Blood Pressure Lowering Effects of Grape Juice

June 16, 2009 updated by: Boston University

Effect of Concord Grape Juice on Blood Pressure and Vascular Function in Subjects With Pre-Hypertension and Stage 1 Hypertension

Recent studies suggest that a diet rich in fruit and vegetables can lower blood pressure, and a number of lines of evidence suggest that grape products may have such an effect. The purpose of this study is to determine whether consuming grape juice lowers blood pressure in individuals with pre-hypertension or stage I hypertension.

Study Overview

Status

Completed

Conditions

Hypertension

Intervention / Treatment

Dietary supplement: Concord Grape Juice

Detailed Description

Elevated blood pressure (BP) is among the most common and important risk factors for atherosclerosis. A number of non-pharmacological therapies have successfully been applied to prevent the development of elevated BP or reduce elevated BP. For example the DASH Study showed that a diet rich in fruits, vegetables and low fat dairy products, and reduced in saturated fat, total fat and cholesterol, substantially lowered blood pressure in normotensive and hypertensive individuals.

Within the past three years a number of small clinical trials have suggested suggest that drinking purple grape juice for a period of 6-12 weeks may lower blood pressure individuals with elevated blood pressure. Other clinical trials have shown that Concord grape juice improves the function of the vascular endothelium, possibly providing an explanation for the beneficial effect. However, there is a need for a prospective, controlled study to determine whether grape juice has a beneficial effect on blood pressure.

The present study will compare the effect of drinking Concord purple grape juice (7 ml/kg or about 16 oz/day for a 70 kg person) and the effect of calorie-matched placebo on 24-hour ambulatory blood pressure, blood pressure reactivity, and vascular function in men and women in the category of "pre-hypertension" (defined as blood pressure greater than 120/80, but less than 149/89 mmHg and Stage 1 hypertension (defined as blood pressure greater than 140/90, but less than 160/100). This study will specifically recruit patients with systolic blood pressure of 130-159 mmHg or diastolic blood pressure of 85-99 mmHg. The study will be double blind and have a crossover design with the order of treatment randomized (grape juice first or placebo first). A dietician will provide all subjects with formal instruction in a low salt diet, which is the current recommended initial therapy for patients with Stage 1 hypertension.

After a 1-week run-in period, subjects will consume each beverage for 8 weeks with a 4-week rest period between treatments. Blood pressure will be measured before and after each treatment period using a 24-hour ambulatory blood pressure recording. After each treatment period, we will measure changes in blood pressure induced by psychological challenge (mental arithmetic and computer tasks) and by the cold pressor test. In order to gain insight into the potential mechanisms of benefit, we will also examine the effects of beverage consumption on endothelial function, stiffness of the central aorta, fasting glucose and insulin, body weight, and markers of systemic inflammation, including CD40 ligand and C-reactive protein. Finally, we will store plasma samples for future investigation of other potential effects of grape juice on the cardiovascular system.

We hypothesize that Concord grape juice will have favorable effects on blood pressure compared to placebo.

Study Type

Interventional

Enrollment (Anticipated)

Phase

Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

United States
- Massachusetts
  - Boston, Massachusetts, United States, 02118
    - Boston Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Genders Eligible for Study

All

Description

Inclusion Criteria:

Adult males and females
Body Mass Index (BMI) of less than 35.0 kg/m2
Systolic blood pressure (130-159 mmHg) and/or diastolic blood pressure (85-99 mm Hg) on two screening visits
Subject must be judged to be in good health on the basis of medical history; 5. Subject must not be taking any antihypertensive medications for at least one month prior to the Screening Visit

Exclusion Criteria:

History of clinically defined coronary artery disease, peripheral artery disease, stroke, active gastrointestinal ulcers, renal, or hepatic disease;
History of bleeding disorders or malabsorption syndromes;
Taking drugs for regulating hemostasis, including stable-dose aspirin;
History of active cancer
Females who are pregnant or planning to become pregnant
Use of weight-loss drugs (including over-the-counter and dietary supplements)
Diagnosed diabetes mellitus
Subjects who consume a vegetarian diet
Recent history (within the past 6 months) of alcohol or substance abuse.
Laboratory values outside the following ranges: serum potassium (3.5-5.1 mg/dl), creatinine (0.5-1.3 mg/dl), hematocrit (36-50%), white blood count (4.0-11.0 K/ul), platelet count (150-400 k/ul)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Interventional Model: Crossover Assignment
Masking: Quadruple

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Blood pressure measured by 24-hour recorder Time Frame: 8 weeks	8 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Pulse wave velocity Time Frame: 8 weeks	8 weeks
Pulse amplitude tonometry Time Frame: 8 weeks	8 weeks
Blood pressure during mental tasks Time Frame: 8 weeks	8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Boston University

Collaborators

Welch's, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Dohadwala MM, Hamburg NM, Holbrook M, Kim BH, Duess MA, Levit A, Titas M, Chung WB, Vincent FB, Caiano TL, Frame AA, Keaney JF Jr, Vita JA. Effects of Concord grape juice on ambulatory blood pressure in prehypertension and stage 1 hypertension. Am J Clin Nutr. 2010 Nov;92(5):1052-9. doi: 10.3945/ajcn.2010.29905. Epub 2010 Sep 15.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2006

Study Completion (Actual)

May 1, 2009

Study Registration Dates

First Submitted

March 13, 2006

First Submitted That Met QC Criteria