Impact of tofu or tofu plus orange juice on hematological indices of lacto-ovo vegetarian females

The purpose of this study was to investigate iron status of premenopausal vegetarian women consuming tofu or tofu plus orange juice. Following a three day pre-period, 14 lacto-ovo vegetarians were randomly divided into two experimental periods of 30 days each. For the first 30 days, one half of the subjects (n = 7) received 6 oz (173 grams) of tofu/day (T) while the other half of the subjects (n = 7) received 6 oz of tofu/day along with 303 mg of vitamin C/d (TO). After 30 days, there was a crossover of the diets. Iron status was assessed by measuring serum ferritin and hemoglobin concentrations on the first day of the study and at the end of each experimental period. The Mann Whitney-U test was significant during the first (W = 17.5; Z = -2.095; p = 0.0361) and over the second (W = 40.0; Z = -2.611; p = 0.009) experimental periods which indicated the change in hemoglobin levels for the T and TO groups were different. Mean ranks showed a greater increase in hemoglobin levels for the TO group. There was no significant difference in the change in serum ferritin levels between the T and TO groups over the first and second experimental periods. In conclusion, bioavailability of iron from tofu is enhanced by supplementation with ascorbic acid.