People who consume a diet high in saturated fats are more likely to experience lung inflammation when obesity is a factor and even when it is not. The study, “Dietary Saturated Fatty Acids Promote Lung Myeloid Cell Inflammasome Activation and IL-1β–Mediated Inflammation in Mice and Humans,” was recently published in Science Translational Medicine.
The research, conducted on both mice and human samples, sheds new light on how specific dietary components influence immune cell behavior in the lungs and may worsen respiratory conditions like asthma.
Researchers from Children’s Hospital of Philadelphia found that high-fat diets lead to the accumulation of saturated long-chain fatty acids, particularly stearic acid (SA), in lung-resident tissue macrophages and monocytes (RTMs). These immune cells showed signs of NLRP3 inflammasome activation — a process known to drive inflammation.
The study found:
- Stearic acid promotes neutrophil-dominant lung inflammation and worsens airway inflammation.
- Oleic acid, a monounsaturated fat, reduces inflammasome activation and alleviates lung inflammation.
According to researchers, the study demonstrated that the inflammation caused by stearic acid could be mitigated by either depleting interleukin-1β (IL-1β), a key inflammatory cytokine, or inhibiting the enzyme IRE1α, which plays a role in cellular stress responses.
Additionally, researchers identified a population of activated lung monocytes in obese individuals with asthma that mirrored the inflammatory profile seen in mice who were fed high-fat diets. This suggests a direct link between dietary fat composition and respiratory health in humans.
Although obesity has long been associated with increased inflammation, this study highlights that the type of fat consumed may be just as critical. Saturated fats like stearic acid can independently prime immune cells in the lungs for heightened inflammatory responses, potentially exacerbating conditions such as asthma.
The study’s authors noted that their findings open the door to dietary interventions as part of asthma and lung disease management, especially in obese patients. They encouraged future research to explore how modifying fat intake — favoring monounsaturated fats over saturated ones — could reduce lung inflammation and improve outcomes in respiratory diseases.
