ClinicalTrials.gg
CompletedNCT03487679Updated Sep 27, 2018

Effects of Prolonged Fasting on Microbiome and HDL

An interventional study of Fasting in Fasting, sponsored by University of California, Davis. Completed at 1 site in United States. Open to participants aged 20 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2018-09-27.

Sponsored by University of California, Davis · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
21
Allocation
Not applicable
Ages
20 Years to 80 Years
Sex
All
01

Study summary

Participants will undergo one day of habitual eating followed by 36 hours of water only fasting and final day of habitual eating of the exact same diet consumed on the first eating day. Blood draws will be performed on Day 1 in a 10-12 hr fasted state and 2 hour postprandial state and again on Day 3 in a 36hr fasted state and a 2 hour post prandial state. Microbiome samples and blood glucose data will be collected throughout the course of the study.

Read the detailed description

Screening and Consent:

Prospective subjects who pass the initial phone screening interview (i.e. meet inclusion/exclusion criteria) will be admitted into the study and scheduled for a consent visit. At the consent visit, subjects who decide to participate will be given a series of questionnaires including a health history questionnaire, physical activity questionnaire, and will be asked to complete a 3-day diet record, to be completed before the baseline visit at the beginning of the study. Women who consent to participate will be scheduled to complete the study within the follicular phase and menses of the menstrual cycle to avoid confounding alterations in lipoproteins.

Study Visit1 (Baseline fasted):

On Day 1 of the study protocolstudy participants will report to the Ragle Human Nutrition Research Center located on the UC Davis campus (1283 Academic Surge, University of California, Davis, in Davis CA 95616) for a 12-hour overnight fasting blood draw and anthropometric measurements at approximately 8AM. Any participants that are found to have fasting glucose above or below 70-100mg/dL will be removed from the study. Study participants will be given a Precision Xtra Blood Ketone Testing Kit to collect blood ketone data during the fasting period of the study protocol, a set of stool collection kits to collect stool samples throughout the rest of the study protocoland fitted with a GoBe activity monitor to track physical activity throughout the rest of the study protocol. Proper use, care, and storage of the Precision Xtra systems, stool collection kits, and GoBe monitors will be explained in detail to study participants during the baseline visit. Study participants will be given a 24-hr food diary to record their food and beverage intake throughout the rest of the day or may be asked to track their diet using GB 360.

Study Visit 2 (Baseline postprandial):

After the baseline visit on Day 1 of the study protocol, study participants will go about their normal routines and eat their habitual diet ad libitum while recording their dietary intake throughout the day. This food record will be used in order for the study participants to mimic their food intake on Day 1 during the eating period on Day 3 of the study protocol. Study participants will eat their last meal of the day at approximately 6PM. Post-prandial blood samples will be collected at 2 hours after the ingestion of this last meal and immediately processed to yield patient plasma and isolated PBMCs to be stored for future analysis. These post-prandial samples will constitute the baseline "Fed" state of each participant. Study participants will also perform their first bloodprick for ketone measurement using the Precision Xtra Monitor under instruction and supervision by study personnel.

Fasting:

After ingestion of their final meal, participants will undergo a full 36 hours of fasting comprising Day 2 and the beginning of Day 3 of the trial without otherwise modifying their typical routine, including drinking coffee or tea (but with no creamers or sweeteners of any kind), if this is part of their normal routine. The time of the ingestion of the standardized meal will be used as the start point (0hr) for the continuous 36 hours of fasting. 36 hrs of fasting has been shown to be well tolerated in human subjects and was chosen for this trial as it represents the approximate amount of time that fasting would be experienced during a single cycle of an alternate day fasting regimen. Therefore, results from this study could be generalized to plan for future studies of alternate day fasting. Subjects will be encouraged to report any feelings of dizziness, headaches, nausea, or severe hunger that they may experience and, based on the severity of their conditions, will be advised whether or not to continue with the trial. Subjects will be asked to take small blood pricks starting immediately after waking up on Day 2 and then every 3 conscious hours thereafter using thePrecision Xtra Blood Ketone Testing Kits in order to test blood ketone levels during the fasting period. Ketone levels obtained from the blood pricks will be recorded automatically by the Precision Xtra monitor.

Study Visit 3 (Post 36h fasted):

At 36 hours of fasting, roughly 8AM on Day 3, subjects will return to the Ragle Center, perform a final blood prick for ketone monitoring by the Precision Xtra and their blood samples will be collected and again immediately processed and stored for future analysis constituting the "Fasted" state for each participant.

Study Visit 4 (Post 36h postprandial):

After the blooddraw at Study Visit 3, study participants will be allowed free access to food throughout the rest of the day and asked to eat an identical diet to the dietary intake the participants recorded on Day 1 in their 24 hour food diary. Subjects will eat their last meal at approximately 6PM. Post-prandial blood samples will be collected at 2 hours after the ingestion of this last meal and immediately processed to yield patient plasma and isolated PBMCs to be stored for future analysis. These post-prandial samples will constitute the "Refed" state of each participant. After this final blood draw, the Precision Xtra system will be collected, the GoBe removed, and the activity and ketone data collected throughout the course of the study will be transferred to a secure computer for analysis. Fasting compliance will be determined as 1) increasing or steady ketone levels throughout the 36hr fasting period and 2) the absence of significant drops in blood ketone levels, which would indicate food intake and noncompliance.

