Nutrition in cancer prevention - proteins and fats

Proteins

Studies have not clearly shown the relationship between proteins (by themselves) and cancer. In the case of research that has found a relationship, for example, between colon and rectal cancer and breast cancer and increased consumption of animal protein, the diets studied were also rich in saturated fat, which could induce error in the interpretation of the results.

In contrast, protein foods such as meat and fish that have been prepared grilled or smoked have been found to contain polycyclic aromatic hydrocarbons, with a high potential to cause cancers.

For its part, cooking meat and fish, by reaction between proteins and sugars, would produce the formation of heterocyclic aromatic amines, also with carcinogenic potential.

The fats

Epidemiological studies find a relationship between high-fat diets (that is, when fats account for more than 40% of the total energy consumed) and an increased risk of lung, prostate, breast, ovarian, and endometrial cancer and colon when compared to low-fat diets (that is, less than 20%). Studies also suggest that the relationship between cancer and fat is due to saturated fat.

The way you cook is very important in the production of cancer. Benzopyrene and other polycyclic aromatic hydrocarbons are present on the surface of all meats and fish cooked on barbecues, as well as smoked meats and fish.

Fat, obesity and cancer

Obesity, as a factor directly related to higher fat intake, is related to colon, endometrial, bile duct, kidney, esophageal, breast cancer in postmenopausal women and, perhaps, to prostate cancer. The increased risk of cancer begins already from values ​​of body mass index (BMI) of 25 kg / m2 and increases as the BMI increases (BMI = weight divided by height squared).

A high-fat diet could increase the risk of colon cancer by increasing the concentration of bile acids in the intestine, which are metabolized into carcinogenic substances by the bacteria there. Fats also produce numerous free radicals with carcinogenic potential during their metabolism.

However, since many substances come into play in the diet, a direct cause and effect relationship between fat and obesity and cancer has not been established. Thus, it is said that low-fat diets are probably associated with other better foods and lifestyle, for example less smoking or less sedentary lifestyle, factors that also cause cancer. In fact, there are studies that find no relationship between fat and cancer in humans.