Science Daily reported on a study today that suggests homocysteine, an amino acid linked to heart attack, stroke and dementia, may also be a player in retinal damage and vision loss. Although the writer's explaination of methionine metabolism is way too simplistic, we will present the material just as they did in Science Daily.
....The study leader, Dr. Sylvis Smith of the Medical College of Georgia, explained that homocysteine levels rise when folic acid levels drop, a problem for many whose diets are poor in folate-rich fruits, tomatoes, vegetables and grains. Smith exposed layers of retina to high levels of homocysteine and found the retina "terribly disrupted."
"Folate and vitamin B12 convert homocysteine to methionine, an amino acid essential to protein synthesis. Without the conversion, rising homocysteine levels interfere with the folding and structure of collagen, a component of bone, tissue and the basement membrane of blood vessel walls," Smith said.
"At any point in your life, too much homocysteine can be problematic, whether you are talking about pregnant women, cardiovascular disease or dementia," Smith says in a statement. "If homocysteine is not converted into methionine or cysteine -- by vitamin B6 -- to aid protein synthesis, it can do something bad."