Long-term Fasting: Multi-system Adaptations in Humans

Study Overview
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Brief Summary
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The aim of this trial is to investigate the effects of long-term fasting on size, mass, composition and function of metabolic active tissues in several organs that reexpand possibly rejuvenated after 1-4 months. Additionally, the lipid metabolism is investigated in depth.

Detailed Description
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Fasting displays numerous positive effects on metabolism, health and aging. Surprisingly, few considerations are given to long-term fasting periods. The metabolic switch from food-derived glucose to adipose tissue-derived fatty acids and ketones as primary cellular fuel is the key to fasting metabolism. Fasting has been shown to improve cardiovascular risk factors and gut microbiota in humans. It provokes profound changes in lipid metabolism. However, many questions are still open concerning the mobilization, exchange, and function of lipids during long-term fasting. Furthermore, recent results show the ability of periodic restrictive nutritional strategies to trigger organ regeneration. This promising regenerative power has not been investigated comprehensively in humans. In addition, the knowledge about the role of human faecal microbiota in health and disease is increasing. Only little is known about its composition and function during fasting. We found indications that the gut microbiome could influence energy metabolism and consequently could influence the dynamic of the metabolic switch. Long-term fasting under medical supervision according to the Buchinger Wilhelmi fasting program has been demonstrated to be safe and well-tolerated. The current project investigates the effects of a 9±3 days fasting period by a multi-systemic approach focusing on lipid metabolism and the gut microbiome in 100 subjects. Additionally, the body composition in combination with muscle performance will be analyzed in-depth in a subgroup of 32 subjects.

Official Title
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Long-term Fasting: Multi-system Adaptations in Humans

Conditions
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Fasting

Intervention / Treatment
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* Other: Long-term fasting according to the Buchinger Wilhelmi fasting program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI between 22 - 35 kg/m2 Exclusion Criteria: intake of medication (cardiovascular diseases, lipid and glucose metabolism) chronic manifest psychical and psychiatric diseases participation in another study pregnancy or breastfeeding in the MRI/MRS sub-study, any MRI contraindication (claustrophobia, pacemakers, MR-incompatible prosthetic valves, metallic implants, foreign metallic body) active uncontrolled gastrointestinal disorders including ulcerative colitis, Crohn's disease, indeterminate colitis, severe irritable bowel syndrome, persistent infectious gastroenteritis, persistent or chronic diarrhea of unknown etiology, recurrent Clostridium difficile infection major surgery of the GI tract, in the past five years. Any major bowel resection at any time intake of antibiotics in the last 2 months

