Phytase supplementation improves blood zinc in rats fed with high phytate Iranian bread.

Background: More than one third of energy intake in Iran is provided from bread. Therefore, improving bread mineral bioavailability through dephytinization can play an important role in decreasing the prevalence of many mineral deficiencies. In this study, effect of phytase supplementation on zinc, iron and calcium status in growing rats fed with a diet containing high phytate Iranian bread (Sangak) was assessed.

Methods: Thirty weanling Wistar male rats were assigned to phytase (Aspergillus niger) or control group for 6 weeks. The diet was designed based on Iranian's food pattern and 34.2% of the energy was supplied from Sangak bread. Food intake, body and organ weight and body height were measured. Zinc was measured in blood, liver and femur. Iron was assessed in blood and liver and calcium was titrated from femur bone. Statistical analyses were performed using SPSS software. Paired sample t-test, Wilcoxon signed-rank test and repeated measurement ANOVA were used for proper analysis of data.

Results: Although weekly weight gain was not different between groups, final weight was in favor of control group. Food intakes, liver and femur bone weight did not differ between the two groups. However, the blood zinc was higher in the phytase group (26.2 ± 7.4 vs. 19.2 ± 5.2, P = 0.03). Thus positive effects of phytase supplementation on zinc, independent of growth was found. Other variables did not show any differences between groups.

Conclusion: Addition of phytase to diet containing high phytate Iranian bread can improve blood zinc status in growing rats.