A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis

Meléndez-Hevia E, de Paz-Lugo P, Cornish-Bowden A, Cárdenas ML · Journal of Biosciences

Calculates that endogenous glycine synthesis (~3 g/day) plus typical dietary intake (1.5-3 g/day) falls well short of the ~10 g/day a 70 kg human needs for collagen turnover, arguing glycine is 'semi-essential'. A hypothesis paper, not an outcome study.

Population

Theoretical metabolic-flux analysis (no subjects)

Limitations

Purely theoretical stoichiometric argument; the 10 g/day requirement figure is modeled, not measured; no clinical endpoint has ever tested it.