Impacts of Fermented Oat-based Product on Gut Microbiota and Health

Impacts of Fermented Plant-based Products High in Protein and Fibre on Gut Microbiota and Health: a Randomized, Controlled, Cross-over Trial

This study aims to investigate the effects of consuming fermented oat-based products on gut and overall human health. It is a randomized, controlled, cross-over trial with a dietary intervention.

A total of 100 participants will be enrolled in this study and they will eat both fermented and unfermented oat-based products for three weeks. Participants will eat their habitual diet between the dietary intervention periods (wash-out).

During the study, participants' perceived health, inflammatory markers, glucose and lipid metabolism, tryptophan metabolites, gastrointestinal symptoms, and gut microbiota will be assessed.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome
• Intervention / Treatment: Other: Fermented oat-based product; Other: Unfermented oat-based product

Detailed Description

Plant-based protein sources, such as those derived from oats, are experiencing high demand due to their role in reducing reliance on animal products and promoting a more sustainable food system. Despite this, there is limited information available regarding the impact of components like fibre in plant-based foods on protein and other nutrients' metabolism.

Food fermentation emerges as a potential solution to enhance the absorption of plant-based protein and various nutrients in the small intestine. This is achieved by reducing antinutrients and facilitating the absorption process. Additionally, food fermentation has implications for the composition and metabolic activity of the gut microbiota, influencing metabolism, immune responses, intestinal function, and overall health. The metabolism of tryptophan in the gut, modulated by the gut microbiota and the production of various metabolites, may serve as a key link in these observed effects.

The fermentation of plant-based foods potentially enhances the beneficial health effects of these foods, and investigating this contributes to an increased understanding of the gut-mediated health effects of foods and the mechanisms behind them. This study will be part of a European research project HealthFerm.

Detailed objectives are to:

1. compare fermented and unfermented plant-based food products to blood lipid and glucose metabolism and gastrointestinal comfort as well as perceived and observed overall well-being.
2. study the effects of fermented and unfermented plant-based food consumption on the markers for gut permeability and inflammation.
3. study the difference in microbiota composition and diversity after consuming fermented and unfermented plant-based foods and its contribution to cardiometabolic outcomes.
4. study the difference in microbiota-related metabolites, especially tryptophan metabolites between fermented and unfermented plant-based foods.

A total of 100 participants will be enrolled in this randomized, controlled, cross-over trial, during which they will eat both fermented and unfermented oat-based products as part of their habitual diet. The study follows this sequence:

Weeks 1-3: Habitual diet Weeks 4-6: Dietary Intervention 1 Weeks 7-9: Habitual diet (wash-out) Weeks 10-12: Dietary Intervention 2

Blood, urinary and faecal samples, as well as food diaries and questionnaires, are collected at the end of each study period to assess participants' perceived health, inflammatory markers, glucose and lipid metabolism, tryptophan metabolites, gastrointestinal symptoms, and gut microbiota. In addition, participants' values and attitudes towards fermented foods are assessed. At the end of the study, participants will receive their laboratory results and dietary guidance for their habitual diet from a registered dietitian.

• Study Type: Interventional
• Enrollment (Actual): 57
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Finland
  • Kuopio, Finland, 70210
    • University of Eastern Finland

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Waist circumference >90 cm (women) or >100 cm (men) OR BMI 26-38 kg/m2

• One of the following:

  • raised blood pressure (systolic ≥ 130 mmHg and/or diastolic 85 mmHg)
  • raised fasting plasma glucose (≥ 5.6 mmol/l)
  • raised triglycerides (≥ 1.7 mmol/l)
  • raised total cholesterol (≥ 5 mmol/l)
  • raised LDL (≥ 3 mmol/l)
  • reduced HDL (women < 1.3 mmol/l, men 1.0 mmol/l)
• Use of cereal products and dairy products or their plant-based alternatives as a part of habitual diet
• Willingness to follow intervention diets for the whole study

