Greater muscle mass means more myoglobin is produced, further raising iron needs. Young children under the age of two are at risk of iron deficiency as they are growing fast and can be fussy eaters. In children, signs of iron deficiency are delayed psychomotor development and poor capacity for exercise. Low birth weight and preterm delivery further put babies at risk. Lean red meat is the best source of iron because it is not only rich in iron but the iron is well-absorbed by the body, as around 40 per cent of meat's iron is in the form of haem iron.
Red meat has twice as much iron as chicken and three times as much as fish.
Generally the redder the meat, the richer it is in iron. In addition, the fibre and oxalates in vegetables plus the phytates in bran and wholegrains all bind and hold iron, so it cannot be properly absorbed. Spinach was once recommended as a rich source of iron. Spinach does contain a lot of iron - but it is not well absorbed. Its naturally-occurring fibre and oxalates bind most of the iron so it cannot pass into the body.