A Personal Microbiome-dependent Glucose Response in Healthy Young Volunteers

A Personal Microbiome-dependent Glucose Response in Healthy Young Volunteers: a Meal Test Study

Individuals eating identical meals present high variability in post-meal blood glucose response making comparisons challenging. This study evaluates in 40 healthy and fasted participants whether the postprandial glucose response upon a standardized breakfast is dependent on gut microbial richness. Gastric emptying rate, intestinal transit time, insulin, appetite hormones and measures of the intestinal microbiome and fermentation will also be analyzed in the context of postprandial glucose metabolism.

Elevated blood glucose levels constitute a major risk factor for pre-diabetic and diabetic patients. Postprandial glucose tests have been used for decades to monitor and compare glucose responses. Yet, individuals eating identical meals present high variability in post-meal blood glucose response making comparisons challenging. A recent landmark study showed that the inter-individual variation of postprandial glucose responses was associated with multiple person-specific factors including faecal microbiome factors. Gut microbial richness has for a long time been considered a hallmark of gut health and stability. Furthermore, microbial richness has been associated with colonic transit time, which together with the gastric emptying rate appear to be major determinants of the initial glycaemic response to carbohydrate-containing meals. Therefore, the aim of the study is to investigate whether postprandial glucose responses are associated with gut microbial richness, as well as secondary measures including gastric emptying rate, intestinal transit time and gut microbial composition and fermentation.

In an acute-meal study, 40 healthy fasted participants will consume a standardized breakfast including one tablet of paracetamol (for estimating gastric emptying rate) and 300 mL of juice.

Inclusion Criteria:

• BMI < 27
• Willing to eat lentils, tomatoes, spaghetti, bread, butter, strawberry jam, and drink juice
• Known ability to tolerate paracetamol
• No current use of medication (oral contraceptive pill and mild antidepressants is allowed)
• Did not take antibiotics, diarrhoea inhibitors and laxatives in the 6 previous months
• Willing to collect and deliver a faecal sample on the intervention day
• Willing to eat corn and fill out a self-reported corn-intestinal transit time questionnaire
• Willing to consume a paracetamol tablet (500 mg paracetamol)

Exclusion Criteria:

• Any condition that makes the project responsible researcher to doubt the feasibility of the volunteer's participation
• Pregnant or lactating women
• Suffering from irritable bowel disease (IBS), small intestine bacterial overgrowth (SIBO) or inflammatory bowel disease (IBD)
• Current chronic or infectious disease
• Current diagnosis of diabetes
• Blood donations within 3 months before participating in the current trial or participation in other scientific experiments
• Frequent intake of painkillers (paracetamol)