Scientists link a strange sugar in red meat to a 63% higher diabetes risk

The sugar, known as N-glycolylneuraminic acid (Neu5Gc), is particularly common in beef and lamb. Researchers found that participants with the highest intake of meat-derived Neu5Gc had a 63% higher risk of developing type 2 diabetes (T2D) compared with those who consumed the least.

The association remained statistically significant after researchers accounted for several established diabetes risk factors, including physical activity, overall diet, smoking, and existing health conditions. It became weaker after body mass index (BMI) was also considered, but remained significant.

The findings were presented at the Annual Meeting of The European Association for the Study of Diabetes (EASD) in Milan, Italy.

“Our findings support chronic inflammation as a specific mechanism linking red meat consumption with T2D, partly beyond the amount of red meat a person eats and partly independent of body fat,” said lead author Dr. Leopold Fezeu from the Université Sorbonne Paris Nord, Bobigny, France.

The researchers also observed that diabetes risk generally increased with greater consumption of meat-derived Neu5Gc, particularly among those with the highest exposure.

“Although we do not know exactly what levels of Neu5Gc trigger an immune response, our data suggest that higher intakes of meat-derived Neu5Gc are associated with a progressively higher risk of T2D.”

Why a Sugar in Red Meat May Trigger Inflammation

Neu5Gc is produced naturally by most mammals, but humans lost the ability to make it following an ancient mutation in the CMAH gene. Despite this evolutionary change, the sugar can still enter the human body through food.

It occurs in red meat (particularly beef and lamb), with smaller amounts also found in dairy products.

After Neu5Gc is consumed, the body absorbs it and can incorporate it into human tissues. Because humans do not naturally produce the molecule, the immune system may recognize it as foreign. Scientists classify it as a xeno-autoantigen, a foreign substance that becomes incorporated into the body’s own tissues and can provoke an immune reaction.

In response, the immune system produces antibodies against Neu5Gc. The resulting prolonged immune activity, called xenosialitis (xenosialitis), has previously been associated with cardiovascular disease and cancer.

Researchers suspect that this persistent inflammatory response could also contribute to type 2 diabetes. However, before this investigation, no large prospective study had examined whether dietary Neu5Gc might promote diabetes through chronic inflammation.

Nearly 90,000 Adults Studied Over Several Years

To investigate the possible connection, the scientists analyzed dietary and health information from 89,953 adults participating in NutriNet-Santé, a large French observational study that follows people over time to examine how nutrition and lifestyle influence health.

Participants were 42 years old on average, and 79% were women. None had type 2 diabetes or cancer when they entered the study.

Each person completed three 24-hour dietary records. The research team then used a validated food database to calculate how much Neu5Gc participants were likely consuming based on the measured amounts of the sugar in different foods.

The analysis included a broad range of red meats, such as beef, lamb, pork, rabbit, goat, and game. Processed meats (such as bacon, sausages and cured meats) were evaluated as a separate category, while dairy products were analyzed independently.

Using the dietary information, the researchers estimated total Neu5Gc intake from all reported foods. They then ranked participants separately by sex according to their intake of meat-derived Neu5Gc and divided them into five equally sized groups (quintiles).

Diabetes risk was compared across these groups, using those with the lowest intake as the reference.

During a median follow-up period of 7.2 years, researchers recorded 966 new cases of type 2 diabetes.

Higher Red Meat Sugar Intake Linked to 63% Greater Diabetes Risk

The results showed a significant relationship between meat-derived Neu5Gc consumption and the likelihood of developing type 2 diabetes. The association became particularly pronounced among participants with the highest estimated intake.

Compared with the lowest intake group, individuals in the highest group had a 63% greater risk of developing the disease. Those in the second-highest group had a 41% greater risk (men and women combined).

These estimates accounted for potentially influential factors, including age, sex, exercise habits, overall dietary quality, smoking, and existing medical conditions.

The researchers also examined how much meat participants typically consumed.

Among men in the highest Neu5Gc intake group, median red meat consumption was 97 grams daily (136 g including processed meat). For women, the corresponding amount was 73 grams (96 g).

By comparison, men in the lowest intake group consumed a median of just 5 grams of red meat per day (21 g), while women consumed 0 grams (9 g).

The relationship between Neu5Gc and diabetes was observed in both sexes, with no statistically significant evidence that it differed between men and women (see tables in notes to editors).

The findings were also consistent when differences in total calorie intake were considered.

Researchers noticed that the increase in diabetes risk was especially steep at higher levels of Neu5Gc exposure. One possible explanation is that the immune system begins to respond more strongly after enough of the foreign sugar has accumulated in body tissues, although this proposed threshold mechanism has not been confirmed.

