Can Microbes Lower Blood Pressure?

Guest BloggerClinical Corner, Microbiome Environment

high blood pressure

Shake the salt habit, get off the couch and don’t forget your meds.

Long the trifecta for managing high blood pressure, those rules demand revision as more of the planet (as many as one-third of adults) struggle with numbers that can lead to early death.

One novel approach may lie with the gut-brain axis.

In a nutshell:

  • The sympathetic nervous system (SNS) and the immune system (IS) are key to hypertension.
  • Gut-brain talk modulates the above systems thereby influencing blood pressure

Not so simple are the myriad mechanisms contributing to hypertension: immune system activation, overactive SNS, dampened parasympathetic nervous system(PNS), faulty renin-angiotensin system, genetic mutations and many external causes including obesity, medications and alcohol.

Now a new review paper describes in detail all the possible ways that microbes may interplay with malfunctions causing hypertension. Researchers Tao Yang and Jasenka Zubcevic propose an integrated network regulating blood pressure that involves feedback between the immune system, nervous system and gut microbiota. Their work appears in Frontiers in Physiology in October 2017.

Included in the discussion are

  • Immune signalling to the brain and back from brain generated immune responses.
  • Short chain fatty acids (SCFAs) including the most studied acetate, propionate and butyrate are vasodilators and have been shown to reduce blood pressure in both rodents and humans.
  • Lactate is primarily fermented to SCFAs by human gut microbiota. Imbalance of lactate and SCFAs may lead to hypertension.
  • Selective vagal nerve stimulation has been shown to lower pressure by reducing heart rate.
  • Endocrine systems and neurotransmitters –including serotonin, GABA, glutamate and dopamine– are also involved.

The modus operandi for all these are unclear. Still the reviewers offer compelling pieces of a puzzling disorder now known to be wrapped up in the gut-brain axis.

Probiotics and hypertension

Probiotics have been tested in clinical trials in relation to blood pressure control. A meta-analysis of 9 randomized trials showed a significant decrease in both systolic and diastolic pressures in patients who consumed a daily dose of Lactobacillus helveticus.

Fecal transplantation from hypertensive rats and human patients induced blood pressure increases in healthy rats and mice, revealing a link for gut dysbiosis.

Why look at the gut microbiota to manage hypertension when scores of drugs are available?

Potentially, reconfiguring gut microbes can be cheaper, less invasive and with no side effects– a win-win prospect for this deadly condition.