Effectiveness of bitter almond (Amygdalus communis L. var. Amara) gum as a prebiotic on glycemic indices, oxidative stress, and antioxidant biomarkers in women with type 2 diabetes mellitus: a randomized, placebo-controlled trial

Abstract

Type 2 diabetes mellitus (T2DM) is marked by hyperglycemia, oxidative stress, and systemic inflammation. Prebiotics, such as bitter almond gum ( Amygdalus communis L. var. amara ), have the potential to influence gut microbiota and metabolic parameters, suggesting their role as dietary interventions for enhancing glycemic control in the management of T2DM. This study evaluated the effects of bitter almond gum on glycemic indices, oxidative stress, and oxidant biomarkers in individuals with T2DM. This randomized, triple-blinded, placebo-controlled, clinical trial included 44 women with T2DM. They were assigned to either the intervention ( n = 22) or control ( n = 22) groups receiving 5 g per day of bitter almond gum or maltodextrin, respectively, for a duration of 8 weeks. Various outcomes, including glycemic indices, lipopolysaccharide (LPS) levels, oxidative stress markers, and antioxidant biomarkers, were measured at baseline and again after 8 weeks. Bitter almond gum supplementation significantly reduced insulin levels (−1.23 mg/dL; 95% CI, [–2.40, –0.03]), LPS ( − 6.32 mg/dL; 95% CI, [–9.51, –3.09]), pentosidine (−38.02 mg/dL; 95% CI, [–55.18, –20.71]), and oxidative stress index (OSI) (−5.59 mg/dL; 95% CI, [–10.81, –0.30]), and increased McAuley_index (0.20 mg/dL; 95% CI, [0.14, 0.32]), total antioxidant capacity (TAC) (0.18 mg/dL; 95% CI, [0.07, 0.26]), superoxide dismutase (SOD) (180.20 mg/dL; 95% CI, [65.27, 295.14]), and glutathione peroxidase (GSH-Px) (2.21 mg/dL; 95% CI, [0.78, 3.62]) compared with the placebo group ( P < 0.05, ANCOVA adjusted for baseline and confounding factors). Bitter almond gum supplementation for 8 weeks led to improvements in glycemic control, a reduction in oxidative stress, and an enhancement of antioxidant defenses in women with T2DM. These findings indicate its potential as a complementary functional food for managing diabetes.