When food is limited, stress hormones tell our immune system to conserve energy. Research from Weill Cornell Medicine highlights this survival mechanism. Senior author Dr. Nicholas Collins notes that both famine and disease have always coexisted throughout human history. Yet, we still don’t fully understand how nutrition impacts our immune responses.
This is crucial, especially for the 47 million Americans who experience food insecurity daily, making them more susceptible to infections. Dr. Collins explains, “Mounting an immune response requires a lot of energy. Our findings reveal a system that modifies immune function to help survive during these tough times.”
A study published on February 10 in Immunity found that mice on a low-calorie diet managed to fight infections as effectively as those on a regular diet. Remarkably, these calorie-restricted mice used less glucose, thanks to glucocorticoids, stress hormones that play a critical role in regulating energy and immune response.
The team experimented with mice on a 50% calorie-restricted diet and exposed them to gut bacteria. Surprisingly, the well-fed mice suffered more, losing both weight and glucose levels. However, the calorie-restricted mice maintained a strong immune response without depleting their energy resources.
Dr. Collins and his colleagues discovered a shift in immune cells. While T cells—key players in targeting infections—were lower in calorie-restricted mice, neutrophils, the body’s first responders to infection, increased. These neutrophils operated in a low-energy mode, which allowed the mice to fend off infection without crashing from low glucose levels. “This hormone rewires the immune system to fight infections while preserving energy,” Dr. Collins says.
The research also reveals how low food intake boosts glucocorticoid levels, leading to critical changes. It shifts immune function from energy-hungry T cells to more abundant neutrophils. This adaptation not only addresses current infections but prepares the immune system for future threats by preserving memory T cells.
Dr. Collins mentions that these findings might extend beyond nutrition. Other forms of stress could also trigger similar immune adaptations. The team plans to further study the failures that can occur with severe calorie restriction. They want to understand why the immune system collapses under extreme malnutrition, a condition that could worsen infection rates among vulnerable groups.
This research is supported by various institutions, including the National Institutes of Health. For more information, you can explore their detailed findings here. Understanding these processes helps inform better strategies to fight infections and malnutrition, ensuring healthier futures for those in need.
