Review · Nutrients · 2023Conflicts declared

Oats, gut bacteria and short-chain fatty acids

What it found

Oats can change the mix of gut bacteria and boost short-chain fatty acids, but most of the evidence comes from animals and lab tests, not people.

What they found

Studies in people

Oat porridge enzymes

In 10 healthy people, 60 g of oat porridge daily for one week lowered fecal β-galactosidase and urease. The authors suggested this shows the gut bacteria adapted to the oats.

Animal and lab studies

Oat bran processing

In lab tests, steaming oat bran led to more short-chain fatty acids than microwaving or hot-air drying. All oat bran treatments reduced Escherichia-Shigella and increased Faecalibacterium prausnitzii.

Cholesterol and weight

In animals on a high-fat diet, oats or oat bran reduced body weight, inflammation and lipid levels, and increased short-chain fatty acids. One study in hamsters also found lower total and LDL cholesterol.

Brain and gut link

In an animal model of atherosclerosis, 0.8% oat fiber for 14 weeks delayed cognitive decline and increased short-chain fatty acid receptors and gut bacteria diversity.

Studies in people and animals

Gut bacteria changes

In a trial, 80 g of oats a day for 45 days increased Bifidobacterium and Akkermansia and reduced the Sutterellaceae family in people. Animal and lab studies also found more Bifidobacterium and Lactobacillus.

Short-chain fatty acids

In animals, oat supplementation raised butyrate, acetate and propionate in the gut. In people, 80 g of oats daily increased acetic acid and propionic acid compared to the start, but not compared to the rice control.

What the authors conclude

“Current evidence suggests that oats can beneficially alter the composition of the gut microbiota and promote the synthesis of SCFAs.”
Fabiano GA, Shinn LM, Antunes AEC, 2023

Also in their conclusions

  • They say current evidence suggests that oats can beneficially alter the gut microbiota and promote short-chain fatty acid synthesis.
  • They note that most research has been done in animals and lab tests, and these suggest plausible ways oats might work.
  • They call for future clinical trials in people to show the impact of oats on the human gut microbiota, taking into account internal and external influences and high differences between individuals.

How it was done

The authors wanted to focus on how oats affect gut health, the balance of colon bacteria, and the short-chain fatty acids these bacteria make, since most research has looked at oats and heart health instead.

They searched for original studies from 2012 to 2023 on oats, gut bacteria and short-chain fatty acids, and included 16 studies: some in animals, some in lab dishes, and two in people.

What it can’t tell you

  • Most of the studies were in animals or lab dishes, so they cannot show what happens in people.
  • The two human trials were small and short, so they cannot show long-term effects or prove cause and effect.
  • The review cannot say whether changes in gut bacteria lead to health benefits in people.

The paper

Title
Relationship between Oat Consumption, Gut Microbiota Modulation, and Short-Chain Fatty Acid Synthesis: An Integrative Review
Type
ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
Evidence
Studies in people · animals · lab
Summarised from
Full text
Cite
Fabiano GA, Shinn LM, Antunes AEC (2023). Relationship between Oat Consumption, Gut Microbiota Modulation, and Short-Chain Fatty Acid Synthesis: An Integrative Review. Nutrients. doi:10.3390/nu15163534Free full textPubMed 37630725DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error