Breastfed infants are less likely to experience short sleep duration at one year of age compared to those fed exclusively with formula, according to findings published on June 26 by researchers from the University of Toyama, Japan. The study analyzed data from 82,918 mother–infant pairs as part of the nationwide Japan Environment and Children's Study.
The research team, led by doctoral researcher Ms. Yuri Nakagawa, examined whether feeding practices during the first six months influenced sleep duration at age one. The findings were published in the European Journal of Clinical Nutrition on March 31.
"WHO widely promotes breastfeeding, and most people are aware of the multiple health benefits it provides. Nevertheless, perceptions that breastfed infants sleep less, or that formula-fed infants sleep for longer periods, remain common. We wanted to provide solid evidence to bust this misconception," says Ms. Nakagawa.
Mothers completed questionnaires about their infant feeding methods at six months and reported their child's sleep duration at one year. Children were grouped into four categories: exclusively formula-fed; breastfed for less than six months; breastfed for six months with formula supplementation; and exclusively breastfed for six months. Short sleep was defined as sleeping less than 11 hours per day based on U.S. National Sleep Foundation recommendations.
The results showed that all groups receiving any amount of breastmilk had a lower risk of insufficient sleep compared to those fed only formula. Infants who received only formula had a 12.2% chance of short sleep, while those breastfed for less than six months had a 10.2% chance; those breastfed for six months with some formula had a 9.7% chance; and those exclusively breastfed for six months had an 8.8% chance of short sleep duration at age one.
"This study provides reassurance against the common perception that breastfed babies sleep less because breast milk is digested more rapidly," says Ms. Nakagawa. "Our findings suggest that such concerns should not discourage parents from considering breastfeeding and its many well-established benefits," she adds.
