Studies involving people have
associated sulfur amino acids with increased body weight, metabolic syndrome, cardiovascular disease and cancer, suggesting that restricting Met and Cys could protect against these conditions.
Furthermore, substituting oxygen for
sulfur — causing oxidation — in
sulfur - containing
amino acids (including in the more rare S - adenosylmethionine) can have effects in methionine residues where the surface is exposed, causing an oxidation - reduction cycle, imparing the activity of «methionine sulfoxide reductase and the subsequent accumulation of methionine sulfoxide residues [that] are
associated with age - related diseases, neurodegeneration, and shorter lifespan.»