Glycemic Index and Appetite Response of Iron-Biofortified Cowpeas (Vigna unguiculata (l.) Walp.) in Healthy Adults and Its Effects on Inflammation and Oxidative Stress in Raw 264.7 Cells.

OBJECTIVE

This study aimed to determine the glycemic index of conventional and biofortified cowpeas, their effects on healthy individuals' appetite, and their anti-inflammatory and antioxidant effects in RAW 264.7 cells.

METHODS

Iron biofortified (BRS Aracê, BRS Tumucumaque, and BRS Xiquexique) and conventional (BRS Pajeú) cowpeas were cooked and their chemical composition was analyzed. Eutrophic adults (n = 11) consumed each cowpea and control glucose and post-prandial glucose and appetite responses were obtained over 120 min. In vitro, the study used RAW 264.7 cells stimulated with lipopolysaccharide-LPS (1 µML) and treated with digested cowpea beans (1 mg/mL). Total antioxidant capacity (TAC), nitric oxide, superoxide dismutase (SOD), TNF-α, and IL-10 were analyzed in the cell and culture medium, and NF-κB by immunohistochemistry. The data were analyzed by ANOVA and post-hoc of Tukey (p < 0.05).

RESULTS

All cowpeas had a lower incremental area under the glycemic curve (iAUC) than glucose. In appetite responses, Pajeú had the lowest "hunger sensation" and higher "satiety sensation" (p < 0.05). In vitro analysis showed that Pajeú and Tumucumaque improved TAC and biofortified cowpeas reduced the activation and translocation of NF-κB to nuclei. However, the cowpeas had no effects on SOD activity, nitric oxide, TNF-α, and IL-10 released and production into cells (p > 0.05).

CONCLUSIONS

Cowpea, biofortified or not, presents benefits in reducing the glycemic index, but has a moderate impact on induced inflammation, being a sustainable option for human intake and health.

CLINICAL TRIAL REGISTRATION: Brazilian Clinical Trials Registry (ReBEC), number RBR-7ntftdv.