Strawberries and Risk of Diabetes in Adults

Strawberries can be categorized as a functional food based on results from several clinical trials in improving cardiometabolic health beyond providing nutrition. Recent studies identify the role of strawberries in improving insulin resistance and risks of type 2 diabetes which urgently warrants further investigation, keeping in view the huge public health burden of diabetes in the US. In this study, the investigators propose to investigate the effects of a dietary achievable dose of strawberries on glycemic control, insulin resistance, and HbA1c (primary variables) and biomarkers of inflammation and endothelial function in a 28- week controlled crossover study.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome; PreDiabetes
• Intervention / Treatment: Drug: Freeze-dried strawberry powder

Detailed Description

Strawberries are popularly consumed fruits in the US and are a rich source of several bioactive compounds with demonstrated health benefits in T2D and cardiovascular disease (CVD). Based on previously reported studies, strawberries have been shown to improve elevated lipid profiles/dyslipidemia, oxidative stress and inflammation in adults with the metabolic syndrome or prediabetes. In a recently reported study, strawberries at a dose of two-and-a-half servings per day for four weeks was shown to significantly reduce insulin resistance and serum adipokines in obese adults. These results conform to only a few reported trials using strawberries in adults with cardiometabolic risks. While these study findings are clinically meaningful, these warrant urgent investigation in trials of longer duration specifically targeting adults with impaired fasting glucose (vs. other features of the metabolic syndrome) as well as adults with diagnosed T2D with poor glycemic control despite taking medications. Furthermore, to the best of our knowledge, only one clinical trial has been reported on the role of strawberries in improving glycemic control, oxidative stress, and inflammation in adults with T2D. While these results are encouraging, they lack generalizability due to the short duration of the study (six weeks) that precludes accurate changes in glycated hemoglobin (HbA1c) as a stable biomarker of glucose control. Based on these gaps in the existing literature, the investigators will examine the effects of strawberry supplementation at a dose of 2.5 servings/day for 12 weeks on glycemic control and related cardiometabolic profiles in prediabetes in a randomized controlled crossover trial.

• Study Type: Interventional
• Enrollment (Actual): 39
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Nevada
    • Las vegas, Nevada, United States, 89154
      • University of Nevada at Las Vegas

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• At least 18 years of age
• Waist size greater than 40 inches in men or 35 inches in women
• Blood glucose greater than 100mg/dL but less than 126 mg/dL or glycated hemoglobin less than 6.5%
• Insulin resistance >1.0
• Not on diabetes medications
• Normal liver and kidney function tests

Exclusion Criteria:

• Allergy to strawberries
• Smoke or drink alcohol on a regular basis
• Pregnant or lactating

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control arm; Each participants on usual diet and lifestyle for 12 weeks
Experimental: Strawberry intervention; Each participants will consume freeze-dried strawberry powder (32g/day) for 12 weeks	Drug: Freeze-dried strawberry powder; Whole strawberries are freeze-dried to form a powder with improved shelf life that will be used in this research study. Strawberry powder will be provided by the California Strawberry Commission (Watsonville, CA); Other Names: Freeze-dried strawberries

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glycemic control	Blood glucose, insulin, glycated hemoglobin	12 weeks
Lipid control	Blood total and LDL cholesterol	12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diabetes risk hormones	adiponectin, leptin	12 weeks
Inflammation	cytokines C-reactive protein adhesion molecules	12 weeks
Oxidative stress	Serum measures of antioxidants	12 weeks

Collaborators and Investigators

• Sponsor: University of Nevada, Las Vegas
• Collaborators: University of Oklahoma
• Investigators: Principal Investigator: Arpita Basu, PhD, University of Nevada at Las Vegas

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2023
• Primary Completion (Actual): May 31, 2024
• Study Completion (Actual): June 3, 2024

Study Registration Dates

• First Submitted: May 2, 2022
• First Submitted That Met QC Criteria: May 2, 2022
• First Posted (Actual): May 5, 2022

Study Record Updates

• Last Update Posted (Actual): May 18, 2025
• Last Update Submitted That Met QC Criteria: May 13, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Glucose Metabolism Disorders; Insulin Resistance; Hyperinsulinism; Metabolic Syndrome
• Other Study ID Numbers: UNLV-2021-252

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No