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Mediterranean-like Unprocessed (CLEAN-MED) Diet Intervention Study of the Gut Microbiome of Healthy Adults

NCT05411120 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 160

Last updated 2026-03-06

No results posted yet for this study

Summary

Background:

Trillions of tiny organisms-including bacteria, fungi, and viruses-live inside our intestines. These microorganisms break down nutrients in our food, aid our immunity, and help keep us healthy. The population balances among these organisms can vary in different people due to factors including genetics, lifestyle, and diet. More studies are needed to understand how dietary habits affect our intestinal microorganisms.

Objective:

To see how switching from a traditional Western diet (low in fiber, high in saturated fat) to a Mediterranean-like unprocessed foods diet (CLEAN-MED) changes the environment in the intestine. The CLEAN-MED diet includes lots of vegetables, fruits, and whole grains with little sugar or red meat.

Eligibility:

Healthy adults aged 18 to 60

Design:

Participants will be divided into 2 groups. All will start with a trial week. Participants will log all the food they eat and answer questions about their diet throughout the entire study.

Participants in the short-term group will eat a Western diet for 4 weeks and a CLEAN-MED diet for 4 weeks. Food will be provided for the CLEAN-MED diet. Participants will visit the clinic each week and complete surveys. They will log everything they eat. They will provide blood, urine, and stool samples.

Participants in the long-term group will eat the CLEAN-MED diet for up to 12 months. They will visit the clinic each month and complete surveys. They will log everything they eat. They will provide blood, urine, and stool samples. Some foods will be provided for the first 2 weeks. Participants may choose to have a scan of their body composition every few months.

Conditions

  • Diet Therapy

Interventions

OTHER

Western Diet

Western Diet is by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy and sweets, fried foods, conventionally-raised animal products, butter and other high-fat dairy products, and low intakes of fruits, vegetables, whole grains.

OTHER

CLEAN-MED

Mediterranean like diet is a high consumption of vegetables, oil and moderate consumption of protein, with no processed foods.

Sponsors & Collaborators

  • National Institutes of Health Clinical Center (CC)

    lead NIH

Principal Investigators

  • David B Sacks, M.D. · National Institutes of Health Clinical Center (CC)

Study Design

Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Model
CROSSOVER

Eligibility

Min Age
18 Years
Max Age
60 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2022-08-26
Primary Completion
2026-02-04
Completion
2026-02-05

Countries

  • United States

Study Locations

More Related Trials

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05411120 on ClinicalTrials.gov