Change of some oxidative stress parameters after supplementation with whey protein isolate in patients with type 2 diabetes

Objectives: The aim of this study was to evaluate the effects of undenatured whey protein isolate (WPI; ≥92.5%) with a high content of native cysteine (2.7%) and a standardized content of lactoferrin (≥0.7%) on parameters related to oxidative stress and inflammation in individuals with type 2 diabetes mellitus. Methods: We assigned 120 white patients with type 2 diabetes and glycated hemoglobin ≥6.5% to two groups. The patients were supplemented daily with WPI or placebo for 3 mo. After 3 mo, the markers of oxidation (superoxide dismutase, glutathione peroxidase, glutathione, and reduced glutathione-to-oxidized glutathione ratio) and inflammation (high sensitivity C-reactive protein, interleukin-6, tumor necrosis factor -α, malondialdehyde) were significantly lower in the WPI group than in the placebo group (P < 0.05). The WPI group obtained a significant improvement in the lipid profile and a reduction in fasting plasma glucose compared with baseline and placebo (P < 0.05). No variations of body weight, body mass index or circumferences and metalloproteinase-2 and -9, or soluble receptor for advanced glycation end product were recorded in either groups. Conclusion: Supplementation with WPI may be useful in patients with diabetes to control fasting glycemia. Moreover, it can help to improve inflammatory and oxidative stress, which play a crucial role in the development of diabetes complications and also in the progression of other chronic diseases.