Nutrition Relationships With Cancer

Due to an increase in welfare, health and nutrition and change of composition of the population, there were also changes in disease patterns is reduced infectious diseases and deficiencies are less on the one hand, and the increase of degenerative diseases such as heart disease, diabetes and cancer on the other.

Cancer is one cause of death in many countries. Approximately 70-90% of cancers are related to environment and lifestyle (life style). Of all cancers are caused by environmental factors, about 40-60% related to nutritional factors.

1. Fat

Although studies of fat intake relationship with cancer still provide results that do not obey the principle, but studies using animal experiments showed that the fat intake is one of the key in preventing, cancer.

Some researchers have successfully demonstrated the relationship between the increase in fat consumption and obesity and breast cancer is found only in older age. Apparently not the total fat consumption is an important factor in cancer, but the amount of polyunsaturated fatty acids in the diet is more instrumental. It should be noted in examining the relationship between fat intake and cancer is the kind of fat (saturated fat compared to unsaturated fats; animal fat than vegetable fat).

On the other hand, some studies suggest that blood cholesterol is too low is the risk of cancer. Still need further study to arrive at definitive conclusions about the correlation between cholesterol input with blood cholesterol and cancer. Fat intake is not only associated with cancer but also with heart disease, and obesity.

In studies with animal trials, limiting the energy input will reduce the incidence of some cancers, and increase the lifespan of the animal trials. Enter the total energy and percent energy derived from fat is associated with risk of cancer, but this relationship varies for different cancer types. Studies conducted by Boissonneault et al, 1986, found the effect of energy derived from fat to cancer depends on the total energy input.

2. Protein

The relationship between the consumption of animal protein, especially proteins with the incidence of some types of specific cancers have been investigated in epidemiological studies. But the correlation between protein consumption and cancer is influenced by the high correlation between the consumption of protein with other nutrients, especially fat. Thus the direct effect of the protein could not be determined.

Studies using animal trials show of excessive protein intake is not necessarily related by complying with the principle of increase in tumor incidence. When animals were fed ad libitum with a protein content of 10-15% of calories, the total incidence of tumors are not affected, although some specific tumors such as bladder papilloma and breast tumors improved by increasing protein intake.

3. Vitamins and minerals

Here are discussed only vitamin A, carotene, vitamin C, E, iron and selenium. Much evidence suggests that foods that contain lots of vitamin A and carotene can prevent some types of epithelial cancers. From several epidemiological studies, the concentration of vitamin A in the blood associated with increased cancer risk, but several other studies found no such relationship. Similarly, the relationship between carotenoids in the blood with cancer.

A cohort study successfully demonstrated that the risk of all types of cancer can be lowered by increasing consumption of vegetables rich in carotenoids. The most robust evidence regarding the role of vitamin D in cancer prevention obtained from epidemiological studies that linked the consumption of vegetables rich in carotene or vitamin A-rich foods with lung cancer.

In animal trials, giving high doses of vitamin A can prevent cervical cancer, vaginal, colon, skin, stomach, tracheobronchi, pancreas, and liver. Carotenoids required for normal cell differentiation. Carotenoid deficiency can lead to the differentiation process is inhibited. In animal trials retinoids may prevent the initiation and promotional stages of carcinogenesis process.

Foods rich in vitamin A can prevent the formation of oxygen radicals and peroxides in fat, and beta carotene are very efficient in neutralizing oxygen radicals. Vitamin A, along with vitamin C, vitamin E, and selenium can neutralize the effects of peroxide and reducing carcinogenesis. Vitamin A and carotenoids have inhibitory effect against cancers of the mouth and esophagus, especially in chewing tobacco (tobacco chewer) and against lung cancer in smokers.

From studies in humans, it can be shown that there is a protective association between vitamin C rich foods with esophageal cancer; gastric cancer. In the digestive tract, vitamin C will block the formation of carcinogenic nitrosamines from nitrates and nitrites, as well as prevent the oxidation of certain chemical substances into the active carcinogenic form. Vitamin C is a limiting factor nitrosated reactions in humans, and this was demonstrated in patients with gastrectomy and atrophic gastritis akuta.

