Effects of a Diet Based on Inulin-rich Vegetables on Gut Health and Nutritional Behaviour in Healthy Humans

Cliniques universitaires Saint-Luc- Université Catholique de Louvain26 enrolled

Overview

Inulin-type fructans (ITF) are fermentable dietary fibres that can confer beneficial health effects through changes in the gut microbiota. However, their effect on gut sensitivity and nutritional behaviour is a matter of debate. The investigators evaluated, in healthy individuals, the impact of shifting from their usual food habits towards a diet based on the daily consumption of ITF-rich vegetables on gut microbiota, gastro-intestinal symptoms and food-related behaviour.

Study Type

INTERVENTIONAL

Allocation

Purpose

OTHER

Masking

NONE

Enrollment

Conditions

Healthy

Interventions

Diet based on inulin-rich vegetablesOTHER

Eligibility

Sex: ALLMin age: 18 YearsMax age: 85 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * BMI between 20 and 25 kg/m² * Caucasian ethnicity * Hydrogen producers (assessed by hydrogen breath test) Exclusion Criteria: * Smokers * Laxative consumption (\<4 weeks) * Severe intestinal problems * Psychiatric problems or use of antipsychotic * Consumption of antibiotics, pro/prebiotics, fibre dietary supplement, or any molecules that modifies the intestinal transit (\<6 weeks) * Specific dietary practise (vegetarian, vegan,...) * Specific dietary treatment (\<6 weeks) (e.g. high protein diet) * Excessive alcohol consumption (\>3 glasses/day) * Consumption of the following drugs: proton pump inhibitor, antidiabetic drugs, cholesterol lowering drugs * Inconclusive acceptability test (regarding the protocol of the intervention and the vegetables used in the protocol)

Outcomes

Primary Outcomes

Gut microbiota composition

Gut microbiota composition is assessed by 16S rRNA pyrosequencing. This analysis allows to obtain the relative abundance (%) of the different bacterial taxa and OTUs (operational taxonomic units).

Time frame: 33 days

Secondary Outcomes

Gut microbiota fermentation in vivo

Gut microbiota fermentation is assessed in vivo by an hydrogen breath test. After an oral load of purified inulin, the level of expired hydrogen (ppm) is measured.

Time frame: 33 days

Gut microbiota fermentation in vitro

Gut microbiota fermentation is assessed in vitro by the measurement of total gas (ml/g of dry matter) produced from subject feces incubated with inulin-rich substrates.

Time frame: 14 days

Gastrointestinal Symptoms

Gastrointestinal symptoms were assessed by Visual Analogue Scale (horizontal line of 100 mm). Each subject completed seven separate scales, one for each symptom (rumble, burp, bloating, discomfort, nausea, flatulence, cramp), ranging from "no sensation" (0 mm) to "very severe sensation" (100 mm).

Time frame: 33 days

Appetite-related feelings

Appetite-related feelings were assessed by Visual Analogue Scale (horizontal line of 100 mm). Each subject completed seven separate scales, one for each appetite-related feeling (satiety, intention to eat, fullness, sweet envy, very sweet envy, fat envy, salt envy), ranging from "no sensation" (0 mm or 100 mm depending on the feeling) , to "very strong sensation" (0 mm or 100 mm depending on the feeling).

Time frame: 33 days

Correlation of gastrointestinal symptoms with gut bacteria

The levels of gastrointestinal symptoms were correlated (Spearman correlations) with the relative abundance of bacterial taxa and OTUs (operational taxonomic units)

Time frame: 33 days

Short chain fatty acids production

Short chain fatty acids (SCFAs) production was assessed in vitro by the measurement of total SCFAs (mg/g of dry matter) produced from subject feces incubated with inulin-rich substrates.

Time frame: 14 days