Researchers in Sweden have identified differences in the make-up of gut bacteria in babies who did and didn’t develop type 1 diabetes in later life. The findings raise questions about the potential of using gut bacteria to identify children who have a higher risk of developing type 1 diabetes, and of altering it to help prevent the condition.
Type 1 diabetes develops when the immune system misfires and destroys the cells in the pancreas that make insulin. But we don’t fully understand what causes the immune system to attack.
Type 1 diabetes and our environment
We know that the risk of type 1 diabetes starts with our genes and our environment then plays a role, in combination with these genes. The trillions of bacteria, viruses and fungi that live inside our gut, known as the gut microbiome, is one of the possible environmental triggers that scientists have been investigating.
Our environment, including diet early on in childhood, use of antibiotics and breastfeeding, influences how the gut microbiome develops and how diverse it is.
Some research has suggested that the gut microbiome could play a role in the development of type 1 diabetes, with previous studies showing that the microbiome in children with type 1 diabetes is different compared to children who don’t have diabetes.
To find out more, researchers used stool samples to measure the types and levels of gut bacteria in 284 1-year old babies. They followed the children over the next 20 years, during which 16 babies went on to develop type 1 diabetes. They compared their gut bacteria with a group of 32 babies who had not developed type 1 diabetes during the study period.
The findings
They discovered that babies who went on to be diagnosed with type 1 diabetes had a different mix and levels of certain gut bacteria compared to those who didn't develop type 1. For example, the researchers found higher numbers of bacteria linked with inflammation and the immune ‘attack’ response.
They also found fewer types of bacteria that help the immune system to work as it should and help our bodies to break down sugars, compared to the group without diabetes.
Co-lead researcher Dr Malin Belteky, from Crown Princess Victoria’s Children’s Hospital, Sweden, said:
“This discovery could be used to help identity infants at highest risk of developing type 1 diabetes before or during the first stage of disease and could offer the opportunity to bolster a healthy gut microbiome to prevent the disease from becoming established.”
The guts of type 1 diabetes prevention
These findings prompt questions about whether sampling gut bacteria might be a new way to spot those at increased risk of the type 1 diabetes, and if treatments to change the make-up of the gut microbiome might help to prevent the condition. But we need to keep in mind that this was a small study, and it doesn’t give us firm answers.
While the findings point to variations in the gut microbiome between those who did and didn’t develop type 1 diabetes, the study does not show that these differences cause type 1 diabetes. The individual importance of gut bacteria in the development of type 1 diabetes, or in combination with other factors in our environment, is still unclear.
As this study only took place in Sweden, we also don’t know if the findings apply to other parts of the world, where differences in environments can mean gut microbiomes vary widely across different populations.
The researchers also only followed people until they were 20 years old. We know a type 1 diabetes diagnosis is just as common in adults as in children, and it’s possible that some of those included in the comparison ‘without diabetes’ group could go on to develop type 1 diabetes further down the line, and this could alter the findings.
We now need larger, longer-term studies to replicate the results in more diverse populations to understand if gut bacteria could be used to predict risk of type 1 diabetes.
Take part in type 1 diabetes risk research
While research into the gut microbiome continues, we already know that screening for early warning signals made by the immune system – called autoantibodies – is an effective way to identify children at high risk of developing type 1 diabetes.
Our ELSA study, co-funded with JDRF, is recruiting children aged 3-13 years to take part and get tested for autoantibodies with a simple finger-prick blood test. Find out more and sign up on the ELSA website.
