Prebiotic diet changes neural correlates of food decision-making in overweight adults: a randomised controlled within-subject cross-over trial

Abstract

ObjectiveAnimal studies suggest that prebiotic, plant-derived nutrients could improve homoeostatic and hedonic brain functions through improvements in microbiome–gut–brain communication. However, little is known if these results are applicable to humans. Therefore, we tested the effects of high-dosed prebiotic fibre on reward-related food decision-making in a randomised controlled within-subject cross-over study and assayed potential microbial and metabolic markers.Design59 overweight young adults (19 females, 18–42 years, body mass index 25–30 kg/m2) underwent functional task MRI before and after 14 days of supplementary intake of 30 g/day of inulin (prebiotics) and equicaloric placebo, respectively. Short chain fatty acids (SCFA), gastrointestinal hormones, glucose/lipid and inflammatory markers were assayed in fasting blood. Gut microbiota and SCFA were measured in stool.ResultsCompared with placebo, participants showed decreased brain activation towards high-caloric wanted food stimuli in the ventral tegmental area and right orbitofrontal cortex after prebiotics (preregistered, family wise error-corrected p <0.05). While fasting blood levels remained largely unchanged, 16S-rRNA sequencing showed significant shifts in the microbiome towards increased occurrence of, among others, SCFA-producingBifidobacteriaceae, and changes in >60 predicted functional signalling pathways after prebiotic intake. Changes in brain activation correlated with changes inActinobacteriamicrobial abundance and associated activity previously linked with SCFA production, such as ABC transporter metabolism.ConclusionsIn this proof-of-concept study, a prebiotic intervention attenuated reward-related brain activation during food decision-making, paralleled by shifts in gut microbiota.Trial registration numberNCT03829189.

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“…Dietary changes can be difficult to maintain, but there are increasing data that changes in the microbiome can facilitate dietary preferences. In a recent study, overweight subjects were given a prebiotic of inulin, which resulted in more short-chain fatty acid (SCFA) producing bacteria with accompanying changes in the brain activation related to food preferences ( 38 ). The implications of this study go beyond just those of food decision making with HE, as SCFA such as butyrate is shown to maintain gut integrity and is protective against HE ( 39 ).…”

The Obese Taste Bud study: Objectives and study design

“…This approach allows the evaluation of differences in wanting scores and brain region activity for food compared to art stimuli. For further details on the design and analysis plan of this decision‐making task, see Medawar et al 8 …”

Complex carbohydrate utilization by gut bacteria modulates host food preference

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