title: Zinc bioavailability in rats fed a plant-based diet: a study of fermentation and zinc supplementation.
abstract: BACKGROUND
  Zinc deficiency is a significant problem, in developing countries and in vegetarians, which can be caused by plant-based diets. Thus, dietary strategies, such as fermentation, to improve zinc bioavailability of diets should be investigated.
  
  
  OBJECTIVE
  To improve zinc bioavailability in a plant-based diet by the inclusion of fermented food.
  
  
  METHODS
  Cassava tubers were fermented and made to replace the unfermented cassava in a basal plant-based diet, and compared with plant-based diets with and without zinc supplement. The zinc bioavailability of the diets was evaluated in Wistar rats that were fed these diets for 28 days. The evaluation was for zinc apparent absorption (ZnAA), serum zinc levels, and zinc deposits in liver and femur; in addition, the feed efficiency ratio (FER) of the diets and femur weight (FW) of the rats were evaluated.
  
  
  RESULTS
  During the cassava fermentation, lactic acid increased and pH decreased (from 6.8 to 3.9), which is favorable for native phytase activity, resulting in a 90.2% reduction of phytate content in cassava. The diet containing fermented cassava showed significantly higher levels of ZnAA, FER, and FW (p<0.001). Moreover, the zinc levels in serum and femur were significantly higher (p<0.001) compared with the results of the diet with unfermented cassava. The results clearly show a higher zinc bioavailability in the diet containing fermented cassava and are comparable with the results obtained with the plant-based diet with zinc supplement.
  
  
  CONCLUSIONS
  In conclusion, the fermentation of cassava reduces the phytate content. The diet containing the fermented cassava represents a better nutritional alternative than the diet with unfermented cassava and is comparable with the zinc-supplemented diets.
authors.affiliation: Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden.|Food and Natural Products Center, San Simon University, Cochabamba, Bolivia; claudia_lazarte15@hotmail.com.
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Lazarte
authors.affiliation: Food and Natural Products Center, San Simon University, Cochabamba, Bolivia.
authors.forename: Mirian
authors.initials: M
authors.lastname: Vargas
authors.affiliation: Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Granfeldt
keywords: Wistar rats; fermentation; phytate; plant-based diets; zinc bioavailability