StoolCollection (Days 1-3):

Study participants will use the provided stool collection kits to collect stool samples from each bowel movement throughout the entire course of the study. Stool samples will be obtained from study participants at the Ragle Center as soon as possible after initial collection by study participants, frozen, and stored at -80C.

02

Conditions studied

  • Fasting

Keywords

  • Microbiome
  • High Density Lipoprotein
  • Inflammation
03

In context

Fasting

392 studies on the registry are indexed under Fasting; 63 are open to participants now.

This study's enrollment of 21 is below the median of 45 across 311 interventional studies indexed under Fasting.

Browse Fasting studies →

Lead sponsor

University of California, Davis is the lead sponsor of 809 studies on the registry; 142 are open to participants now.

Of its 67 completed or terminated interventional studies of FDA-regulated products, 43 (64%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
20 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Age: 20-40 years old to constitute a young study population; 60-80 years old to constitute an elderly study population
  • : 19-27 kg/m2 to constitute a normal/healthy weight population
  • Weight: 133lbs or more
  • Fasting Glucose: 70-100mg/dL to ensure that fasting can be tolerated without inducing dangerously low levels of blood glucose
  • Subjects must be willing to undergo a period of 36 hours of water-only fasting
  • Subjects must be willing to collect samples of each bowel movement produced throughout the entire study period for microbiome analysis.
  • Subjects must be willing to collect and test blood pricks for blood glucose levels using a Contour Next ONE Blood Glucose Kit during the fasting stage of the study protocol.
  • Subjects must be willing to continuously wear a GoBe activity monitor throughout the course of the trial.

Exclusion criteria

Exclusion Criteria:

  • Smoker
  • Anemia
  • Pregnancy or current breast-feeding
  • Documented chronic diseases including diabetes, thyroid disease, metabolic syndrome, cancer, or previous cardiovascular events
  • Any inflammatory bowel disease including IBS, Crohn's Disease, Celiac Disease
  • Consumption of >1 alcoholic drink/day
  • Current consumption of any probiotic or prebiotic supplements
  • Extreme dietary or exercise patterns
  • Recent weight fluctuations (greater than 10% in the last six months)
  • Regular use of over-the-counter allergy or pain medications (>1/week)
  • Taking prescription lipid medications (e.g. statins) or other supplements known to alter lipoprotein metabolism such as isoflavones.
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
21 participants (actual)

Study arms

  • Experimental
    Fasting

    Participants will undergo one day of habitual eating followed by 36 hours of water only fasting and final day of habitual eating of the exact same diet consumed on the first eating day. Blood draws will be performed on Day 1 in a 10-12 hr fasted state and 2 hour postprandial state and again on Day 3 in a 36hr fasted state and a 2 hour post prandial state. Microbiome samples and blood glucose data will be collected throughout the course of the study.

    Other: Fasting

Interventions

  • OtherFasting

    Participants will undergo one day of habitual eating followed by 36 hours of water-only fasting and final day of habitual eating consuming the exact same diet consumed on the first eating day. Blood draws will be performed on Day 1 in a 10-12 hr fasted state and 2 hour postprandial state and again on Day 3 in a 36hr fasted state and a 2 hour post prandial state. Microbiome samples and blood glucose data will be collected throughout the course of the study.

06

What researchers measure

Primary outcomes

  1. Change in HDL Immunomodulatory Capacity

    HDL will be isolated from plasma samples and HDL immunomodulatory capacity will be assessed in isolated HDL with an in vitro assay using stimulated macrophages.

    Time frame: Baseline fasted vs. Post 36 hours fasted

Secondary outcomes

  1. Change in Gut Microbiome Composition

    Gut microbial composition will be assessed by sequencing of isolated DNA from stool samples.

    Time frame: Baseline fasted vs. Post 36 hours fasted

07

Study locations

1 site
  • University of California Davis
    Davis, California 95616, United States
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Apr 2018 to primary completion in May 2018, 1 month.

Of 144 non-industry interventional studies with no phase under Fasting, half reached primary completion within 19 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 40. This study's 1 month is below that.

Counting every sponsor, half of 149 studies reached it within 18 months; a quarter within 6 and three quarters within 40.

How these figures are worked out, and which studies are left out of them.

Registered
Mar 1, 2018
First posted
Apr 4, 2018
StartActual
Apr 9, 2018
Primary completionActual
May 30, 2018
CompletionActual
May 30, 2018
Last update
Sep 27, 2018
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 27, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT03487679
Responsible party
Sponsor
First posted
Apr 4, 2018
Start date
Apr 9, 2018
Primary completion
May 30, 2018
Completion
May 30, 2018
Last update
Sep 27, 2018

Study contacts

Angela M Zivkovic, Ph.D.
principal investigator · UC Davis

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Sep 2018. You cannot join it, but the record below documents what was studied.

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