Patients with diabetic nephropathy should avoid taking high doses of B vitamins to lower homocysteine levels, Canadian researchers reported in the Journal of the American Medical Association (2010;303:1603-1609).
David Spence, MD, of the University of Western Ontario in London, studied 238 patients with type 1 or type 2 diabetes and diabetic nephropathy. Researchers randomly assigned subjects to receive vitamin B (a single tablet containing folic acid, vitamin B6, and vitamin B12) or placebo.
At 36 months, renal function declined by a mean of 16.5 mL/min/1.73 m2 in the vitamin B group compared with 10.7 mL/min/1.73 min2.
In addition, the 36-month risk of the composite outcome of heart attack, stroke, revacularization, and all-cause mortality, was twice as high in the vitamin group as in the placebo group.