Promoting Immune Health by Intermittent Fasting: a Pilot Study

Study Overview
=================
Brief Summary
-----------------
The goal is to study the direct effects of long-term intermittent fasting on immune cell populations in the blood, combined with analyses of systemic metabolic fitness and inflammatory activation of leukocytes.

Detailed Description
-----------------
the investigators aim to investigate the direct effects of intermittent fasting on the molecular characteristics of monocytes and their related health benefits. In addition,the investigators want to assess the post-prandial inflammation and the potential protective role of IF on post-prandial monocyte activation and its related health benefits. This pilot study may better understand the molecular mechanisms behind IF, which could further personalize lifestyle guidance and identify novel anti-inflammatory processes that control immune responses and inflammation.

Official Title
-----------------
Promoting Immune Health by Intermittent

Conditions
-----------------
Metabolic Syndrome, HEALTHY VOLUNTEERS, Time Restricted Feeding, Insulin Resistance, Inflammation

Intervention / Treatment
-----------------
* Combination Product: Time Restricted Eating
* Other: normal diet


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria metsyn: BMI 30 to 43 kg/m2 HOMA-IR index larger/same as 2.5 And At least 3 out of 5 NCEP (National Cholesterol Education Program) metabolic syndrome criteria: Fasting plasma glucose ≥ 6.1 mmol/l, Triglycerides≥1.7mmol/l, Waist-circumference>102cm, HDL-cholesterol<1.04mmol/l, Bloodpressure≥130/85mmHg). Inclusion healthy volunteers Body mass index (BMI) 18 to 25 kg/m2, Waist circumference between 79 cm and 94 cm and HOMA-IR index: ≤ 2.0 (measured as fasting insulin (pmol/L) x fasting glucose (mmol/L)) / 135) Exclusion criteria; (all) Excessive weight loss of >10% in the last months; Use of any medication, including proton pomp inhibitors and antibiotics in the past three months; Cholecystectomy; Untreated GI disease/abnormal bowel habits; Plasma aspartate aminotransferase and alanine aminotransferase are 2.5 times or more the upper limit of the normal range; A history of cardiovascular event (MI or pacemaker implantation); A history of heavy alcohol use (>12 to 15 g of alcohol per day, or >12 oz of beer, 5 oz of wine, or 1.5 oz of distilled spirits); A dependency on alcohol or unable to pause the consumption of alcohol during the study period. An (expected) prolonged compromised immunity (due to recent cytotoxic chemotherapy or HIV infection with a CD4 count < 240); Unmotivated or not able to adhere to a specific diet; History of eating disorder; Night workers or people with deviant day/night rhythm; Pregnant, trying to get pregnant or breast feeding at inclusion; Irregular menstrual cycle; Hormonal replacement therapy (other than oral contraceptives).

Ages Eligible for Study
-----------------
Minimum Age: 21 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: daily time-restricted eating (TRE) protocol and a control protocol for each two weeks, separated by a four-week wash-out period
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: daily time-restricted eating (TRE) for 2 weeks<br>Subjects will be instructed to consume all calories needed for a stable weight (based on their resting energy expenditure) in either one meal per day (TRE; between 10:00-11:00; a protein snack at 13 h) or in three meals per day (control; breakfast, lunch and dinner). Prior to the intervention, a dietician will instruct subjects on nutritional intake based on their caloric need measured by indirect calorimetry (see indirect calorimetry). During the intervention, subjects will fill in online or written dietary diary (e.g. eetmeter) and a physical activity diary. Halfway the intervention, a telephone consult with a dietician will take place | Combination Product: Time Restricted Eating<br>* time restricted eating<br>|
| Placebo Comparator: control protocol for each two weeks<br>Subjects will be instructed to consume normal diet/calories. Prior to the intervention, a dietician will instruct subjects on nutritional intake based on their caloric need measured by indirect calorimetry (see indirect calorimetry). During the intervention, subjects will fill in online or written dietary diary (e.g. eetmeter) and a physical activity diary. Halfway the intervention, a telephone consult with a dietician will take place | Other: normal diet<br>* normal diet<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immune health | measured by transcriptomic assays for immune phenotyping | 0-2 weeks | 
| inflammatory activation of leukocytes | measured by flow cytometry | 0-2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in post-prandial bile acid metabolism | area under the curve of bile acid concentrations | 2 hours | 
| The effect of IF on glucose tolerance | measured during high fat meal test as well during the inverention (by FSL) | 2 hours and 0-2 weeks | 
| The effect of IF on the transcriptional and epigenetic repertoire of whole blood monocytes by stimulation assays | the effect on the inflammatory status | 0-2 weeks | 
| The effect on energy expenditure | resting energy expenditure measured by indirect calorimetry during high fat meal test | 2 hours | 
| The effect of Impaired fasting on gut microbiota composition. | measured at the end of the intervention by 16S sequencing | 0-2 weeks | 
| Effect on Body composition and Appetite (visual analog scale scores + quantity of food consumed) | measured during high fat meal test in terms of fat mass(kg) and fat free mass (kg) | 0-2 weeks | 
| effect on appetie | visual scale scores (0(worst)-100%(best)) and quantity of food consumed | 0-2 weeks |