A sugar molecule found in beef and lamb was tied to a 63% higher risk of type 2 diabetes in a French study of 89,953 adults. The adults who ate the most of the molecule, called Neu5Gc, were compared with those who ate the least, and the gap showed up over a median follow-up of 7.2 years and 966 new diabetes cases. The researchers stress that the findings are preliminary, observational and not yet validated.
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What Neu5Gc is and where it comes from
Neu5Gc is short for N-glycolylneuraminic acid. Most mammals make it, but humans cannot, because of a mutation in the CMAH gene. People get it from food, chiefly beef and lamb. In the analysis, red meat also included pork, rabbit, goat and game, processed meats such as bacon and sausages were counted separately, and dairy contains smaller amounts. According to the ScienceDaily release on the study, the work was presented by Dr. Leopold Fezeu of Université Sorbonne Paris Nord in Bobigny, France, at the annual meeting of the European Association for the Study of Diabetes in Milan.
The proposed mechanism is immunological. Fezeu and colleagues suggest that Neu5Gc absorbed into body tissues may be treated by the immune system as foreign, prompting antibodies against it and a prolonged immune response sometimes called xenosialitis, which earlier research has linked to cardiovascular disease and cancer. Fezeu said the findings support chronic inflammation as a specific mechanism connecting red meat with type 2 diabetes. The researchers describe the idea as unconfirmed, and they say they do not know which Neu5Gc levels would trigger such a response.
NutriNet-Santé: 89,953 adults and a 63% gap
The data come from NutriNet-Santé, a large French study of diet, lifestyle and health. The 89,953 participants had an average age of 42, and 79% were women. None had type 2 diabetes or cancer when they joined. Each completed three 24-hour dietary records, which the team matched against a validated food database to estimate Neu5Gc intake. Participants were then ranked by sex into five equal groups by intake, with the lowest group as the reference.
In results adjusted for age, sex, physical activity, overall diet quality, smoking and existing conditions, the second-highest group had a hazard ratio of 1.41, or 41% higher risk. The highest group had a hazard ratio of 1.63, which is the 63% figure, with a confidence interval of 1.29 to 2.06. The lower three groups showed no significant difference from the reference group. Dairy-derived Neu5Gc was not associated with higher risk, while all sources combined produced a 37% higher risk in the top group that was driven mainly by meat.
Median red meat intake in the top group was 136 grams a day for men and 96 grams for women when processed meat is included, against 21 and 9 grams in the lowest group, as ThePrint’s coverage of the EASD presentation reported. The researchers say these figures do not indicate a safe or risky amount.
Red meat as a confounder limits the finding
The strongest caveat is that Neu5Gc and red meat travel together. When the researchers adjusted for total red meat intake, the Neu5Gc association weakened to non-significance, although its direction stayed the same. That means the study cannot separate the molecule from everything else in red meat. Fezeu acknowledged as much, saying there may be differences between sources, or other components of red meat may contribute. Heme iron is one candidate the team wants to study.
Obesity explained about 13% of the association, which weakened after adjustment for body mass index but stayed significant. The design cannot establish causation. Intake came from food records rather than a direct measurement of Neu5Gc in the body, dietary changes during follow-up were not accounted for, and unmeasured lifestyle or social influences could still bias the result. The cohort was also mostly women and relatively young. Fezeu called the strong association between meat-derived Neu5Gc and type 2 diabetes risk an important finding in ThePrint’s reporting, and ThePrint noted that it carried no independent expert comment.
Red meat and diabetes: what earlier studies found
The new result sits next to a larger body of work on red meat. A 2023 study in The American Journal of Clinical Nutrition, led by Xiao Gu and Walter Willett of the Harvard T.H. Chan School of Public Health, followed 216,695 participants and reported that people who ate the most red meat had a 62% higher risk of type 2 diabetes than those who ate the least, as ScienceDaily summarized it. Each extra daily serving of processed red meat was linked to a 46% higher risk, and of unprocessed red meat to 24%.
The Neu5Gc study asks a narrower question: whether one molecule might help explain such results. ScienceDaily has also covered related red meat work on heart disease and gut microbes and on red meat and the brain, none of which settles the question for diabetes.
Next steps named by the team are direct measurement of anti-Neu5Gc antibodies in large cohorts, tests of interactions with other red meat components such as heme iron, and trials of whether swapping beef and lamb for poultry or plant proteins lowers diabetes risk.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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