High-fiber Diet on the Body and the Brain

Interventional Study Comparing the Effect of a High-fiber Supplement Versus Placebo on the Body and the Brain

The central research question aims to understand what drives individuals to make and maintain a vegan / vegetarian dietary decision, to investigate whether there are possible predictors that might influence such a decision and whether personality differences already exist or can only be measured after the change in diet. The investigators will examine the effects of a high-fiber diet on food wanting on a neural and on a behavioral level. The microbiome is suggested to mediate the expected changes in food wanting.

Study Overview

• Status: Completed
• Conditions: Overweight; Diet Modification
• Intervention / Treatment: Dietary supplement: inulin; Dietary supplement: maltodextrin

• Study Type: Interventional
• Enrollment (Actual): 61
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Saxonia
    • Leipzig, Saxonia, Germany, 04103
      • Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• body-mass-index 25-30kg/m^2
• females on contraception only

Exclusion Criteria:

• current neurological or psychiatric illness
• daily consumption of more than 50 g of alcohol, more than 10 cigarettes or more than 6 cups of coffee
• use of antidepressants or other centrally acting drugs
• type 2 diabetes mellitus or other serious metabolic disorders
• MRI contraindication (e.g. cardiac pacemaker, drug pump, shunts)
• major untreated medical condition, including gastrointestinal organs, lungs, heart, cardiovascular system, liver and kidney)
• diet-related restrictions (food allergies, food intolerances, known nutrient deficiencies or a recent history of dieting or restrictive eating behaviour, including vegan, vegetarian diet)
• current pregnancy or lactation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: inulin	Dietary supplement: inulin; prebiotic supplement
PLACEBO_COMPARATOR: maltodextrin	Dietary supplement: maltodextrin; placebo supplement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fMRI BOLD activity during food wanting		14 days
microbial alpha and beta diversity	The taxonomic structure of the microbial community will be determined using 16S rRNA gene sequencing. The reads from the sequencing data will be assigned to taxa by sequence similarity using puplic available data bases. Relative distribution of microbial taxa is then based on the number of reads assigned to each taxa. For the description of the the community the alpha diversity of each sample will be determined based on species richness, evenness of species distribution which is combined in the single value of the Shannon diversity index. Furthermore beta-diversity, how the microbial communities differ between sample, will be analysed by principal component analysis as well as non-metric multidimensional scaling. In addition, for each taxa significant difference between sample groups will be assessed by comparing the relative number of reads.	14 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fMRI BOLD activity memory performance		14 days
positive and negative affect	PANAS (Positive and Negative Affect Schedule); scores can range from 10 - 50, with higher (lower) scores representing higher (lower) levels of positive (negative) affect	14 days
mood	POMS (Profile of Mood States); four scales (Depression/Anxiety, Fatigue, Vigor, Anger), 35 items, 7 point scale, instruction "How you have been feeling during the past 24 hours?"	14 days
emotional health	BDI-II (Beck Depression Inventory); score minimum 0 to maximum 21	14 days
well-being	WHO-5 (World Health Organization Well-Being Index); measures life quality and life contentment; score minimum 0 to maximum 5 with higher score representing higher life quality and life contentment	14 days
satiety	self-reported hunger scale; visual analogue scale; score minimum 0 to maximum 8	14 days
serum lipid metabolism markers	total cholesterol, triglycerides, high density lipoprotein, low density lipoprotein	14 days
serum glucose metabolism markers	glucose, insulin	14 days
serum glucose metabolism markers	long-term glucose marker HbA1C	14 days
serum inflammatory markers	high sensitivity C-reactive protein, interleukin-6	14 days
hunger hormones	leptin, ghrelin, Glucagon-like peptide-1 (GLP-1), peptide YY	14 days
serum microbial metabolic markers	short-chain fatty acids (SCFA), trimethylamine N-oxide (TMAO), bile acids	14 days
personality traits	BFMM (BIG FIVE Mine Marker); measures the Big Five personality traits as states; 5 subscales (neuroticism, extraversion, openness, agreeableness, conscientiousness); higher scores means being more extreme for a certain state	14 days
gastrointestinal health	GQLI-10 (Gastrointestinal Quality of Life Index); 10 items to measure quality of life regarding gastrointestinal symptoms; the higher the score the stronger the symptoms	14 days

Collaborators and Investigators

• Sponsor: Max Planck Institute for Human Cognitive and Brain Sciences

Publications and helpful links

General Publications

• Medawar E, Haange SB, Rolle-Kampczyk U, Engelmann B, Dietrich A, Thieleking R, Wiegank C, Fries C, Horstmann A, Villringer A, von Bergen M, Fenske W, Veronica Witte A. Gut microbiota link dietary fiber intake and short-chain fatty acid metabolism with eating behavior. Transl Psychiatry. 2021 Oct 1;11(1):500. doi: 10.1038/s41398-021-01620-3.

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 14, 2019
• Primary Completion (ACTUAL): November 24, 2020
• Study Completion (ACTUAL): November 24, 2020

Study Registration Dates

• First Submitted: January 11, 2019
• First Submitted That Met QC Criteria: January 31, 2019
• First Posted (ACTUAL): February 4, 2019

Study Record Updates

• Last Update Posted (ACTUAL): November 27, 2020
• Last Update Submitted That Met QC Criteria: November 25, 2020
• Last Verified: November 1, 2020

More Information

Terms related to this study

• Keywords: memory; microbiome; fiber; food wanting
• Additional Relevant MeSH Terms: Body Weight; Overweight
• Other Study ID Numbers: GUT_BRAIN

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No