LIVRO “Role of Dietary polyunsaturated fatty acids in cancers of the breast and colorectum”: Polyunsaturated fat and the risk of cancer. (English Edition) PDF Dr. Hakim Saboowala

Dietary fat is thought to be one of the main risk factors on the basis of reports of positive correlations between dietary fat intake and increased risks for cancers of the breast, colon and prostate. Although the role of individual fatty acids in human cancer risk has hitherto been poorly investigated, some recent epidemiological and clear experimental data have now linked a high dietary intake of ω-6 polyunsaturated fatty acids (PUFAs) such as linoleic acid (C18:2), especially in association with a low intake of ω-3 PUFAs such as docosahexaenoic acid (C22:6), to increased risks for cancers of the breast, colon and, possibly, prostate. ω-6 PUFAs enhance tumorigenesis and metastasis in experimental animals by several mechanisms, whereas ω-3 PUFAs can inhibit the growth of initiated cancer cells. Furthermore, persistent oxidative stress, often involving enhanced peroxidation of PUFAs in cell membranes by intracellularly produced O – and N -centred free radicals, altered cellular redox potential, activation of protein kinases and subsequent changes in transcription factors, are now known to enhance the development of malignant diseases. Thus, the carcinogenic process could be initiated and/or accelerated by lipid peroxidation-induced DNA and protein damage. In this Booklet, an attempt has been made to focus on current evidence from experimental and human studies that implicates a high intake of ω-6 PUFAs in cancers of the breast, colon and, possibly, prostate and which indicates that ω-3 PUFAs and monounsaturated fatty acids such as oleic acid (ω-9) are protective. Several plausible mechanisms for modulation of steps in the multistage carcinogenesis process by fats are summarized briefly in order to provide guidance for the design of epidemiological studies that include mechanistically relevant biomarkers. ………Dr. H.K.Saboowala.