Consumption of a Sourdough-Leavened Croissant Enriched with a Blend of Fibers Influences Fasting Blood Glucose in a Randomized Controlled Trial in Healthy Subjects

Abstract

Background

An incorrect lifestyle, including diet, is responsible for the worldwide dramatic increase in obesity and type 2 diabetes. Increasing dietary fiber consumption may lead to health benefits, and reformulation of bakery products may be a strategy to globally improve the diet.

Objectives

This study aimed to assess the impact of a 2-wk breakfast consumption with a sourdough-leavened croissant containing a blend of dietary fiber from 10 sources (4.8 g/100 g, croissant enriched with dietary fibers [FIBCRO]), compared with a control croissant (dietary fibers 1.3 g/100 g, CONCRO) on daily energy intake, appetite, metabolic variables, and the gut microbiome.

Methods

Thirty-two healthy participants were randomly allocated to 2 groups consuming FIBCRO or CONCRO. Participants self-recorded their diet and appetite through 7-d weighted food diaries and visual analog scales every day over the 2 wk. At baseline and after the intervention, fasting blood and urine samples, and fecal samples were collected beside blood pressure, anthropometry, and body composition. Serum glucose, lipids, C-reactive protein, and insulin according to the official methods and serum dipeptidyl peptidase-4 (DPPIV) activity by photometric method were measured. Polyphenols and urolithins in urines were analyzed by Liquid chromatography–tandem mass spectrometry (LC/MS/MS), whereas gut microbiome in feces by shotgun metagenomics.

Results

FIBCRO consumption improved fasting blood glucose compared with CONCRO (mean changes from baseline −2.0 mg/dL in FIBCRO compared with +3.1 mg/dL in CONCRO, P = 0.022), also reducing serum DPPIV activity by 1.7 IU/L (P = 0.01) and increasing urinary excretion of urolithin A-sulfate by 6.9 ng/mg creatinine (P = 0.04) compared with baseline. No further changes in any of the monitored variables or in the gut microbiome were detected.

Conclusions

Results suggested that a 2-wk consumption of a sourdough croissant claimed as “source of dietary fiber” improved fasting glycemia compared with a conventional sourdough croissant in healthy subjects. The reduced serum DPPIV activity and increased bioavailability of urolithin likely contributed to determine that effect independently from gut microbiome changes.

This trial was registered at clinicaltrials.gov as NCT04999280.