Diet Modification, Overweight
Conditions
Keywords
microbiome, food wanting, memory, fiber
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.
Interventions
DIETARY_SUPPLEMENTinulin
prebiotic supplement
DIETARY_SUPPLEMENTmaltodextrin
placebo supplement
Sponsors
Max Planck Institute for Human Cognitive and Brain Sciences
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Arm 1: inulin; minimum of 14 days wash-out; 14 days placebo Arm 2: 14 days placebo; minimum of 14 days wash-out; 14 days placebo
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| fMRI BOLD activity during food wanting | 14 days | — |
| microbial alpha and beta diversity | 14 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
| Measure | Time frame | Description |
|---|---|---|
| mood | 14 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 health | 14 days | BDI-II (Beck Depression Inventory); score minimum 0 to maximum 21 |
| well-being | 14 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 |
| satiety | 14 days | self-reported hunger scale; visual analogue scale; score minimum 0 to maximum 8 |
| serum lipid metabolism markers | 14 days | total cholesterol, triglycerides, high density lipoprotein, low density lipoprotein |
| fMRI BOLD activity memory performance | 14 days | — |
| serum inflammatory markers | 14 days | high sensitivity C-reactive protein, interleukin-6 |
| hunger hormones | 14 days | leptin, ghrelin, Glucagon-like peptide-1 (GLP-1), peptide YY |
| serum microbial metabolic markers | 14 days | short-chain fatty acids (SCFA), trimethylamine N-oxide (TMAO), bile acids |
| personality traits | 14 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 |
| gastrointestinal health | 14 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 |
| serum glucose metabolism markers | 14 days | glucose, insulin |
| positive and negative affect | 14 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 |
Countries
Germany
Outcome results
None listed