Foods High in Iron: UK Portions, Haem and Non-Haem, and What Blocks It

The foods highest in iron are liver, mussels and clams, red meat and sardines on the animal side, and fortified breakfast cereals, pulses, tofu, dark chocolate, pumpkin seeds, dried apricots and leafy greens on the plant side; what separates them is not only how much iron they hold but how much of it you absorb. Haem iron, from meat, fish and poultry, is taken up at 15 to 35%; non-haem iron, from plants, eggs and fortified foods, at 2 to 20%, depending on what is eaten with it.^{1, 2} That is why the UK reference intake is set high, 14.8 mg a day for women aged 19 to 50 and 8.7 mg for men and for women after the menopause, and why women with heavy periods and people on plant-based diets are the ones who run short. The table below gives UK portions in milligrams, and the rest of the page is about pairing: vitamin C alongside, tea and coffee an hour away, and calcium at a different meal.

• Richest animal sources: liver, mussels, clams, beef, lamb, sardines, venison
• Richest plant sources: fortified cereals, lentils, chickpeas, kidney beans, tofu, pumpkin seeds, dark chocolate, dried apricots, spinach
• Need: 14.8 mg women 19 to 50; 8.7 mg men and women over 50; vegetarians aim higher
• Helps absorption: vitamin C in the same meal; meat or fish eaten with plant iron
• Blocks absorption: tea, coffee, calcium and dairy at the meal, phytates in unsoaked grains and pulses

Foods high in iron, per UK portion

Approximate figures from UK food composition data; haem sources marked H, non-haem N. Fortified products vary by brand.

• Lamb's liver, 100 g: about 8 to 10 mg (H); not in pregnancy, because of vitamin A
• Mussels or clams, 100 g: about 6 mg (H)
• Fortified bran flakes or similar, 30 g: about 4 to 5 mg (N); check the label, brands range widely
• Lentils, cooked, 120 g: about 4 mg (N)
• Dark chocolate, 70 to 85%, 30 g: about 3.5 mg (N)
• Tofu, 100 g: about 2.5 to 3.5 mg (N); calcium-set tofu is the higher end
• Kidney beans or black beans, cooked, 150 g: about 3 mg (N)
• Beef, lean, 100 g cooked: about 2.5 to 3 mg (H); lamb about 2; venison about 4
• Sardines, tinned, 100 g: about 2.5 to 3 mg (H)
• Pumpkin seeds, 30 g: about 2.5 to 3 mg (N)
• Chickpeas, tinned, 120 g: about 2.5 mg (N)
• Quinoa, cooked, 150 g: about 2 mg (N)
• Wholemeal bread, 2 slices: about 2 mg (N); white bread, fortified by law, about 1.5
• Cashews, 30 g: about 1.8 mg (N)
• Spinach, boiled, 90 g: about 1.5 mg (N), poorly absorbed because of oxalates
• Chicken thigh, 100 g: about 1.3 mg (H); breast about 0.5
• Tahini, 1 tablespoon: about 1.3 mg (N)
• Dried apricots, 30 g (about 4): about 1 mg (N)
• Egg, one medium: about 0.9 mg (N), so two eggs give under 2 mg

Because absorption differs so much, 3 mg from beef and 3 mg from kidney beans are not equal on the plate: the beef might deliver 0.6 to 0.9 mg into the blood, the beans 0.1 to 0.5 mg depending on what they are eaten with. That is the whole reason pairing matters, and why vegetarians are advised to aim for roughly 1.8 times the reference intake.³

What helps iron absorption

Vitamin C in the same meal. It converts plant iron into the form the gut takes up and can double or treble non-haem absorption: a glass of orange juice, peppers, tomatoes, broccoli, berries or a squeeze of lemon with pulses, cereal or greens.^{2, 4} This is the single most useful change for anyone eating plant iron.

Meat, fish or poultry eaten with plant iron. A small amount of haem food in the same meal improves absorption of the non-haem iron alongside it; a little chicken in a lentil dish does more than the chicken's own iron suggests.

Soaking, sprouting and fermenting grains and pulses, and sourdough bread, reduce the phytates that bind iron.

Being low. The body absorbs more iron when stores are low and less when they are full, one reason food works slowly for a deficiency and why excess from food is rare.

