Type 2 diabetes, from gut bacteria to red meat: two new clues to help spot it early
An Italian-British study has identified hundreds of bacterial species linked to the risk of the disease even before blood sugar levels change, whilst French research has linked a molecule found in red meat to a 63 per cent higher risk
Identifying those at risk of developing type 2 diabetes even before the first changes in blood glucose levels appear: this is the aim of two studies presented at the annual congress of the European Association for the Study of Diabetes (EASD), currently taking place in Milan, which focus on the gut microbiome and diet respectively.
The first, conducted by researchers from the University of Trento and the United Kingdom, analysed metagenomic data and health information from over 229,000 adults in the UK and the US, of whom 3,627 had type 2 diabetes and 14,022 had prediabetes. The researchers identified 789 gut bacterial species associated with the condition: 168 were more abundant in people with diabetes, whilst 621 were less abundant, including species that had never before been isolated or characterised. The most significant finding concerns undiagnosed individuals: by comparing the bacterial profiles of over 135,000 normoglycaemic individuals with their glucose levels in the two hours following meals, the authors observed that those with postprandial blood glucose levels higher than normal – an early sign of insulin resistance – already exhibited the bacterial profile typical of type 2 diabetes, even though their blood glucose levels were not yet abnormal.
“These findings represent a significant step forward in understanding the direct link between the gut microbiome and metabolic diseases,” explains Tim Spector, Professor of Genetic Epidemiology at King’s College London and scientific co-founder of the company Zoe. For Gabriel Baldanzi, of Cibio at the University of Trento and lead author of the study, the aim is not to replace current diagnostic tests, but to provide an additional early warning sign: ‘If we could identify changes in the gut microbiome at an early stage and show the individual that they are on the right track, this could provide strong motivation to continue with lifestyle changes.’
The second study, carried out in France on nearly 90,000 adults from the NutriNet-Santé survey, focuses instead on a possible dietary mechanism: Neu5Gc, a sugar not produced by the human body but found in red meat – particularly beef and lamb – and, to a lesser extent, in dairy products. Once absorbed, Neu5Gc is incorporated into human tissues, where the immune system recognises it as foreign, triggering low-grade chronic inflammation.
According to the analysis, led by Leopold Fezeu of the Université Sorbonne Paris Nord, those who consume more Neu5Gc from meat have a 63 per cent higher risk of developing type 2 diabetes than those who consume less, even when taking into account physical activity, diet quality, smoking and other health conditions; the association remains significant even when BMI is taken into account, and the researchers estimate that only 13 per cent of the link can be explained by obesity. By contrast, no significant association was found for Neu5Gc from dairy products, which is present in much smaller quantities.
