Why does glycine matter for cartilage?
Glycine is one of the three building blocks of glutathione, and it is also the most common amino acid in collagen, making up about one in every three. In cow cartilage cells, raising glycine increased type II collagen production by 60 to 75% (de Paz-Lugo 2018), and one analysis estimates the body's glycine supply may fall about 10 g a day short of its needs (Meléndez-Hevia 2009).
Two jobs in one amino acid
Glycine finishes the glutathione molecule in the second step of its synthesis (Lu 2013). It is also every third amino acid in the collagen triple helix, so cartilage cells need a great deal of it to build and maintain type II collagen.
Is there enough?
A 2009 analysis compared all reported sources and uses of glycine in an adult. The body makes about 3 g a day, mostly from serine, and the diet adds 1.5 to 3 g. That may fall about 10 g a day short of everything glycine is needed for, collagen included, which led the authors to describe glycine as semi-essential (Meléndez-Hevia 2009).
In cartilage cells
When cow cartilage cells were grown with more glycine, type II collagen production rose by 60 to 75% once glycine passed 1 mM, a stronger and longer-lasting effect than extra proline or lysine (de Paz-Lugo 2018).
In people
Older adults had lower red-cell glycine than younger adults, and supplying glycine with cysteine raised their glutathione (Sekhar 2011). L-glycine is one of the four parts of Gluthanol™.
Other questions people ask
Can't the body make its own glycine?
It can, about 3 g a day, but the 2009 analysis estimates that is not enough for all its uses (Meléndez-Hevia 2009).
Sources
- de Paz-Lugo P, Lupiáñez JA, Meléndez-Hevia E. High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis. Amino Acids 2018.
- Meléndez-Hevia E, De Paz-Lugo P, Cornish-Bowden A et al. A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis. J Biosci 2009.
- Lu SC. Glutathione synthesis. Biochim Biophys Acta 2013.
- Sekhar RV, Patel SG, Guthikonda AP et al. Deficient synthesis of glutathione underlies oxidative stress in aging and can be corrected by dietary cysteine and glycine supplementation. Am J Clin Nutr 2011.
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