The nutrients such as protein, calcium, iron and all three of them, either by natural or chemical substances were added to the recipes of yeast breads. Acceptability test was carried for the each formulated bread before selecting eight experimental diets. Sixty albino rats were separated into ten dietary groups including eight enriched breads and two control diets of plain breads from the market, which were used as the carbohydrate sources of the each basal diet. Experimental regime was seven weeks. The growth rate, hematology, total serum protein and organ weights we compared. Generally animals on the enriched bread showed the better growth rate than the rats fed control diet. Diet H enriched protein, iron and calcium by natural foods, brought up the highest weight gain among all of the rats. Hemoglobin concentrations of the rats on the diet H and G (enriched with three nutrients by chemicals) were 14.3 and 14.2 gram % comparing with other two control groups (12.9 and 13.1 gram%). Rats on diet K (fed nothing but diet H enriched bread) showed the significantly higher growth rate, total serum protein and hemoglobin level than these on the diet L (fed only plain bread from the market).