Short-chain fatty acids in blood pressure, friend or foe
Xiao-Feng Chen¹,², Si-Chong Ren³, Guo Tang², Chuan Wu¹, Xiangqi Chen¹, Xiao-Qiang Tang¹
¹Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610041, China; ²Department of Biochemistry and Molecular Biology, Basic Medical College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137, China; ³Department of Nephrology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, Sichuan 610500, China
If you’ve ever heard that “gut health affects everything,” there’s growing science to back it up—including how your gut bacteria might influence your blood pressure. For the 1.28 billion people worldwide living with hypertension (high blood pressure), this connection could unlock new ways to prevent or manage the condition. At the center of this link are short-chain fatty acids (SCFAs)—tiny molecules made by gut bacteria when they digest fiber. But are SCFAs friends or foes when it comes to blood pressure? Let’s break down the research.
What Are Gut Microbiota and SCFAs?
Your gut is home to trillions of microbes—bacteria, fungi, and viruses—collectively called the gut microbiota. These microbes aren’t just passengers: they help digest food, make vitamins, and communicate with your immune and cardiovascular systems. One of their most important jobs is fermenting indigestible dietary fiber (think: the parts of fruits, veggies, and whole grains your body can’t break down) into SCFAs. The three main SCFAs are acetate (the most abundant), propionate, and butyrate.
The HELIUS Study: A Key Piece of the Puzzle
Until recently, most research on SCFAs and blood pressure was in animals. That changed with the HEalthy Life In an Urban Setting (HELIUS) study, a large cohort of 4672 participants across ethnic groups published in European Heart Journal in 2020. The results were eye-opening:
- Gut bacteria composition explained 4.4% of differences in systolic blood pressure (SBP)—the “top number” that measures pressure when your heart beats.
- People with more SCFA-producing bacteria had lower SBP.
- But here’s the twist: people with higher levels of SCFAs in their stool had higher SBP.
This paradox suggests fecal SCFAs (what’s left in your gut after digestion) aren’t the direct link between gut bacteria and blood pressure. Instead, researchers hypothesize circulating SCFAs (those in your blood) might be a better marker—since they reflect how much your body actually absorbs and uses. Factors like how SCFAs are transported or how many SCFA receptors your cells have could also change their effects.
The “Good” SCFAs: Acetate, Propionate, Butyrate
While fecal SCFAs are confusing, studies on individual SCFAs tell a clearer story—especially in preclinical (animal) research:
1. Acetate: The Most Abundant SCFA
Acetate is the workhorse of SCFAs. A high-fiber diet increases acetate-producing bacteria, which reduces “gut dysbiosis” (an imbalance of good vs. bad bacteria) and lowers blood pressure. Even direct acetate supplementation has reduced blood pressure in mice—a sign gut-derived acetate plays a protective role.
2. Propionate: The Immune Regulator
Propionate helps keep your immune system in balance. In mice with high blood pressure (induced by a hormone called angiotensin II), propionate protected against heart damage by maintaining “regulatory T cells”—immune cells that calm inflammation. This suggests propionate’s benefits come from reducing harmful inflammation in blood vessels.
3. Butyrate: The Kidney Protector
Butyrate targets the kidneys, which play a key role in blood pressure regulation. It blocks the renin-angiotensin system—a pathway that raises blood pressure when overactive. In mice, butyrate supplementation reduced high blood pressure by suppressing this system.
It’s Not Just SCFAs: Other Gut Metabolites Matter
SCFAs aren’t the only gut-derived molecules that affect blood pressure. Trimethylamine N-oxide (TMAO)—made when bacteria break down choline (found in red meat, eggs, and dairy)—is linked to a higher risk of hypertension. This shows gut bacteria can produce both “good” (SCFAs) and “bad” (TMAO) metabolites—balance is key.
The Next Frontier: Epigenetics and SCFAs
Scientists are also exploring how SCFAs affect gene regulation (epigenetics). A 2021 study in Circulation found crotonate (a SCFA) changes how DNA is packaged in cells (via “histone crotonylation”). This process might protect against pathological cardiac hypertrophy—an enlarged heart that’s a common complication of high blood pressure. While early, this suggests SCFAs could work through epigenetic pathways—adding another layer to their complexity.
So, Are SCFAs Friends or Foes?
The answer is: it depends—but the evidence leans toward “friend” for most people. Here’s what we know:
- More SCFA-producing bacteria = lower blood pressure.
- Individual SCFAs (acetate, propionate, butyrate) have protective effects in animals.
- A high-fiber diet (which feeds SCFA-producing bacteria) is linked to lower hypertension risk.
The fecal SCFA paradox reminds us we’re still learning how these molecules work in the human body. Circulating SCFAs, SCFA receptors, and individual differences (like diet or genetics) all play a role.
What Does This Mean for You?
While we need more human studies, the research points to two potential strategies for blood pressure management:
- Eat more fiber: Fruits, veggies, whole grains, and legumes feed SCFA-producing bacteria.
- SCFA supplementation: Early research suggests acetate, propionate, or butyrate supplements could help—but they’re not yet approved for hypertension.
The Bottom Line
Gut microbiota and SCFAs are critical players in blood pressure regulation. The HELIUS study’s paradox highlights the complexity of this relationship, but the evidence for SCFA-producing bacteria and individual SCFAs is strong. Targeting the gut—whether through diet or supplements—could be a novel way to treat hypertension. But as with all emerging science, more research is needed to turn these findings into real-world therapies.
References
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- Wang L, Zhu Q, Lu A, Liu X, Zhang L, Xu C, et al. Sodium butyrate suppresses angiotensin II-induced hypertension by inhibition of renal (pro)renin receptor and intrarenal renin-angiotensin system. J Hypertens 2017;35:1899–1908. doi:10.1097/HJH.0000000000001378
- Tang X, Chen XF, Sun X, Xu P, Zhao X, Tong Y, et al. Short-chain enoyl-CoA hydratase mediates histone crotonylation and contributes to cardiac homeostasis. Circulation 2021;143:1066–1069. doi:10.1161/CIRCULATIONAHA.120.049438
doi.org/10.1097/CM9.0000000000001578
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