Flaxseed Oil and cancer: alpha-linolenic acid and carcinogenesis. In: Flaxseed in Human Nutrition.
Flaxseed Oil and cancer: alpha-linolenic acid and carcinogenesis. In: Flaxseed in Human Nutrition.
Year: 1995
Authors: P V Johnson.
Publication Name: AOCS Press Champaign, Illinois
Publication Details: 207 .218
Abstract:
In this book chapter, a review of research in the area of the effects of ALA in flaxseed oil on the prevention and treatment of cancer is presented. The author focuses the article on those studies where only flaxseed oil was fed rather than research that has examined omega 3 PUFAs from fish oil. The results of studies using flaxseed rather than only flaxseed oil have been confounded due to the presence of lignans which appear to have significant anti-carcinogenic effects. Most studies in which ALA has been the FA of interest have been conducted on mammary tumor models and have shown that ALA, EPA and DHA levels of tumor lipids are increased with ALA feeding. Similar results have been reported with peripheral lymphocytes, splenocytes and mast cells. Early studies in mice have shown that ALA, unlike LA, failed to stimulate the growth of transplantable mammary adenocarcinoma and reduced DMBA-induced mammary tumorigenesis. ALA has also been shown to enhance cell-mediated cytotoxicity. The authors describe a study in which mammary tumor cells were transplanted into mice who were fed corn oil, flaxseed oil or fish oil. After 8 weeks, tumor size and weights were larger in the corn oil fed mice than in flaxseed oil fed animals. Overall, the author indicates that there are now several studies indicating an inhibitory effect of dietary ALA on tumor incidence and growth in models using chemically induced, transplantable and spontaneous tumors. Research is continuing to determine the possible mechanisms responsible for anti-carcinogenic effects of ALA. A positive correlation has been identified between enhanced PGE2 synthesis, derived from AA, and tumor growth. ALA, through conversion to EPA, may act to reduce the generation of AA derived eicosanoids. ALA may also affect cytokine production and other immunomodulatory indices in cancer. It is also possible that ALA may have inhibitory effects which are independent from its conversion to EPA and DHA. In humans, data on the anti-carcinogenic effects of ALA is lacking but epidemiological studies have shown that low plasma levels of ALA are associated with enhanced risk of mammary, colon and prostate cancers. The author recommends further studies in humans as well as investigations at the molecular level to ascertain more definitively the effects of ALA on cancer prevention and treatment.
