0

The full content of Annals is available to subscribers

Subscribe/Learn More  >
Articles |

Effect of Soybean Protein on Blood Pressure: A Randomized, Controlled Trial

Jiang He, MD, PhD; Dongfeng Gu, MD, MS; Xigui Wu, MD; Jichun Chen, MSc; Xiufang Duan, MD; Jing Chen, MD, MSc; and Paul K. Whelton, MD, MSc
[+] Article and Author Information

From Tulane University, New Orleans, Louisiana; and Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College, Beijing, People's Republic of China.


This trial is registered as NCT00107744 on http://clinicaltrials.gov.

Note: Drs. He and Gu contributed equally to this work.

Grant Support: By a Career Development Award from the Tulane University Health Sciences Center (Dr. He); grant R01 HL68057 from the National Heart, Lung, and Blood Institute of the National Institutes of Health (Dr. He); and grant 96-906-02-02 of the National Ninth Five-Year Plan Key Program from the Ministry of Science and Technology of the People's Republic of China (Dr. Gu).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Jiang He, MD, PhD, Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1430 Tulane Avenue SL 18, New Orleans, LA 70112-2699; e-mail, jhe@tulane.edu.

Current Author Addresses: Dr. He: Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1430 Tulane Avenue, SL 18, New Orleans, LA 70112-2699.

Drs. Gu, Wu, and Duan and Ms. Chen: Cardiovascular Institute and Fuwai Hospital, 167 Beilishi Road, Beijing, 100037 People's Republic of China.

Dr. Chen: Department of Medicine, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112.

Dr. Whelton: Office of Senior Vice President for Health Sciences, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112.

Author Contributions: Conception and design: J. He, D. Gu, X. Wu, Jing Chen, P.K. Whelton.

Analysis and interpretation of the data: J. He.

Drafting of the article: J. He.

Critical revision of the article for important intellectual content: J. He, D. Gu, X. Wu, Jing Chen, P.K. Whelton.

Final approval of the article: J. He, D. Gu, X. Wu, Jichun Chen, X. Duan, Jing Chen, P.K. Whelton.

Provision of study materials or patients: J. He, D. Gu, X. Wu, Jichun Chen, X. Duan.

Statistical expertise: J. He.

Obtaining of funding: J. He, D. Gu.

Administrative, technical, or logistic support: J. He.

Collection and assembly of data: J. He, D. Gu, X. Wu, Jichun Chen, X. Duan.


Ann Intern Med. 2005;143(1):1-9. doi:10.7326/0003-4819-143-1-200507050-00004
Text Size: A A A

Our study was a randomized, double-blind, complex carbohydrate–controlled multicenter clinical trial designed to test the efficacy of 40 g of isolated soybean protein supplementation per day in lowering systolic and diastolic blood pressure among individuals with prehypertension or stage 1 hypertension. Three clinical centers in the People's Republic of China, located in Beijing, Xiulo (Hebei province), and Wuhan (Hubei province), participated in the trial. Demographic characteristics and lifestyle, including dietary habits, were similar in the 3 communities. In Beijing, the clinical center used a 2 × 2 factorial design to assign the study participants to soybean protein and potassium (60 mmol/d) interventions (17). The other 2 centers used a 2-group parallel design to assign the study participants to soybean protein supplements or a complex carbohydrate control. Investigators obtained informed consent before the initial screening visit and before randomization. The institutional review boards at the Tulane University Health Sciences Center and the Cardiovascular Institute of the Chinese Academy of Medical Sciences approved the protocol.

First Page Preview

View Large
First page PDF preview

Figures

Grahic Jump Location
Figure 1.
Study participant flow chart.

BP = blood pressure.

Grahic Jump Location
Grahic Jump Location
Figure 2.
The effect of soybean protein supplementation on systolic (top) and diastolic (bottom) blood pressure.