From several studies had shown that the toxic effects of ozone on the lung can be efficiently prevented by vitamin E. Levels of vitamin E in serum have a protective association with lung cancer.

In biochemical studies, vitamin E serves as a fat-soluble antioxidant and as a free radical scavenger. Thus the role of vitamin E in cancer prevention effects similar to vitamin A and C. Vitamin E, like vitamin C, can prevent the formation of nitrosamines in vitro. But it must be remembered that vitamin E is fat soluble, so the effect of prevention is influenced by the presence of fat, while vitamin C did not, because it dissolves in water.

Much evidence suggests that increased iron deposits in the body associated with an increased risk of cancer. Stevens, et al in a study found able to bind iron (total iron binding capacity) is lower, whereas transferrin saturation was higher in cancer patients than non-sufferers.

Selenium in plant and animal-shaped selenat, selenocystin, selenomethionin, and other forms that have not been identified. Assessment of the average per capita consumption of selenium originating from 27 countries, have an inverse relationship with total deaths from cancer, mortality due to leukemia, and cancers of the colon, rectum, breast, ovanum, and lung cancer.

From several case-control study found that cancer patients have lower blood selenium than the controls. However, the data of this study should be interpreted with caution, because of low blood selenium levels may be a consequence of illness. Prospective studies may show that cancer risk increased in the group with blood selenium, vitamin E and vitamin A blood levels. Selenium inhibits neoplastic transformation in various epithelial organs in animals.

Some studies show a protective effect against liver cancer, breast, colon, and skin. However, the dose given to produce this protective effect, in various studies with doses can cause poisoning in long-term administration.

4. Dietary fiber

Dietary fiber includes cellulose, hemicellulose, lignin, gums, pectin. The main source of dietary fiber are vegetables, fruits and grains full or complete. From several epidemiological studies, found a correlation between dietary fiber intake with risk of colon cancer.

In studies with humans, is still not enough information about the components of dietary fiber and the effect on cancer risk. It is estimated that fiber type plays an important role. In some other studies also observed a relationship with other nutrients, because although there is strong correlation between the risk of colon cancer sera with high diet, other dietary components might affect this correlation.

Of the 19 case-control studies that measure the role of dietary fiber on colon cancer, three studies found no role, three studies found a relationship with an increased risk of cancer, and 13 studies found a protective effect of dietary fiber, especially vegetables. Protective effects noted in two case-control studies that examined the relative risk to a diet high in fat and low in fat.

Overall, case-control studies present mixed results, some studies suggest dietary fiber has a protective effect and others do not. In studies using animal trials, also obtained results that do not obey the principle in the relationship between dietary fiber with colon cancer. This is influenced by several factors such as the nature of the carcinogen used, the composition of the diet, differences in quantitative and qualitative as well as food, animal strains trials are used, and duration of the experiment.

5. Processed foods

How to storage and processing of food varies between countries, and these differences may provide a major contribution in the variation of several types of cancer.

Fumigation of food can form polycyclic aromatic hydrocarbons (polycyclic aromatic hydrocarbons), some of which are known to be carcinogenic in animals. Substances that are carcinogenic can be formed at the time of the ripening process and the number is associated with the use of high temperatures and long cooking time. Eg cooking by using a fire burning oven, can form polycyclic aromatic hydrocarbons on the surface of the food is burned. Burning of amino acids with sugars during the cooking process, producing a variety of chemical substances that are mutagenic, and some of which are carcinogenic.

Salinisation and acidification of foods can form nitrosamines which are carcinogenic to the mouth and stomach. Evidence from epidemiological studies indicate that many people consume foods that are preserved in salted, diasam, and smoked, had gastric and oesophageal cancer incidence more. Esophageal cancer associated with consumption of pickled vegetables, salted fish and smoked foods. From several epidemiological studies, nitrate, nitrite and N-nitroso components in food and water and salted foods associated with stomach cancer.

Esophageal cancer and gastric cancer is also associated with the state of malnutrition. In fact, almost all studies on diet with gastric cancer, have found a protective effect from consumption of vegetables and fruits, and even in experiments in vitro formation of N-nitriso components can be reduced to a minimum by antioxidants such as vitamin E and vitamin C.

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