A new study has found that certain combinations of risk factors can put children at a higher risk of having iron deficiency than when these risks occur independently.

Researchers looked at how a combination of factors can affect iron deficiency in children rather than single factors because they wanted to look at the problem of iron deficiency in context rather than as an isolated event.

“The individual risk factors in the study have long been known, but knowledge of the context gives us a broader and much more clinically useful picture," said Associate Professor Cameron Grant from the Department of Paediatrics at the University of Auckland in a statement.

The study was based on a random community-based sample of approximately 300 children between the ages of 6 months and 23 months. Around 13 percent of children in the study group had iron deficiency.

There are few known risk factors that cause iron deficiency like eating fruits infrequently as snacks, low birth weight, increased body mass index, premature birth and no early exposure to milk formula.

According to the researchers, eating fruit isn't just enough. When a child eats a fruit is also as important. Eating a fruit only as a snack (and not with meal) increases risk of iron deficiency by three fold because the iron in the fruit isn't being absorbed by the body.  

"It (study) has allowed us to demonstrate how much one factor can intensify the effects of another. For example, the research findings now enable me to say: ‘Here is a young child who has cows’ milk daily and only has fruit as a snack (rather than with the main meal) : the combination of these two factors increases the risk of iron deficiency 11 fold. Therefore we know we need to do something about it," Dr. Grant said.

Previous research had shown that obese mothers are more likely to give birth to babies with low iron levels.

Packaged food isn't the only culprit behind iron deficiency and even though homemade food is good, it may not have the recommended amount of nutrients in them and that can lead to iron deficiency, researchers say.

“Home-made foods are good, of course, as long as they are rich in nutrients – but the quality can vary greatly. The commercial products are regulated and consistent in the nutrients they supply," Dr Grant said.

According to Centers for Disease Control and Prevention (CDC), about 14 percent of children between 1 and 2 years suffer from iron deficiency.

Iron deficiency can delay normal activity and movement  and even mental function in the child, according to CDC.

The study was published in Nutrition and Dietetics.