Effect of Combination Therapy with Probiotic Bulgarian Goat Yoghurt Enriched with Aronia melanocarpa Fruit Juice in Patients with Type 2 Diabetes Mellitus and Complication of Diabetic Nephropathy: A Pilot Study

Background: Goat milk and its fermented products exhibit unique nutritional and therapeutic characteristics corresponding to the management of metabolic disorders, such as type 2 diabetes mellitus (T2DM) and its associated complications, including diabetic nephropathy (DN). Due to its rich content of bioactive compounds and superior digestibility compared to cow’s milk, goat milk enhances nutrient assimilation and exhibits notable anti-inflammatory and antioxidant effects. The primary aim of this investigation was to systematically evaluate the efficacy of goat milk-based nutritional interventions as an integral component of a multifaceted therapeutic approach aimed at attenuating oxidative stress (OS), restoring metabolic homeostasis, and mitigating the progression of long-term complications in patients with diabetes mellitus and concurrent renal dysfunction. Methods: Participants diagnosed with T2DM were stratified into three subgroups based on the severity of renal dysfunction. The results were analyzed in comparison with those of healthy control subjects. Results: Following a dietary regimen that included goat milk enriched with Aronia (Aronia melanocarpa) fruit juice patients—particularly those with DN—exhibited marked reductions in free radical concentrations, decreased cytokine production, and diminished levels of lipid and protein oxidation byproducts. Moreover, a significant improvement was observed in nitric oxide (NO) levels, along with partial restoration of the nitric oxide synthase (NOS) system and an upregulation of endogenous antioxidant enzyme activity (p < 0.05) relative to pre-intervention measurements. Conclusions: These outcomes suggest that the dietary intervention not only attenuated OS but also contributed to improved renal function in affected individuals. The results support the therapeutic potential of functional dairy-based diets—specifically those incorporating bioactive ingredients such as Aronia melanocarpa fruit juice and goat milk—in mitigating oxidative damage and enhancing metabolic and renal health in patients with T2DM and DN.