Whenever the topic of kidney disease arises in my practice, the first thought that crosses my mind is diabetes, since almost 40 percent will eventually have kidney problems.1
Homocysteine: What Is Normal?
Normal plasma homocysteine values vary widely between labs and can range from as low as 2.2 to as high as 17 micromoles per liter (abbreviated as mcmol/L or umol/L). Homocysteine increases with age and runs ~1.5 umol/L higher in males than females. There is a debate on what is optimal, and this too is affected by gender and age. In general, "optimal homocysteine" ranges run from less than 10 to under 6 umol/L.
The DIVINe Study
The Diabetic Intervention with Vitamins to Improve Nephropathy (DIVINe) study followed a screened group of diabetic patients with kidney disease for three years. Those who met the criteria had diabetic nephropathy, but their condition was not considered advanced.4 The 238 subjects who qualified were divided into two groups. One took 2,500 mcg of folic acid, 1,000 mcg of vitamin B12, and 25 mg of vitamin B6 a day. The second group took a look-alike placebo. Eighty-three percent of the patients were white male, 81 percent had type 2 (as opposed to type 1) diabetes, and their mean age was 60. Plasma homocysteine levels at baseline were 16.4 umol/L and 14.7 umol/L in the placebo and B-vitamin groups, respectively.
In approximately three years of follow-up, the B-vitamin group had mean homocysteine levels decline from 14.7 umol/L to 12.5 umol/L, while those assigned to placebo had their averages increase from 16.4 umol/L to 19 umol/L. However, the B-vitamin group also had an accelerated rate of GFR decrease, more strokes and more heart attacks. [See table]
|Results From the Diabetic Intervention with Vitamins to
Improve Nephropathy (DIVINe) Study
|Variable||Placebo Group (119 Patients)||B-Vitamin Group (119 Patients)|
These results were unexpected, disappointing and will undoubtedly lead to further research since the successful reduction of this biomarker had an outcome associated with its elevation. Unless patients with diabetes and kidney dysfunction have compelling reasons to use the levels of folic acid, vitamin B6 and vitamin B12 in this study for other, more serious comorbidities, they should stick to RDA dosing until there is conclusive evidence to disprove or explain the findings in this study.
- Palmer AJ, Valentine WJ, Chen R, et al. A health economic analysis of screening and optimal treatment of nephropathy in patients with type 2 diabetes and hypertension in the USA. Nephrol Dial Transplant, 2008;23(4):1216-23.
- Refsum H, Nurk E, Smith AD, et al. The Hordal and Homocysteine Study: a community-based study of homocysteine, its determinants, and associations with disease. J Nutr, 2006;136(6 Suppl):1731S-1740S.
- Andersen, G.D. "Homocysteine." Dynamic Chiropractic, March 23, 1998;16(7):28.
- House AA, Eliasziw M, Cattran DC, et al. Effects of B-vitamin therapy on progression of diabetic nephropathy. JAMA, 2010;303(16):1603-9.
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