MONDAY, MAY 2, 2011 (HealthDay News) -- Infants who aren't breast-fed may experience long-term health consequences, a new study suggests.
French researchers compared growth, body composition (fat mass vs. lean body mass) and blood pressure in three groups of newborns. One group was breast-fed for the first four months of life, while infants in the two other groups received one of two types of formula: a lower-protein formula with 1.8 grams (g) of protein per 100 kilocalories (kcal) or a higher-protein formula with 2.7 g/100 kcal.
The protein content of both formulas fell within the recommended range of formula protein levels, researchers noted.
After four months, the infants in the formula-fed groups continued to receive the same formula while the breast-fed infants were switched to the low-protein formula, if needed.
Researchers then followed the 234 children for three years.
By age 3, diastolic and average blood pressure for babies fed the higher-protein formulas was higher than for breast-fed kids, though the blood pressure was still within the normal range.
Children who were breast-fed also showed a different pattern of growth and metabolic profile than formula-fed infants. The breast-fed infants had lower blood insulin levels when they were 15 days and 4 months old, but not when they were 9 months old.
The breast-fed infants also had different growth patterns during their first year of life, but by age 3, there were no differences in length, weight or body composition (fat. vs. lean mass).
Though what these differences mean over a lifespan is unclear, researchers said it may be evidence of a "metabolic programming effect," or the concept that nutritional experiences at critical points early in life can influence a person's future metabolism and health.
"It appears that formula feeding induces differences in some hormonal profiles as well as in patterns of growth compared with breast-feeding," study co-author Dr. Guy Putet said in an American Academy of Pediatrics news release. "The long-term consequences of such changes are not well-understood in humans and may play a role in later health. Well-designed studies with long-term follow-up are needed."
The study was to be presented Monday at the annual meeting of the Pediatric Academic Societies in Denver. The data and conclusions should be viewed as preliminary until confirmed in large long-term studies.
The U.S. National Women's Health Information Center has more about breastfeeding.