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: single-arm interventional study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Long-term fasting<br>The participants will undergo 6-12 fasting days according to the Buchinger Wilhelmi fasting program | Other: Long-term fasting according to the Buchinger Wilhelmi fasting program<br>* the participants will undergo a fasting program that includes the daily intake of 250 kcal under medical supervision<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in whole body composition | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the heart | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the liver | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the kidney | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the spleen | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the quadriceps | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in the composition of the adipose tissue | Fat mass, lean mass, water content measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in HDL cholesterol efflux capacity | measured in serum by a standardized used radioisotopic technique | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in serum cholesterol loading capacity | measured in serum using radioactive cholesterol loaded macrophages | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in HS-Omega-3 Index | Determination of fatty acid (C 14:0; 16:0; 18:0; 20:0; 22:0; 24:0; 16:1 n-7; 18:1 n-9; 20:1 n-9; 24:1 n-9; 18:2 n-6; 18: 3 n-6; 20: 3 n-6; 22:2 n-6; 20:4 n-6; 22:4 n-6; 22:5 n-6; 18: 3 n-3; 20:5 n-3; 22:5 n-3; 22:6 n-3; 16:1 n-7t; 18:1 n-9t; 18:2 n-6tt; 18:2 n-6ct; 18:2 n-6tc) in erythrocyte membranes with highly standardized analytical procedure | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in faecal microbiota composition and function (carbohydrate metabolism) | Shotgun metagenomics, 5Gb of DNA sequencing data. | Baseline and changes after an average of 10 (+/-3) fasting days | 
| Changes in metabolome | using an untargeted metabolomics approach to investigate changes in the metabolome, with a focus on the polyamine biosynthetic pathway at the cellular level in PBMCs and compare them with changes in the circulating plasma/serum metabolome | Baseline and changes after 3 fasting days, the end of fasting as well as one and four months afterwards | 
| Changes in hydrogen sulfide production capacity | measured in serum and urine using the lead acetate assay | Baseline and changes at the end of fasting as well as one and four months afterwards | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in brain morphometry | measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in cardiac mass | measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in lower limbs (quadriceps, hamstrings, calves) | measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in lumbosacral muscle mass | measured by magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in systolic cardiac function | global and regional function (right and left ejection fraction, right and left end-diastolic and end-systolic volumes, peak regional strains (circumferential, longitudinal strain) measured with magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in diastolic cardiac function | global and regional diastolic function (peak filling rate, torsion rate, diastolic strain rate) measured with magnetic resonance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in apparent diffusion coefficient (ADC) | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in fiber strain (Eff) | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in fractional anisotropy (FA) | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in helix angle (HA) | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in mean diffusivity (MD) | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in cardiovascular fitness | using the maximal oxygen consumption (VO2max) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: TauPCr(s) | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: PCr hydrolysis (%) | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: PCr concentration | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: Pi concentration | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: ATP concentration | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: pH at rest and post exercise in mM | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: T1 of metabolites at rest | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in muscle metabolism and mitochondrial oxidative capacity: PCr consumption | during ergometric effort in MRI at the level of the sural muscle (31P spectroscopy) | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in multiparametric muscle quantification: T2 | measured with quantitative magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in multiparametric muscle quantification: T2 * relaxation time | measured with quantitative magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in multiparametric muscle quantification: susceptibility (chi) | measured with quantitative magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in multiparametric muscle quantification: fat fraction (PDFF) | measured with quantitative magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in quadricipital maximum voluntary contraction | measured with magnetic impedance imaging | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in DNA methylation | biomarker of biological aging using erythrocytes | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in serum amyloid A levels | determined in serum | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in paraoxonase (PON-1) activity | determined in serum | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in lipoprotein transfer enzymes | CETP activity, determined as U/ml using a commercially available assay | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in GlycA | determined in serum | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in proprotein convertase subtilisin/kexin type 9 (PCSK9) | determined in serum by ELISA | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in chylomicrons | determined in serum | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in oxidized phospholipids | determined in serum | Baseline and changes at the end of fasting as well as one and four months afterwards | 
| Changes in enzymes | immunoblotting of relevantly altered enzymes in PBMCs | Baseline and changes after 3 fasting days, the end of fasting as well as one and four months afterwards | 
| Changes in persulfidation | persulfidation in serum and urine | Baseline, and changes after 3 fasting days, at the end of fasting as well as one and four months afterwards | 
| Changes in sulfur compounds | amino acids (using a targeted approach), thiosulfate (measured using the monobromobimane method using HPLC and LC-MS/MS), cysteine and cystine (use the S-sulfocysteine (SSC) method which is a HPLC-based method using automated precolumn derivatization with OPA and UV detection at 338 nm) in serum and urine | Baseline and changes after 3 fasting days, at the end of fasting as well as one and four months afterwards | 
| Changes in thiosulfate levels | measured using the monobromobimane method using HPLC and LC-MS/MS | Baseline and changes after 3 fasting days, at the end of fasting as well as one and four months afterwards | 
| Changes in cysteine and cystine levels | using the S-sulfocysteine (SSC) method which is a HPLC-based method using automated precolumn derivatization with OPA and UV detection at 338 nm in serum and urine | Baseline and changes after 3 fasting days, at the end of fasting as well as one and four months afterwards | 
| Changes in amino acids | using a targeted approach in serum and urine | Baseline and changes after 3 fasting days, at the end of fasting as well as one and four months afterwards | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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long-term fasting, Buchinger Wilhelmi program, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), HDL efflux capacity, fatty acid profile in erythrocyte membrane, gut microbiota, metabolomics, hydrogen sulfide and transsulfuration pathway