Impact of menstrual blood loss and diet on iron deficiency among women in the UK

Abstract

Women of childbearing age are at risk of Fe deficiency if insufficient dietary Fe is available to replace menstrual and other Fe losses. Haem Fe represents 10–15 % of dietary Fe intake in meat-rich diets but may contribute 40 % of the total absorbed Fe. The aim of the present study was to determine the relative effects of type of diet and menstrual Fe loss on Fe status in women. Ninety healthy premenopausal women were recruited according to their habitual diet: red meat, poultry/fish or lacto-ovo-vegetarian. Intake of Fe was determined by analysing 7 d duplicate diets, and menstrual Fe loss was measured using the alkaline haematin method. A substantial proportion of women (60 % red meat, 40 % lacto-ovo-vegetarian, 20 % poultry/fish) had low Fe stores (serum ferritin <10 μg/l), but the median serum ferritin concentration was significantly lower in the red meat group (6·8 μg/l (interquartile range 3·3, 16·25)) than in the poultry/fish group (17·5 μg/l (interquartile range 11·3, 22·4) (P<0·01). The mean and standard deviation of dietary Fe intake were significantly different between the groups (P=0·025); the red meat group had a significantly lower intake (10·9 (sd 4·3) mg/d) than the lacto-ovo-vegetarians (14·5 (sd 5·5) mg/d), whereas that of the poultry/fish group (12·8 (sd 5·1) mg/d) was not significantly different from the other groups. There was no relationship between total Fe intake and Fe status, but menstrual Fe loss (P=0·001) and dietary group (P=0·040) were significant predictors of Fe status: poultry/fish diets were associated with higher Fe stores than lacto-ovo-vegetarian diets. Identifying individuals with high menstrual losses should be a key component of strategies to prevent Fe deficiency.