Study Links Fiber Intake to Lower Blood Pressure

by | Apr 22, 2016 | 2015, Blood Pressure, Cardiovascular Health, Fiber

Written by Greg Arnold, DC, CSCS. Increasing total fiber intake by 6.8 grams per 1000 calories decreased systemic blood pressure by 1.69 mmHg while insoluble fiber of 4.6 grams per 1000 calories decreased blood pressure by 1.81 mmHg.

High blood pressure has been deemed a worldwide epidemic (1) and was estimated to cost our healthcare system $73 billion in 2009 (2). The National Institutes of Health classify a healthy blood pressure as 120/80 mmHg or less, a blood pressure between 120/80 and 140/90 as “prehypertension”, and 140/90 mmHg or greater as high blood pressure (3).

Fortunately, research has identified a number of ways to help maintain a healthy blood pressure, from physical activity (4) to increased omega-3 fatty acid intake (5) to increased potassium intake (6). Now a new study (7) suggests increased fiber intake, specifically total and insoluble fiber, may also be a benefit. In the study, researchers analyzed data on 2,195 subjects (1,092 men, 1,093 women) aged 40 to 59 from the International Study on Macro/micronutrients and Blood Pressure (INTERMAP) study (8). Over the course of four physicians’ visits (two on consecutive days and two on consecutive days approximately 3 weeks later), blood pressure was measured 8 times, and four 24-hour dietary recalls were conducted (19).

The researchers found that after making adjustments for lifestyle factors and body mass index, increasing total fiber intake by 6.8 grams per 1,000 calories decreased systolic blood pressure by 1.69 mmHg (p = 0.01). For insoluble fiber, increasing intake by 4.6 grams per 1,000 calories decreased systolic blood pressure by 1.81 mmHg (p = 0.04). No benefits were seen on blood pressure with increased soluble fiber intake (p > 0.05). When looking at the specific foods from dietary recalls, raw fruit was the main source of total and insoluble fiber, followed by whole grains and vegetables.

When attempting to explain how fiber produces these healthful effects on blood pressure, researchers cited studies showing that fiber increases levels of nitric oxide, a strong blood vessel dilator (10). It also possibly decreases absorption of sodium (11) and improves insulin sensitivity (12, 13), both of which are risk factors for cardiovascular disease, of which high blood pressure is a significant contributor (14).

Although the researchers conclude that “higher intakes of total fiber and insoluble fiber were associated with lower BP”, and that “it may be a favorable approach to choose fiber-rich foods to prevent elevated blood pressure”, they cite the need for “large-scale, prospective population studies with high-quality dietary data and blood pressure measurements and intervention studies.”

Source: Aljuraiban, Ghadeer S., et al. “Total, insoluble and soluble dietary fibre intake in relation to blood pressure: the INTERMAP Study.” British Journal of Nutrition 114.09 (2015): 1480-1486.

© The Authors 2015

Posted October 5, 2015.

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.  You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

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