Hyperhomocysteinemia (HHcy) is related to
central nervous system diseases. Epidemiological studies show a positive, dose-dependent relationship between plasma total
homocysteine (tHcy) concentration and
neurodegenerative disease risk. tHcy is a marker of
B-vitamin (
folate, B(12), B(6)) status. Hypomethylation, caused by low
B-vitamin status and HHcy, is linked to key pathomechanisms of
dementia;
B-vitamin supplementation could potentially reduce neurological damage. In retrospective studies, the association between tHcy and cognition is impressive; there is also evidence that tHcy-lowering treatment could be effective in primary and secondary
stroke prevention. Increased tHcy and low serum
folate occur in patients with
Parkinson's disease, especially those receiving
L-dopa. There is also an association between HHcy and
multiple sclerosis, and between
B-vitamin status and depression. Studies also confirm a causal role for tHcy in
epilepsy, and certain anti-epileptics enhance HHcy.
B-vitamin status should be optimized by ensuring sufficient intake in patients with neuropsychiatric diseases. HHcy occurs commonly in the elderly and can contribute to age-related neurodegeneration. Treatment with
folic acid, B(12) and B(6) lowers tHcy. For secondary and primary prevention from several neuropsychiatric disorders, it seems prudent to actively identify deficient subjects and ensure sufficient
vitamin intake.