Effects of Excess Vitamin B_6 Intake on Serum Lipid Profile and Cerebral Cortex in Rats


Abstract: Aim: The present study was undertaken to investigate the effects of dietary excess of vitamin B_6 on certain blood parameters [serum total cholesterol, high density lipoprotein (HDL) cholesterol and total lipid] and the cerebral cortex. Materials and Methods: A total of 36 albino rats were included in the study. Saline solution was administered to control groups (CG-10, n = 6 for 10 days; CG-15, n = 6 for 15 days; CG-20, n = 6 for 20 days). The experimental groups (EG-10, n = 6; EG-15, n = 6; EG-20, n = 6) received 5 mg/kg vitamin B_6 daily for 10 days, 15 days and 20 days, respectively. Serum total cholesterol, HDL cholesterol and total lipid levels were measured and compared in CGs and EGs. The cerebral cortex tissue samples were examined by electron microscopy. Results: The total serum cholesterol levels were significantly lower (P < 0.05) although serum HDL levels were significantly higher (P < 0.01) in all EGs. Total serum lipid levels were higher in EG-15 and EG-20 groups than in CGs. The structural degenerations in the perikaryon and neuropil were found prominent in EG-15 and EG-20 groups but not in EG-10. Marked damage in the neuronal and neuropilic structure was observed in rats who received long-term high doses of vitamin B_6. Based on these results, a relationship between cerebral cortex damage and serum total lipid and HDL levels in the EG-15 and EG-20 groups is suggested. Conclusions: Dietary excess of vitamin B_6 intake reduces serum total cholesterol levels, but not serum HDL and total lipid levels, and also causes cerebral cortex damage in long-term treatment. Thus, a careful diet plan and monitoring of vitamin B6 dose are recommended in patients who are supplemented with this vitamin.

Keywords: Vitamin B_6, blood, cholesterol, rat, cerebral cortex

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