High-fiber Diet on the Body and the Brain

Max Planck Institute for Human Cognitive and Brain Sciences61 enrolled

Overview

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 Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Diet Modification Overweight

Interventions

inulinDIETARY_SUPPLEMENT

prebiotic supplement

maltodextrinDIETARY_SUPPLEMENT

placebo supplement

Eligibility

Sex: ALLMin age: 18 YearsMax age: 45 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences

Leipzig, Saxony, Germany

Outcomes

Primary Outcomes

fMRI BOLD activity during food wanting

Time frame: 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.

Time frame: 14 days

Secondary Outcomes

fMRI BOLD activity memory performance

Time frame: 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

Time frame: 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?"

Time frame: 14 days

emotional health

BDI-II (Beck Depression Inventory); score minimum 0 to maximum 21

Time frame: 14 days

Data from ClinicalTrials.gov

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