Soy and Lupin Protein Beverages Improve Metabolic Health, Gut Microbiome in Overweight Adolescents

The escalating prevalence of pediatric overweight and obesity necessitates effective nutritional strategies for metabolic management. Current interventions often fall short, highlighting a need for accessible, food-based solutions. Soy and lupin proteins, beyond their basic nutritional value, possess bioactive properties that may influence metabolic pathways and the gut microbiome. This study investigated whether these plant-based proteins could offer a novel approach to attenuate metabolic dysregulation in a vulnerable adolescent population.

A randomized, double-blind clinical trial involved 30 Mexican male adolescents (12-16 years old) with overweight or obesity. Participants were assigned to consume a functional beverage providing a daily 10 g portion of either soy protein or lupin protein for 5 weeks. Primary endpoints included changes in metabolic markers (fasting glucose, C-peptide, HOMA2 index), lipid profiles (total cholesterol, triglycerides), inflammatory markers (PAI-1, visfatin), and gut microbiota composition (16S rDNA sequencing).

Following the 5-week intervention, both protein groups demonstrated significant improvements in key metabolic parameters. Fasting glucose levels were notably attenuated (soy: 93.1 vs. 99.5 mg/dL; lupin: 92.3 vs. 97.9 mg/dL), alongside reductions in C-peptide levels. Consequently, insulin sensitivity, assessed by the HOMA2 index, improved significantly in both cohorts. The soy protein group specifically showed a marked reduction in total cholesterol (-10.4%) and triglycerides (-17.1%). Serum levels of plasminogen activator inhibitor-1 (PAI-1) and visfatin were decreased after both interventions, indicating reduced inflammation. A post-treatment reduction in glucose-dependent insulinotropic polypeptide (GIP) was uniquely observed in the lupin group. Regarding the gut microbiota, both protein interventions correlated with enhanced 16S rDNA diversity and increased the abundance of the Bacillota phylum and butyryl-CoA transferase-positive bacteria. These changes suggest a beneficial modulation of the gut ecosystem.

Both groups exhibited significantly attenuated fasting glucose (soy: 93.1 vs. 99.5 mg/dL; lupin: 92.3 vs. 97.9 mg/dL) and C-peptide levels, leading to improved insulin sensitivity via the HOMA2 index.