Low Ferritin in a Vegetarian Teenager
Mei is 16 and has been vegetarian for 18 months. She complains of tiredness and has a ferritin of 9 µg/L, which is below the laboratory reference range. Her GP has not prescribed iron yet. A 24-hour recall shows: breakfast - two slices of white toast with butter and a cup of strong milk tea; lunch - rice with stir-fried Chinese cabbage and two egg yolks; snack - a handful of almonds; dinner - rice with fried tofu and broccoli; no fruit or vitamin C drink. She drinks tea with most meals because her family does. Her periods are heavy and last six days. The family food budget is HK$600 per week for four people. She wants to eat more spinach and buy an iron supplement from a pharmacy.
1. Prioritise the dietary changes Mei should make, with reasons, and explain why spinach alone is not the answer.
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The recall is low in vitamin C and high in tea at meals, while the iron sources are mostly non-heme and modest. First priority is to move tea away from meals by at least one hour, because tannins inhibit non-heme iron absorption. Second, add a vitamin C source to lunch and dinner, such as orange, guava, tomato or capsicum; this enhances absorption of the plant iron eaten at the same meal. Third, increase affordable non-heme iron foods: tofu, lentils, chickpeas, fortified cereal, eggs and dark green vegetables. Spinach alone is not the answer because it contains oxalates, which reduce iron bioavailability, and it supplies only a modest amount per serving. Heavy periods increase iron losses, so diet changes may not correct ferritin quickly. The GP should be informed and iron studies reviewed; a pharmacy supplement should not be started without advice because the dose and need depend on blood results.
2. Plan one day of affordable meals for Mei that improves iron intake and absorption. Justify each choice.
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Breakfast: fortified wheat or oat cereal with milk, one egg, and a small orange. The cereal and egg add iron; the orange adds vitamin C. Lunch: rice, tofu and tomato stir-fry, and broccoli. Tofu supplies plant iron, tomato supplies vitamin C, and broccoli adds folate. Afternoon snack: roasted chickpeas and a guava. Chickpeas are cheap per gram of protein and iron; guava is high in vitamin C. Dinner: rice, lentil dhal, dark green leafy vegetables and capsicum. Lentils are inexpensive and iron-rich; capsicum improves absorption. Drinks: water with meals; tea at least one hour after eating. This plan stays within a tight budget because dried legumes, eggs and seasonal vegetables are cheaper than almonds and supplements. It also spreads iron across meals rather than relying on one large dose.
3. Mei says a supplement is cheaper and easier than changing her diet. How should you respond?
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Acknowledge that a supplement may eventually be needed, but explain that ferritin of 9 µg/L is a clinical finding, not a diagnosis to self-treat. The cause matters: heavy periods, low dietary intake and tea at meals all contribute, and the GP needs to decide whether iron is appropriate and at what dose. High-dose iron can cause constipation, nausea and dark stools, and unnecessary iron is harmful. A supplement also does not fix the absorption problem if tea continues at meals. Food changes are not mutually exclusive with supplements; they make any supplement more effective and are sustainable. Cost should be compared over time: dried lentils and eggs are cheaper per nourishing meal than many supplements, and they provide protein and other nutrients. The responsible advice is to discuss the result with the GP, request a review, and use diet changes now while waiting.