Clinical trial NCT00107744: Clinical Trial of Protein and Blood Pressure
Official title: Clinical Trial of Protein and Blood Pressure
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hypertension
Hypercholesterolemia
Keywords: Blood Pressure; Lipids; Dietary Protein
Lead sponsor: Tulane University
Sponsor class: OTHER
Collaborators: name: National Heart, Lung, and Blood Institute (NHLBI)
First posted: 2005-04-08
Enrollment: 352
Sex: ALL
Minimum age (years): 22
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
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.
Primary purpose: PREVENTION

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.

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.

Eligibility 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

Primary outcomes:
measure: Change From Baseline in Average Systolic Blood Pressure at 8 Weeks
timeFrame: Baseline and 8 Weeks
Secondary outcomes:
measure: Change From Baseline in Serum LDL-cholesterol at 8 Weeks
timeFrame: Baseline and 8 Weeks
measure: Body Weight at 8 Weeks
timeFrame: Baseline and 8 Weeks
Other outcomes:
Locations:
Study officials:
affiliation: Tulane University
name: Jiang He, MD, PhD
role: STUDY_CHAIR
References:
citation: 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. doi: 10.1016/S0140-6736(05)17741-1.
citation: 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.
citation: 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.
citation: 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.