Iron deficiency carries substantial risks, including anaemia and transfusional requirements; suboptimal immune, skeletal muscle, and thyroid function; prematurity; poor maternal and perinatal outcomes in pregnancy; and impaired motor and cognitive development in children.1 The reference nutrient intake (RNI) for iron is 8.7 mg/day for men and postmenopausal women, and 14.8 mg/day for premenopausal women,2 but half of all women in the UK do not consume the 8.7 mg/day RNI.3 Iron requirements are higher still in pregnancy, and following non-menstrual ‘haemorrhagic’ losses such as blood donation, peripartum, gastrointestinal haemorrhage, surgery, and epistaxis.4 Although the proportion of dietary iron absorbed increases in iron deficiency, the degree of compensation for dietary shortfalls is not known.
To assist in advising patients with high iron requirements (patients with frequent epistaxis due to hereditary haemorrhagic telangiectasia), we used gold standard, prospective 7-day weighed food diaries to determine predominant dietary sources of iron in a real-life setting in the UK. We believe the results will be generally informative for medical practitioners.
The high proportions of dietary iron contributed by fortified cereals and breads were remarkable, particularly as these are not currently listed as good iron sources by NHS Choices,5 and were not recognised as such by the study cohort. Participants could consume 87% of the RNI for men and/or postmenopausal women, and 51.4% of the RNI for premenopausal women, through breakfast cereals alone. Iron intake was higher from boxed, fortified cereals (87% maximal contribution to male RNI) than from porridge (5.5% maximal contribution to male RNI). Participants could also consume 51% of the RNI for men and/or postmenopausal women through bread, which included iron-fortified white breads as well as wholewheat. Dedicated vegetarian meals provided similar proportions of dietary iron to red meat. Eggs, fish, and other vegetables (especially potatoes, beans, and lentils) also provided high individual contributions. Conversely, large volumes of inhibitors of dietary iron absorption were ingested, particularly polyphenol-containing tea (average 829 mls/ day) and coffee (155 mls/day). Nelson and Poulter 6 advise that to enhance iron absorption, tea should be avoided 1 hour after an iron rich meal because 150 ml reduces non-haem iron absorption by 60–80%.
These data provide an easy route to identify individuals at risk of iron deficiency, and simple advice to address, particularly suggesting a bowl (or extra bowl) of their favourite iron-fortified breakfast cereals, and reducing tea and coffee intake with meals. The data may also help patients with iron overload states aiming to reduce dietary iron intake.
- © British Journal of General Practice 2014