Dietary supplementation during diabetes therapy and the potential risk of interactions

Abstract

Background: The classification of dietary supplements as foodstuffs promotes widespread access to them and increases the possibility of patients using them without being monitored. Unreasonable or excessive consumption of these preparations poses risks to type-2 diabetes mellitus (T2DM) patients (among others) because it may induce disturbances in glycemic control. The aim of this study was to assess the frequency of dietary supplementation among patients using anti-diabetic drugs and such patients' nutrient intake in order to evaluate the potential risk of interactions. Material and Methods: The study participants were 150 diabetic patients who were asked about the type of pharmacotherapy and dietary supplementation they used. The intake of minerals, vitamins, dietary fiber and long-chain polyunsaturated fatty acids (LC-PUFAs) from the patients' diets were also assessed, using the 24-h dietary recall method. Results: The highest percentage of patients taking individual anti-diabetic drugs used supplements containing magnesium and herbs. They also often took antioxidant vitamins, B-group vitamins and omega-3 fatty acids. In the majority of patients (both those using supplements and those not), the dietary recall showed insufficient intake of potassium, calcium and magnesium, as well as of vitamin E, folic acid, vitamin D and LC-PUFAs. In addition, their diets provided high median amounts of iron, copper, vitamin A and β-carotene. Conclusions: The level of dietary supplementation and the ill-balanced diets reported by the majority of the recruited T2DM patients indicate a high possible risk of interactions with the anti-diabetic drugs. Therefore, patients should always consult their physicians regarding dietary supplementation, and medically trained staff should routinely assess dietary intake to avoid hazardous changes in the activity of drugs.