The Influence of Daily Strawberry Intake on Vascular Health in Elderly Men

The overall objective of this proposed trial is to examine the vascular protective effects provided by the daily consumption of 39g of freeze dried strawberry powder (FDSP) for four weeks. The study population will be older men (60-80 years of age).

Study Overview

• Status: Terminated
• Conditions: Vascular Dilation
• Intervention / Treatment: Other: freeze dried strawberry powder

Detailed Description

The proposed project will determine the influence of short-term FDSP intake on microvascular function in older men (60-80 years of age). The Framingham reactive hyperemia index (fRHI) will be used as a measure of microvascular function, and will be measured using peripheral arterial tonometry (PAT; EndoPAT200). Secondary outcomes will assess circulating levels of nitrate and nitrite, insulin-like growth factor (IGF), inflammatory cytokines, NADPH oxidase, platelet aggregation, plasma lipids and blood pressure. This suite of markers will provide insight on physiological outcomes and risk factors associated with CVD development, and the metabolic and signaling pathways that influence them. To accomplish the above, after a 4 week run in period of no powder intake, twenty men (60-80 years of age) will be randomly assigned to consume 39 g of FDSP or a control powder for four weeks in a randomized, double-blind, controlled crossover study. This study design will compare the short-term (four week) response of FDSP intake to an isocaloric control powder that provides no polyphenols, as well as to their habitual diet where no powder was consumed.

• Study Type: Interventional
• Enrollment (Actual): 4
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Davis, California, United States, 95616
      • University of California, Davis; Department of Nutrition

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Subject is willing and able to comply with the study protocols.
• Subject is willing to participate in all study procedures
• BMI 25.0 - 35 kg/m2

Exclusion Criteria:

• BMI ≥ 35 kg/m2
• Visit 1 Reactive Hyperemia Index (RHI; EndoPAT 2000) ≥ 2.8
• Dislike or allergy strawberries
• Self-reported use of daily anticoagulation agents including aspirin, NSAIDs
• Prescription medications other than on a 6 month self-reported stable dose of medications for lipid lowering and/or hypertension.
• Vegan, Vegetarians, food faddists or those consuming a non-traditional diet
• Fruit consumption ≥ 3 cups/day
• Regular consumption of strawberries (2-3 servings/week)
• Vegetable consumption ≥ 4 cups/day
• Coffee/tea ≥ 3 cups/day
• Dark chocolate ≥ 3 oz/day
• Self-reported restriction of physical activity due to a chronic health condition
• Self-reported chronic/routine high intensity exercise
• Self-reported diabetes
• Blood pressure ≥ 140/90 mm Hg
• Self-reported renal or liver disease
• Self-reported heart disease, which includes cardiovascular events and stroke
• Peripheral artery disease Raynaud's syndrome or disease
• Inability to properly place or wear the PAT probes or abnormal measurements on pre- screening PAT
• Abnormal Metabolic or CBC panels (laboratory values outside the reference range) if determined to be clinically significant by the study physician.
• Self-reported cancer within past 5 years
• Self-reported malabsorption
• Supplement use other than a general formula of vitamins and minerals that meet the RDA
• Not willing to stop any supplement use, including herbal, plant or botanical, fish oil, oil supplements a month prior to study enrollment.
• Indications of substance or alcohol abuse within the last 3 years
• Cannabis use
• Current enrollee in a clinical research study.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Freeze dried strawberry powder; 39g of freeze dried strawberry powder, which represents three daily servings of strawberries. The powder will be mixed in one cup of water.	Other: freeze dried strawberry powder; approximately 24 strawberries that have been freeze dried into a powder
Placebo Comparator: control powder; 39 g of a powder that matches the sugar and caloric content of the experimental powder. The powder will be mixed in one cup of water.	Other: freeze dried strawberry powder; approximately 24 strawberries that have been freeze dried into a powder

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Framingham Reactive Hyperemia Index (fRHI)	fRHI as a measure of microvascular function will be measured by peripheral arterial tonometry (PAT).	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
platelet aggregation	optimal platelet aggregometry using collagen and adp as agonist	4 weeks
Th17 cytokines	TH17 Luminex panel: Interleukin (IL)-1b, IL-4, IL-6, IL-10, IL-17a, IL-21, IL-22, IL-23, IL-31, IL-33, IFNgamma, TNFalpha, IL-17f.	4 weeks
insulin like growth factor (IGF) and binding proteins (IGFBP)	Luminex panel: IGF-1, -2 and IGFBP 1-7	4 weeks
Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase	soluble form marker of oxidative stress	4 weeks
total nitrate and nitrite	plasma total nitrate and nitrite	4 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood pressure	systolic and diastolic blood pressure	4 weeks
plasma lipids	clinical lipid panel	4 weeks

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Carl L Keen, PhD, Professor of Nutrition and Internal Medicine

Publications and helpful links

Helpful Links

• Learn more or sign up for the study here!

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2021
• Primary Completion (Actual): December 31, 2022
• Study Completion (Actual): December 31, 2022

Study Registration Dates

• First Submitted: February 16, 2021
• First Submitted That Met QC Criteria: February 18, 2021
• First Posted (Actual): February 21, 2021

Study Record Updates

• Last Update Posted (Estimate): May 11, 2023
• Last Update Submitted That Met QC Criteria: May 9, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: strawberry, diet, vascular function, inflammation
• Additional Relevant MeSH Terms: Pathological Conditions, Anatomical; Dilatation, Pathologic
• Other Study ID Numbers: 1567320

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