What blocks iron absorption

Tea and coffee, whose polyphenols can cut non-haem iron absorption by half or more when drunk with a meal; have them an hour before or after.⁵ Calcium and dairy, which compete at the meal; a glass of milk with iron-rich food reduces uptake, so put dairy at a different meal if iron is a concern. Phytates in unsoaked wholegrains, bran and pulses. Oxalates in spinach, chard and rhubarb, which is why spinach's iron figure flatters it. Antacids and acid-suppressing medicines, because stomach acid is needed to free iron from food. None of these means avoiding the foods, only arranging them: the lentil curry with tomatoes and a glass of juice, the tea an hour later.

Top iron-rich foods for vegetarians and vegans

Fortified cereal with berries at breakfast; lentils, chickpeas and beans most days with tomatoes or peppers; tofu and tempeh; pumpkin and sunflower seeds, cashews and tahini; dried apricots and figs; wholemeal and sourdough bread; quinoa; dark chocolate; and dark green vegetables for the small amounts they add. Cook in a cast-iron pan, which adds measurable iron to acidic foods. Keep tea and coffee away from meals. With those habits a plant-based diet reaches 20 to 25 mg a day, which at the lower absorption rate meets the need for most people; women with heavy periods on a vegan diet are the group most likely to need a test and a supplement despite good eating.³

What drink is full of iron?

No everyday drink is a real iron source. Prune juice carries about 1 mg per 150 ml, fortified plant milks a little, and some "iron drinks" sold as tonics are liquid supplements rather than foods. The drink that matters for iron is orange juice, not for its own iron but for the vitamin C that helps you absorb iron from the food beside it. Tea and coffee are the drinks to move away from the meal.

How quickly can you raise iron with food?

Slowly. Food can hold a healthy level and prevent a shortfall; it cannot correct an established deficiency in weeks, because even a well-arranged diet delivers only a few milligrams into the blood each day against stores that may be a gram short. If you have the signs of low iron, tiredness, breathlessness, pallor, hair shedding, restless legs, a ferritin test from your GP is the first step, and a supplement taken correctly is the fix; iron and heavy periods explains the test and the threshold, and iron supplement side effects how to take one. Food is what keeps you there afterwards.

What we don't know

• Exact absorption from mixed UK meals. The 2 to 20% range for plant iron comes from single-meal studies; real diets vary.²
• How much the vitamin C effect persists over a whole diet. Strong in single meals; smaller in long-term studies.⁴

Frequently asked questions

What food is highest in iron?

Liver, at 8 to 10 mg per 100 g, then mussels and clams. Among plant foods, fortified cereal and lentils lead per portion.¹

Which fruit is rich in iron?

Dried apricots, figs and prunes at about 1 mg a portion; fresh fruit carries little. Fruit's main iron role is the vitamin C that helps absorb iron from other foods.

Is 2 eggs a day enough iron?

No. Two eggs give under 2 mg, an eighth of a woman's need, and egg iron is poorly absorbed.

What boosts iron immediately?

Nothing from food works immediately. Vitamin C with iron-rich food maximises what you absorb; an established deficiency needs a tested, supplemented approach over months.

What drains iron from your body?

Blood loss, above all heavy periods; frequent blood donation; gut bleeding; and, for absorption, tea and coffee with meals, calcium at the meal and acid-suppressing medicines.⁵

Sources

1. Lopez A, et al. Iron deficiency anaemia. Lancet, 2016. PubMed 26314490.
2. Hunt JR. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. American Journal of Clinical Nutrition, 2003. PubMed 12936958.
3. NHS. Iron: vitamins and minerals. nhs.uk.
4. Hallberg L, Brune M, Rossander L. Effect of ascorbic acid on iron absorption from different types of meals. Human Nutrition: Applied Nutrition, 1986. PubMed 3700141.
5. Zijp IM, Korver O, Tijburg LB. Effect of tea and other dietary factors on iron absorption. Critical Reviews in Food Science and Nutrition, 2000. PubMed 11029010.

This article is general information, not medical advice. If you have symptoms of low iron, ask your GP for a ferritin test before taking an iron supplement; food maintains a healthy level but does not correct an established deficiency quickly.