The effects of dietary supplementation with inulin and inulin‐propionate ester on hepatic steatosis in adults with non‐alcoholic fatty liver disease

Abstract

The short chain fatty acid (SCFA) propionate, produced through fermentation of dietary fibre by the gut microbiota, has been shown to alter hepatic metabolic processes that reduce lipid storage. We aimed to investigate the impact of raising colonic propionate production on hepatic steatosis in adults with non-alcoholic fatty liver disease (NAFLD). Eighteen adults were randomized to receive 20 g/d of an inulin-propionate ester (IPE), designed to deliver propionate to the colon, or an inulin control for 42 days in a parallel design. The change in intrahepatocellular lipid (IHCL) following the supplementation period was not different between the groups (P = 0.082), however, IHCL significantly increased within the inulin-control group (20.9% ± 2.9% to 26.8% ± 3.9%; P = 0.012; n = 9), which was not observed within the IPE group (22.6% ± 6.9% to 23.5% ± 6.8%; P = 0.635; n = 9). The predominant SCFA from colonic fermentation of inulin is acetate, which, in a background of NAFLD and a hepatic metabolic profile that promotes fat accretion, may provide surplus lipogenic substrate to the liver. The increased colonic delivery of propionate from IPE appears to attenuate this acetate-mediated increase in IHCL.

Gut‐derived short‐chain fatty acids: A friend or foe for hepatic lipid metabolism?

“…), volunteers in the recent study (Chambers et al . ) had considerably higher fasting glucose and HbA1c at baseline (Table ) and we speculate that this poorer metabolic profile might impact the metabolic processing of gut‐derived SCFAs in the liver.…”

“…The study outcomes were unexpected and did not support our hypothesis that liver fat would be significantly reduced in the IPE group compared to those supplemented with the inulin‐control (Chambers et al . ). The change in IHCL was not significantly different between groups following the 42‐day supplementation period.…”

“…Funding from the British Nutrition Foundation Drummond Pump Priming Award helped support a follow‐up investigation to develop in vivo proof of concept for IPE as a therapeutic strategy to reduce liver fat in adults with NAFLD (Chambers et al . ). The clinical trial (ISRCTN71814178) recruited patients from liver clinics at St Mary's Hospital, Imperial College Healthcare National Health Service Trust, London, UK.…”

“…In comparison with the inulin‐control group, we showed that IPE supplementation did not raise IHCL content in individuals with a histological confirmation of NAFLD (Chambers et al . ). Our previous study has shown that, compared to inulin, IPE substantially increases the molar ratio of propionate:acetate produced in the gut (Chambers et al .…”

“…In contrast to our recent study (Chambers et al . ), an increased dietary intake of inulin has repeatedly been shown to have positive effects on liver fat content in rodent studies (Anastasovska et al . ; Kumar et al .…”