Walnut Consumption and Gut Microbiota

Obesity Clinical Trial

Official title:

The Microbial and Metabolic Impact of Walnut Consumption in Adults With Obesity

Clinical Trial Details — Status: Active, not recruiting

Administrative data

• NCT number: NCT05441748
• Other study ID #: 20164
• Status: Active, not recruiting
• Phase: N/A
• Start date: June 1, 2022
• Est. completion date: July 2024

Study information

• Verified date: June 2023
• Source: University of Illinois at Urbana-Champaign
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Obesity is a growing health issue that effects the majority of adults in the United States. Prevalence of other metabolic diseases are increased in obese adults, including systemic inflammation. There is emerging evidence that the gut microbiota have a mediating role in controlling inflammation by producing butyrate when ingested fiber is fermented. Since these microbes are modifiable by diet, the investigators plan to introduce walnuts to the diets of participants with obesity because they are rich in fiber and unsaturated fatty acids. The purpose of this study is to understand the impacts of walnut consumption on the gut microbiota and the effect they have on bile acid profiles and systemic inflammation. The investigators intention is to identify how these walnut-derived molecules influence Faecalibacterium spp., a butyrate producing microbe. Increased levels of butyrate have shown to decrease secondary bile acids and decrease inflammation.

Recruitment information / eligibility

• Status: Active, not recruiting
• Enrollment: 30
• Est. completion date: July 2024
• Est. primary completion date: August 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 25 Years to 75 Years

Eligibility

Inclusion Criteria:

Participants will include adults ages 25-75 years BMI of > 30 kg/m2 Ability to drop-off fecal sample within 15 minutes of defecation

Exclusion Criteria:

• Walnut allergy or intolerance

• Food allergies or intolerances

• Prior diagnosis of metabolic or gastrointestinal disease (cardiovascular disease and type 1 or type 2 diabetes, chronic constipation, diarrhea, Crohn's disease, celiac disease, ulcerative colitis, irritable bowel syndrome, diverticulosis, stomach or duodenal ulcers, hepatitis, HIV, cancer, etc.)

• Women that are pregnant, had a baby within the last 12 months, or lactating

• Individuals that smoke, use tobacco, abuse drugs, or consume > 2 alcoholic beverages per day.

• > 5% weight change in the past month or > 10% change in the past year

• Oral antibiotics during the previous 6 weeks

• Fasting blood glucose >126 mg/dL, blood pressure >160/100 mm Hg, elevation in serum transaminases (i.e. >3 times the upper limit of normal) or with evidence of liver disease, including primary biliary cirrhosis or gallbladder disease, constipation, are currently taking lipid-lowering medications, oral hypoglycemic agents, or insulin, or certain medications (laxatives, bile acid sequestrants, and opiates)

• History of malabsorptive or restrictive bariatric surgeries (e.g., gastric bypass, sleeve gastrectomy, adjustable gastric band) or gall bladder removal surgery.

• Are unable to consume the experimental meals/snacks.

• Participants who have donated blood within the last 8 weeks

• Recent diagnosis of anemia

• Concurrent enrollment in another dietary, exercise, or medication study

Related Conditions & MeSH terms

• Inflammation
• Obesity

Intervention

Other:
• Walnuts
The intervention treatment will contain walnuts.
• Walnut Oil
The intervention treatment will contain walnut oil.
• Control
The control treatment will contain corn oil.

Locations

Country	Name	City	State
United States	Hannah Holscher	Urbana	Illinois

Sponsors (1)

Lead Sponsor	Collaborator
University of Illinois at Urbana-Champaign

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Fecal Microbiome	Relative abundance of microbial genes and genera measured using metagenomic sequencing of extracted fecal DNA to compare abundances between walnut, walnut oil, and corn oil.	Fecal samples will be collected at the end of each 3 week condition.
Other	Inflammatory markers	LPS-binding protein and inflammatory markers (CRP and TNFa) concentrations in walnut and walnut oil vs. control (corn oil)	Blood samples will be collected at the end of each 3 week condition.
Other	Serum bile acid profiles	Serum bile acid concentrations will be measured using LC-ESI-MS/MS to compare concentrations between walnut and walnut oil and control (corn oil)	Blood samples will be collected during a mixed-meal tolerance test that occurs at the end of each 3 week condition.
Other	Mixed-meal tolerance test	Blood glucose and insulin concentrations and area under the curve will be measured in blood during a mixed meal tolerance test that includes a standard glucose beverage and the respective walnut, walnut oil, or corn oil treatment.	At the end of each 3 week condition.
Other	Intestinal permeability	Intestinal permeability will be measured using a orally ingested sugar substitutes. 24-hour urinary appearance of the sugars will be quantified using GC-MS.	24-hour urine collections will occur at the end of each 3 week condition
Primary	Fecal Microbial Species	Abundances of fecal Faecalibacterium spp. and Roseburia spp measured using metagenomic sequencing in walnut and walnut oil vs. control.	Fecal samples will be collected at the end of each 3 week condition.
Primary	Concentration of fecal bile acids	Fecal bile acid concentrations measured using HPLC in walnut and walnut oil vs. control	Fecal samples will be collected at the end of each 3 week condition.
Secondary	Fecal Microbial Metabolites	Concentrations of fecal microbial metabolite (phenol/indoles, short chain fatty acids, and ammonia) concentrations measured using GC-MS in walnut and walnut oil in comparison to a control (corn oil)	Fecal samples will be collected once at the end of each 3 week condition.