CLEAN-MED Diet for Healthy Gut Microbiome

Overseen By Crystal K Ayensu

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: National Institutes of Health Clinical Center (CC)

Must not be taking: Weight control, Antidiabetics, Cholesterol drugs, others

Disqualifiers: Diabetes, Kidney disease, Liver disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 21

1000 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial requires that you do not use certain medications, such as those for weight control, diabetes, cholesterol, and some others. If you are taking any of these, you may need to stop before joining the study.

What data supports the effectiveness of the CLEAN-MED Diet treatment for a healthy gut microbiome?

Research shows that the Mediterranean diet, which is similar to the CLEAN-MED Diet, can positively change the gut microbiome by increasing beneficial bacteria and reducing inflammation. This diet is linked to lower risks of diseases like heart disease and some cancers, suggesting it may help maintain a healthy gut. ^{1 2 3 4 5}

Is the CLEAN-MED Diet safe for humans?

The Mediterranean diet, which is similar to the CLEAN-MED Diet, is generally considered safe for humans and is associated with health benefits like reduced inflammation and improved gut health. ^{1 3 4 5 6}

How does the CLEAN-MED Diet treatment differ from other treatments for a healthy gut microbiome?

The CLEAN-MED Diet, a Mediterranean-like Unprocessed Diet, is unique because it focuses on modulating the gut microbiome through a diet rich in plant-based foods, healthy fats, and low in processed foods, which can lead to beneficial changes in gut bacteria and reduce inflammation. Unlike other treatments, it emphasizes a holistic lifestyle approach, including dietary counseling and physical activity, to improve gut health. ^{1 2 5 6 7}

What is the purpose of this trial?

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.

Research Team

Karen M Frank, M.D.

Principal Investigator

National Institutes of Health Clinical Center (CC)

Eligibility Criteria

Healthy adults aged 18-60 who currently follow a Western diet and are willing to switch to a Mediterranean-like unprocessed foods diet (CLEAN-MED) for the study. They must be able to attend clinic visits, provide blood and stool samples, have internet access, and not have any severe health conditions or recent significant weight changes.

Inclusion Criteria

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 specific dietary scores and items/week criteria

I can prepare and eat fresh meals.

My gender, race, or ethnicity does not limit my participation.

Exclusion Criteria

I have painful gallstones.

I am currently taking certain medications.

I have not had heart disease or conditions in the last year.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Trial Week

Participants log all food intake and answer dietary questions

1 week

1 visit (in-person)

Short-term Treatment

Participants in the short-term group consume a Western diet for 4 weeks followed by a CLEAN-MED diet for 4 weeks

8 weeks

8 visits (in-person)

Long-term Treatment

Participants in the long-term group consume a CLEAN-MED diet for up to 12 months

12 months

12 visits (in-person)

Follow-up

Participants are monitored for changes in gut microbiome and quality of life

4 weeks

Treatment Details

Interventions

• CLEAN-MED Diet
• Western Diet

Trial Overview The trial is testing how changing from a traditional Western diet to a CLEAN-MED diet affects gut microbiome in healthy adults. Participants will either adopt the CLEAN-MED diet short-term (8 weeks) with provided food or long-term (up to 12 months), logging their intake and providing regular biological samples.

Participant Groups

Group I: Short-term, Western Diet, low MedDiet score a Intervention: We Experimental Treatment 1 Intervention

Study arm will consume a Mediterranean like diet, while tracking their food intake for 9 weeks. With low MEdDIet score.

Group II: Short-term, Western Diet, low MedDiet score a Intervention: CL Experimental Treatment 1 Intervention

Study arm will consume a western diet eating as they normally would for 9 weeks. With low MEdDIet score.

Group III: Short-term, Western Diet, high MedDiet score a Intervention: W Experimental Treatment 1 Intervention

Study arm will consume a Mediterranean like diet, while tracking their food intake for 9 weeks, With high MEdDIet score.

Group IV: Short-term, Western Diet, high MedDiet score a Intervention: C Experimental Treatment 1 Intervention

Study arm will consume a Mediterranean like diet, while tracking their food intake for 9 weeks, With high MEdDIet score.

Group V: Long-term a Intervention: CLEAN-MED Experimental Treatment 1 Intervention

Study arm will consume a Mediterranean like diet, while tracking their food intake for 12 months

Who Is Running the Clinical Trial?

National Institutes of Health Clinical Center (CC)

Lead Sponsor

Trials

391

Recruited

30,880,000+

Findings from Research

A 4-week Mediterranean diet (MED) intervention in 20 healthy participants led to significant improvements in dietary adherence, with increased fiber intake and reduced saturated fat, which correlated with beneficial changes in gut microbiota composition.

