How are breastfeeding and gut bacteria linked in type 1 diabetes?

Posted on 25 October 2018


Breastfeeding has a significant effect on gut bacteria and may help protect people from developing type 1 diabetes in childhood, a new study suggests.

At this stage however, it is too early to say whether breastfeeding does indeed protect against type 1 diabetes and there is no evidence to suggest cow’s milk or formula increases the risk of type 1 diabetes.

It is also too early to say whether breastfeeding plays any role in protecting against type 1 diabetes.

The point of this research is to look at what factors may influence the production of gut bacteria and the role of gut bacteria in auto-immunity protection. If it turns out that there is a difference in the development of a ‘protective’ microbiome between breastfed and formula-fed babies, it may be that a supplement can be developed to give all babies that same protection, however they are fed.

The results come from two studies that analysed gut bacteria in hundreds of babies at high genetic risk of type 1 diabetes. Previous research has suggested that gut bacteria may play a role in type 1 diabetes, but until now, no large studies have been carried out to investigate changes in gut bacteria from early childhood.

The researchers carried out these studies as part of the TEDDY programme, which stands for The Environmental Determinants of Diabetes in the Young – an international study tracking thousands of babies at high genetic risk of type 1 diabetes. The aim is to see if there are patterns as to who develops type 1 diabetes and who doesn’t, in order to point towards potential triggers for the condition.

The TEDDY data shows that the difference between the breastfed babies and the formula-fed babies is unlikely to be explained by random variations, so something is happening with the immune system. It isn’t straightforward though – given that many people who later develop type 1 were breastfed and many people who do not develop type 1 had formula.

Rachel Connor, Director of Research Partnerships at JDRF in the UK, said:

“These studies found some interesting changes to patterns of gut bacteria development in early childhood. But the relationship between gut bacteria, genetics and type 1 diabetes risk is still a complicated picture.

“We will need to carry out more research to work out how exactly factors like breastfeeding and may be able to affect the risk of developing type 1 diabetes, and how strong these effects may be.”

What did they do?

One study looked at the changes in gut bacteria from shortly after birth until diagnosis. The other study compared differences in gut bacteria between children who developed type 1 diabetes and those who didn’t. These studies were partly funded by JDRF.

Over 900 children at genetic risk of type 1 diabetes took part in these two studies. The team collected stool samples every month from the age of three months until the children developed type 1 diabetes or the stage just before, when researchers were able to detect autoantibodies, meaning that the autoimmune process at the heart of type 1 diabetes had already begun.

The researchers then analysed the samples to see what kinds of bacteria were present, and whether that was linked to factors such as how the children were born, whether they were breast-fed, and the presence of siblings and pets.

What did they find?

One study found that there are three main phases as gut bacteria communities develop in children. The development of these gut bacteria communities and the transition between the phases is particularly affected by breast milk, vaginal birth, siblings and pets, although there appeared to be no real link between gut bacteria stability and onset of type 1 diabetes.

The second study found that the gut bacteria of children who didn’t develop type 1 diabetes and children who had been breast-fed had more genes related to the production of a particular type of molecule. Researchers have previously found that greater levels of these molecules – known as short-chain fatty acids – protect mice models from developing type 1 diabetes.

In their paper, the researchers said that their findings support previous work on the protective effect of short-chain fatty acids.

In addition, the children in the study were largely white and genetically predisposed to type 1 diabetes, and so the researchers have highlighted in their papers that these findings may not reflect gut bacteria changes in all children.

What does this mean for type 1 diabetes?

Any factor  uncovered through high quality research studies may help us understand how to make life better for people living with type 1 today, and those who may be at risk of developing the condition in the future.

If you would like to find out about the range of research we are conducting in the UK please find the link here. You can find out more about our global research and impact here.

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