Pediatric Diabetes: Association With Particular Gut Microbacteria Interview with:
Dr. Marcus de Goffau and Dr. Hermie Harmsen
Department of Medical Microbiology
University Medical Center Groningen

MedicalResearch: What are the main findings of the study?

Dr. Marcus de Goffau: In this study we aimed at analysing the gut microbiota composition of children aged 1–5 years with new-onset type 1 diabetes with the microbiota of age-matched healthy controls with a 16S rRNA based method (HITChip). The reason for this selection is that the increase in the incidence of type 1 diabetes worldwide is particularly sharp under the age of 5 years; recent studies indicate that adverse changes in gut microbiota are associated with the development of type 1 diabetes, but little is known about the microbiota in children who have diabetes at an early age. In this study we found that the differences between healthy controls and diabetics change over time, highlighting the importance of a normal gut microbial development. Diabetic children younger than 3 years old often had lower numbers of the Clostridium clusters XIVa and IV, which contain many of the beneficial butyrate producers, than their healthy age-matched controls. The diabetic children older than 3 years have normal numbers of Clostridium clusters XIVa and IV yet not the right species composition; the ones which produce butyrate were underrepresented. The development of the microbiota of diabetic children appears to be one step behind that of healthy controls and/or appears to be going into an aberrant direction. The abundances of other bacteria such as Bacteroides and streptococci were also found to be aberrant in diabetic children.

MedicalResearch: Were any of the findings unexpected?

Dr. Marcus de Goffau: Though we expected to find an aberrant microbiota in relation to type 1 diabetes in young children we did not expect that the age of the children and the development of their microbiota would play such a crucial role.

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Marcus de Goffau: Though differences do exist between countries the combined literature on the role of the gut microbiota in relation to diabetes does seem to paint a consistent picture in which particular microbial groups are often associated with an increased risk of diabetes while other groups, in particular various butyrate producers, appear to be protective. Though gut microbial composition analyses might become a routine procedure in the future, including possible supplementation of the diet to steer the gut microbiota into a more desired direction, this is not yet a possibility.

We think there are some elements in the current western diet which might not be desirable, which include insufficient levels of dietary fibre and possibly an excess of simple (processed) sugars, protein and animal fats.

The sugars may increase streptococci, a bacterial group which is normally dominant in the small intestine (and not in the large intestine) which is extremely proficient in rapidly utilising simple sugars (hence its predominance in the small intestine). In this study a subset of the patients had elevated numbers of streptococci. Dietary patterns associated with a high consumption of protein and animal fat have been associated in other high impact studies with a high abundance of Bacteroides, which is also found to be found to be a possible risk factor in many type 1 diabetes studies.

We recommend a diet rich in fruits and vegetables (fibres/complex sugars) in order to (indirectly) stimulate butyrate producing bacteria. An apple a day might not keep diabetes away but it may help.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Dr. Marcus de Goffau: This particular study had an especially strong focus on the development of the gut microbiota. As children become older their gut microbiota changes and as such an “optimal/normal” gut microbiota is age dependent. Future gut microbiota studies involving children under the age of 3 should be very aware of the importance of this in their design/statistical analysis. In regards to type 1 diabetes, prospective studies following large cohorts of children in time in which some of the children develop T1D will likely have the greatest power in further elucidating the role of gut microbiota at a young age though their analyses will be challenging.


Aberrant gut microbiota composition at the onset of type 1 diabetes in young children

Harmsen HJM, Welling GW, Honkanen H, et al. Aberrant gut microbiota composition at the onset of type 1 diabetes in young children. Diabetologia. 2014.