Oxtail soup (gelatin)

“In the tradional diet, rather than just eating muscle meats, all the animal parts were used. Since collagen makes up about 50% of the protein in an animal, and is free of tryptophan, this means that peoole were getting aoout half as much tryptophan in proportion to other amino acids when they used foods such as “head cheese” oxtails, and chicken feet."

“A recent publication shows that glycine alleviates colitis; but the use of gelatin, especially in the form of a concentrated gelatinous beef broth, for colitis, dysentery, ulcers, celiac disease, and other diseases of the digestive system, goes far back in medical history. Pavlov’s observation of its effectiveness in stimulating the secretion of digestive juices occurred because the stimulating value of broth was already recognized”

“The simplest, nonessential, amino acid, glycine, has been found to protect against carcinogenesis, inflammation, fibrosis, neurological damage, shock, asthma and hypertension. Increased glycine improves learning, glycine antagonists usually impair it. Its antitoxic anc cytoprotective actions are remarkable. Collagen, besides being free of tryptophan, contains a large amount of glycine–32% of its amino acic units, 22% of its weight.” - Ray Peat