Short-chain fatty acids, or SCFAs, are helpful molecules that gut bacteria produce as they break down nutrients, such as fibre, in your diet.
Bacteria make SCFAs in the large intestine, and these molecules go on to support your health in many ways – within and beyond the gut.
The most common types of SCFAs are acetate, propionate and butyrate. They’re produced by different bacteria, in different amounts and have different effects.
Below, we dive further into what SCFAs are, what they do, and how to help your gut microbiome make more.
How are SCFAs produced in the gut?
SCFAs are created when gut bacteria break down nutrients, such as fibre. Fibre is a type of carbohydrate that our bodies don’t digest because we don’t have the right enzymes.
So, when you eat fruits and veggies, for example, the fibre inside these plants passes through your digestive tract until it reaches your large intestine. There, your gut microbes settle in for a feast. They break down the fibre by fermenting it, and this releases SCFAs.
SCFAs support your gut health and provide other benefits as they circulate throughout your body. To name just one achievement, SCFAs contribute almost 10% of the overall energy your body needs.
Why are SCFAs important for gut health?
SCFAs help your gut work well, which in turn supports a host of other important functions.
Within the gut, SCFAs affect the pH level to encourage the growth of helpful bacteria and limit the growth of harmful ones.
SCFAs, particularly butyrate, also nourish and energise the cells that line your large intestine. They make sure these cells overlap tightly, so nothing unwelcome can pass in or out.
Supporting the gut’s lining is crucial – it helps the body digest and absorb nutrients, communicates with your nervous system and influences your immune response.
The gut’s wall houses an incredible 70% of your immune system. SCFAs interact with the immune system by helping to keep inflammation in check. As a result, scientists continue to explore the use of SCFAs in treating chronic inflammatory gut conditions, such as inflammatory bowel disease.
Diet and lifestyle factors, such as a lack of sleep and consistently high levels of stress, can increase the ‘leakiness’ of the gut’s lining. In response, the immune system triggers low-grade inflammation. Inflammation is a healthy, vital reaction to infection or injury, but if inflammation lasts, it can cause damage.
Metabolism is another gut-related area where SCFAs contribute. These fatty acids help regulate appetite, blood pressure and blood sugar levels, as well as the way we process fats.
Gut health and brain health are deeply connected, and SCFAs play a role in the gut-brain axis, the network of continuous communication between your gut and brain. Studies continue to explore how SCFAs might pass into the brain and affect its structure, function and signalling.
Learn more about the gut-brain connection here.
What is butyrate, and why is it often mentioned?
Among the three most common SCFAs, butyrate stands out for promoting gut health. Around 70% of the butyrate produced is used to energise cells that line the large intestine.
For decades, researchers have investigated whether increasing levels of butyrate could help treat health conditions. It’s worth keeping in mind, though, that when these studies were conducted in humans, results were mixed.
A review from 2025 describes growing evidence that butyrate may help ease symptoms of chronic inflammatory gut conditions.
Other studies suggest that butyrate’s influence on cells lining the large intestine point to its potential for lowering the risk of colon cancer and limiting its progression. Research into the broader use of SCFAs in cancer treatment is ongoing.
Studies show that butyrate can help ease diarrhoea and intestinal inflammation, reduce after-effects of surgery and chemotherapy, and help restore balance to the gut microbiome. Butyrate helps keep the gut microbiome diverse, which has a wide range of broader health benefits.
Given this molecule’s reputation, it may be tempting to try butyrate supplements. But your microbiome already produces a range of SCFAs, each with different roles and benefits.
Butyrate makes up only about 20% of the SCFAs in our bodies. So, rather than focusing on one SCFA, consider a more holistic strategy: encourage your microbiome to make more SCFAs by feeding your microbes different types of fibre.
Here, find simple strategies for adding fibre to your diet.
How can you support SCFA production through everyday habits?
Helping your gut microbes produce more SCFAs generally involves eating a range of fibre-rich plant foods consistently over time.
Here are three habits that tend to support SCFA production:
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Eat a wide variety of plant foods: Different plants provide different fuel for the bacteria that produce SCFAs. By eating a wide range of vegetables, fruits, legumes, whole grains, nuts, seeds, herbs and spices, you’ll boost the diversity of your gut microbiome and support its many functions, including SCFA production.
