Study Links Weight Gain in Infants to Higher IQ Later in Life

A link between weight gain in an infant's first month of life and higher IQ during early school years has been established by a team of researchers in Australia and Canada.

The study collected data from 14,000 healthy babies in Belarus and found that when compared to babies who only gained 15 percent of their birth weight in the first month of life, babies who gained 40 percent of their birth weight in the initial four weeks had an IQ 1.5 times higher by the time they were 6 years old. Babies with the biggest growth in head circumference also had the highest IQs.

"Head circumference is an indicator of brain volume, so a greater increase in head circumference in a newborn baby suggests more rapid brain growth," said Lisa Smithers, lead researcher at University of Adelaide.

She said researchers were not surprised by their finding, as other studies pointed to the same effect. But Smithers said other studies have never carefully looked at data from first four weeks of life.

"This was additional to that other research which says growth in the first year [is important]; well, actually what we've shown is growth in those first four weeks is also very, very important," she told the Australian Broadcasting Corporation.

"Overall, newborn children who grew faster in the first four weeks had higher IQ scores later in life," Smithers said in a statement.

"Those children who gained the most weight scored especially high on verbal IQ at age 6. This may be because the neural structures for verbal IQ develop earlier in life, which means the rapid weight gain during that neonatal period could be having a direct cognitive benefit for the child."

Smithers said their finding highlights the importance of successful feeding of newborn babies.

"We know that many mothers have difficulty establishing breastfeeding in the first weeks of their baby's life," Smithers said.

"The findings of our study suggest that if infants are having feeding problems, there needs to be early intervention in the management of that feeding."

Though, Smithers did warn that the study should not be taken as a green light to overfeed a baby in order to increase its IQ.

"We don't want to send the message that parents should overfeed their baby to get a higher IQ," she said, according to Australia's Herald Sun.

"Babies should never be overfed, or force fed, but fed on demand which is consistent with the advice in our national guidelines."

She also warned overfeeding could lead to other health problems such as obesity.

The study is published in the journal Pediatrics