high doses of selenium in the form of supplements. Selenium is contained in protein-rich foods such as meat, fish and cereals.

Vitamin d (cholecalciferol (d3), ergocalciferol (d2))p:

• There is evidence that vitamin d may reduce the risks of some types of cancer, especially colon, prostate and breast cancer. Vitamin d promotes the intestinal absorption of calcium and phosphates from food, and intervenes in the reabsorption of calcium at the renal level, to reduce losses through urine.

• It is suggested that the action of vitamin d occurs through calcium metabolism, since adequate calcium levels are associated with a lower risk of cancer. Vitamin d is suspected to be involved in the protection against leukemias, colon, bone and kidney cancer.

Sources of vitamin d (cholecalciferol (d3), ergocalciferol (d2)): under normal conditions, the human body obtains vitamin d in two ways:

• Through cutaneous synthesis by the action of ultraviolet rays of sunlight. By the digestive route, through the ingestion of foods containing it.

• Of animal origin: Foods rich in vitamin D are: cod liver oil and blue fish such as tuna, mackerel, sardines and salmon. Foods that provide smaller amounts: calf liver and egg yolk.

• Of vegetable origin: mushrooms and mushrooms.

Zinc: Zinc has antioxidant action, its deficiencies have been linked to the increase in the rate of esophageal cancer caused by nitrosamines. Its action linked to those of vitamins a, c and e is fundamental in the prevention of cancer.

Vitamin b9 (folic acid): It has several important functions, such as the formation of blood cells and