Being obese can actually save your life during a severe lung infection because of a hormone made in your gut.
April 14, 2026
Original Paper
Inhibition of Alveolar Macrophage Ferroptosis by Gut Produced Serotonin Accounts for the Obesity Paradox in ARDS
SSRN · 6556559
AI-generated illustration
The Takeaway
Diet-driven serotonin from the gut travels to the lungs to prevent the death of critical immune cells during respiratory failure. This explains the 'obesity paradox,' where patients with a high BMI have a weirdly high survival rate in intensive care.
From the abstract
Acute respiratory distress syndrome (ARDS) accounts for 75,000 deaths annually in the US, a burden made larger by the Covid-19 pandemic. Although obesity increases ARDS risk, many overweight and obese individuals counterintuitively experience better clinical outcomes than normal-weight counterparts. This poorly understood and unexplained phenomenon termed the “obesity paradox”, was also observed in other life-threatening illnesses. Here we show that obese male mice challenged with SARS-CoV-2 or