Bioavailability of iron from four different local food plants in Jordan

The bioavailability of iron from local plants (black cumin seeds, milk thistle seeds, sesame seeds and thyme leaves) was investigated. Apparent absorption of iron was calculated by subtracting fecal iron (using total collection of feces) from iron intake in Sprague-Dawley rats. Two trials of animal feeding were performed. Liver and serum concentrations of iron, and serum hemoglobin concentration were taken as response parameters for the bioavailability. Dry thyme was particularly rich in iron (117.2 mg/100 g dry matter) and milk thistle seeds in crude fiber (25 g/100 g dry matter). Rats fed the dry thyme diet or that supplemented with 5% egg white died but when the diet was supplemented with 10% egg white, the animals survived. Iron intake and apparent and total iron absorption were highest for the rats fed the dry thyme-egg white diet. Liver weights for the groups fed black cumin seeds and dry thyme were significantly higher (p < 0.05) than those for the groups fed milk thistle and sesame seeds. Liver content of iron was highest for the animals fed black cumin seeds. Serum iron content increased significantly (p < 0.05) for the animals fed black cumin seeds, and serum hemoglobin concentration increased significantly (p < 0.05) in the groups fed milk thistle seed and black cumin seed diets, but decreased for the group fed the thyme-egg white diet. It is concluded from this study that iron was better utilized from black cumin seeds as indicated by liver storage of iron. On the other hand, thyme had the highest iron absorption but lowest utilization.