Diverse influences of dietary factors on cancer in Asia.
The major environmental risk factors for cancer are carcinogen and co-carcinogen exposure in tobacco, insufficient exercise and above all an unhealthy diet. What we eat or do not eat is exceedingly important in determining what cancers or other chronic disease we may suffer from. Carcinogens may be integral contaminants of the diet, like nitrosamines in some situations and aflatoxins, or may be generated by cooking processes, as is known to be the case for heterocyclic amine pyrolysis products. Examples of co-carcinogenic agents may include grit in bread products, salt in pickles or betel in chewing quids. Dietary insufficiencies, for example of zinc, may also act to increase sensitivity to genetic damage, for example. Influence on metabolism of carcinogens, like induction of phase II enzymes like glutathione S transferases, further directly impacts on carcinogenicity. Antioxidants in fruits and vegetables are typical examples of protective agents acting in this way. In addition we have dietary fibre which can decrease carcinogen exposure through accelerating passage of faeces through the gut. Other types of fibre, the soluble forms, can act to decrease uptake of glucose and thus suppress insulin exposure, an important factor for colon cancer. Natural anti-inflammatory agents like N-3 fatty acids in fish offer another example of preventive factors in the diet. Individual dietary components, like isoflavones in soy products, can interfere with hormone function to exert a beneficial action, as on the breast. Other compounds may act via stimulation of the immune system like lactoferrin and betaglucans. Perhaps the most important influence of diet on cancer, however, in a world of increasing comfort and ease of access to foodstuffs, is through over-eating and consequent obesity. Given the importance of diet to all our lives, we need to focus on all possible interactive effects in providing an evidence base to guide our choices regarding what we should eat in Asia.
Moore
Malcolm A
MA
UICC Asian Regional Office, Bangkok and Tokyo. apocpcontrol@yahoo.com
D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D001208:Asia / Q000453:epidemiology; D002273:Carcinogens / Q000633:toxicity; D003296:Cooking; D004032:Diet; D004043:Dietary Fiber / Q000494:pharmacology; D005506:Food Contamination; D006801:Humans; D008019:Life Style; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors
D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D002273:Carcinogens; D004043:Dietary Fiber