Dietary thiols accelerate aging of C. elegans

Glutathione (GSH) is the most abundant cellular antioxidant. As reactive oxygen species (ROS) are widely believed to promote aging and age-related diseases, and antioxidants can neutralize ROS, it follows that GSH and its precursor, N-acetyl cysteine (NAC), are among the most popular dietary supplements. However, the long- term effects of GSH or NAC on healthy animals have not been thoroughly investigated. We employed C. elegans to demonstrate that chronic administration of GSH or NAC to young or aged animals perturbs global gene expression, inhibits skn-1-mediated transcription, and accelerates aging. In contrast, limiting the consumption of dietary thiols, including those naturally derived from the microbiota, extended lifespan. Pharmacological GSH restriction activates the unfolded protein response and increases proteotoxic stress resistance in worms and human cells. It is thus advantageous for healthy individuals to avoid excessive dietary antioxidants and, instead, rely on intrinsic GSH biosynthesis, which is fine-tuned to match the cellular redox status and to promote homeostatic ROS signaling. Reactive oxygen species are required for the long lifespan, and glutathione is an antioxidant. Here the authors show that limiting the consumption of dietary thiols, including those naturally derived from the microbiota, increases proteotoxic stress resistance in worms and human cells, and extends C. elegans lifespan.

Automated summary

Restricting dietary thiols, including GSH and NAC, can extend lifespan and increase proteotoxic stress resistance in organisms. Excessive intake of dietary antioxidants like GSH may accelerate aging, and healthy individuals are better off relying on intrinsic GSH biosynthesis to promote cellular redox balance.