Randomised clinical trial of long term glutathione supplementation offers protection from oxidative damage, improves HbA1c in elderly type 2 diabetic patients

Sustained hyperglycemia in type 2 diabetes is associated with low levels of the endogenous antioxidant glutathione (GSH), which leads to oxidative stress and tissue damage. It is therefore important to investigate whether oral GSH supplementation would restore GSH levels, and also help improve redox state and glycaemia in diabetic individuals. We conducted a pragmatic clinical trial to assess effectiveness of oral GSH supplementation along with anti-diabetic treatment. 104 non-diabetic and 250 diabetic individuals were recruited. All the 250 diabetic individuals were on anti-diabetic therapy; of these 125 were given oral GSH supplementation additionally for a period of six months. Fasting and PP glucose and insulin, HbA1c, GSH and the oxidative DNA damage marker 8-OHdG were measured at the recruitment time and after three and six months of supplementation. GSH supplementation increased blood GSH and decreased 8-OHdG significantly within three months in diabetic individuals. It also reduced HbA1c within three months and stabilized it thereafter in diabetic population overall. Patients above 55 years benefited more as evidenced by a significant decrease in HbA1c and 8-OHdG and an increase in fasting insulin. Data suggest that GSH supplementation can be used as an adjunct therapy to anti-diabetic treatment to achieve better glycemic targets, especially in elderly population.