Attenuation of colonic inflammation by partial replacement of dietary linoleic acid with α-linolenic acid in a rat model of inflammatory bowel disease

Abstract

Increasing prevalence of inflammatory bowel disease may be due to imbalance in the intake of n-6 and n-3 PUFA in the diet. This study investigates the impact of varying ratios of dietary linoleic acid (LA, 18 : 2n-6) to a-linolenic acid (ALA, 18 : 3n-3) on the inflammatory response in dextran sulphate sodium (DSS)-induced colitis. Weanling male Sprague -Dawley rats were divided into five groups: a non-colitic group with a LA:ALA ratio of 215 (CON-215), and colitic groups with LA:ALA ratios of 215 (DSS-215), 50 (DSS-50), 10 (DSS-10) and 2 (DSS-2). Blends of groundnut, palmolein and linseed oils were used to provide varying LA:ALA ratios. All the rats were fed the respective experimental isoenergetic diets containing 10 % fat for 90 d and DSS was administered during the last 11 d. Colonic inflammation was evaluated by clinical, biochemical and histological parameters. The results showed attenuation of colitis in the DSS-2 group as evidenced by significant reductions in disease activity index, mucosal myeloperoxidase activity (P,0·05), alkaline phosphatase activity (P,0·01) and increase in colon length (P, 0·01) compared to the groups fed with higher ratios (DSS-215). This was accompanied by significant reductions in mucosal proinflammatory cytokines TNF-a (P,0·01) and IL-1b (P,0·01) and improvement in the histological score. Further, ALA supplementation increased long-chain (LC) n-3 PUFA and decreased LC n-6 PUFA in colon structural lipids. These data suggest that substitution of one-third of LA with ALA (LA:ALA ratio 2) mitigates experimental colitis by down-regulating proinflammatory mediators.

Controversies in omega-3 efficacy and novel concepts for application

“…Having an LCn6 to LCn3 ratio of 3:1 or lower prevented damage of intestinal mucosal layer and resolved inflammatory colitis manifestations in both SpragueDawley and Wistar rats [147,148].…”

“…Consumption of fish oil-rich diets containing 25%-30% (w/w) EPA and DHA or perilla oil containing 55%-60% (w/w) α-linolenic acid (C18:3n-3) relieved chronic ileitis in M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT senescence-accelerated P1/Yit mice by inhibiting monocyte recruitment in inflamed intestinal tissue [146]. Supplementation of LCn3s has also been shown to reduce plasma endotoxin levels in dextran sodium sulfate (DSS)-induced colitis in rats [147].…”

Association of Dietary Factors With Ulcerative Colitis in India

“…The dietary practices in India are very different from the West. The present study endeavours to address some of the above dietary issues for UC in India as data is scarce and limited to animal studies [5,6] . fig, brinjal, cucumber, tomato, onion, chilli varieties, plantain, beet, garlic, ginger, peas, ladies' fingers, carrot, pumpkin, gourd varieties, radish, beans, perbol, salads and mixed vegetables].…”

Alpha linolenic acid and oleic acid additively down-regulate malignant potential and positively cross-regulate AMPK/S6 axis in OE19 and OE33 esophageal cancer cells

“…Alpha-linolenic acid (ALA) is an essential omega-3 fatty acid and organic compound found in seeds (chia and flaxseed), nuts (notably walnuts), and many common vegetable oils [12,13]. ALA can only be obtained by humans through their diets because the absence of the required 12-and 15-desaturase enzymes makes de novo synthesis from stearic acid impossible [14]. Dietary ALA has been assessed for its role in cardiovascular health, showing that the weight of the evidence favors recommendations for modest dietary consumption of ALA (2-3 g/day) for the primary and secondary prevention of coronary heart disease [15].…”