Nonheme-iron absorption, fecal ferritin excretion, and blood indexes of iron status in women consuming controlled lactoovovegetarian diets for 8 wk

Background: The characteristics of vegetarian diets suggest that these diet s would have lower dietary iron bioavailability than nonvegetarian diets, b ut there is no evidence of iron deficiency in vegetarians. Objective: We evaluated the responsiveness of serum and fecal ferritin to d ifferences in iron absorption from controlled lactoovovegetarian and nonveg etarian diets. Design: Twenty-one women aged 20-42 y with serum ferritin concentrations fr om 6 to 149 mu g/L consumed lactoovovegetarian and nonvegetarian weighed di ets for 8 wk each (crossover design). The diets differed substantially in m eat and phytic acid contents. Nonheme-iron absorption was measured from the whole diets after 4 wk by using extrinsic Fe-59 and whole-body counting. F erritin in extracts of fecal composites and in serum was measured by enzyme -linked immunosorbent assay the last 2 wk of each diet. Results: Nonheme-iron absorption was less from the lactoovovegetarian diet than from the nonvegetarian diet (1.1% compared with 3.8%; P < 0.01; n = 10 ). Diet did not affect hemoglobin, transferrin saturation, erythrocyte prot oporphyrin, or serum ferritin. Substantially less fecal ferritin was excret ed with the lactoovovegetarian diet than with the nonvegetarian diet (1.1% compared with 6.0 mu g/d, respectively; P < 0.01; n = 21). Conclusions: This research indicates 1) 70% lower nonhemeiron absorption fr om a lactoovovegetarian diet than from a nonvegetarian diet; 2) an associat ed decrease in fecal ferritin excretion, suggesting partial physiologic ada ptation to increase the efficiency of iron absorption; and 3) an insensitiv ity of blood iron indexes, including serum ferritin, to substantial differe nces in dietary iron absorption for 8 wk.