Common food additive may increase gut inflammation and diabetes risk

Carrageenan, a common food additive (E 407) used as a thickener and stabilizer in processed foods, has been linked to gut inflammation, ulcers, and increased blood sugar levels in animals. However, its impact on human health, particularly in relation to type 2 diabetes, has been unclear.

A new study, led by researchers from the German Center for Diabetes Research (DZD) and published in BMC Medicine, has now provided clinical evidence that carrageenan may weaken the gut barrier and contribute to metabolic changes.

How Carrageenan Affects the Gut

In the study, 20 young, healthy men with a BMI below 30 kg/m² (average BMI 24.5 kg/m²) were divided into two groups. One group consumed carrageenan in amounts equivalent to two to three times the average daily intake in the U.S., while the other received a placebo. The participants followed their usual diets, and the study lasted two weeks.

Results showed that carrageenan increased the permeability of the small intestine, likely due to gut inflammation. This means that the protective lining of the gut became weaker, allowing more harmful substances to pass into the bloodstream.

“Our investigation suggests that carrageenan, similar to what has been observed in animal studies, can impair the barrier function of the intestine,” explains Prof. Robert Wagner, one of the study’s lead researchers. “This could have long-term health consequences and increase the risk of inflammatory diseases.”

Potential Impact on Insulin Sensitivity

The study also looked at insulin sensitivity, which measures how effectively insulin regulates blood sugar. While the overall insulin response did not significantly change in the study participants, some important patterns emerged:

Participants with higher body weight showed a reduction in insulin effectiveness, particularly in the liver.
Overweight participants also had increased inflammation markers in their blood, suggesting a possible link between carrageenan and metabolic changes.
Signs of inflammation were observed in the hypothalamus, the brain region responsible for controlling sugar metabolism and appetite.

These findings suggest that people with higher body weight may be more vulnerable to the negative effects of carrageenan, especially in terms of insulin function and inflammation.

More Research Needed

Despite these concerning results, the study was conducted on young, healthy individuals who may not have been at high risk for significant metabolic effects.

“Our subjects were probably still too healthy to show strong metabolic effects from carrageenan,” explains Prof. Norbert Stefan, co-author of the study. “However, in older or overweight individuals, the effects could be stronger. To confirm this, further studies in these population groups are necessary.”

Should We Be Concerned About Carrageenan?

Carrageenan is widely used in processed foods such as dairy products, plant-based milk alternatives, sauces, and processed meats. While regulatory agencies consider it safe for consumption, this study raises questions about its long-term impact on gut health and metabolism.

Prof. Wagner emphasizes the importance of further research:
“Given the widespread use of carrageenan in foods, potential health risks should be taken seriously. It’s important that we understand how food additives can affect our health in order to make informed recommendations to the public.”

For now, while more research is needed, people—especially those with metabolic conditions or higher body weight—may want to be mindful of their carrageenan intake and choose whole, minimally processed foods when possible.

The research findings can be found in BMC Medicine.