Abstract
OBJECTIVES: Nutritious underutilized foods (NUFs) such as Solanum torvum (STO) and edible insects are potential sustainable dietary approaches to prevent malnutrition and improve food security. However, little is known about nutrient bioavailability from NUFs. This study determined the effect of STO and insect powders on improving nutritional status of malnourished rats. METHODS: Malnutrition was induced in weanling male Sprague-Dawley rats by feeding 5% protein with low Fe (LPI) diet for 21 days. During 14-day repletion, 5 groups of rats (n = 8) were fed the LPI diet supplemented with cricket, palm weevil larvae, STO, cricket + STO and casein + ferrous sulfate (HPI, positive control) while another group remained on the LPI diet (negative control). Repletion diets contained 15% protein and 20 ppm Fe, but palm larvae diet contained only 10 ppm Fe. Body composition was measured by dual X-ray absorptiometry. Hemoglobin (Hb) repletion method was used to compare relative bioavailability (RBV) of the HPI group to the other groups. RESULTS: Collectively, there were no differences in improved growth rate and body composition measures in groups repleted with edible insects and HPI (P = 0.08). Growth rate was 7.9 times higher in HPI compared to STO and 4.2 times higher in HPI compared to LPI (P < 0.0001). Changes in body composition were similar in STO and LPI but significantly different from HPI. Increase in Hb Fe with cricket (2.00 ± 0.90 mg) and palm weevil larvae (1.17 ± 0.75 mg) was comparable to HPI (1.94 ± 0.74 mg) (P = 0.27). Compared to HPI, there were significant differences in Hb Fe with STO (−0.08 ± 0.37 mg) and LPI (0.55 ± 0.18 mg). When RBV was calculated based on Hb Fe and food intake, RBV was 1.3 for palm weevil larvae but this was not significantly different from HPI (RBV = 1.00) and cricket (RBV = 0.99) (P = 0.83). RBV was similar in STO and LPI, and 100 times lower compared to HPI (P < 0.0001). CONCLUSIONS: Though other benefits of STO may be plausible, no nutritional benefits were found in this study, but cricket and palm weevil larvae could be excellent alternative sources of protein and bioavailable Fe and can be sustainable, cheap and locally available foods to prevent malnutrition in humans in countries where they are culturally accepted. FUNDING SOURCES: Doris A. Adams endowment funds from the College of Human Sciences at Iowa State University, Ames.