ビタミンとミネラル

Thiamin Status and Supplementation in the Management of Diabetes Mellitus and its Vascular Comorbidities

Abstract

Carly J Moss

The water soluble B vitamin, thiamin, in its coenzyme form as thiamin pyrophosphate (TPP), is necessary for key reactions in glucose metabolism. For this reason, associations between thiamin status or thiamin supplementation and diabetes have been the focus of recent research. Currently, it is not clear how occurrence of diabetes relates to parameters of thiamin status, such as plasma thiamin levels. However, there is strong evidence that the diabetic state increases urinary thiamin excretion and decreases the activity of transketolase (TK), a TPP-dependent enzyme of the hexose monophosphate (HMP) shunt in various body tissues. Impairment of TK activity and subsequent downregulation of the HMP shunt activates several pathways that contribute to vascular damage and development of diabetes-related comorbidities such as retinopathy, cardiomyopathy, and nephropathy. Thiamin supplementation has been shown to be effective in restoring TK activity in animal models of diabetes, and in type 1 and type 2 diabetic individuals. Thiamin supplementation has also been shown to be effective in preventing or reversing, either partially or completely, hyperglycemia-induced damage to vascular endothelial cells, and microalbuminuria associated with diabetic nephropathy. Here, we review from current literature examining the relationship between diabetes and thiamin status as well as intervention trials evaluating the effect of thiamin supplementation on glycemic control and prevention of vascular comorbidities of diabetes.