Animal trials hint that short-chain fatty acids produced by a fibre-rich diet could protect against early-onset diabetes
Scientists have raised hope for the prevention of early-onset diabetes in children after a fibre-rich diet was found to protect animals from the disease.
More than 20 million people worldwide are affected by juvenile, or type 1, diabetes, which takes hold when the immune system turns on the body and destroys pancreatic cells that make the hormone insulin.
It is unclear what causes the immune system to malfunction, but patients are usually diagnosed with type 1 diabetes before the age of 14 and must have daily shots of insulin to control their blood sugar levels.
Working with Australias national science agency, CSIRO, researchers at Monash University in Melbourne created a diet rich in fibre that is broken down in the lower intestine into molecules known as short-chain fatty acids.
The team, led by immunologist Charles Mackay, believe that short-chain fatty acids called butyrate and acetate dampen down the immune system, and have the potential to treat a range of disorders from asthma to irritable bowel syndrome.
For the latest study, the scientists monitored the health of mice that were bred to develop the rodent equivalent of juvenile diabetes. On a normal diet, more than 70% of the animals had developed the condition after 30 weeks. But another group that received the high fibre diet was nearly entirely protected from the condition.
What we saw was dramatic, Mackay said. When we give the diet to mice that spontaneously develop type 1 diabetes, we could almost completely eliminate their disease.
Mackay said it was too early to know whether such medicinal foods could protect people from juvenile diabetes. There have been frustrations in the past that findings in these animals have not translated particularly well to human patients, but at other times they do, he said. But we think our study establishes the concept that we can stop a disease with natural medicinal food.
The diet is rich in a specific type of fibre that comes from a plant product called high amylose corn starch. The fibre is resistant to digestion in the upper intestine, and instead is fermented into acetate and butyrate by bacteria in the large intestine, or colon.
Tests on the mice found that acetate and butyrate may work in different ways to cool down the immune reaction that destroys pancreatic cells in type 1 diabetes. Acetate appeared to lower the number of immune cells primed to attack the pancreatic cells, while butyrate boosted other cells that dampen the immune reaction. The study is reported in the journal Nature Immunology.
Mackay now hopes to test the diet in humans. If trials show that it can slow or prevent juvenile diabetes, children could potentially have it as a powder on their meals, or dissolved in a drink.
John Cryan, professor of anatomy and neuroscience at University College Cork, said: It really reinforces the importance of diet at shaping physiology and offers potential for tailored dietary-based interventions for diabetes. It highlights how little we know about short-chain fatty acids despite them being the among the most important microbial-mediated dietary breakdown products.
But he said more work was needed on the potential side effects of diets that boost levels of short-chain fatty acids. One recent study found that in the brain, the compounds could affect immune processes that underlie Parkinsons disease. Of course, all diet studies in mice need caution as human diet, the microbiome, and their interactions, are so much more complex, he added.
Emily Burns at Diabetes UK said: We know that our immune system and gut work closely together. Understanding how the gut works in more detail could shed light on how to combat conditions that involve an immune attack, like type 1 diabetes. But theres still a lot we dont know.
The idea that a special medicinal diet could help to regulate the immune system and prevent type 1 diabetes from developing is interesting, but this research is at a very early stage. We wont know how effective this approach could be in people at risk of type 1 diabetes until research moves into human clinical trials.
What we currently know is that type 1 diabetes is not linked to diet or lifestyle and it cant be prevented. Diabetes UK is funding a great deal of research to find ways to stop the immune attack against the pancreas, in order to prevent type 1 diabetes in the future.