Nasturtium (Tropaeolum majus L.) sub-chronic consumption modulates oxidative stress biomarker response in prediabetic subjects: A pilot study

Background: Nasturtium (Tropaeolum majus L.), an edible flower originating from the Andean region of South America, is rich in phenolic compounds derived from quinic acid, flavonoids, glucosinolates (GLS), and their secondary metabolites, isothiocyanates (ITCs), which possess antioxidant and anti-inflammatory effects. Objective: This study evaluated the impact of sub-chronic consumption of a freeze-dried nasturtium leaves drink on inflammatory and antioxidant biomarkers in individuals diagnosed with prediabetes. Methods: In this randomized, crossover trial, 10 prediabetic adults (aged 25-70 years) received either nasturtium (NT) or placebo (PLC) for 4 weeks, then crossed over to the other treatment for another 4 weeks. Blood samples before and after each treatment were analyzed for gene expression related to inflammation and antioxidant response, and total antioxidant capacity (TAC) was measured using ORAC and ABTS assays, along with oxidized LDL (ox-LDL) levels. Results: Weekly consumption of 15 g NT for four weeks significantly increased TAC by 21% (ORAC) and 10% (ABTS), and reduced ox-LDL by 13%. No changes in gene expression were observed. Novelty of the Study: This study is the first to demonstrate that consuming nasturtium specifically increases TAC and decreases ox-LDL in prediabetic patients. The results underscore the antioxidant potential of nasturtium as a functional food or nutraceutical to reduce oxidative stress-driven progression toward type 2 diabetes. Conclusions: Nasturtium intake enhances antioxidant capacity and may help reduce oxidative stress associated with the development of type 2 diabetes. Further research is needed to confirm its role in T2D prevention. Trial registration: NCT05346978, dated 23 April 2022.