DOES THE MICROBIOME AFFECT THE RISK OF DEVELOPING TYPE 1 DIABETES?
The number of people developing type 1 diabetes has increased significantly all around the world since World War II, but incidence rates (number of new cases in a year) vary amongst regions. It is most common in Northern Europe, with Finland having the highest rate in the world, with more than 60 new cases per 100,000 people per year. Surprisingly, there is a 5- to 6-fold higher incidence of type 1 diabetes in Finnish Karelia compared to Russian Karelia. Karelia is a region in Finland that crosses into Russia. The border between Finnish and Russian Karelia marks one of the sharpest boundaries in the standard of living and health in the world.
The risk factors for type 1 diabetes are still not fully known or understood and are the subject of ongoing scientific research. Environmental factors (e.g., sunlight and vitamin D production) and exposure to certain infectious diseases have been linked to the risk of developing type 1 diabetes, but the research is not conclusive. There is emerging evidence that the microbiome can affect the risk of developing type 1 diabetes in genetically susceptible individuals.
Recently, 148 infants who were at risk of developing type 1 diabetes and living in Finland and Russia were followed from birth to 3 years of age. Each month, stool samples and laboratory assays were collected, and questionnaires regarding breastfeeding, diet, allergies, infections, family history, use of medications, and clinical examinations were conducted. It was found that Finnish infants had a greater proportion of Bacteroides species, whereas the Russians had more Bifidobacterium in their stools. The nature and composition of different lipopolysaccharides derived from the respective microbiomes determined the level of immune activation in the infants. It is interesting to note that it has also been found that the injection of an immunogenic subtype of lipopolysaccharides from E. coli in to mice can decrease the incidence of diabetes. More research is needed to determine if changing the microbiome can decrease the risk of developing type 1 diabetes in susceptible humans.
The gut microbiome composition within the first year of an infant’s life is largely shaped by milk, the sole nutrient source available to infants, whether from breast- or bottle-feeding. After that, foods and drinks consumed have an increasingly large impact. Traditional Russian Karelian cuisine has been developing for centuries and incorporates a variety of local foods including fish (lake), wild mushrooms, berries and honey. Milk and dairy foods are popular, along with bread made from barley, rye or oat flour. Meat is traditionally a winter dish and is not eaten every day. Drinks include bread and turnip “kvas” (In Russian “kvas” means mildly alcoholic drink made from fermented rye bread, yeast or berries) and teas from wild raspberries and currants.
While we are unable to prevent type 1 diabetes at this point in time, research into our microbiome may help certain at-risk individuals prevent it in the future. Stay tuned.
- The emerging global epidemic of type 1 diabetes.
- Hunt for the origin of allergy – comparing the Finnish and Russian Karelia.
- Environmental risk factors for type 1 diabetes.
- The Role of the Intestinal Microbiome in Type 1 Diabetes Pathogenesis.
- The Karelia study of type 1 diabetes.
- Russian Karelian cuisine.
Alan Barclay, PhD is a consultant dietitian and chef (Cert III). He worked for Diabetes Australia (NSW) from 1998–2014 . He is author/co-author of more than 30 scientific publications, and author/co-author of The good Carbs Cookbook (Murdoch Books), Reversing Diabetes (Murdoch Books), The Low GI Diet: Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment, New York).