By Next Biosciences

10 September 2026

The Heart-Gut Axis: How Your Microbiome Affects Blood Pressure

Yes, your gut microbiome can influence blood pressure. Imbalances in gut bacteria are linked to inflammation, reduced production of blood-vessel-relaxing compounds, and byproducts like TMAO that stiffen arteries. In South Africa, where hypertension affects an estimated 40 to 50% of adults, understanding this gut-heart connection offers a new, practical angle on prevention.

Why Blood Pressure is a Bigger Issue in South Africa than Most Realise

Cardiovascular disease is a leading cause of death in South Africa, and high blood pressure sits at the centre of it. Research published in the South African General Practitioner journal puts hypertension prevalence among South African adults at 40 to 50%, with control rates remaining low even once diagnosed. 

Lifestyle factors such as diet, alcohol use, and inactivity are well-known contributors. What's less well known, even among people actively managing their blood pressure, is the role played by the gut microbiome.

What is the Heart-Gut Axis?

The heart-gut axis refers to the two-way relationship between your gut bacteria and your cardiovascular system. Researchers haven't mapped every mechanism yet, but the evidence for a genuine biological link is strong, and it runs through several distinct pathways.

How Does Gut Bacteria Affect Blood Pressure?

     1. An imbalanced gut can trigger a stress response in the body

When gut bacteria are out of balance, a state researchers call dysbiosis, the body can shift into a low-grade stress state. This can increase production of harmful byproducts, including trimethylamine N-oxide (TMAO), a compound associated with plaque build-up in the arteries.

     2. People with high blood pressure tend to have less diverse gut bacteria

Studies comparing people with elevated blood pressure to those with normal readings consistently find lower microbial diversity in the hypertensive group, along with a different bacterial mix. One consistent pattern is a higher ratio of Firmicutes to Bacteroidetes. That matters because Bacteroidetes help reinforce the gut's mucosal barrier and support immune function. Reduced gut barrier function has also been linked to lower levels of short-chain fatty acids (SCFAs), compounds that normally help regulate immune responses and protect cardiovascular health.

     3. Can You Improve Blood Pressure Through Your Microbiome?

Genetics plays a smaller role in blood pressure regulation than most people assume. That's good news: it means lifestyle and microbiome-focused changes carry real, measurable potential.

Practical, evidence-based steps include:

  • Consider a quality probiotic. Research shows probiotics can help rebalance gut bacteria and support healthier blood pressure, with the strongest results seen in supplements combining several bacterial strains, taken for eight weeks or more. Speak to your doctor before starting any new supplement.
  • Eat more prebiotic fibre. Onions, leeks, bananas, garlic, and Jerusalem artichokes feed the beneficial bacteria already living in your gut.
  • Only take antibiotics when prescribed. Unnecessary antibiotic use disrupts your gut's bacterial balance in ways that can persist for months.
  • Add nitrate-rich foods like beetroot. Beetroot, in particular, has consistently been linked to modest blood pressure reductions. Toss cooked beetroot into salads, smoothies, or juice it with a squeeze of citrus.

How Do I Know What's Happening in My Own Gut?

This is where most generic advice runs out. Two people can eat the same diet and take the same probiotic, and see completely different results, because their underlying microbiome activity is different.

Viome's gut microbiome test, available in South Africa exclusively through Next Biosciences, uses RNA sequencing to show what your gut bacteria are actually doing right now, not just which species are present. That distinction matters: a DNA-only test can show identical bacteria in two people whose gut function is completely different. RNA sequencing reveals microbial activity, metabolic pathways, and functional gut processes, giving a far more actionable picture.

Your results translate into a personalised report with clear food recommendations, foods to enjoy, minimise, or avoid, based on your own biology rather than generic dietary guidelines. Results are tracked through the Viome app, so your recommendations update as your gut health changes over time.

Learn more about the Viome Gut Microbiome Test in South Africa

 

Frequently Asked Questions

  1. Does gut health really affect blood pressure? Yes. Multiple studies link gut bacteria imbalances to inflammation, arterial plaque-related compounds like TMAO, and reduced production of nitric oxide, all of which play a role in blood pressure regulation.

  2. What percentage of South Africans have high blood pressure? Estimates place hypertension prevalence among South African adults at 40 to 50%, with some community-level studies recording even higher rates.

  3. Can a gut microbiome test help with blood pressure management? A gut microbiome test won't diagnose hypertension, but it can identify imbalances and functional patterns in your gut that are associated with cardiovascular and metabolic health, informing more targeted nutrition choices.

  4. Where can I get a Viome gut microbiome test in South Africa? Next Biosciences is the exclusive South African distributor of Viome testing, with results delivered through the Viome app within four weeks of sample submission.

 

References:

Inspired by / adapted from:

South African hypertension data:

  • Hypertension in South Africa: a growing epidemic and evolving treatment paradigms. South African General Practitioner, 2025. https://doi.org/10.36303/SAPJ.2566
  • Woodiwiss AJ, Orchard A, Mels CM, et al. High prevalence but lack of awareness of hypertension in South Africa, particularly among men and young adults. J Hum Hypertens, 2025;39:111-119 (published online 2023). https://doi.org/10.1038/s41371-023-00873-3
  • Self-reported hypertension prevalence, risk factors, and knowledge among South Africans aged 24 to 40 years old. J Hum Hypertens, 2025. https://doi.org/10.1038/s41371-024-00957-8

Gut microbiome and blood pressure regulation:

Probiotics and blood pressure (animal study):

  • Yuan L, Li Y, Chen M, et al. Antihypertensive activity of milk fermented by Lactiplantibacillus plantarum SR37-3 and SR61-2 in L-NAME-induced hypertensive rats. Foods, 2022;11(15):2332. https://doi.org/10.3390/foods11152332

 

This article is for educational purposes and is not a substitute for professional medical advice. Speak to your doctor about any changes to your diet, supplements, or medication.

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