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Clinical Trial of Protein and Blood Pressure (ProBP)

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ClinicalTrials.gov Identifier: NCT00107744
Recruitment Status : Completed
First Posted : April 8, 2005
Results First Posted : July 4, 2018
Last Update Posted : July 4, 2018
Sponsor:
Collaborator:
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Tulane University

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.


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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

Resource links provided by the National Library of Medicine

Drug Information available for: Casein

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.




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.



Information from the National Library of Medicine

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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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00107744


Sponsors and Collaborators
Tulane University
National Heart, Lung, and Blood Institute (NHLBI)
Investigators
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Study Chair: Jiang He, MD, PhD Tulane University

Publications of Results:
Other Publications:
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Responsible Party: Tulane University
ClinicalTrials.gov Identifier: NCT00107744     History of Changes
Other Study ID Numbers: H0330
R01HL068057 ( U.S. NIH Grant/Contract )
First Posted: April 8, 2005    Key Record Dates
Results First Posted: July 4, 2018
Last Update Posted: July 4, 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:
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Hypercholesterolemia
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Metabolic Diseases
Caseins
Chelating Agents
Sequestering Agents
Molecular Mechanisms of Pharmacological Action