Prostate cancer is the second-leading cause of cancer-related deaths among men in many Western countries. Age, race, and family history are all established risk factors for prostate cancer. In the UK, about 47,000 men are diagnosed every year and more than 200,000 cases are reported in the United States every year.
Current treatment options for prostate cancer patients including curative options (e.g. radical prostatectomy and radiotherapy) or containment options (e.g. hormonal therapy ) are associated with significant morbidity and greatly diminish the quality of one’s life.For example, a common complaint among men who had undergone prostate cancer treatment is the loss of penile length up to 2-3cm, which often, is accompanied by the penile deformities. These treatments can also cause fatigue, hot flashes, loss of libido, decreased muscle mass, and osteoporosis.
Prostate cancer varies greatly by geographic location. Incidence is greater in western countries, with the highest rate observed in the USA (124.8 per 100 000 population) and the lowest in Bangladesh (0.3 per 100 000 population). As a result, the field of preventive medicine suggested that the process of carcinogenesis as related to prostate cancer results from the interaction of environmental exposures, mostly due to diet.
In fact, many observational studies have noted increased risk of Prostate cancer in migrants who migrate to western countries from a low-risk region. One such study highlights that Japanese and Chinese native whose diets comprises of low-fat and high-fibre diet with high consumption of phytochemicals plant derivatives that include soy products and green tea, has the lower incidence of prostate cancer as compared to Japanese or Chinese immigrants to western culture.
Because many more studies have suggested prostate cancer or any other cancers for that matter could be the result of migrants adopting Western dietary practices. The last 20 years have seen, many epidemiological studies investigating the roles diets may play both in the development and progression of prostate cancer.
One study, for example, looks into the role milk in relation to prostate cancer. Milk and milk products, though, an essential staple in the western diet, appear to be associated with increased risk of Prostate cancer; especially in the progression of the tumour. The possibility of this association is that branched fatty acids present mainly in milk fat may up-regulate the a-methylacyl Co A racemase ( AMACR ) gene, previously shown to be over-expressed in Prostate cancer tumours, and not in healthy prostates.
However, many epidemiological studies strongly suggest that diet consist of plant-derived foods may play an important role in prostate cancer prevention and/or treatment.
Although, there is a general health recommendation to eat five or more servings of fruits and vegetables per day. These studies, however, emphasise plant-derived phytochemical fruits and vegetables of which polyphenols and flavonoids chemicals should make up a large proportion of everyone diet.
For example, resveratrol from grapes and red wine, sulforaphane from broccoli and other cruciferous vegetables((specifically cabbage, broccoli, cauliflower, and Brussel-sprouts), organo- sulfides from garlic and other allium species, limonene and perillyl alcohol from the lipid fraction of citrus peels, isoflavones such as genistein and daidzein and enterodiol from soy and flax proteins, catechins from green tea, and lycopene from tomatoes have been proposed as potential chemoprevention agents based on animal and laboratory evidence of antitumor effects.
Suggested mechanisms of anticancer effects of plants with phytochemicals are many and range from;
- Anticarcinogenic activities that can induce antioxidative enzymes and counteract the oxidative damage.
2. the inhibition of human cancer cell growth by interfering with growth factor receptor signalling and cell cycle progression.
3. Inhibition of inflammation causing cancers, and
4. They have also been shown to have proapoptotic, antiproliferative, and anti-metastatic properties in animal investigative studies.
Furthermore, there are also some specific micronutrients that have nutritional protective factors such vitamin E and selenium.
Vitamin E, an antioxidant found mainly in vegetable oil, nuts and oils, has been observed to significantly reduce the risk of prostate cancer in smokers.
Selenium is an essential micronutrient present mainly in grains, fish, and eggs. There are several studies showing that fish consumption decreases PC incidence and mortality.
However, the reductionist approach of many of these observational dietary studies has also been met with great scepticism from dietetic and nutrition experts.The notion that single component of food( e.g. lycopene from tomato) exerting potential chemopreventive effects are seen at best to be exaggerations. the sceptic caution, chemoprevention studies using dietary strategies may be expected to have mild effects, and large studies may be required to confirm statistical significance.
Therefore, trials with a sufficient sample size, ample follow-up, an extended duration of treatment, and validated biomarkers of risk, effect, and prognosis are needed to clarify the association between FUNCTIONAL FOODS and cancer in relation to their protection and prevention capabilities.