The impact of a meat- versus a vegetable-based diet on iron status in women of childbearing age with small iron stores.

BACKGROUND: Single-meal and short-term studies have shown an enhancing effect of meat on iron absorption, but there are few interventions of longer duration comprising measurements of biomarkers of iron status.

AIMS OF THE STUDY: To assess the impact of a meat-based and a vegetable-based diet on iron status of women of childbearing age.

METHODS: For 20 weeks, 57 women aged 19-39 years with low iron stores (serum ferritin < or =30 microg/l and haemoglobin > or =120 g/l) consumed either a meat-based or a vegetable-based diet. Haemoglobin and serum ferritin concentrations were measured at baseline, after 10 and 20 weeks. Information about dietary intake before and during intervention, meat/fish intake, menstruation and contraceptive methods were recorded.

RESULTS: The women who consumed the meat-based diet had a significantly (P < 0.001) higher intake of meat/fish, 152 (147-168) g/day (median (Q1-Q3)) compared to the women consuming the vegetable-based diet 31 (24-36) g/day, while the total iron intake was similar in the two groups (mean +/- SE) 11.0 +/- 0.5 and 12.3 +/- 0.3/day mg/day, respectively. Serum ferritin remained unchanged in women on the meat-based diet (n = 29)(before intervention (median (Q1-Q3)): 16.3 (12.7-25.3) microg/l and after intervention: 16.5 (10.3-25.3) microg/l, but declined from 17.3 (10.9-23.7) to 11.2 (8.8-14.6) mug/l (P < 0.001) in women on the vegetable-based diet (n = 28).

CONCLUSION: Our results emphasize the importance of the delicate balance between dietary iron content and iron bioavailability for the maintenance of blood indicators of iron stores in women with initially low iron status.