Homocysteine

Homocysteine (Hcy) is an endogenous (made within the body) amino acid that increases with age or as a result of an inborn error of metabolism, known as homocystinuria. Elevated total plasma levels of Hcy are often referred to as hyperhomocysteinaemia (HHcy).  Causes of this condition include enzyme deficiencies and mutations, vitamin deficiencies (folate, vitamins B6 and B12), demographic characteristics (increasing age, male sex, tobacco use, physical inactivity) or chronic medical disorders such as decreased renal function, hypothyroidism and transplantation.

Homocysteine plays a part in preventative health. A rang of different disease states can be linked to the improper metabolism of Hcy and consequent HHcy. Until recently, the emphasis on Hcy research was driven by the need to discover more about cardiovascular disease (CVD).  This follows the theory that HHcy may predispose people to atherothrombosis, and as a risk factor for cerebrovascular and peripheral vascular disease. It also has links with gene expression (DNA functioning) and cancer. Pregnancy is also a time when Hcy can become an issue. Elevated Hcy concentrations in pregnant women can relate to many adverse pregnancy outcomes including birth defects. Hcy levels are also found to be high in patients with Parkinson’s disease, Alzheimer’s disease, and many other neurological problems.

Dietary factors have a particularly strong influence on the cause of increase total homocysteine (tHcy). Widespread evidence shows that optimal nutriture with respect to vitamins B2, B6, B9 and B12 is important, because these nutrients are effective in lowering tHcy concentrations. Finally, both serine (an amino acid derived from glycine) and zinc also help Hcy metabolism (also known as anti-homocysteine factors).

Elevated Hcy levels have also been linked to a wide range of ailments above those previously mentioned, including osteoporosis and complications in diabetes.