Risk of Colorectal Cancer Is Linked to Erythrocyte Compositions of Fatty Acids as Biomarkers for Dietary Intakes of Fish, Fat, and Fatty Acids

Abstract

Consumption of fish rich in n-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid, is suggested to reduce colorectal cancer risk through inhibition of the arachidonic acid (AA) cascade related to tumorigenesis and cell proliferation. High intake of saturated fatty acids (SFAs) may increase the risk. To examine associations between colorectal cancer risk and fatty acid compositions in erythrocyte membranes, as biomarkers for dietary intakes of fish, fat, and fatty acids, we conducted a case-control study with 74 incident cases and 221 noncancer controls (matched by age, sex, and season of sample collection). Erythrocyte fatty acids were measured using an accelerated solvent extraction and a gas-liquid chromatography. Colorectal cancer had no association with dietary intakes of meat, fish, fat, and fatty acids. However, the risk was inversely associated with erythrocyte compositions of docosahexaenoic acid, AA, and PUFAs [the highest to the lowest tertile, odds ratios, 0.36, 0.42, and 0.15; 95% confidence intervals, 0.14-0.93, 0.18-0.95, and 0.05-0.46; P trend < 0.05, respectively] and positively with those of palmitic acid, SFAs, and the ratio of SFAs/PUFAs (odds ratios, 6.46, 8.20, and 9.45; 95% confidence intervals, 2.41-17.26, 2.86-23.52, and 2.84-31.43; P trend < 0.005, respectively). In conclusion, we could clearly show decreased and increased risks for colorectal cancer related to PUFAs and SFAs compositions in erythrocyte membranes, respectively, but further research is needed to investigate the discrepancy between our findings and the generally accepted role of the AA cascade. (Cancer Epidemiol Biomarkers Prev 2006;15(10):1791 -8)

Opposing associations of serum n‐3 and n‐6 polyunsaturated fatty acids with colorectal adenoma risk: An endoscopy‐based case–control study

“…[4][5][6]10,[12][13][14] It is hypothesized that n-3 and n-6 PUFA can have opposing effects on colorectal tumor formation via modulation of the AA pathway; by changing the substrates and products, like eicosanoids, or by a direct effect on the genes involved in this pathway, although the precise mechanisms are far from clear. 3 One could question whether the observed association of n-3 PUFA and colorectal adenomas could partly be explained by n-6 PUFA, and vice versa.…”

“…However, studies, which assessed n-3 and n-6 PUFA intake by food frequency questionnaire 10,[12][13][14] or by serum levels, [4][5][6] did not show opposed associations.…”

Breast cancer risk and erythrocyte compositions of n‐3 highly unsaturated fatty acids in Japanese

“…The study design has been elsewhere described, 30 and this study was executed in a series within the Aichi Fatty Acid (AiFat) Research project to clarify associations between a large number of blood parameters and cancers in several sites. 28,29 Briefly, all first-visit outpatients (n 5 18,103), including all cancer cases (n 5 3,972), are asked to fill out a selfadministrated questionnaire regarding their lifestyle and to provide 7 mL blood samples. All subjects are provided with an explanatory document and requested to give their written informed consent for participation in the study, which was approved by the Ethics Committee of the Aichi Cancer Center.…”

“…Finally, 309 controls were individually matched for age (65 years) and season of sample collection to cases with a 1: 3 case-control ratio, considering seasonal differences in biomarkers for dietary intakes of fish, fat and fatty acids. 28,31 Approximately 57.9% of them had no current or past diseases according to the questionnaire, and others had the following current or past diseases; tuberculosis (1.6%), gastric ulcer (4.2%), duodenal ulcer (3.9), appendicitis (14.9%), hemorrhoids (10.4%), asthma (5.5%), hypertension (8.4%), angina (1.0%) and acute pneumonia (1.2%). Most of control subjects visited for their health check or cancer screening at ACCH.…”

“…27 Estimated die-tary intake of fish is high in Japanese; the percentage of energy from fish in a period of 1961-1994 was 6.21%, compared with 0.90% in Italians and 2.20% in Swedes, 22 so that Japanese are a particularly appropriate population to examine the role of n-3 HUFAs derived from fish intake. Correlation coefficients (r) between dietary intakes of EPA and DHA and the corresponding fatty acid compositions in erythrocyte membranes have been reported as 0.20 for EPA in Japan, 28 0.48 for DHA in Italy, 26 and 0.23-0.27 for EPA and DHA in Swedes. 27 Recently, we have developed a new analytical method for measuring fatty acids in biomaterials using an automatic solvent extractor and gas-liquid chromatography, with confirmed high precision and accuracy, making it feasible to use small volume multi-samples, routinely, rapidly and cheaply.…”