Impact of type 1 Diabetes (T1D) on Vitamin B6 Metabolism

Document Type


Presentation Date


Conference Name

FASEB Experimental Biology

Conference Location

Anaheim, California


B6-metabolites were analyzed in plasma (P), erythrocytes (E) and urine (U) of 22 insulin-treated T1D patients without renal complication and 27 healthy controls in early adulthood (30–40 yrs). Groups were comparable due to rigorous selection criteria, excluding women on oral contraceptives, obese, vegetarian, pregnant or lactating. T1D (averaging 21 yrs) was relatively well-controlled according to HbA1c. Kidney functions, assessed by U-albumin/creatinine, did not differ between groups as well as U-4-pyridoxic acid (end-metabolite), hemoglobin and serum albumin which were both adequate. P-pyridoxal phosphate (PLP, indicator of B6-nutritional status) was slightly below the cut-off reference in T1D group. Its mean value and total B6-aldehydes (PLP+PL) were not decreased significantly. Greater (p<0.01) alkaline phosphatase (ALP) activity in T1D group increased PL slightly (NS), resulting in inferior (p<0.05) P-PLP/P-PL ratio. ALP correlated strongly (p<0.001) with HbA1c. Elevated (NS) E-PLP did not originate from pyridoxamine phosphate (unchanged), indicating no perturbation in B6-dependent aminotransferase activity. Inferior (p<0.01) P-PLP/E-PLP ratio revealed a change between the two blood compartments. E-PLP was highly (p<0.001) correlated with P-PL. T1D impairs vitamin B6 metabolism through the elevation of ALP, dephosphorylating PLP to PL, the transfer form through cell membrane (P to E).


Type 1 diabetes, vitamin B6, pyridoxal phosphate, alkaline phosphatase, albumin, hemoglobin


Biochemistry | Human and Clinical Nutrition

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