Background and objectives: The sudden change in the dietary habits of the Japanese population towards a European/American-style diet since the 1960s is thought to be responsible for the recent increase in the incidence of inflammatory bowel disease (IBD) in Japan. Dietary fatty acid intake influences the fatty acid profiles of vital cell membranes, which might be a source of inflammatory mediators.
Methods: We investigated the fatty acid composition of the erythrocyte membrane in 90 healthy Japanese and 43 initial-onset IBD patients (ulcerative colitis, UC: 25; Crohn's disease, CD: 18) who had not undergone any dietary intervention to examine the role fatty acids play in the onset of IBD.
Results: The erythrocyte membrane n-3/n-6 ratio of the initial-onset IBD patients was 0.42 ± 0.13, which was not significantly different from that of the healthy Japanese subjects (0.41 ± 0.13). However, the CD patients displayed a significantly lower mean percentage weight (MPW) of linoleic acid (LA) than the healthy subjects (8.25 ± 1.75 vs. 9.90 ± 1.29; p < 0.001), while their MPW of arachidonic acid (AA) was significantly higher than those of the healthy subjects and UC patients (11.22 ± 2.18 vs. 9.76 ± 1.64, p < 0.01; vs. 9.58 ± 1.97, p < 0.01, respectively). The mean delta 6-desaturation index of the CD patients was significantly higher than that of the healthy subjects (1.61 ± 0.65 vs. 1.11 ± 0.26; p < 0.001).
Conclusions: The CD patients displayed significantly higher and lower MPW of AA and LA, respectively, than the healthy subjects, suggesting that delta 6-desaturase is hyperactivated in CD. The cell membrane fatty acid profile might be a therapeutic target in CD.