Associations among plasma homocysteine, amino acids and nutritional status in hemodialysis patients

Hyperhomocysteinemia and cardiovascular disease are prevalent among hemodialysis (HD) patients. The influence of amino acid metabolism and nutritional status on plasma homocysteine (tHcy) was examined in 45 HD patients prescribed 1mg/d folate and 6μg/d vitamin B₁₂ (B12). A pre-dialysis blood sample was analyzed for tHcy, amino acids, folate, and B12. tHcy was elevated in 89% of patients (27.3 ± 12.6μmol/L, mean ± SD), and was 42% higher in 7 patients who were non-compliant with vitamin supplementation versus compliers (p = 0.003). tHcy correlated with serum folate, plasma methionine and cystine (p < 0.01 each). tHcy was similar in well-nourished vs. malnourished patients, based on subjective global assessment. Intakes of energy, protein, folate and B12 determined from weighed 3-day food records and food frequency questionnaires, were inversely correlated with tHcy (p < 0.02 each). B12 intake and plasma cystine accounted for 53.6% of the variance in tHcy, suggesting that diet and altered amino acid metabolism contribute to hyperhomocysteinemia in HD patients.