Effects of Freeze Dried Strawberry Powder Supplementation on Vascular Function and Blood Markers of Cardiovascular Risk

The purpose of this study is to evaluate the effects of freeze dried strawberry powder on LDL cholesterol, central and peripheral blood pressure, indices of arterial stiffness, and other lipid and lipoprotein concentrations. The investigators hypothesize that the bioactive compounds in freeze dried strawberry powder may elicit beneficial effects on LDL cholesterol, as well as blood pressure and arterial health.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Disease
• Intervention / Treatment: Dietary supplement: Low Dose Strawberry Powder; Dietary supplement: High Dose Strawberry Powder; Dietary supplement: Placebo Powder

Detailed Description

The proposed study design is a 3-period randomized crossover dose-response study to evaluate the effect of freeze dried strawberry powder supplementation on LDL-C and vascular health. Research participants will be overweight or obese (BMI 25-39 kg/m^2) but otherwise healthy adults with moderately elevated LDL-C (>116 mg/dL or >3.0mmol/L), blood pressure <160/100 mmHg, total cholesterol below 273 mg/dL for men and below 284 mg/dL for women, and triglycerides below 350 mg/dL. Subjects will be randomly assigned to three supplementation periods: 1) low dose freeze dried strawberry powder (13 g/d); 2) high dose freeze dried strawberry powder (40 g/d); and 3) a placebo powder. Each powder will be provided for 4-6 weeks, separated by a 2-week washout period between treatment periods. Baseline and endpoint testing will include blood collection and vascular testing.

• Study Type: Interventional
• Enrollment (Actual): 42
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • University Park, Pennsylvania, United States, 16803
      • Penn State CRC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 35 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Men and women 35-65 years of age
2. BMI ≥ 25 and ≤ 39 kg/m^2
3. LDL-C > 116 mg/dL
4. Total Cholesterol below 273 mg/dL for men and below 284 mg/dL for women
5. Triglycerides below 350 mg/d
6. Non-smokers
7. Blood pressure < 160/100 mmHg

Exclusion Criteria:

1. History of acute or chronic inflammatory conditions or heart disease, kidney disease, liver disease, autoimmune disorders, or thyroid disease (unless controlled by medication and blood results within the previous 6 months are provided)
2. History of diabetes mellitus (and/or a fasting glucose > 126 mg/dL at screening)
3. Stage II hypertension (blood pressure ≥ 160/100 mmHg)
4. Lactation, pregnancy, or desire to become pregnant during the study
5. Unwillingness to discontinue nutritional supplements, herbs, or vitamins, unless approved by investigator
6. Use of medications/supplements for elevated lipids, blood pressure, or glucose
7. Chronic use of non-steroidal anti-inflammatory or immunosuppressant medication
8. Conditions requiring the use of steroids
9. Unwillingness to refrain from blood donation prior to and during the study
10. Any medical condition or abnormal laboratory value that is judged clinically significant by an investigator
11. Allergy or sensitivity to strawberries or any ingredient in the study powders

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low Dose Strawberry Powder; 40 g composed of 13 g freeze dried strawberry powder + 27 g placebo powder	Dietary supplement: Low Dose Strawberry Powder; 40 g composed of 13 g freeze dried strawberry powder + 27 g placebo powder
Experimental: High Dose Strawberry Powder; 40 g freeze dried strawberry powder	Dietary supplement: High Dose Strawberry Powder; 40 g freeze dried strawberry powder
Placebo Comparator: Placebo Powder; 40 g color and taste matched placebo powder	Dietary supplement: Placebo Powder; 40 g color and taste matched placebo powder

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
LDL-C	LDL-C values calculated using the Friedewald equation	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Central Blood Pressure	Aortic (central) blood pressure measured using the SphygmoCor System	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Peripheral Blood Pressure	Peripheral blood pressure measured using the SphygmoCor System	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Augmentation Index	Augmentation index measured using the SphygmoCor System	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Pulse Wave Velocity	Pulse wave velocity measured using the SphygmoCor System	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Total Cholesterol	Total cholesterol values determined by enzymatic procedures	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Triglycerides	Triglyceride values determined using enzymatic procedures	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
HDL-C	HDL-C will be estimated according to the modified heparin-manganese procedure	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Oxidized LDL (oxLDL)	Plasma concentrations of oxLDL will be measured using ELISA kits	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
Malondialdehyde (MDA)	MDA will be measured using the thiobarbituric acid reactive substances (TBARS) assay	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage
High Sensitivity C Reactive Protein (hs-CRP)	hs-CRP will be measured by latex-enhanced immunonephelometry	Change from baseline after 4 week treatments of low dose, high dose, and placebo strawberry beverage

Collaborators and Investigators

• Sponsor: Penn State University
• Collaborators: California Strawberry Commission
• Investigators: Principal Investigator: Penny Kris-Etherton, PhD, RD, Penn State University

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2015
• Primary Completion (Actual): May 1, 2019
• Study Completion (Actual): May 1, 2019

Study Registration Dates

• First Submitted: September 18, 2015
• First Submitted That Met QC Criteria: September 21, 2015
• First Posted (Estimated): September 23, 2015

Study Record Updates

• Last Update Posted (Actual): August 18, 2023
• Last Update Submitted That Met QC Criteria: August 15, 2023
• Last Verified: August 1, 2023

More Information

Terms related to this study

• Keywords: Cardiovascular Disease Risk Factors; Strawberry Powder
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: PKE STRAW II