The Forgotten Amino Acid in Slow-Cooked Foods

The expensive protein powders on the market offer an amino acid your great-grandmother got for free—from the parts of the animal nobody wanted.

Bone broth simmered for hours, fall-off-the-bone lamb shank, rich slow-cooked meats, buttery bone marrow spread onto toast—these foods weren’t delicacies; they were once regular meals. Without knowing it, generations of home cooks were providing an overlooked nutrient—glycine.