Iron supplements may help reduce behavioral problems in babies who are born slightly underweight, according to a new Swedish study.

Researchers Umeå University studied 285 marginally low birth weight infants with 95 infants who had normal birth weight. The marginally lower birth weight infants were born weighting between 4 pounds, 7 ounces and 5 pounds 8 ounces.

Researchers randomly assigned the children with low birth weight to 0, 1, or 2mg/kg of iron supplements a day from six weeks of age to six months of age.

Researchers noted that there were no differences in IQ between the groups. All three of the low birth weight groups had scores between 104 and 105; the researchers defined cognitive impairment as having an IQ below 85.

However, researchers found that babies who received no iron supplements were significantly more likely to experience behavioral problems, as reported by their parents. Some of the behavioral issues reported in the study include problems managing emotional reactions, anxiety and depression as well as sleep and attention problems.

Results of the study showed that low birth weight babies who weren't given iron supplements were 4.5 times more likely to show signs of behavioral problems at age 3 compared with other low-birth-weight babies who received iron supplements during early infancy.

Researchers said that while 13 percent of the placebo-group babies scored above the cutoff for clinical behavior problems, only 2.9 percent of the infants in the 1mg iron group and 2.7 percent of the 2mg group and 3.2 percent of the children in the control group showed signs of behavioral problems.

The latest findings suggest that iron deficiency in infancy may be a direct cause of behavioral problems later in life, the researchers wrote in the study published Monday in the journal of Pediatrics.

"In some ways [the findings are] not surprising because we know iron is an important micronutrient in the diet of very young children," Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center of New York, told Mother Nature Network. Past animal studies found that iron was essential for the development of brain cells.

Co-researchers Dr. Magnus Domellof of Umea University told Reuters that the latest finding "further solidifies the evidence that it's a very good idea to give these (marginally low birth-weight) children iron supplements."

He said that he did not see any delayed growth or stomach problems that could be linked to the use of iron supplements. Previous studies have found that giving young children who aren't deficient excessive iron may stunt their growth.

"Here's where an ounce of prevention is worth a pound of cure," Dr. Michael Georgieff, a child development researcher at the University of Minnesota in Minneapolis who had reviewed the study as part of Berglund's dissertation committee, told Reuters.

He recommends that all parents know their baby's iron requirements when they leave the hospital.

"The issue with these marginally low birth-weight infants is, people really haven't paid a lot of attention to them, but the evidence is accumulating that they are at risk for behavioral problems and less than ideal cognitive function," Dr. Betsy Lozoff, who studies the effects of iron deficiency in infants at the University of Michigan in Ann Arbor but was not involved in the current research, said, according to Reuters.

In the United States, most parents are advised to give their babies extra iron supplements starting at four to six months either through supplements if the mother is breastfeeding or through formula. However, very small or premature babies generally have their iron levels monitored from birth.

Lozoff noted that currently there are no recommendations for treating babies who are just below a normal birth weight.

"This would suggest that it should just be a routine supplementation, and it can be at a low level of iron," said Lozoff, according to Reuters.