Antioxidants are important groups of anticarcinogenic compounds that may help remove ROS or potentially harmful chemicals. These may be found naturally in fruits and vegetables.[24] Example of antioxidants are vitamin A and its carotenoidprecursors, vitamin C, vitamin E, polyphenols, and various other compounds. β-Carotene, the red-orange colored compounds found in carrots, tomatoes and other fruits and vegetables have been shown to be effective in cancer prevention. Vitamin C may prevent various cancers by inhibiting the formation of mutagenic N-nitroso compounds (nitrosamine). Flavonoids such as EGCG in green tea have also been shown to be effective antioxidants and may have anti-cancer properties.
Other chemicals may reduce mutagenesis via other mechanisms, although for some the precise mechanism for their protective property may not be certain. Selenium, which is present as a micronutrient in vegetable, is a component of selenoproteins which are important antioxidant enzymes such as gluthathione peroxidase. Many phytonutrients may counter effect of mutagens, for example, sulforaphane in vegetables such as broccoli has been shown to be protective against prostate cancer.[25]Others that may be effective against cancer include indole-3-carbinol from cruciferous vegetables and resveratrol from red wine.[26]
An effective precautionary measure an individual can undertake to protect themselves is by limiting exposure to mutagens such as UV radiations and tobacco smoke. In Australia where people with pale skin are often exposed to strong sunlight,melanoma is the most common cancer diagnosed in people aged 15-44 years.[27][28] In 1981, human epidemiological analysis by Richard Doll and Richard Peto indicated that smoking caused 30% of cancers in the US.[29] Doll and Peto also estimated that diet may cause perhaps around 35% of cancers. Mutagens identified in food include mycotoxins from food contaminated with fungal growths, such as aflatoxins which may be present in contaminated peanuts (prevalent in Southern China) and corn, heterocyclic amines generated in meat when cooked at high temperature, PAHs in charred meat and smoked fish, as well as in oils, fats, bread, and cereal,[30] and nitrosamines generated from nitrites used as food preservatives incured meat such as bacon (ascobate, which is added to cured meat, however, reduces nitrosamine formation).[24] Excessive alcohol consumption has also been linked to carcinogenesis, the possible mechanisms for its carcinogenicity include formation of acetaldehyde which may be mutagenic, and the induction of cytochrome P450 system which is known to produce mutagenic compounds from promutagens.[31]
For certain mutagens, such as dangerous chemicals and radiations, as well as infectious agents known to cause cancer, government legislations and regulatory bodies are necessary for their country.
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