The mean systolic and diastolic blood pressures are shown for the soybean protein supplementation and complex carbohydrate control groups at the baseline, 6-week, and 12-week visits. The numbers next to the dotted lines are the mean differences (95% CIs) in blood pressure change from baseline to 6-week and 12-week visits between the soybean protein supplementation group and the complex carbohydrate control group. Data presented are from the 281 trial participants at week 6 and the 276 trial participants at week 12 who completed the intervention.

Grahic Jump Location
Grahic Jump Location
Figure 3.
The effect of soybean protein supplementation on systolic (top) and diastolic (bottom) blood pressure according to subgroup.

The mean difference and 95% CIs are shown for change in blood pressure from the baseline to 12-week visits between the soybean protein supplementation group and the complex carbohydrate control group. Overweight was defined as a body mass index ≥25 kg/m , and hypertension was defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or both. Error bars represent 95% CIs. p values are for interaction between a characteristic and the blood pressure effect of soybean protein.

Grahic Jump Location

Tables

References

Letters

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Comments

Submit a Comment
Letter to Editor
Posted on July 22, 2005
Balavenkatesh Kanna
Lincoln Medical & Mental Health Center, Affl. with Weill Medical College of Cornell University
Conflict of Interest: None Declared

In reference to the interesting study by He et al on the efficacy of soy protein in the reduction of blood pressure (BP) for patients with pre- hypertension and stage I hypertension (1), we would like to offer the following comments.

Firstly, participants in both study groups were given potassium supplements in one of the study sites. As potassium supplementation is associated with systolic blood pressure reduction (2, 3), we are interested to know how the investigators established a lack of effect modification between soy bean protein and potassium.

Secondly, Hawksley random-zero sphygmomanometers have been found to under-record up to 1.4 mm Hg in systolic and 2.5 mm Hg in diastolic BP measurements.(4) This bias, mainly attributed to overestimation of the final zero correction during BP measurement could potentially undermine the observed results.

Further, the level of physical activity is a confounding variable that needs careful evaluation in the study groups. Physical activity can lead to significant reduction in mean systolic and diastolic blood pressures of up to 3.84 and 2.58 mm Hg respectively. (5)

References:

1. He J, Gu D, Wu X, Chen J, Duan X, Chen J, et al. Effect of soybean protein on blood pressure: a randomized, controlled trial. Ann Intern Med. 2005; 143:1-9.

2. Gu, Dongfong; He, Jiang; Wu, Xigui; Duan, Xiufang; Whelton, Paul K. Effect of potassium supplementation on blood pressure in Chinese: a randomized, placebo-controlled trial. Journal of Hypertension. 2001; 19(7):1325-1331.

3. Haddy FJ. Dietary sodium and potassium in the genesis, therapy, and prevention of hypertension. Journal of the American College of Nutrition. 1987; 6(3): 261-70.

4. McGurk C, Nugent A, McAuley D, Silke B. Sources of inaccuracy in the use of the Hawksley random-zero sphygmomanometers. Journal of Hypertension.1997;15:1379-84

5. Seamus P. Whelton; Ashley Chin, MPH, MA; Xue Xin, MD, MS; and Jiang He, MD, PhD. Effect of Aerobic Exercise on Blood Pressure: A Meta- Analysis of Randomized, Controlled Trials. 2002; 136 (7): 493-503.

Conflict of Interest:

None declared

Submit a Comment

Summary for Patients

Soybean Protein May Lower Blood Pressure

The summary below is from the full report titled “Effect of Soybean Protein on Blood Pressure: A Randomized, Controlled Trial.” It is in the 5 July 2005 issue of Annals of Internal Medicine (volume 143, pages 1-9). The authors are J. He, D. Gu, X. Wu, J. Chen, X. Duan, J. Chen, and P.K. Whelton.

Read More...

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.

Toolkit

Buy Now

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Advertisement
Related Articles
Related Point of Care
Topic Collections
PubMed Articles
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.
(Required)
(Required)