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Eat more fibre, even if it comes from supplements, your gut microbes will thank you © Getty Images
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Our gut microbiomes aren't getting enough fibre, but supplements can help study finds

Published: 03rd August, 2022 at 17:29
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Modern low-fibre diets are thought to have a negative impact on our health and could increase the risk of cardiovascular disease, digestive disorders and colon cancer.

Current NHS guidelines state that an average adult should aim to consume around 30g of dietary fibre a day. However, recent figures released by the British Dietetic Association suggest that UK adults are eating just 18g a day.


This is bad news, as not getting enough fibre in our diets can have a negative impact on our health and could increase the risk of cardiovascular disease, digestive disorders and colon cancer.

Of course, the most straightforward way to address this would be to simply eat more fibre as a natural part of our diets. But in today’s world of fast food, ready meals and sugary desserts, some of us find this difficult.

Now, a study carried out at Duke University in the US has found that taking dietary fibre supplements may help to make up the shortfall. And what’s more, it appears that any type of supplement will do the trick.

When we consume a high-fibre diet, the organisms that make up our gut microbiome produce fatty acids that protect us from digestive diseases, obesity and colorectal cancer. One particular fatty acid, butyrate, has been shown to improve the gut’s resistance to disease, lower inflammation and improve the health of cells lining the intestine.

“We’ve evolved to depend on nutrients that our microbiomes produce for us,” said study co-author Zack Holmes, a former PhD student at Duke.

“But with recent shifts in diet away from fibre-rich foods, we’ve stopped feeding our microbes what they need.”

The team split 28 participants into groups and gave them one of three types of commonly available fibre supplements - inulin, dextrin and galactooligosaccharides - for one week in different orders.

On the first day of each week the participants were given 4.5g of inulin or dextrin or 1.8 g of galactooligosaccharides to let their guts get accustomed to the new fibre intake. The dose was then doubled in each case for the rest of the week.

After each week-long course, they gave the participants a week off to allow their guts to return to their normal state.

Participants who were already consuming a high-fibre diet saw little change in their gut microbiomes. However, participants who had been consuming the least fibre saw a significant increase in butyrate, regardless of which supplement was being consumed.

“We didn’t see a lot of difference between the fibre supplements we tested. Rather, they looked interchangeable,” said study leader Lawrence David, an associate professor of molecular genetics and microbiology at Duke University.

“Regardless of which of the test supplements you pick, it seems your microbiome will thank you with more butyrate.”

Read more about the gut microbiome:



Jason Goodyer
Jason GoodyerCommissioning editor, BBC Science Focus

Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.


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