Tree Nut Consumption to Reduce Abdominal Adiposity

Tree Nut Consumption to Reduce Abdominal Adiposity and Risk for Metabolic Syndrome in Millennials

A major contributing factor to the rising waist circumference of U.S. young adults is the increase in snacking behavior. Both the frequency of snacking during the day and the percentage of adults who engage in snacking has risen; national data indicates snacking comprises 15-25% of the total daily caloric intake of young and middle-aged adults. The overarching hypothesis, based on significant preliminary data, is that the quantity and metabolic function of abdominal fat is a key intermediary factor by which greater tree nut consumption reduces ectopic lipid storage (including the accumulation of intra-abdominal [visceral] fat), improves fatty acid and lipoprotein metabolism, reduces systemic inflammation and insulin resistance, and thus, reduces risk for MetS in millennial-generation age individuals.

Study Overview

• Status: Completed
• Conditions: Millenials; Risk for Metabolic Syndrome
• Intervention / Treatment: Other: High Carbohydrate or Tree Nut Food Snacks

Detailed Description

A major contributing factor to the rising waist circumference of U.S. young adults is the increase in snacking behavior. Both the frequency of snacking during the day and the percentage of adults who engage in snacking has risen; national data indicates snacking comprises 15-25% of the total daily caloric intake of young and middle-aged adults. Unfortunately, current typical snack items are energy rich, providing high intake of carbohydrates and sugars, as opposed to nuts that are nutrient rich. In prior work with middle-aged adults, the investigators found that consuming tree nuts daily as between-meal snacks for a period of 16 weeks significantly reduced intra-abdominal (visceral) fat and waist circumference, which was associated with altered plasma fatty acid profiles and higher fatty acid oxidation rates. Based on prior findings, the investigators propose to determine whether consuming mixed tree nuts as replacement for typical high carbohydrate snacks reduces abdominal obesity and waist circumference in millennials at risk for MetS. The overarching hypothesis, based on significant preliminary data, is that the quantity and metabolic function of abdominal fat is a key intermediary factor by which greater tree nut consumption reduces ectopic lipid storage (including the accumulation of intra-abdominal [visceral] fat), improves fatty acid and lipoprotein metabolism, reduces systemic inflammation and insulin resistance, and thus, reduces risk for MetS in millennial-generation age individuals. The hypothesis will be tested by determining: 1) the effect of consuming mixed tree nuts as daily snacks for 16 weeks on waist circumference and the quantity of abdominal fat (subcutaneous and visceral fat); 2) the effect of consuming mixed tree nuts as daily snacks for 16 weeks on circulating fatty acid profiles, glucose tolerance and insulin resistance, circulating lipids and lipoproteins, and circulating markers of inflammation; and 3) the effect of consuming mixed tree nuts as daily snacks for 16 weeks on abdominal tissue expression of genes that regulate inflammation, insulin resistance, and cardiometabolic mediators of MetS risk.

• Study Type: Interventional
• Enrollment (Actual): 84
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Heidi Silver, PhD; Phone Number: 6158759355; Email: heidi.j.silver@vumc.org
• Study Contact Backup: Name: Dianna Olson, RD; Phone Number: 6159360365; Email: dianna.olson@vumc.org

Study Locations

• United States
  • Tennessee
    • Nashville, Tennessee, United States, 37232
      • Vanderbilt University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 22 years to 36 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 22-36 years
• BMI 18.5 to 34.9
• At least one risk factor for metabolic syndrome based on waist circumference, HDL level or triglyceride level

Exclusion Criteria:

• Tree nut allergy
• Diagnosed chronic disease
• Medication for dyslipidemia or hypertension
• Smoke
• Weight loss medication
• Narcotic medication or illicit drug use
• Pregnancy or lactation or postmenopausal

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Carb Snacks; Will follow study diet based on the Dietary Guidelines and consume study carbohydrate snacks between meals.	Other: High Carbohydrate or Tree Nut Food Snacks; Snack consumption
Experimental: Tree Nut Snacks; Will follow study diet based on the Dietary Guidelines and consume study tree nut snacks between meals.	Other: High Carbohydrate or Tree Nut Food Snacks; Snack consumption

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Waist circumference	Change in waist circumference (in centimeters)	18 weeks
Visceral Fat	Change in quantity of intra-abdominal fat by CT scan	18 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gene Expression in Adipose Tissue	Change in expression of genes involved in regulation of inflammation and insulin resistance	18 weeks
Inflammation	Change in CRP level (mg/dl)	18 weeks
Dietary Macronutrient Intake	Change in macronutrient composition of the diet	18 weeks
Glucose	Change in fasting blood glucose (mg/dl)	18 weeks
Insulin	Change in serum insulin (mg/dl)	18 weeks

Collaborators and Investigators

• Sponsor: Vanderbilt University Medical Center
• Collaborators: International Tree Nut Council Research and Education Foundation
• Investigators: Principal Investigator: Heidi Silver, PhD, Vanderbilt University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): July 15, 2019
• Primary Completion (Actual): June 30, 2023
• Study Completion (Actual): June 30, 2023

Study Registration Dates

• First Submitted: May 23, 2019
• First Submitted That Met QC Criteria: May 28, 2019
• First Posted (Actual): May 31, 2019

Study Record Updates

• Last Update Posted (Estimated): December 5, 2023
• Last Update Submitted That Met QC Criteria: December 4, 2023
• Last Verified: December 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Glucose Metabolism Disorders; Metabolic Diseases; Disease; Insulin Resistance; Hyperinsulinism; Syndrome; Metabolic Syndrome
• Other Study ID Numbers: VUMC71426

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: No current plan to share IPD with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No