Dietary fatty acids may lead to a severe form of asthma

September 23, 2025

Dietary fatty acids may lead to a severe form of asthma

At a Glance

In mouse models, specific dietary fatty acids affected inflammatory responses in the lungs.
Obese patients with asthma shared similar immune hallmarks.
While more study is needed, the findings suggest that dietary changes could be a potential approach to prevent a severe form of asthma.

3D illustration of a neutrophil surrounded by red blood cells.

The findings suggest that a severe form of asthma, called neutrophilic asthma, might be prevented via targeted dietary modifications.

Kateryna Kon / Shutterstock

Roughly 8% of the U.S. population has asthma. This chronic condition inflames and narrows the airways in the lungs, making it hard to breathe. Many people with asthma are triggered by allergens that inflame the airways. But other forms of asthma are associated with excess neutrophils—a type of immune cell—in the lungs. This type of asthma is often more severe and difficult to treat than allergic asthma.

Neutrophilic asthma is linked with obesity. Obesity can lead to increased inflammation throughout the body, including the lungs. But whether specific diets affect the immune system and drive chronic lung inflammation remains an open question.

A research team led by Dr. David Hill at the Children’s Hospital of Philadelphia wanted to take a closer look. They studied how diet shaped immune responses and inflammation in the lungs of mice. Results were published in Science Translational Medicine on August 27, 2025.

First, the researchers fed mice a normal or high-fat diet for 12 weeks. They found that the high-fat diet activated an inflammatory response and increased certain types of immune cells, including neutrophils, in the lungs. They also found an increase in accumulated saturated fatty acids in lung immune cells, especially stearic acid.

The researchers next fed mice a high-fat diet rich in stearic acid. After four weeks, the team found that the stearic acid diet also increased certain immune cells in the lungs. Yet the mice on the stearic acid diet didn’t gain weight compared with those on a normal diet. These results suggest that dietary fats can affect lung immune responses independent of obesity.

The team also wanted to investigate how different types of fatty acids affect lung function. Stearic acid is a saturated fatty acid. Its unsaturated counterpart is oleic acid, which is common in olive oil. In a mouse model of airway inflammation, a diet with increased stearic acid impaired lung function. But a diet with increased oleic acid was protective.

In cultured immune cells, stearic acid increased the activity of an enzyme involved in inflammation. Treating mice with a drug that blocks the activity of this enzyme reduced the inflammatory effects of the stearic acid diet.

Finally, the researchers studied lung fluid from patients who underwent a routine bronchoscopy. They found that obese patients with asthma shared immune hallmarks similar to mice fed a high-fat diet.

“Asthma is one of the most common chronic diseases in children, and different treatments may be needed depending on the subtype of asthma,” says study co-author Dr. Lisa Young. “While there are many risk factors and triggers that are associated with asthma, this study provides evidence about how specific dietary components are linked to a particularly difficult-to-treat form of asthma.”

The researchers note that because most of the results were obtained in mouse models, further studies will be needed to confirm their relevance in humans. But the findings suggest that targeted dietary modifications may help to prevent this type of asthma.

—by Karen Olsen, Ph.D.

References

McCright S, Harding O, Chini J, DeMarco N, Hung L, Pastore C, Lu W, Rabinowtiz J, Henao-Mejia J, Herbert DR, Young LR, Hill DA. Sci Transl Med 2025 Aug 27. doi: 10.1126/scitranslmed.adp5653. Online ahead of print. PMID: 40864681.

Funding

NIH’s �鶹�� Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), �鶹�� Heart, Lung, and Blood Institute (NHLBI), �鶹�� Institute of Allergy and Infectious Diseases (NIAID), �鶹�� Cancer Institute (NCI), and �鶹�� Institute of General Medical Sciences (NIGMS); American College of Allergy, Asthma, and Immunology Junior Faculty Grant; Children’s Hospital of Philadelphia Research Institute; University of Pennsylvania Michael Brown Graduate Research Fellowship; Mark Foundation for Cancer Research; Burroughs Wellcome Fund; Chan Zuckerberg Institute; PEW Charitable Trust.

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