Fermented Quinoa and Canihua in Plant-Based Diets Increase Iron and Zinc Bioavailability in Growing Rats

Abstract

This study aimed at evaluating the effects of non-fermented and fermented pseudocereal flours, quinoa and canihua, on iron and zinc bioavailability in Wistar rats. Two diets prepared with 92% fermented quinoa or 79.5% fermented canihua were compared with diets prepared with the same amount of non-fermented pseudocereals. Other two quinoa diets were prepared with 60% non-fermented or fermented quinoa and compared with a refence diet which was free of phytates. Body weight, feed efficiency ratio, and the absorption, retention and bioavailability of iron and zinc were evaluated. While body weight and feed efficiency ratio were higher (p < 0.05) in animals after non-fermented diets, the results of mineral absorption and bioavailability were consistently higher in the diets containing fermented pseudocereals. Iron concentration in the livers of animals after the fermented quinoa (92%) and canihua diet (79.5%), were 34% and 30% higher than after the diets with non-fermented pseudocereals. Zinc bioavailability, indicated by zinc in femur of animals fed the 60% fermented quinoa diet was 53.2 μg g⁻¹ Zn_Int g⁻¹ BW, comparable to that in animals fed a reference diet with no phytates (58.2 μg g⁻¹ Zn_Int g⁻¹ BW), and significantly higher (p < 0.05) than in animals fed the non-fermented quinoa diet (34.5 μg g⁻¹ Zn_Int g⁻¹ BW). Zinc bioavailability was mainly influenced by phytate content in the diet (R² = 0.665 and p = 0.000). The retention of iron in the liver (2220 μg g⁻¹ Fe_Int g⁻¹ BW) was higher in the diet containing 60% of fermented quinoa than in the non-fermented diet (1429 μg g⁻¹ Zn_Int g⁻¹ BW). Differences in iron absorption were mainly impacted by iron content in the diets (R² = 0.828 and p = 0.000). In conclusion, the addition of fermented pseudocereals to diets increased the bioavailability of iron and zinc in Wistar rats. These findings will encourage further research into fermented pseudocereals and their potential health effects.