The Effects of Strawberries on Blood Pressure in Postmenopausal Women

Daily Incorporation of Strawberries Into a Diet Favorably Improves Vascular Function and Lowers Aortic Blood Pressure in Postmenopausal Women With Prehypertension

Cardiovascular disease (CVD) is the leading cause of death in the US. Statistics show that approximately 91% of individuals with CVD have vascular dysfunction. Hypertension is a major modifiable risk factor for CVD and approximately 60% of adults in the US are pre-hypertensive and hypertensive. In addition, the prevalence of hypertension is associated with aging in both genders; however, the increase in blood pressure (BP) in women after menopause exceeds that of men.

The development of effective and safe strategies to improve vascular function is of significance as it can have a great impact on quality of life, productivity and economic burden for the affected populations. One such alternative would be to introduce into the diet food sources that are rich in naturally occurring bioactive compounds. Thus, the long-term goal of the investigators is to provide feasible and effective dietary ways for postmenopausal women to improve their vascular function and quality of life.

Strawberries are a rich source of bioactive compounds and its total antioxidant content ranks third among all fruits and vegetables. Hence, the purpose of this study is to bring forth evidence that incorporation of strawberries into the diet will reduce blood pressure and improve cardiovascular function in pre- and stage 1-hypertensive postmenopausal women.

Sixty eligible postmenopausal women between the ages of 45 and 65 and a seated BP of ≥ 130/85 mm Hg but ≤ 160/100 mmHg at the screening visit will be randomly assigned to one of three groups:

1. 25 g freeze-dried strawberry powder;
2. 50 g freeze-dried strawberry powder; or
3. placebo powder. Participants will be asked to consume the supplements for 8-weeks. Medical history, medication use, dietary intake, and physical activity will be assessed at 0-, 4-, and 8-weeks followed by blood draw. Serum levels of markers of cardiovascular function as well as oxidative stress and inflammation will be measured.

The investigators hypothesize that regular consumption of strawberry will improve cardiovascular function, decrease BP and blood markers of oxidative stress as well as inflammation. Investigators also expect the findings of this study to provide a foundation for further studies to examine the effects of long-term incorporation of strawberry into the diet and the integrity of cardiovascular system.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Intervention / Treatment: Dietary supplement: Placebo Powder; Dietary supplement: 25 g of Freeze-dried Strawberry Powder; Dietary supplement: 50 g of Freeze-dried Strawberry Powder

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Tallahassee, Florida, United States, 32306
      • Florida State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years to 65 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• Postmenopausal women (1 to 10 years after natural menopause or bilateral oophorectomy)
• 45-65 years of age
• Seated blood pressure ≥ 130/85 mm Hg but ≤ 160/100 mm Hg
• BMI > 25 but < 40 kg/m2

Exclusion Criteria:

• Seated blood pressure ≤ 129/84 or ≥160/101 mmHg
• Type I Diabetes
• Cardiovascular disease
• Active cancer
• Glaucoma
• Thyroid disease
• Kidney disease
• Liver disease
• Pancreatic disease
• Enrollment in a weight loss program
• Heavy smokers (>20 cigarettes per day)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: FACTORIAL
• Masking: DOUBLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
PLACEBO_COMPARATOR: Control Group; Freeze-dried placebo powder - two doses of 25 g/day for 8 weeks	Dietary supplement: Placebo Powder; Participants will be given two packets of 25 g of placebo powder and asked to consume one packet in the morning and one at night.; Other Names: California Strawberry Commission
ACTIVE_COMPARATOR: 25 g of Freeze-dried Strawberry Powder; Freeze-dried strawberry and placebo powder - one dose of 25 g/day of each for 8 weeks	Dietary supplement: Placebo Powder; Participants will be given two packets of 25 g of placebo powder and asked to consume one packet in the morning and one at night.; Other Names: California Strawberry Commission; Dietary supplement: 25 g of Freeze-dried Strawberry Powder; Participants will be given one packet of 25 g of freeze-dried strawberry powder and one packet of 25 g of placebo powder and asked to consume one packet in the morning and one at night.; Other Names: California Strawberry Commission
EXPERIMENTAL: 50 g of Freeze-dried Strawberry Powder; Freeze-dried strawberry powder - two doses of 25 g/day for 8 weeks	Dietary supplement: 50 g of Freeze-dried Strawberry Powder; Participants will be given two packets of 25 g of freeze-dried strawberry powder and asked to consume one packet in the morning and one at night.; Other Names: California Strawberry Commission

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood Pressure	By measuring blood pressure variability and baroreflex sensitivity at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).	8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Arterial Stiffness	By assessing pulse wave velocity and augmentation index at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).	8 weeks
Endothelial function	By assessing blood biomarkers of vascular function (adiponectin, leptin, endothelin-1, angiotensin II and 8-isoprostane).	8 weeks
Oxidative Stress	By assessing blood biomarkers of oxidative stress (superoxide dismutase, nitrate/nitrite, 8-isoprostane, malondialdehyde , and oxidized low density lipoprotein).	8 weeks
Inflammation	By assessing blood biomarkers of inflammation (tumor necrosis factor-α and C-reactive protein).	8 weeks

Collaborators and Investigators

• Sponsor: Florida State University
• Collaborators: California Strawberry Commission
• Investigators: Principal Investigator: Arturo Figueroa, PhD, Florida State University

Publications and helpful links

General Publications

• Feresin RG, Johnson SA, Pourafshar S, Campbell JC, Jaime SJ, Navaei N, Elam ML, Akhavan NS, Alvarez-Alvarado S, Tenenbaum G, Brummel-Smith K, Salazar G, Figueroa A, Arjmandi BH. Impact of daily strawberry consumption on blood pressure and arterial stiffness in pre- and stage 1-hypertensive postmenopausal women: a randomized controlled trial. Food Funct. 2017 Nov 15;8(11):4139-4149. doi: 10.1039/c7fo01183k.

Study record dates

Study Major Dates

• Study Start: February 1, 2013
• Primary Completion (ACTUAL): July 1, 2014
• Study Completion (ACTUAL): July 1, 2014

Study Registration Dates

• First Submitted: March 26, 2014
• First Submitted That Met QC Criteria: March 26, 2014
• First Posted (ESTIMATE): March 31, 2014

Study Record Updates

• Last Update Posted (ESTIMATE): December 16, 2016
• Last Update Submitted That Met QC Criteria: December 15, 2016
• Last Verified: December 1, 2016

More Information

Terms related to this study

• Keywords: Oxidative stress; Endothelial function; Arterial stiffness; Blood pressure; Postmenopausal women; Pulse wave velocity; Strawberries
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases
• Other Study ID Numbers: 2013.11762

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED