Effect of dietary fiber intake on blood pressure: a... : Journal of Hypertension (original) (raw)

Original papers: Diet

He, Jianga,b; Streiffer, Richard Hc; Muntner, Paula,b; Krousel-Wood, Marie Ac; Whelton, Paul Ka,b

aDepartment of Epidemiology, Tulane University School of Public Health and Tropical Medicine, bDepartment of Medicine and cDepartment of Family and Community Medicine, Tulane University School of Medicine, New Orleans, Louisiana, USA.

Sponsorship: This study was supported by a grant (HL60300) from the National Heart, Lung, and Blood Institute of the National Institutes of Health and partially by Tulane-Charity-LSU General Clinical Research Center (RR05096).

Correspondence and requests for reprints to Jiang He, Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1430 Tulane Avenue, SL18, New Orleans, Louisiana, USA. Tel: +1 504 588 5165; fax: +1 504 988 1568; e-mail address: [email protected]

Received 30 April 2003 Revised 11 July 2003 Accepted 1 September 2003

See editorial commentary on page 25

Abstract

Objective

To examine the effect of dietary fiber intake on blood pressure (BP).

Design

Randomized, double-blind, placebo-controlled trial.

Setting and participants

A total of 110 trial participants aged 30 to 65 years who had untreated, but higher than optimal BP or stage-1 hypertension were recruited from the community in New Orleans, Louisiana, USA.

Interventions

Study participants were randomly assigned to receive 8 g/day of water-soluble fiber from oat bran or a control intervention.

Main outcome measures

Nine BP measurements were obtained by trained observers using random-zero sphygmomanometers, over three clinical visits, at the baseline and termination visits of the trial. An average of the nine measurements was used to determine mean BP at the baseline and termination visits.

Results

The net changes [95% confidence interval, (CI)] in systolic blood pressure were −1.8 mmHg (−4.3 to 0.8, P = 0.17) following 12 weeks, −2.2 mmHg (−5.3 to 1.0, P = 0.18) following 6 weeks, and −2.0 mmHg (−4.4 to 0.3, P = 0.09) for an average of the 6- and 12-week visits. The corresponding net changes (95% CI) in diastolic blood pressure were −1.2 mmHg (−3.0 to 0.5, P = 0.17) following 12 weeks, −0.8 mmHg (−3.1 to 1.4, P = 0.47) following 6 weeks, and −1.0 mmHg (−2.6 to 0.5, P = 0.19) for an average of the 6- and 12-week visits.

Conclusions

Our findings suggest that a diet rich in fiber may have a moderate BP-lowering effect and indicate the need for further investigation of this important question.