Appendix: Homocysteine and Kidney Disease

Homocysteine can be greatly elevated for people on dialysis or with a kidney transplant (typical average amounts range from 20-60 µmol/l).¹ Thus far, there have been no studies examining whether reducing homocysteine in these patients can reduce cardiovascular problems. Shemin et al.¹ report that, for this reason, the American Heart Association and the American Society of Nephrology consider screening and treatment of elevated HCY to be inappropriate. However, if I had kidney disease, the mere lack of direct evidence would not be comforting.

Unfortunately, to date, very high doses of folic acid (1,000-60,000 µg/day), B6 (50-110 mg/day), and B12 (12-1,000 µg/day) have not succeeded in normalizing homocysteine levels to 12 µmol/l in kidney disease patients. However, they have often succeeded in reducing homocysteine to 16-20 µmol/l which could be worthwhile. Note: vitamin B6 is sometimes toxic at very high doses for long periods of time.

Because people with kidney disease can have impaired cyanide metabolism or clearance, a non-cyanocobalamin form of B12 is preferable. Anyone with kidney disease who is concerned about homocysteine can suggest the review by Shemin et al.¹ to their dietitian and/or doctor.