Dietary fat in relation to fatty acid composition of red cells and adipose tissue in colorectal cancer

Abstract

Summary Fatty acids were determined in erythrocytes in 49 patients with colorectal cancer and compared with age and sex-matched controls. Marginally increased levels of stearic acid (P=0.057) and oleic acid (P=0.064) and decreased arachidonic acid (P=0.043) occurred in cancer patients. There was no difference in the stearic to oleic acid ratio between the two groups. Dietary intake, assessed by dietary recall and adipose tissue analysis was also not different. In control subjects the polyunsaturated:saturated (P:S) fatty acid ratio correlated betwen diet and adipose tissue (P<0.001) but not erythrocytes; there was a three way correlation between dietary, erythrocyte and adipose linoleic acid (P<0.01, at least). In contrast cancer patients showed different correlations; in particular dietary and erythrocyte P:S fatty acid ratios correlated (P<0.01).These findings may indicate disturbed fat metabolism in cancer patients. The erythrocyte stearic to oleic acid ratio is of no diagnostic value.Recently much interest has been aroused by reports of abnormalities of fatty acids in erythrocytes obtained from patients with a variety of solid tumours arising from the gastrointestinal tract (Wood et al., 1985;Habib et al., 1987). In particular, a reduced ratio of stearic acid (18:0) to oleic acid (18:1, n-9) has been found (Wood et al., 1985). This has been attributed to a circulating desaturation factor of cell membrane fatty acids in cancer patients (Habib et al., 1987). A close correlation has been reported between this ratio and the Dukes' stage of colonic cancers (Habib et al., 1986) and curative resection results in the fatty acid ratio returning to normal (Wood et al., 1985). However, others have raised objections about the matching of the patients with control subjects (Metcalfe et al., 1985).The present study was therefore undertaken to assess the erythrocyte fatty acid profile in a relatively homogeneous group of patients with cancer (colon and rectum) using closely matched controls. The possible influence of dietary fat on the red cell fatty acid profile was also assessed by determining intake using seven-day dietary recall and measuring the fatty acid composition of adipose tisue. Patients and methodsForty-nine patients with colorectal cancer were studied, of whom 42 were admitted for elective surgery. None of these patients had sutained any weight loss. Eleven had Dukes' A, 20 had Dukes' B and 11 had Dukes' C adenocarcinomas. The other seven patients had clinically recurrent colorectal cancer following previous resection, although only four had sustained a > 10% weight loss. The mean age was 69.0 years (range 49-92 years) of whom 30 were men and 19 were women. Patients presenting as emergencies with obstruction, perforation and bleeding requiring blood transfusion were deliberately excluded.The control population consisted of an equal number of patients admitted for elective surgery for benign diseases (e.g., varicose veins or abdominal wall herniae) at the same time as those with cancer and were matched for age...

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

“…Previous reports in United Kingdom and Spain, however, have shown to be lower erythrocyte composition of AA in colorectal cancer patients than in controls, but the findings were inconsistent (17)(18)(19)(20). In Italian women, the higher composition of 18:2n-6 and n-6 PUFAs were associated with breast cancer risk, but that of AA had no association (21).…”

“…In erythrocyte membranes, the composition of 18:0 has been reported to be higher in colorectal cancer patients than in noncancer controls (17). Although the erythrocyte ratio of 18:0/18:1n-9 (i.e., saturation index n-9 ), suggested to reflect activity of the rate-limiting enzyme D9 desaturase (catalyzing conversion from 18:0 to 18:1n-9), is associated with cancer risk in the colorectum and breast, findings are inconsistent (18)(19)(20)(21).…”

“…In previous studies, erythrocyte compositions of 18:0 and 18:1n-9 were higher in colorectal cancer patients (17,18), and those of MUFAs, 16:1n-7 and 18:1n-9 were related to increased risk of breast cancer (21). The saturation index n-9 in erythrocyte membranes has been observed to be lower in colorectal cancer patients than in controls (20) and in Italian postmenopausal women was linked to decrease breast cancer risk, with activity of D9 desaturase suggested to play a modifying role, especially with dietary intakes of SFAs and PUFAs, because this enzyme is linked to fat content in the diet (21).…”

“…We also defined the ratios of specific fatty acid as follows: the ratios of 18:0/18:1n-9 (as saturated index n-9 ), 16:0/16:1n-7 (as saturated index n-7 ), SFAs/ PUFAs, SFAs/n-6 PUFAs, SFAs/n-3 PUFAs, SFAs/n-3 HUFAs, n-6 PUFAs/n-3 PUFAs, n-6 PUFAs/n-3 HUFAs, AA/EPA, and AA/DHA. The saturated indices are indicators of membrane fluidity; its reciprocal can be considered to be and index of the activity of the rate-limiting enzyme D9 desaturase that transforms SFAs into the corresponding MUFAs (17)(18)(19)21). The ratio of n-6 PUFAs/n-3 PUFAs has been suggested to be important for human health (41 and erythrocyte compositions (mol%) were adjusted for age, sex, BMI, and season of sample collection.…”

Erythrocyte Membrane Stearic Acid : Oleic Acid Ratios in Colorectal Cancer Using Tube Capillary Column Gas Liquid Chromatography

“…Thus, a base catalysed transesterification method which does not generate dimethyl-acetals was used in a previous study with packed column GLC. 8 Alternatively, separation of FAMES from dimethyl-acetals should be undertaken prior to GLC or sensitive separation techniques should be used which can clearly separate dimethyl-acetals from FAMES of interest.'! Other pitfalls have recently been described by Popp-Snijders.i"…”