Prostate cancer is the commonest malignant disease in men in some Western countries. Although Asia has not been found, in the last ten years there was significant increase in cases.
The risk of prostate cancer is determined by two things: genetic factors and environmental factors. The role of migration research environment proved to be from where the incidence of prostate cancer found an increase in first-generation immigrants from Japan and China in U.S.. From the research, explained that the diet play a role as one of the risk of the occurrence or spread of prostate cancer.
Fat
Research on animals proved that fat-free diet can reduce the growth of malignant prostate tumors. Conversely, high-fat diet causes the growth of prostate cancer cells more quickly. The role of fats in increasing the risk of prostate cancer occurs with several mechanisms. First, it proved that the fat may affect levels of testosterone, a hormone that is needed for the growth of prostate cells, both benign or malignant. Men who ate less fat would have testosterone levels that are relatively low.
Second, fat is a source of free radicals, and the third is the result of fatty acid metabolism is thought to be carcinogenic. Examples are unsaturated fatty acids omega-6 that can spur the growth of prostate cancer cells.
The correlation between fat consumption and prostate cancer risk is also evidenced in several epidemiological studies. Giovannucci and colleagues conducted a prospective study of the relationship between diet and prostate cancer. This research proved that a diet high in fat increase the risk of developing advanced prostate cancer.
In addition, there are still some other studies that support such a cohort study in Hawaii. Unfortunately, few other epidemiological studies failed to prove the same thing among others is a prospective study in Norway. Thus, although many epidemiological studies and biological studies that prove the relationship between high dietary fat and risk of prostate cancer, still needed additional epidemiological studies to prove this with certainty.
Soybean
Significant differences between the diets of Asian society and the Western countries is on the consumption of soy products. Epidemiological study reported that Asian societies consuming large amounts of soy products, whereas the low incidence of prostate cancer.
Soy contains several ingredients that have a weak estrogenic activity. This Phytooestrogen, or isoflavones, thought to have anticarcinogenic capability.
Isoflavone genistein is most often found in soy products, have the ability to inhibit receptor tyrosine kinases like EGFR and HER-2/neu which both affect the process of prostate cancer.
Another mechanism is the ability of genistein to reduce the expression of androgen receptors and estrogen receptors in prostate tissue. Reduction of androgen receptors and estrogen can cause the low incidence of prostate cancer in populations that consume diets containing many many phytooestrogen.
In the study concluded that men who consumed soy milk has the incidence of prostate cancer 70 percent lower than that do not consume. However, this study has only a low statistical power where there might be other dietary factors that cause this.
Thus, additional research is still needed to ensure the role of soy for prevention of prostate cancer.
Lycopene
Lycopene is a carotenoid substances obtained in high concentrations in tomatoes and is a powerful antioxidant. Several case-control studies and prospective studies have concluded that consumption of tomatoes or tomato products may be associated with a lower risk of prostate cancer.
Although this time could not be ascertained, this benefit more in terms of preventing the expansion or aggressive prostate cancer.
Tomato fruit ripening process does not seem to reduce this advantage, quite the opposite will increase the bioavailability of useful components. Mechanism of action of lycopene to reduced risk of prostate cancer remains unclear until today. Chances are that the ability of lycopene protection against aging prostate epithelial cells caused by reactive oxygen species.
Another thing is the ability of lycopene to inhibit cell proliferation through inhibition of IGF receptor tyrosine phosphorylase in breast cancer cells. At least, there are four studies that have reported a link between lycopene consumption and prostate cancer risk and decreased risk of prostate cancer by 21 percent in men who consume large amounts of lycopene. Other studies also reported that populations who consume high lycopene had a risk of 36 per cent lower than the population who consume little lycopene.
Men with high levels of lycopene in the blood of 25 percent lower risk of prostate cancer.
Above studies also reported that consumption of tomato juice (without the cooking process) had no preventive effect, thus concluded that the cooking process even enhance bioavailibilitas lycopene.
The third addition to the diet, there are several other dietary substances are vitamin E, selenium, and green tea that may also have the ability to reduce the risk of prostate cancer. These three materials are known as antioxidants, but until now there is no certainty of its mechanism of action and also not supported by epidemiological studies or other clinical
0 comments:
Post a Comment