Fat-soluble vitamins in patients with acute renal failure

Abstract

Objective: Systematic investigations on the status of fat-soluble vitamins in patients with acute renal failure (ARF) are lacking and hence no recommendations for vitamin supply can be defined for these subjects. Thus we compared the status of fat-soluble vitamins, of transport molecules and some vitamin-dependent proteins in patients with ARF and healthy controls.

Setting: Nephrology unit of a university hospital.

Patients and methods: Eight patients with ARF requiring hemodialysis therapy were investigated and 28 healthy volunteers served as controls. Plasma concentrations of retinol (vitamin A) and retinol-binding protein (RBP), 25-OH and 1,25-(OH)2 vitamin D3, of parathyroid hormone (PTH), of alpha-tocopherol (vitamin E) and of phylloquinone (vitamin K), osteocalcin and noncarboxylated osteocalcin, respectively, were measured and plasma lipoprotein fractions (as vitamin transport vehicle) were evaluated.

Results: Vitamin A levels were decreased (p < 0.001), but RBP levels were normal in ARF patients. Vitamin D3 metabolites 25-OH and 1,25-(OH)2 vitamin D3 plasma levels were profoundly depressed, and PTH was elevated (p < 0.001). Vitamin E plasma concentration was reduced (p < 0.001) but this cannot be accounted for by decreased LDL cholesterol or triglyceride levels. In contrast, vitamin K plasma level was rather elevated in ARF patients with a broad range of individual values. Blood coagulation was normal but total and carboxylated osteocalcin were decreased. No correlation of vitamin K concentrations and any of the plasma lipoprotein fractions could be identified.

Conclusion: With the exception of vitamin K, profound deficiencies of fat-soluble vitamins develop in patients with ARF. Current recommendations for vitamin supplementation are inadequate and should be reevaluated for these patients.