OAT-GUT-BRAIN: Effects of Oats and Rice on Comprehensive Health of Metabolically Challenged Individuals

OAT-GUT-BRAIN: Comprehensive Health Effects of Long-term Consumption of Oats in Metabolically Challenged Volunteers - Gut-mediated Metabolomics and Vitality

The overall objective of this research entity is to reveal the comprehensive health impact of oats in metabolically challenged individuals in a 6-week intervention, compared to that of rice. This is achieved by investigation of the lipids, short-chain fatty acids, inflammation markers and antioxidant status from plasma, fecal microbiome, and plasma metabolome. Additionally the effect of the 6-week diet on postprandial glycemia and postprandial satiety and vitality are investigated.

Aims in this 6-week randomised, single-blinded clinical trial, including a postprandial study, with metabolically challenged volunteers on oat-rich low-gluten diet, are to:

1. Compare effect of oat and rice rich diets to blood lipid and glucose status, perceived gut and general well-being and dietary intake.
2. Investigate changes in fecal microbiome, SCFAs, plasma antioxidant status and inflammation markers resulting from consumption of oat or rice rich low-gluten diets.
3. Examine the impact of the oat or rice-rich low-gluten diet on the change in metabolite profiles in blood by non-targeted metabolomics approach.
4. Find out the long-term effects of oat and rice consumption on recovery and vitality by modulating the gut-brain axis and measured with neuropsychological testing and using tryptophan metabolites as biomarkers.
5. Discover how the long-term consumption of oats and rice and their possible alterations in fecal microbiome affect subsequent postprandial glycaemia and response of microbiota to the meal (as seen in plasma SCFAs).

Inclusion Criteria:

• Commits to follow the instructed low-gluten diet for 6 weeks
• 30 - 68 years of age
• BMI > 25 kg/m^2
• High cholesterol (without medication) characterized as total cholesterol > 5 mmol/l, AND either LDL > 3 mmol/l OR HDL (men/women) < 1.0/1.2 mmol/l AND/OR Hypertension (systolic > 140 mmHg or diastolic > 90 mmHg).

Exclusion Criteria:

• Regular medication that can affect the research outcomes (balanced medication for hypertension, hypo-/hyperthyroidism, hormone replacement therapy, and inhaled medicines allowed)
• Pregnancy or lactation
• Heavy smoking
• Recent course of antibiotics (less than 3 months prior to the study)