Clinical trial NCT05441748: Walnut Consumption and Gut Microbiota
Official title: The Microbial and Metabolic Impact of Walnut Consumption in Adults With Obesity
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Obesity
Inflammation
Keywords: Walnuts
gastrointestinal microbiota
bile acid profiles
inflammation
glycemia
insulinemia
Lead sponsor: University of Illinois at Urbana-Champaign
Sponsor class: OTHER
First posted: 2022-07-01
Enrollment: 30
Sex: ALL
Minimum age (years): 25
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief 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.


Eligibility criteria: 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

Primary outcomes:
measure: Fecal Microbial Species
timeFrame: Fecal samples will be collected at the end of each 3 week condition.
measure: Concentration of fecal bile acids
timeFrame: Fecal samples will be collected at the end of each 3 week condition.
Secondary outcomes:
measure: Fecal Microbial Metabolites
timeFrame: Fecal samples will be collected once at the end of each 3 week condition.
Other outcomes:
measure: Fecal Microbiome
timeFrame: Fecal samples will be collected at the end of each 3 week condition.
measure: Inflammatory markers
timeFrame: Blood samples will be collected at the end of each 3 week condition.
measure: Serum bile acid profiles
timeFrame: Blood samples will be collected during a mixed-meal tolerance test that occurs at the end of each 3 week condition.
measure: Mixed-meal tolerance test
timeFrame: At the end of each 3 week condition.
measure: Intestinal permeability
timeFrame: 24-hour urine collections will occur at the end of each 3 week condition
Locations:
city: Urbana
country: United States
facility: Hannah Holscher
state: Illinois
Study officials:
References: