Iron Status in a Vegetarian Teenager
A 16-year-old girl has been vegetarian for two years. She eats no meat, fish or eggs but does consume dairy. A blood test shows low ferritin (12 µg/L) and low haemoglobin. Her typical day includes: breakfast of white toast with margarine and tea; lunch of a white bread cheese sandwich and a diet cola; dinner of pasta with tomato sauce and a small side salad; and snacks of biscuits and fruit. She drinks tea with most meals. She reports fatigue and poor concentration at school. Her GP has referred her to a dietitian.
1. Analyse the dietary factors most likely contributing to her low iron status, distinguishing between iron intake and iron absorption.
Read the worked answer
Intake problems:
- Her diet is low in haem iron (absent, as she eats no meat or fish) and low in non-haem iron sources such as legumes, tofu, wholegrains, nuts and dark leafy greens.
- White bread and white pasta are low in iron compared with wholegrain versions.
- The salad is small; green leafy vegetables are limited.
Absorption problems:
- She drinks tea with most meals; tannins inhibit non-haem iron absorption.
- She drinks diet cola, which adds no nutrients and may displace iron-rich foods.
- Calcium from dairy can inhibit iron absorption when eaten at the same meal.
- Vitamin C enhances non-haem iron absorption, but her meals contain little (tomato sauce is a modest source).
Judgement point: The low ferritin reflects long-term depletion, not just recent intake. Both increasing iron-rich foods and improving absorption are needed; changing only one will be insufficient.
2. Recommend practical changes to her day and justify each using nutrition principles.
Read the worked answer
- Swap white bread and pasta for wholegrain - increases non-haem iron and fibre without changing meal structure.
- Add legumes or tofu to dinner (e.g. lentils in the pasta sauce) - a concentrated non-haem iron source suited to vegetarian eating.
- Move tea to between meals - removes tannin inhibition at the meal where iron is eaten.
- Pair iron foods with vitamin C - e.g. add capsicum or citrus to the salad, or drink orange juice with a legume meal, to enhance non-haem iron absorption.
- Include eggs? - she avoids them, so respect that; use dairy separately from the main iron meal where possible.
- Snack on nuts and dried fruit instead of biscuits - adds iron and protein.
Judgement point: The GP should also monitor ferritin and consider supplements, but supplements are a clinical decision, not a dietary one. The dietitian's role is to build sustainable food habits that raise both intake and absorption.