Inulin is a type of fiber found in many everyday foods, such as bananas, garlic, and asparagus. It’s also added to many fiber supplements and is known for its benefits to gut health and digestion. Inulin can help grow good bacteria in the gut and reduce inflammation, making it a popular choice for people trying to improve their overall health.
But a new study from researchers at Weill Cornell Medicine shows that inulin might have more complex effects on the immune system than previously thought. While it can still support health in many ways, it may also trigger a certain kind of immune reaction that’s linked to allergies and asthma.
The researchers focused on what’s called type 2 inflammation. This type of immune response is the body’s way of fighting off parasitic worm infections, but in today’s world, it can sometimes be activated for the wrong reasons—like in cases of seasonal allergies or asthma.
Although this kind of inflammation can be harmful in people with immune-related conditions, it also plays a role in repairing tissues and keeping the body balanced.
To better understand how inulin works, the research team fed mice a diet high in inulin for two weeks and compared them to another group that didn’t eat inulin.
The mice on the inulin-rich diet had more white blood cells called eosinophils in their lungs and gut—these are cells that often show up in people with allergies or asthma. This told the researchers that inulin was causing a type 2 immune response.
Digging deeper, they found that special immune cells known as group 2 innate lymphoid cells (or ILC2s) were being activated. These cells were responding to changes in the mice’s bile acids—chemicals made in the liver that help digest fats. Inulin changed the mix of bacteria in the gut, which in turn changed the bile acids.
When the researchers blocked the mice’s bile acid receptor, the inflammation disappeared. This confirmed that the immune reaction was linked to changes in gut bacteria and bile acids caused by inulin.
Interestingly, the study also showed a good side to inulin. While it increased inflammation in some cases, it also boosted the number of regulatory T cells (Tregs), which are known to calm down the immune system.
Tregs help prevent too much inflammation and play a key role in maintaining immune balance. So even though inulin can trigger certain immune responses, it also helps control them through other pathways.
This means that for most healthy people, the immune response caused by inulin may not be a problem. In fact, it could even help the body fight off parasites or heal faster. However, people with asthma, allergies, or other immune system issues may want to talk to a doctor before using inulin supplements.
The study does not say that inulin is bad. Instead, it shows that the way fiber affects our health is more complicated than we once thought. It reminds us that even natural supplements can have different effects depending on the person’s health, diet, and immune system.
The research, led by Dr. David Artis and his team, was published in the journal Nature. It opens the door for more studies on how fibers like inulin interact with the immune system, and how we might use this knowledge to develop better diets or treatments for immune-related conditions.
In the end, this study adds to our understanding of how food affects health—not just through nutrients and digestion, but through the immune system too.
If you care about lungs, please read studies about a review of COPD-friendly foods for lung health, and can Vitamin C and E help fight lung cancer.
For more health information, please see recent studies about how diet influences lung health, and these vegetables could benefit your lung health.
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