Key Findings
This case control study found no significant correlations regarding total fat, saturated fat, monounsaturated fat, and n6 fat intake and the risk of colorectal cancer. ALA and long-chain n3 fat intakes were related to a reduced risk of colorectal cancer in both men and women, colon and rectal cancers. ALA and long chain n3 appear to decrease the synthesis of AA eicosanoids, modify estrogen metabolism; and effect free radicals and reactive oxygen species generation; all of which require further research.
ABSTRACT
The associations between dietary fat intakes and the risk of colorectal cancer have been examined in many epidemiological studies, but the results have remained inconsistent. This study aimed to examine the associations of total fat and fatty acid intakes with the risk of colorectal cancer in Guangzhou, China. A case control study was carried out between July 2010 and May 2012 in Guangzhou, China. Four hundred and eighty nine consecutively recruited colorectal cancer cases were frequency matched to 976 controls by age (5 year interval) and sex. A validated food frequency questionnaire was used to collect dietary information by face to face interviews. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95 per cent confidence intervals (CIs). The total fat intake was not related to the risk of colorectal cancer, with an OR (95 per cent CI) of 0.95 (0.68 to 1.32) comparing the highest with the lowest quartiles. Intakes of saturated fat, monounsaturated fat, and n 6 polyunsaturated fat were also not associated with the risk of colorectal cancer. However, a significant inverse association was found between total n 3 polyunsaturated fat, alpha linolenic acid (ALA), and long chain n 3 polyunsaturated fat consumption and the risk of colorectal cancer. The adjusted ORs of the highest versus the lowest quartile were 0.45 for total n 3 polyunsaturated fat, 0.54 for ALA, and 0.58 for long chain n 3 polyunsaturated fat. This study suggested that total fat, saturated fat, monounsaturated fat, and n 6 polyunsaturated fat intakes were not related to the risk of colorectal cancer. However, increased consumption of n 3 polyunsaturated fat might reduce the risk. (Authors abstract)
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