Homocysteine and cardiovascular disease: interactions between nutrition, genetics and lifestyle.
Homocysteine is a sulfur-containing amino acid that arises during methionine metabolism. Although its concentration in plasma is only about 10 micromolar, even moderate hyperhomocysteinemia is associated with increased incidence of cardiovascular disease and Alzheimer's disease. Elevations in plasma homocysteine are commonly found as a result of vitamin deficiencies, polymorphisms of enzymes of methionine metabolism, and renal disease. Pyridoxal, folic acid, riboflavin, and Vitamin B(12) are all required for methionine metabolism, and deficiency of each of these vitamins result in elevated plasma homocysteine. A polymorphism of methylenetetrahydrofolate reductase (C677T), which is quite common in most populations with a homozygosity rate of 10-15 %, is associated with moderate hyperhomocysteinemia, especially in the context of marginal folate intake. Plasma homocysteine is inversely related to plasma creatinine in patients with renal disease. This is due to an impairment in homocysteine removal in renal disease. The role of these factors, and of modifiable lifestyle factors, in affecting methionone metabolism and in determining plasma homocysteine levels is discussed.
Brosnan
John T
JT
Biochemistry Department, Memorial University of Newfoundland, St Johns, Newfouondland.
D001361:Avitaminosis / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology* / Q000235:genetics; D003404:Creatinine / Q000097:blood; D005492:Folic Acid / Q000502:physiology; D006710:Homocysteine / Q000097:blood* / Q000502:physiology; D006801:Humans; D015994:Incidence; D007674:Kidney Diseases / Q000097:blood; D008019:Life Style; D008715:Methionine / Q000378:metabolism; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics / Q000502:physiology; D009747:Nutritional Physiological Phenomena; D011110:Polymorphism, Genetic; D011730:Pyridoxal / Q000502:physiology; D012256:Riboflavin / Q000502:physiology; D014805:Vitamin B 12 / Q000502:physiology
D006710:Homocysteine; D011730:Pyridoxal; D005492:Folic Acid; D008715:Methionine; D003404:Creatinine; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D014805:Vitamin B 12; D012256:Riboflavin