For centuries, naval planners simply accepted that half a crew might die at sea, and George Anson's 18th century voyage lost nearly two thirds of its men to a single disease. This episode explains what scurvy actually does to the body: a vitamin C deficiency that collapses catecholamine production, carnitine-driven energy metabolism and collagen synthesis, leading first to depression and lethargy, then to bleeding gums, lost teeth, and old scars splitting open. We also cover the broken GULO gene that leaves humans, guinea pigs and capybaras unable to make their own vitamin C.

The frustrating part is how often the cure was discovered and discarded. Jacques Cartier learned a cedar tea from the Iroquoian people in 1536, James Lancaster ran a rough lemon juice trial in 1601, and James Lind's 1747 experiment aboard HMS Salisbury proved citrus wo ...