The MED intervention also resulted in modest reductions in inflammatory markers like fecal calprotectin and white blood cell counts, suggesting potential health benefits related to gut health and inflammation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Increasing adherence to the Mediterranean diet and lifestyle is associated with reduced fecal calprotectin and intra-individual changes in microbial composition of healthy subjects. Godny, L., Reshef, L., Sharar Fischler, T., et al.[2022]

The Mediterranean diet (MD) is linked to increased gut microbiota diversity and specific characteristics that differ significantly from those following a Western diet, which is associated with higher gut permeability and metabolic issues.

Adhering to a Mediterranean diet may help prevent chronic diseases like cardiovascular diseases and certain cancers by positively influencing gut microbiota, but more controlled studies are needed to confirm these effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Influence of Mediterranean Diet on Human Gut Microbiota. Merra, G., Noce, A., Marrone, G., et al.[2021]

The Mediterranean diet (MD) is associated with a gut microbiota that promotes an anti-inflammatory environment, which may help prevent colorectal cancer (CRC) and inflammatory bowel diseases (IBD).

In contrast, patients with CRC and IBD have a microbiota profile that is enriched in pro-inflammatory bacteria, suggesting that adopting MD could be a beneficial lifestyle change to improve gut health and reduce disease risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mediterranean Diet to Prevent the Development of Colon Diseases: A Meta-Analysis of Gut Microbiota Studies. Illescas, O., Rodríguez-Sosa, M., Gariboldi, M.[2021]

A study involving 106 subjects over 2 years found that obese patients with severe metabolic disease (MetS-OB) had significant gut microbiome dysbiosis compared to those without metabolic dysfunction and non-obese individuals.

Both Mediterranean and low-fat diets were effective in partially restoring the gut microbiome in obese patients with severe metabolic disease, indicating that dietary interventions can positively impact gut health based on metabolic status.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consumption of Two Healthy Dietary Patterns Restored Microbiota Dysbiosis in Obese Patients with Metabolic Dysfunction. Haro, C., García-Carpintero, S., Rangel-Zúñiga, OA., et al.[2018]

The Mediterranean diet (MedDiet) is linked to numerous health benefits, including lower rates of cardiometabolic diseases, cancer, and inflammation, suggesting it plays a significant role in promoting overall health.

Recent research indicates that the MedDiet influences the gut microbiome, which in turn may enhance the diet's health benefits through bioactive compounds, highlighting the potential for personalized nutrition strategies to optimize these effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The role of the Mediterranean diet in modulating the gut microbiome: A review of current evidence. Gundogdu, A., Nalbantoglu, OU.[2023]

A study involving 27 healthy adults found that adherence to the Mediterranean diet (MD) is linked to a healthier gut microbiome, with higher levels of beneficial bacteria and short-chain fatty acids (SCFA) that can positively influence metabolism.

In contrast, higher intakes of animal proteins, saturated fats, and sugars were associated with reduced gut microbiota diversity and an increased risk of obesity and related diseases, highlighting the importance of dietary patterns on gut health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Shifts on Gut Microbiota Associated to Mediterranean Diet Adherence and Specific Dietary Intakes on General Adult Population. Garcia-Mantrana, I., Selma-Royo, M., Alcantara, C., et al.[2020]

In a study of 120 adults, those who adhered more closely to the Mediterranean diet showed a healthier gut microbiota profile, including lower levels of harmful E. coli and a higher ratio of beneficial bifidobacteria.

Higher adherence to the Mediterranean diet was associated with increased gastrointestinal symptoms and a greater frequency of bowel movements, suggesting a complex relationship between diet and gut health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Adherence to the Mediterranean diet is associated with the gut microbiota pattern and gastrointestinal characteristics in an adult population. Mitsou, EK., Kakali, A., Antonopoulou, S., et al.[2017]

References

1. United States pubmed.ncbi.nlm.nih.gov

Increasing adherence to the Mediterranean diet and lifestyle is associated with reduced fecal calprotectin and intra-individual changes in microbial composition of healthy subjects. [2022]

2. Switzerland pubmed.ncbi.nlm.nih.gov

Influence of Mediterranean Diet on Human Gut Microbiota. [2021]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Mediterranean Diet to Prevent the Development of Colon Diseases: A Meta-Analysis of Gut Microbiota Studies. [2021]

4. Germany pubmed.ncbi.nlm.nih.gov

Consumption of Two Healthy Dietary Patterns Restored Microbiota Dysbiosis in Obese Patients with Metabolic Dysfunction. [2018]

5. United States pubmed.ncbi.nlm.nih.gov

The role of the Mediterranean diet in modulating the gut microbiome: A review of current evidence. [2023]

6. Switzerland pubmed.ncbi.nlm.nih.gov

Shifts on Gut Microbiota Associated to Mediterranean Diet Adherence and Specific Dietary Intakes on General Adult Population. [2020]

7. England pubmed.ncbi.nlm.nih.gov

Adherence to the Mediterranean diet is associated with the gut microbiota pattern and gastrointestinal characteristics in an adult population. [2017]