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

Description

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

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Study Overview

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Study Details

Study overview

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.

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

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

Condition
Diet Therapy
Intervention / Treatment

-

Contacts and Locations

Bethesda

National Institutes of Health Clinical Center, Bethesda, Maryland, United States, 20892

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

For general information about clinical research, read Learn About Studies.

Eligibility Criteria

  • * Ability of subject to understand and the willingness to sign a written informed consent document
  • * All genders, races, and ethnicities
  • * Age 18-60, at the time of consent
  • * Willingness to adhere to the dietary regimen and report any major stressors that occur during the study (i.e. changing jobs, moving, death of a close relative/friend, etc.)
  • * Willingness to provide blood and stool specimens as specified
  • * BMI \>=18 and \<= 35 kg/m\^2
  • * Access to necessary resources for participating in a technology-based intervention: computer, smartphone, internet access, etc.
  • * Has the ability/transportation methods to attend on-site visits
  • * For 50 of the 60 participants in short-term cohort and for 40 of the 50 participants in the long-term cohort: Currently following a Western diet with PREDIMED-17 MedDiet score \<= 7 for \>= 1 months and a CLEAN-MED NOVA score of \>= 35% kcal in NOVA 4 category with \>= 14 items/week in NOVA 4
  • * For 10 of the 60 participants in short-term cohort and for 10 of the 50 participants in the long-term cohort: Currently following a Western diet with PREDIMED-17 MedDiet score \<= 10 for \>= 1 months and a CLEAN-MED NOVA score of \>= 20% kcal in NOVA 4 category with \>= 7 items/week in NOVA 4
  • * CLEAN-MED Logging Score of \>= 43 after initial trial week to continue in the study for the randomization step
  • * For long-term cohort only: Have resources and capability to consume freshly-cooked (i.e. not pre-packaged or frozen) meals
  • * Current use of medications or dietary supplements for weight or appetite control, whether prescribed or not, including laxatives (within the last 4 weeks)
  • * Currently eating a vegan, vegetarian, keto or other restrictive diet plan, or food allergies that would affect eating the study diet, at the discretion of the PI
  • * Active cardiovascular disease (in past year with myocardial infarction, coronary stent or bypass surgery)
  • * Diabetes (type 1 and 2) or history of gestational diabetes or on hypoglycemic medications or any other indication
  • * Kidney disease (eGFR less than 50 mL/min per 1.73 m\^2)
  • * Liver disease (liver transaminase higher than 3 times the normal range for the laboratory)
  • * Symptomatic gallstones
  • * History of active cancer in the past 3 years except for squamous or basal cell carcinomas of the skin that have been medically managed by local excision
  • * Has a diagnosed autoimmune condition (i.e. HIV, lupus, etc.) or other immunosuppressive or immunodeficient state, at the discretion of the PI
  • * Musculoskeletal disorders precluding regular physical activity
  • * Consumption of the following drugs: proton pump inhibitors, antidiabetic drugs, cholesterol lowering drugs, SGLT-2 inhibitors, GLP-1 receptor agonist, insulin, Amylin analog, Alpha-glucosidase inhibitor, Dopamine agonist, Bile acid sequestrant, corticosteroids, methotrexate or immunosuppressive cytotoxic agents
  • * Some types of abdominal surgery, including bariatric surgery, or severe intestinal problems (by discretion of study physician), including:
  • * Inflammatory bowel disease (IBD) including ulcerative colitis (mild-moderate-severe), Crohn s disease (mild-moderate-severe), or indeterminate colitis;
  • * Irritable bowel syndrome (IBS) (moderate-severe);
  • * Persistent, infectious gastroenteritis, colitis or gastritis, persistent or chronic diarrhea of unknown etiology, Clostridium difficile infection (recurrent) or Helicobacter pylori infection (untreated);
  • * Chronic constipation
  • * Consumes more than 3 alcoholic beverages per day
  • * Currently receiving or has received antibiotics, antifungals, antivirals, or antiparasitics in past 2 months
  • * Is currently using or has used probiotic supplements within the last 2 months
  • * Is currently on a weight-loss program or has experienced a weight change (gain or loss) of greater than 15 pounds in the past 3 months
  • * Has a history of hospitalization for mental health condition and/or has had a change in depression or anxiety prescription medications within the past 10 weeks (by discretion of study physician)
  • * Is pregnant or breastfeeding or planning pregnancy within the time of the study
  • * Subjects who are not fluent in English
  • * Use of smoking or chewing tobacco, e-cigarettes, cigars, or other nicotine-containing products, or cannabis
  • * Regular use of prescription opiate pain medication
  • * Weight \<100 lbs
  • * Acute disease, defined as the presence of a moderate or severe illness with or without fever, at the time of enrollment
  • * Inability to communicate effectively with study personnel
  • * Lack of commitment with the intervention or non-compliance (at the discretion of the investigator)
  • * Eating disorders

Ages Eligible for Study

18 Years to 60 Years

Sexes Eligible for Study

ALL

Accepts Healthy Volunteers

Yes

Collaborators and Investigators

National Institutes of Health Clinical Center (CC),

Karen M Frank, M.D., PRINCIPAL_INVESTIGATOR, National Institutes of Health Clinical Center (CC)

Study Record Dates

2027-04-01