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Look for fermentable fibres: Soluble fibre is easily fermented, so it’s prime fuel for the microbes that make SCFAs. You can find it in oats, beans, lentils, apples and some other fruits. Foods rich in prebiotic fibre are also a great place to start.
The fibre in fermented plant foods, like kimchi and sauerkraut, may also be particularly helpful.
Resistant starch is another type of fermentable fibre. It’s in lentils, oats and green bananas. Resistant starch forms when starchy foods – like potatoes, rice and pasta – are cooled after they’re cooked. This starch reaches your large intestine intact, where gut bacteria ferment it and produce SCFAs. -
Aim for consistency: Developing a nutritious, delicious diet full of fibre-rich plant foods may take time and creativity. Behavioural science tells us that gradual, consistent changes are more effective than short-term overhauls.
Learn more about prebiotic fibre and where to find it.
How long does it take for fibre changes to affect the gut?
Eating more fibre can begin to influence your gut microbiome within days. But these changes can take weeks to have meaningful effects. Also, each person’s diet and gut microbiome are unique, so the timing and changes can vary greatly from person to person.
When you’re looking to support your gut health, it’s important to make changes gradually and consistently.
Adapt your approach to make sure you’re enjoying your meals and regularly eating a range of plant-based foods, including fruits, vegetables, legumes, whole grains, nuts, seeds, herbs and spices.
Find tips for eating 30 different plants each week.
What if increasing fibre feels uncomfortable?
If eating more fibre causes discomfort, slow down. A gentle approach might involve adding just one portion of fruit or vegetables (with the skins on) each day for a week. Give your body time to adjust to the added fibre, and tailor your approach to suit your tastes and tolerances.
Health guidelines in the United Kingdom recommend that adults eat around 30 grams of fibre per day, but most of us aren’t getting nearly enough. It’s important to build up your fibre intake gradually, as sudden increases can lead to temporary bloating, wind and changes to your digestion.
Registered Dietitian Laura Tilt confirms that suddenly ‘going from a low-fibre to a high-fibre diet within a day or two’ can lead to discomfort, and that a gradual approach is well worth the effort: ‘For most people, purposefully adding more fibre to meals is a good thing.’
She adds that it’s important to drink more hydrating fluids as you increase your fibre intake, as ‘Some types of fibre need fluid to move through the gut.’
If you’re experiencing discomfort related to fibre-rich foods, a registered dietitian can help you spot specific triggers and make gut-friendly choices.
Also, if you have certain health conditions, eating too much fibre may aggravate the symptoms. So, if discomfort is concerning or persists, it’s important to speak with a doctor.
Why does diversity matter more than perfection?
Different microbes prefer different forms of fibre. By eating a broad range of fibre-rich plant-foods, you’re welcoming a diverse group of SCFA-producing bacteria to the table. Of course, producing SCFAs is just one way that helpful gut microbes keep us healthy.
And fibre is just one of the many nutrients that plants offer. Enjoying a broad ‘rainbow’ of plant foods helps your gut microbiome thrive and supports your overall health.
Why a rainbow? Inside fruits and vegetables are naturally occurring chemicals called polyphenols. These ‘phytochemicals’ give plant foods their vibrant hue. They also have antioxidant and anti-inflammatory properties, and they help keep the population of bacteria in your gut balanced and working well. When your microbiome is well-balanced, it’s generating the right amount of SCFAs.
Rather than designing a ‘perfect’ diet, aim for small, regular changes along the way. And to support your gut health, it’s important to stay hydrated, well-rested and physically active.
Find 20 science-backed strategies for better sleep.
Summary
SCFAs are small molecules that support our gut health and overall health in many ways. They’re produced when gut bacteria ferment nutrients, such as fibre, from our diets. Eating a wide range of plant foods helps optimise the production of SCFAs and the diversity of the gut microbiome.
If you’re looking to support your gut health by encouraging SCFA production, it’s important to make small, gradual changes. Pay attention to how much fibre your body can tolerate and remember that consistency matters more than intensity.
Just as SCFAs are tiny but powerful contributors to your health, small tweaks to your diet can have significant benefits over time.
To learn more about other gut health topics, visit Symprove’s Gut Hub.
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