Feeding toddlers fortified milk or red meat can improve their levels of iron, critical for brain development.
Otago University researchers altered what 225 South Island toddlers ate for five months. Placing them on a diet featuring either fortified milk or red meat seemed to stop dropping iron levels.
The children were split into three groups - some ate red meat dishes twice a day, another group was given iron-fortified powdered milk, a third was given non-fortified powdered milk.
The researchers measured the protein ferritin, which indicated levels of iron in the blood, at the start and end of the five-month experiment.
The levels for those drinking the fortified milk increased 44 per cent, while they stayed about the same for those fed red meat and fell for those on regular milk powder.
Researcher Anne-Louise Heath said about one in three New Zealand toddlers had low iron levels, which could lead to anaemia.
Specifically, the meat-eating tots were fed lean beef mince, "not because there was a problem with them having too much fat, but because they don't eat much and we wanted to maximise the nutrients in each serving".
Iron deficiency could slow brain development, impair cognitive function and cause behavioural problems, Dr Heath said.
Though often thought of as an adult food, mince was a better option for young children than luncheon meat and sausages.
She said the bodies of rapidly growing 2-year-olds needed large amounts of iron, though little research had yet been done into nutrition of toddlers.
"They really are the lost age group."
Iron-fortified milk could be introduced without much disruption to most toddlers' diets, though it was expensive and could delay the child's transition to an adult diet, Dr Heath said.
By comparison, meat was cheaper, and required only a small amount of extra food - about 25 grams, or two heaped tablespoons - to stop falling iron levels.
It also helped toddlers' transition into more adult-style eating, and gave them access to other nutrients.
The results of the study were published in the American Journal of Clinical Nutrition yesterday.