Soluble Fiber Inulin Consumption Limits Alterations of the Gut Microbiota and Hepatic Fatty Acid Metabolism Caused by High-Fat Diet

Abstract

Diet shapes the gut microbiota which impacts hepatic lipid metabolism. Modifications in liver fat content are associated with metabolic disorders. We investigated the extent of dietary fat and fiber-induced alterations in the composition of gut microbiota and hepatic fatty acids (FAs). Mice were fed a purified low-fat diet (LFD) or high-fat diet (HFD) containing non-soluble fiber cellulose or soluble fiber inulin. HFD induced hepatic decreases in the amounts of C14:0, C16:1n-7, C18:1n-7 and increases in the amounts of C17:0, C20:0, C16:1n-9, C22:5n-3, C20:2n-6, C20:3n-6, and C22:4n-6. When incorporated in a LFD, inulin poorly affected the profile of FAs. However, when incorporated in a HFD, it (i) specifically led to an increase in the amounts of hepatic C18:0, C22:0, total polyunsaturated FAs (PUFAs), total n-6 PUFAs, C18:3n-3, and C18:2n-6, (ii) exacerbated the HFD-induced increase in the amount of C17:0, and (iii) prevented the HFD-induced increases in C16:1n-9 and C20:3n-6. Importantly, the expression/activity of some elongases and desaturases, as well as the gut microbiota composition, were impacted by the dietary fat and fiber content. To conclude, inulin modulated gut microbiota and hepatic fatty acid composition, and further investigations will determine whether a causal relationship exists between these two parameters.

Dietary Inulin Supplementation Affects Specific Plasmalogen Species in the Brain

“…Mice were maintained on 12 h light:dark cycles with ad libitum access to food and water. After 1 week of acclimation, mice were randomly divided into two groups: a control group (CTRL; n = 12) received a purified diet supplemented with 50 g cellulose/kg (Research Diet; #D12450J) and an inulin group (INU; n = 11) received a purified diet supplemented with 200 g inulin/kg (Research Diet; #D13081108) [ 34 ]. Cellulose as a source of fiber is generally poorly fermented by the gut.…”

“…The influence of inulin on the gut microbiota is particularly well documented. Data obtained from mouse models as well as from studies of humans showed that inulin consumption is associated with the expansion of bacteria that are described as conferring health benefits and with a reduction in pathobionts [ 34 , 35 , 36 , 37 ]. Modulation of the host lipid metabolism is also associated with inulin consumption.…”

“…Indeed, effects of inulin on triglyceride and cholesterol blood levels have been reported, but these findings are still controversial [ 38 , 39 , 40 ]. In addition, we recently showed that supplementation of a low- or high-fat diet with inulin affects the fatty acid content of mouse liver [ 34 ]. Although no direct causal relationship has been established, some inulin-induced changes in the gut microbiota were correlated with modification of the expression of genes encoding enzymes involved in fatty acid biosynthesis [ 34 ].…”

“…In addition, we recently showed that supplementation of a low- or high-fat diet with inulin affects the fatty acid content of mouse liver [ 34 ]. Although no direct causal relationship has been established, some inulin-induced changes in the gut microbiota were correlated with modification of the expression of genes encoding enzymes involved in fatty acid biosynthesis [ 34 ]. The aim of this study was to investigate whether dietary intake of inulin affects the Pl content of the brain.…”

Immunomodulation by probiotics and prebiotics in hepatocellular carcinoma

“…Inulin is a non-digestible functional polysaccharide, present in plants such as onions, chicory, Jerusalem artichoke, leeks, garlic, bananas, rye, barley and wheat[ 61 ]. A recent study showed that inulin modulates GM and hepatic fatty acid composition limiting dysbiosis and its negative effect on host health[ 62 ].…”