Response of Gut Microbiota and Cardiometabolic Biomarkers to Consumption of Walnuts

NCT04307628 | Withdrawn

• 1 other identifier: 1562149
• Study Type: interventional
• Target: N/A
• Locations: 1 country
• Sites: 1

Brief Summary

The researchers will investigate blood and fecal responses in qualified study participants after eating walnuts for 4 weeks compared to not eating walnuts for 4 weeks. The two dietary interventions will be separated by a 4 week washout period. The order of diets will be random; study participants will complete both interventions. Dietary modifications will be part of the study protocol.

Conditions

Healthy; Normal Weight; Overweight; Obese

Outcome Measures

Primary Outcomes (5)

• Assessing the influence of walnuts on the fecal metagenome

  Changes in fecal metagenomics will be assessed via Illumina sequencing

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on fecal secondary bile acids

  Fecal secondary bile acids will be measured by LC-QTOF/MS

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on fecal short-chain fatty acids

  Short-chain fatty acids in fecal matter will be measured by LC-MS/MS

  Through study completion, an average of 12 weeks

• Urolithins measured in plasma by UPLC/MS

  Measure for changes in the levels of urolithins in separated plasma; measured in units of ug/uL. Blood will be assessed at each of the 4 study visits.

  Through study completion, an average of 12 weeks

• Fecal calprotectin will be measured by ELISA

  Measure for changes in the levels of calprotectin in collected fecal matter; measured in units of ug/g. Feces will be assessed at each of the 4 study visits.

  Through study completion, an average of 12 weeks

Secondary Outcomes (11)

• Assessing the influence of walnuts on blood lipid measurements

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on paraoxonase-1 (PON-1) activity

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on cholesterol ester transfer protein activity (CETP)

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on hsCRP will be measured in blood

  Through study completion, an average of 12 weeks

• Assessing the influence of walnuts on SAA will be measured in blood

  Through study completion, an average of 12 weeks

Study Arms (2)

Walnut

ACTIVE COMPARATOR

Eat 2 ounces of walnuts provided by the study. Eating any other nuts is to be avoided. Background diet will be low in polyphenols.

Other: Walnut

Nut-Free

PLACEBO COMPARATOR

Eating any other nuts is to be avoided. Background diet will be low in polyphenols.

Other: Nut-Free

Interventions

Walnut OTHER

Study participants will eat 2 ounces of walnuts each day.

Walnut

Nut-Free OTHER

Study participants will not eat nuts.

Nut-Free

Eligibility Criteria

• Age: 20 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Generally healthy men and women between 20-65 years of age and BMI range of 20.0-34.9 kg/m2 will be recruited from the Davis - Sacramento metropolitan area. Enrolled subjects must be willing to consume 2 ounces (approximately 1/2 cup) of walnuts daily and modify their diet to avoid eating walnuts and other nuts, and foods or beverages high in polyphenols (a list will be provided) during study enrollment . Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant or lactating women, women planning to become pregnant in the next four months and prisoners will be specifically excluded. Screening will take place by phone interview and through in-person screening and consent, including anthropometric and biochemical assessments and health history questionnaires.

You may not qualify if:

• Allergy to walnuts or other nuts
• Eating more than 25 grams of fiber per day, assessed by the Block Dietary-Fruit-Vegetable-Fiber Screener©
• Taking medications or supplements known to affect metabolism or gut microbiota composition (i.e. Metformin, statins, antibiotics within the past 3 months, fiber supplements, probiotics, and others)
• Documented chronic diseases including diabetes, renal or liver disease, metabolic syndrome, active cancer, MI or stroke, history of gastric bypass or GI disease (e.g. Crohn's Disease, Irritable Bowel Disease, diverticulosis/diverticulitis,etc)
• Smoker or living with a smoker, including vaporizer and/or electronic cigarettes.
• Illicit drug use, cannabis usage, or consuming \>1 alcoholic drink/day
• Extreme dietary or exercise patterns; vegan diet.
• Recent weight fluctuations (\>10% in the last 6 months)
• Taking prescription lipid medications or supplements that may affect lipoprotein metabolism (i.e. \>1 g of fish oil/day, antioxidant supplements)
• Taking exogenous hormones (e.g. hormonal birth control)
• Poor venous access
• Unwillingness to comply with study protocols

Sponsors & Collaborators

• University of California, Davis: lead

Study Sites (1)

Ragle Human Nutrition Research Center

Davis, California, 95616, United States

Location

MeSH Terms

Conditions

Overweight; Obesity

Interventions

PR-10 protein, walnut birch pollen

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Francene M Steinberg, PhD, RD

  University of California, Davis

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 10, 2020
• First Posted: March 13, 2020
• Study Start: June 1, 2022
• Primary Completion: June 30, 2024
• Study Completion: November 30, 2024
• Last Updated: May 22, 2024

Record last verified: 2024-05

Locations

US (1)