Clinical Trial of Protein and Blood Pressure (ProBP)

• ClinicalTrials.gov Identifier: NCT00107744
• Recruitment Status: Completed
• First Posted: April 8, 2005
• Results First Posted: July 5, 2018
• Last Update Posted: July 5, 2018
• Sponsor: Tulane University
• Collaborator: National Heart, Lung, and Blood Institute (NHLBI)
• Information provided by (Responsible Party): Tulane University

Study Description

Brief Summary:

The purpose of this randomized, double-blind, controlled trial is to examine the effect of soybean protein supplementation on blood pressure in persons with prehypertension or stage-1 hypertension.

Condition or disease	Intervention/treatment	Phase
Hypertension; Hypercholesterolemia	Dietary Supplement: Soy protein-milk protein-carbohydrate; Dietary Supplement: Milk protein-carbohydrate-soy protein; Dietary Supplement: Carbohydrate-soy protein-milk protein	Not Applicable

Detailed Description:

Background: Epidemiologic studies suggest that vegetable protein intake is inversely related to blood pressure.

Objectives: To examine the effect of soybean protein supplementation on blood pressure in persons with prehypertension or stage-1 hypertension

Design: Randomized, double-blind, controlled trial

Study Participants: 350 participants, aged 35-64 years, with an initial untreated systolic blood pressure of 130-159 mmHg and/or diastolic blood pressure of 80-99 mmHg

Intervention: Study participants will be randomly assigned to take 40-grams of isolated soybean protein supplements per day or complex carbohydrate control for 12 weeks.

Outcomes: Blood pressure measurements will be obtained using random-zero sphygmomanometers at baseline and during the trial at weeks 6 and 12. Net changes in systolic and diastolic blood pressure before and after the intervention is the primary outcome.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 352 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Intervention Model Description: The trial participants were assigned to take 40 g/d soy protein, milk protein, or carbohydrate supplementation each for 8 weeks in a random order. A 3-week washout period was implemented between the interventions.
• Masking: Triple (Participant, Investigator, Outcomes Assessor)
• Masking Description: The randomization assignment list was generated by a computer program that could only be accessed by the study data coordinator. Apart from the data coordinator, all research personnel, including investigators, study coordinators, and BP technicians, and the study participants were unaware of treatment assignment.
• Primary Purpose: Prevention
• Official Title: Clinical Trial of Protein and Blood Pressure
• Study Start Date: September 2003
• Actual Primary Completion Date: April 2008
• Actual Study Completion Date: April 2008

Arms and Interventions

Arm	Intervention/treatment
Active Comparator: Soy protein-milk protein-carbohydrate; Participants received 40 grams of soy protein daily for 8 weeks, 40 grams of milk protein daily for 8 weeks, and 40 grams of carbohydrate daily for 8 weeks.	Dietary Supplement: Soy protein-milk protein-carbohydrate; 40 grams of soy protein per day for 8 weeks, 40 grams of milk protein per day for 8 weeks, and 40 grams of carbohydrate per day for 8 weeks
Active Comparator: Milk protein-carbohydrate-soy protein; Participants received 40 grams of milk protein daily for 8 weeks, 40 grams of carbohydrate daily for 8 weeks, and 40 grams of soy protein daily for 8 weeks.	Dietary Supplement: Milk protein-carbohydrate-soy protein; 40 grams of milk protein per day for 8 weeks, 40 grams of carbohydrate per day for 8 weeks, 40 grams of soy protein per day for 8 weeks.
Active Comparator: Carbohydrate-soy protein-milk protein; Participants received 40 grams of complex carbohydrate daily for 8 weeks, 40 grams of soy protein daily for 8 weeks, and 40 grams of milk protein daily for 8 weeks.	Dietary Supplement: Carbohydrate-soy protein-milk protein; 40 grams of carbohydrate per day for 8 weeks, 40 grams of soy protein per day for 8 weeks, 40 grams of milk protein per day for 8 weeks.

Outcome Measures

Primary Outcome Measures :

1. Change From Baseline in Average Systolic Blood Pressure at 8 Weeks [ Time Frame: Baseline and 8 Weeks ]
   The change of systolic blood pressure was calculated as the mean of 6 blood pressure values from two 8-week visits minus the mean of 6 values from 2 baseline visits within each intervention phase. At each visit, 3 BP values were measured with a Hawksley random-zero sphygmomanometer by trained and certified observers who were masked to group assignment. BP readings were taken from the right arm with appropriately sized cuffs after the participant had been seated quietly for 5 minutes. The participant was instructed not to eat, smoke, drink alcohol, or exercise for at least 30 minutes before their BP measurements.

