Effect of Probiotics on Blood Pressure

Maybe in the far far distant future we will finally get a diet protocol for reducing high blood pressure. But not if pharma has any say about it.
http://hyper.ahajournals.org/content/64/4/897.long

A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

1. Saman Khalesi,
2. Jing Sun,
3. Nicholas Buys,
4. Rohan Jayasinghe

+ Author Affiliations

1. From the Griffith Health Institute (S.K., J.S., N.B.) and School of Medicine (S.K., J.S., R.J.), Griffith University, Australia; and Australia and Cardiac Services/Cardiology, Gold Coast Health, Australia (R.J.)

1. Correspondence to Jing Sun, School of Medicine and Griffith Health Institute, Griffith University, Gold Coast Campus, Parkland, Gold Coast, Queensland 4222, Australia. E-mail j.sun@griffith.edu.au

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Abstract

Previous human clinical trials have shown that probiotic consumption may improve blood pressure (BP) control. The aim of the present systematic review was to clarify the effects of probiotics on BP using a meta-analysis of randomized, controlled trials. PubMed, Scopus, Cochrane Library (Central), Physiotherapy Evidence Database, and Clinicaltrial.gov databases were searched until January 2014 to identify eligible articles. Meta-analysis using a random-effects model was chosen to analyze the impact of combined trials. Nine trials were included. Probiotic consumption significantly changed systolic BP by −3.56 mm Hg (95% confidence interval, −6.46 to −0.66) and diastolic BP by −2.38 mm Hg (95% confidence interval, −2.38 to −0.93) compared with control groups. A greater reduction was found with multiple as compared with single species of probiotics, for both systolic and diastolic BP. Subgroup analysis of trials with baseline BP ≥130/85 mm Hg compared with <130/85 mm Hg found a more significant improvement in diastolic BP. Duration of intervention <8 weeks did not result in a significant reduction in systolic or diastolic BP. Furthermore, subgroup analysis of trials with daily dose of probiotics <10¹¹ colony-forming units did not result in a significant meta-analysis effect. The present meta-analysis suggests that consuming probiotics may improve BP by a modest degree, with a potentially greater effect when baseline BP is elevated, multiple species of probiotics are consumed, the duration of intervention is ≥8 weeks, or daily consumption dose is ≥10¹¹ colony-forming units.

Key Words:

• blood pressure
• hypertension
• meta-analysis
• probiotics
• review

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Introduction

Blood pressure (BP) has been strongly and positively associated with the risk of chronic diseases, including ischemic heart disease, heart failure, stroke, and kidney disease.^1,2 BP can be controlled through diet and lifestyle modification to prevent hypertension (systolic BP [SBP] ≥140 mm Hg or diastolic BP [DBP] ≥90 mm Hg) or related complications.³ Evidence suggests that low-fat diets rich in fruits and vegetables and low in sodium can lower BP.^4–6 Previous studies have also found that dietary constituents and supplements such as omega-3 fatty acids,⁷ garlic,⁸ and green tea^9,10 can improve BP control.

In recent years, the health benefits of probiotics have attracted increased attention. Probiotics are defined as live microorganisms that may have health benefits for the host if consumed in adequate amounts.¹¹ Probiotics are well studied for their health benefits in improving immune system function¹² and preventing diarrhea.^13,14 It has also been demonstrated that probiotics and their products can improve BP through mechanisms including improving total cholesterol and low-density lipoprotein cholesterol levels,^15–17 reducing blood glucose level and insulin resistance,^18,19 and regulating the renin–angiotensin system.^20,21

A recent systematic review and meta-analysis of 14 randomized, controlled trials showed that consumption of fermented milk containing inhibitory peptides (with or without probiotics) can significantly reduce SBP and DBP.²² However, the effects of probiotics (live bacteria) and their species or dose were not systematically investigated. Some previous studies on probiotics have reported that consumption of probiotic yogurt for 8 weeks can significantly improve BP,^23,24 whereas another study showed no benefit.²⁵ Because of inconclusive reports on the effect of probiotics on BP and lack of information on effective intervention characteristics, the current systematic review and meta-analysis of randomized, controlled trials has been conducted. The findings from this meta-analysis may provide further information on the effective probiotic species, duration or dose of consumption required to confer health, and BP benefits.