One suggests that 6-year-olds who were breast-fed have a lower risk of ear, throat and sinus infections compared to bottle-fed infants, while the other finds a similar trend when it comes to allergies.
The research upholds the "many benefits of breast-feeding in the immediate newborn period," said Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City. She was not involved in the new studies.
The studies were published online Sept. 1 in the journal Pediatrics.
Current recommendations from the American Academy of Pediatrics urge women to breast-feed baby exclusively for the first six months of life, and then combine breast milk and other foods until at least 12 months.
The two studies sought to determine if breast-feeding's health benefits lingered long after solid foods were introduced.
In one study, a group led by Dr. Ruowei Li, of the U.S. Centers for Disease Control and Prevention, looked at data on medical office visits for nearly 1,300 6-year-olds.
Compared to children who hadn't been breast-fed for an extended time, children who had been breast-fed for nine or more months had lower odds of contracting an infection of the ear, throat or sinus, the team said.
For example, the breast-fed children had 31 percent lower odds of developing an ear infection over the past year, 32 percent lower odds for a throat infection and 53 percent lower likelihood for a sinus infection, the CDC team found.
Wu also noted that, "there was a decrease in infections if the mothers had breast-fed and there was a greater decrease depending on the amount of breast-feeding."
Why the effect? Li's team noted that "human milk is the best source of nutrition for most newborns and infants. In addition, human milk provides immunologic protection against many infections during infancy."
The new study now suggests that, "breast-feeding may protect against ear, throat and sinus infections well beyond infancy," the researchers added.
In the second study, a team led by Dr. Stefano Luccioli, of the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition, looked at the rate of "probable food allergies" in 6-year-olds.
They found that children who had been exclusively breast-fed for four months or more had about half the odds of developing a food allergy compared to children who had been breast-fed for a lesser amount of time.
As Wu noted, the finding did have one limitation, however. "While breast-feeding did not decrease food allergies in high-risk populations, such as families who already have a history of food allergy, there was a decrease in low-risk populations," she said.
Another expert said the studies provide valuable information.
Nina Eng, chief clinical dietitian at Plainview Hospital in Plainview, N.Y., said the findings "point out two of the many important benefits of breast-feeding."
"These articles provide evidence that should inspire new moms to breast-feed their children," she said.
Here are the AAP's recommendations on infant feeding.