Breastfeeding past two years linked to infant tooth decay

Breastfeeding is credited with a long list of benefits, but one downside of extended and intensive breastfeeding may be a higher risk of cavities in baby's first teeth, according to a new study.

The more frequently a mother breastfed her child beyond the age of 24 months during the day, the greater the child's risk of severe early tooth decay, researchers found.

"The No. 1 priority for the breastfeeding mother is to make sure that her child is getting optimal nutrition," lead author Benjamin Chaffee of the University of California, San Francisco told Reuters Health.

Chaffee completed the study as a doctoral student at the University of California at Berkeley.

He and his team looked at a possible link between longer-term breastfeeding and the risk of tooth decay and cavities in a survey of 458 babies in low-income families in the city of Porto Alegre, Brazil.

Because the study lasted more than one year, most babies were eating various kinds of solid food and liquids in addition to breast milk.

The World Health Organization (WHO) recommends that babies are fed breast milk exclusively for the first six months of their lives, with solid foods added to the diet at that point. However, the WHO also recommends continued breastfeeding up to age two and beyond, the authors note.

For the study, the researchers checked in on babies when they were about 6, 12 and 38 months old. At six months, the study team gathered data on the number of breast milk bottles the baby drank the day before and any other liquids, like juice.

At the 12-month mark, parents reported whether they fed their babies any of 29 specific foods, including fruits, vegetables, beans, organ meat, candy chips, chocolate milk, cookies, honey, soft drinks or sweet biscuits.

Two trained dentists examined all of the babies at each of the visits.

Nearly half of the children had consumed a prepared infant formula drink by age 6 months, the researchers write in the Annals of Epidemiology, but very few still drank formula by age 1.

The researchers found that about 40 percent of children breastfed between ages 6 and 24 months had some tooth decay by the end of the study. For babies breastfed for longer than two years and frequently, that number rose to 48 percent.

"Our study does not suggest that breastfeeding causes caries," Chaffee said.

It is possible that breast milk in conjunction with excess refined sugar in modern foods may be contributing to the greater tooth decay seen in babies breastfed the longest and most often, the authors speculate in their report.

More research is needed to determine what's going on, but the findings are in keeping with professional dental guidelines that suggest avoiding on-demand breastfeeding after tooth eruption, they write.