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High-fiber Diet on the Body and the Brain

Not Applicable
Completed
Conditions
Overweight
Diet Modification
Interventions
Dietary Supplement: maltodextrin
Dietary Supplement: inulin
Registration Number
NCT03829189
Lead Sponsor
Max Planck Institute for Human Cognitive and Brain Sciences
Brief Summary

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.

Detailed Description

Not available

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
61
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 & Design

Study Type
INTERVENTIONAL
Study Design
CROSSOVER
Arm && Interventions
GroupInterventionDescription
maltodextrinmaltodextrin-
inulininulin-
Primary Outcome Measures
NameTimeMethod
fMRI BOLD activity during food wanting14 days
microbial alpha and beta diversity14 days

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.

Secondary Outcome Measures
NameTimeMethod
positive and negative affect14 days

PANAS (Positive and Negative Affect Schedule); scores can range from 10 - 50, with higher (lower) scores representing higher (lower) levels of positive (negative) affect

mood14 days

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?"

emotional health14 days

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

satiety14 days

self-reported hunger scale; visual analogue scale; score minimum 0 to maximum 8

hunger hormones14 days

leptin, ghrelin, Glucagon-like peptide-1 (GLP-1), peptide YY

fMRI BOLD activity memory performance14 days
well-being14 days

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

serum lipid metabolism markers14 days

total cholesterol, triglycerides, high density lipoprotein, low density lipoprotein

serum glucose metabolism markers14 days

long-term glucose marker HbA1C

serum inflammatory markers14 days

high sensitivity C-reactive protein, interleukin-6

personality traits14 days

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

serum microbial metabolic markers14 days

short-chain fatty acids (SCFA), trimethylamine N-oxide (TMAO), bile acids

gastrointestinal health14 days

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

Trial Locations

Locations (1)

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

🇩🇪

Leipzig, Saxonia, Germany

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