Exclusion Criteria:

• Diagnosed chronic diseases and conditions which could hamper the adherence to the dietary intervention protocol, e.g., chronic liver, thyroid, kidney, or gastrointestinal diseases
• Pregnancy and lactation
• Gluten-free or vegan diet
• Recent use of antibiotics (within 3 months)
• Gastrointestinal surgery (within 6 months)
• Alcohol abuse (AUDIT ≥ 15 p and measures of liver function)
• regular smoking or use of snus

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fermented product; Participants will consume a fermented oat-based product daily for three weeks within their diet.	Other: Fermented oat-based product; Participants will incorporate a novel fermented product into their habitual diet for three weeks. In addition, the consumption of dairy and plant-based dairy alternatives is restricted. Cereal product consumption, specifically bread and porridge, is slightly restricted to prevent gastrointestinal symptoms caused by the increased intake of dietary fibre. Participants will receive dietary guidance on how to follow the intervention diet, as well as potential supplement recommendations provided by the authorized nutritionist.
Active Comparator: Unfermented product; Participants will consume an unfermented oat-based product daily for three weeks within their diet.	Other: Unfermented oat-based product; Participants will incorporate a novel unfermented product into their habitual diet for three weeks. Dietary adjustments and other guidance are consistent with those described during the fermented product intervention.
No Intervention: Habitual diet; Participants consume their habitual diet without any intervention products.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Inflammatory marker 1	P-hs-CRP (mg/l)	Weeks 3, 6, 9, and 12
Inflammatory marker 2	IL-22	Weeks 3, 6, 9, and 12
Inflammatory marker 3	LBP (μg/ml)	Weeks 3, 6, 9, and 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in the composition gut microbiota	Composition of gut microbiota will be analysed from faecal samples	Weeks 3, 6, and 12
Glucose metabolism	fP-Gluk and B-HbA1C (mmol/l)	Weeks 3, 6, 9, and 12
Insulin response	fP-Insu (mU/l)	Weeks 3, 6, 9, and 12
Lipid metabolism	fP-Kol, fP-Kol-HDL, fP-Kol-LDL, fP-Trigly, and fP-FFA (mmol/l)	Weeks 3, 6, 9, and 12
Tryptophan metabolism	Tryptophan metabolites will be analysed with non-targeted metabolomics.	Weeks 3, 6, 9, and 12
Self-reported overall health	Short Form-36 Health Survey (SF-36). Different sections are rated from 0 to 100 points, where higher scores mean better perceived health.	Weeks 3, 6, 9, and 12
Self-reported mental health	General Health Questionnaire-12 (GHQ-12). The questionnaire is rated from 0 to 12 points, where higher score means greater psychological distress.	Weeks 3, 6, 9, and 12
Self-reported gut health	Gastrointestinal Symptoms Rating Scale (GSRS)	Weeks 3, 6, 9, and 12
Attitudes and values	Unvalidated questionnaire	Weeks 0 and 12
Opinions about the study products	Unvalidated questionnaire	Weeks 6 and 12

Collaborators and Investigators

• Sponsor: University of Eastern Finland
• Collaborators: University of Turku; KU Leuven; Umeå University; ETH Zurich
• Investigators: Principal Investigator: Marjukka Kolehmainen, PROFESSOR

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2024
• Primary Completion (Actual): December 18, 2024
• Study Completion (Actual): December 18, 2024

Study Registration Dates

• First Submitted: April 2, 2024
• First Submitted That Met QC Criteria: April 26, 2024
• First Posted (Actual): May 1, 2024

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 7, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Gastrointestinal Microbiome; Inflammation Mediators; Fermentation; Tryptophan; Plant Proteins, Dietary
• Additional Relevant MeSH Terms: Metabolic Diseases; Glucose Metabolism Disorders; Insulin Resistance; Hyperinsulinism; Metabolic Syndrome
• Other Study ID Numbers: HE 101060247

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No