Importantly, when the analysis additionally accounted for the total amount of red meat consumed, the relationship between Neu5Gc and diabetes weakened and was no longer statistically significant. The direction of the association remained the same, however.

This means the researchers cannot determine whether Neu5Gc itself (rather than other components of red meat) is responsible for the increased risk. The findings suggest it could contribute to the relationship, but they do not establish that the sugar acts independently of red meat consumption.

Diabetes Risk May Extend Beyond Weight Gain

Another notable finding was that obesity appeared to explain only a relatively small portion of the association.

According to the researchers’ estimates, obesity accounted for approximately 13% of the relationship between meat-derived Neu5Gc consumption and type 2 diabetes.

This suggests that factors unrelated to excess body weight may contribute substantially to the observed connection.

One possibility is that immune reactions to Neu5Gc produce chronic inflammation that interferes with insulin-producing cells or tissues that normally respond to insulin. Such effects could potentially increase the likelihood of developing type 2 diabetes even without substantial weight gain.

However, additional studies are necessary to establish whether these inflammatory processes actually explain the association.

Why Dairy Products Showed Different Results

Although Neu5Gc occurs in both red meat and dairy products, the researchers found an important difference between these dietary sources.

Higher consumption of Neu5Gc from dairy products was not associated with an increased risk of type 2 diabetes.

This finding may reflect the relatively small amounts of Neu5Gc in cow’s milk compared with red meats such as beef and lamb. The typically smaller amounts of Neu5Gc consumed through dairy servings may also contribute to the difference.

When the scientists considered Neu5Gc intake from all dietary sources combined, participants in the highest intake group had a 37% greater risk of developing type 2 diabetes compared with those in the lowest group.

That association appeared to be driven primarily by Neu5Gc obtained from red meat.

“Together, these findings suggest that the association between Neu5Gc and T2D may depend on its dietary source, with meat-derived Neu5Gc showing a stronger association with T2D risk than total dietary Neu5Gc,” said Dr. Fezeu. “There may be differences between sources, or other components of red meat may contribute.”

Could Changing Protein Sources Lower Diabetes Risk?

The findings raise the possibility that reducing dietary exposure to meat-derived Neu5Gc could eventually become one approach to lowering diabetes risk.

However, researchers emphasize that studies are still needed to determine whether replacing foods rich in Neu5Gc with other protein sources would actually produce measurable health benefits.

“Given how common red meat is in Western diets, the strong association between meat-derived Neu5Gc and T2D risk is an important finding. Future research should explore whether reducing exposure to meat-derived Neu5Gc, for example by favoring poultry or plant-based proteins over beef and lamb, which have the highest Neu5Gc content, could help prevent T2D. Studies directly measuring anti-Neu5Gc antibodies in large cohorts would also help to directly test the xenosialitis mechanism in humans.”

The research team plans to investigate how Neu5Gc interacts with other substances found in red meat, including heme iron (a form of dietary iron), and how these components may collectively relate to diabetes risk.

They also intend to measure antibodies against Neu5Gc directly. Doing so could help determine whether the proposed immune response is an important biological mechanism connecting red meat consumption with type 2 diabetes.

Important Limitations of the Findings

The researchers caution that their findings are preliminary and have not yet been validated. The reported estimates could change once the final analysis is completed.

Because the study was observational, it cannot establish that Neu5Gc causes type 2 diabetes or identify precisely which factors are responsible for the higher risk.

Although the analysis accounted for several established diabetes risk factors, unmeasured lifestyle and social influences could still have affected the results.

There were also limitations in how dietary exposure was assessed. Neu5Gc consumption was estimated using participants’ food records rather than measured directly, and the researchers did not account for possible dietary changes during the follow-up period. Both factors could have introduced errors into the exposure estimates.

The findings therefore offer a potential new explanation for the established connection between red meat consumption and diabetes, but further investigation is needed to determine whether Neu5Gc directly contributes to the disease.

Table 1. Median Meat Consumption by Neu5Gc Intake

The table shows typical daily meat consumption in each of the five groups, ranked according to estimated intake of meat-derived Neu5Gc.

Participants were assigned to these groups based on their estimated Neu5Gc intake, calculated from all reported foods and their measured Neu5Gc content.

The meat consumption figures represent the typical amounts eaten by participants in each group. They do not establish a specific risk threshold or indicate how much meat can be considered safe.

Table 2. Type 2 Diabetes Risk by Neu5Gc Intake

Results for men and women combined, using the fully adjusted statistical model.

The results suggest a similar association in men and women, without a statistically significant difference between the sexes.

However, relatively few diabetes cases occurred within each sex-specific intake group, making the separate estimates less precise. For this reason, the researchers presented their principal findings using the combined data.