Secondary Outcome Measures :

1. Change From Baseline in Serum LDL-cholesterol at 8 Weeks [ Time Frame: Baseline and 8 Weeks ]
   Change in serum LDL-cholesterol was calculated as LDL-cholesterol at 8 weeks minus LDL-cholesterol at baseline. Over-night fasting serum LDL-cholesterol was measured with an enzymatic method.
2. Body Weight at 8 Weeks [ Time Frame: Baseline and 8 Weeks ]
   Body weight was measured by trained staff using a standard protocol at week 8.

Eligibility Criteria

• Ages Eligible for Study: 22 Years and older (Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

1. Systolic BP of 120 to 159 mm Hg and diastolic BP of 80 to 95 mm Hg (average of 6 measurements at 2 screening visits)
2. Willing to participate in all aspects of the study

Exclusion Criteria:

1. Consumption of dietary protein greater than or equal to 1.63 grams/kg per day, as determined by two 24-hour dietary recalls
2. Stage-2 or higher severe hypertension (systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 95 mm Hg)
3. Use of antihypertensive medications or medications that affect BP
4. History of clinical heart disease (e.g., angina/heart attack, coronary revascularization, heart failure, stroke/transient ischemic attack, peripheral arterial disease)
5. Kidney disease (serum creatinine level greater than or equal to 1.7 mg/dL for men and greater than or equal to 1.5 mg/dL for women)
6. Current hypercholesterolemia (fasting serum total cholesterol greater than or equal to 240 mg/dL) or use of cholesterol-lowering medications
7. Current diabetes (fasting serum glucose greater than or equal to 126 mg/dL) or use of insulin or oral hypoglycemic agents
8. Severe obesity (body mass index greater than or equal to 40 kg/m²)
9. Current use of prescription weight loss medications, underwent weight loss surgery, and/or experienced weight loss greater than 15 pounds within the 6 months prior to study entry
10. Cancer (except non-melanoma skin cancer) that required treatment during the year prior to study entry
11. Consumption of more than 14 alcoholic beverages per week
12. Current participation in another medical study
13. Consumption of milk or soy protein greater than or equal to the 90th percentile of intake in the U.S. general population
14. Has another member of the household participating in the study
15. Study employees or living with study employees
16. Allergy or intolerance to soy protein or milk protein products
17. Allergy to aspartame
18. Plans to move out of the study area (greater than or equal to 50 miles from the study site) and has difficulty coming to the study site
19. Inability or unwillingness to cooperate during the screening visits
20. Poor compliance during the screening period (intake of less than 85% of supplements)
21. Pregnant or plans to become pregnant during the study

Contacts and Locations

Sponsors and Collaborators

Tulane University

National Heart, Lung, and Blood Institute (NHLBI)

Investigators

• Study Chair: Jiang He, MD, PhD; Tulane University

More Information

Publications of Results:

He J, Wofford MR, Reynolds K, Chen J, Chen CS, Myers L, Minor DL, Elmer PJ, Jones DW, Whelton PK. Effect of dietary protein supplementation on blood pressure: a randomized, controlled trial. Circulation. 2011 Aug 2;124(5):589-95. doi: 10.1161/CIRCULATIONAHA.110.009159. Epub 2011 Jul 18.

Wofford MR, Rebholz CM, Reynolds K, Chen J, Chen CS, Myers L, Xu J, Jones DW, Whelton PK, He J. Effect of soy and milk protein supplementation on serum lipid levels: a randomized controlled trial. Eur J Clin Nutr. 2012 Apr;66(4):419-25. doi: 10.1038/ejcn.2011.168. Epub 2011 Sep 28.

Rebholz CM, Reynolds K, Wofford MR, Chen J, Kelly TN, Mei H, Whelton PK, He J. Effect of soybean protein on novel cardiovascular disease risk factors: a randomized controlled trial. Eur J Clin Nutr. 2013 Jan;67(1):58-63. doi: 10.1038/ejcn.2012.186. Epub 2012 Nov 28.

Other Publications:

Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet. 2005 Jan 15-21;365(9455):217-23.

• Responsible Party: Tulane University
• ClinicalTrials.gov Identifier: NCT00107744
• Other Study ID Numbers: H0330; R01HL068057 ( U.S. NIH Grant/Contract )
• First Posted: April 8, 2005
• Results First Posted: July 5, 2018
• Last Update Posted: July 5, 2018
• Last Verified: June 2018

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: No

Keywords provided by Tulane University:

Blood Pressure; Lipids; Dietary Protein

Additional relevant MeSH terms:

Hypercholesterolemia; Hyperlipidemias; Dyslipidemias; Lipid Metabolism Disorders; Metabolic Diseases; Caseins; Chelating Agents; Sequestering Agents; Molecular Mechanisms of Pharmacological Action