Extra glycine raised type II collagen production by cartilage cells by 60 to 75%
This 2018 lab study grew cartilage cells from cattle in a range of glycine, proline and lysine levels, the amino acids collagen needs most. Proline and lysine boosted type II collagen at low levels, but the effect faded. Glycine from 1.0 mM upwards raised it by 60 to 75%, and the effect lasted longer.
What they did
Researchers grew chondrocytes, the cells inside cartilage, taken from the joints of steers (castrated male cattle) obtained from an abattoir. They varied the amounts of glycine, proline and lysine in the culture medium over a wide range, and measured type II collagen, the main collagen in cartilage, every 48 hours for 15 days.
What they found
Raising proline and lysine increased type II collagen production at low concentrations, but the effect faded before 1.0 mM. Raising glycine from 1.0 mM upwards produced a larger increase, of 60 to 75%, that persisted for longer.
The authors argue that because glycine's effect appeared only at concentrations well above normal body levels, cartilage cells are severely short of glycine for making collagen. They suggest more dietary glycine might help cartilage rebuild collagen.
What it can't tell us
These were cow cells in a dish, not cartilage in a person. The glycine levels that worked were higher than normal body levels, and the study did not test whether eating more glycine raises glycine inside human cartilage. The link to osteoarthritis is the authors' interpretation. The study did not measure glutathione.
The senior author's research institute has applied for a patent on using glycine for osteoarthritis, as declared in the paper.
Why it matters
Glycine is one of the three building blocks of glutathione, and, as the authors note, collagen needs it in large amounts. This study shows that cartilage cells can use more glycine than they normally get for collagen alone. That matters for glutathione because the same cells draw on the same glycine supply for both jobs.
The paper
- 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.