KORN investigates the effects of wholegrain oat and rye intake on health and cognitive wellbeing in children with overweight.

The purpose of KORN is to investigate the effects of wholegrain oat and rye intake on cardiometabolic health in slightly overweight 8-13-year-old children. Moreover, KORN aims to investigate effects on body weight and body composition, inflammatory markers, gastrointestinal wellbeing and cognitive function and explore the potential underlying mechanisms through assessment of changes in the children's gut microbiota as well as potential genotype-dependent and sex-specific effects.

The study has a randomized controlled cross-over design. In two 8-week dietary periods the children will receive grain products (cereals, breads, pasta etc) with either high or low content of wholegrain from oat and rye in random order. Measurements and biological sampling will be performed at 0, 8 and 16 weeks.

Inclusion Criteria:

• Boys and girls 8-13 years of age
• Be overweight i.e. have a parent-reported BMI of at least +1 standard deviation above the median according to the age and sex-standardized Danish growth curves
• Be healthy
• Like grain products and eat them daily
• Speak Danish in order to understand the study procedures
• At least one parent must read and speak Danish, in order to be properly informed about the study procedures
• Parents must have freezer capacity for 2 weeks bread provision

Exclusion Criteria:

• Allergy or intolerance to the study foods, including gluten
• Use of dietary fiber supplements (e.g. HUSK) or probiotic supplements
• Dieting or on a special diet
• Serious chronic illnesses and diseases that may interfere with study outcomes
• Use of medication that may affect study outcomes, including use of antibiotics the last month
• Concomitant participation in other studies involving dietary supplements, drugs or blood sampling
• Living in a household with another participating child

The intervention and data collection will be conducted unmasked. The data set will be masked before data analysis by staff not involved in the study.