Winter JC1, Sponder G2, Aschenbach JR2, Gehlen H1

1 Equine Clinic: Surgery and Radiology, Freie Universität Berlin
2 Institute of Veterinary Physiology, Freie Universität Berlin

Human diabetes type 2 patients often show a magnesium deficit on the cellular level or in the serum. A supplementation with magnesium beyond demands can help to improve the insulin sensitivity. The metabolic syndrome in horses resembles many key symptoms of diabetes mellitus type 2. In our study, so far 25 horses with metabolic syndrome were supplemented for three month with 30 mg/kg magnesium as magnesiumaspartate-hydrochloride or a placebo product. Distribution into both groups was randomized. Horse owner and examiner were blinded. Horses were weighed, Body Condition Score (BCS) and Cresty Neck Score (CNS) were determined and a clinical exam and combined glucose-insulin tolerance test were performed before and after magnesium supplementation. Additionally liver enzymes, triglycerides, fructosamine concentration, ACTH-concentration, RISQI (reciprocal inverse square of insulin) and MIRG (modified insulin to glucose ratio) were determined. The magnesium concentration was measured in the serum and in blood lymphocytes. The most sensitive parameters for the assessment of insulin sensitivity are the time to regain the glucose baseline as well as the insulin concentration after stimulation. The normally distributed data were examined with a t-test for independent samples, the non-normally distributed data by Mann-Whitney-U-test. The horses did not lose weight in the supplementation phase, BCS and CNS remained unchanged, as desired. No significant differences werefound in liver enzymes, triglycerides, fructosamine- or ACTH-concentration in both groups. Insulin concentration after stimulation also showed no significant differences. The time to regain glucose baseline was examined by means of survival time analysis and Cox regression. A difference between the two groups showed a faster decrease to the glucose baseline in group A. This would correspond to an improved insulin sensitivity in the animals in group A after supplementation. A conclusion of this study will be made after 15 further patients.