By Lisa Rapaport

(Reuters Health) – Babies who consume nothing but breast milk for their first three months of life may have healthier cholesterol levels by adolescence than infants who drink formula, a new study suggests.

Pediatricians recommend that mothers exclusively breastfeed infants until they’re at least 6 months old because it can bolster babies’ immune systems and reduce their risk of ear and respiratory infections, sudden infant death syndrome, allergies, obesity and diabetes. Breast milk does contain more cholesterol than formula, however, and little is known about how this might impact cholesterol levels later in life, researchers note in Pediatrics.

For the current study, researchers tracked 3,261 babies born in Hong Kong in 1997, until they reached an average age of 17.5 years. Overall, about 7.5 percent of these infants were exclusively breastfed for the first three months of life; another 40 percent consumed a combination of breast milk and formula and 52 percent drank only formula.

By their late teens, compared to kids who had some formula as babies, those who didn’t had lower total cholesterol levels as well as lower levels of “bad” LDL cholesterol, the study found.

“The differences we saw between breastfed and formula fed infants could be due to differences between the mothers who did and did not breastfeed,” senior study author Mary Schooling of the University of Hong Kong said by email. “However, the adolescents in our study were born in Hong Kong in 1997 when breastfeeding was not so common and there were few differences between the mothers who did and did not breastfeed.”

Only about 1 percent of the teens in the study had high levels of low-density lipoprotein (LDL) cholesterol, the type that builds up in blood vessels and can lead to blood clots and heart attacks.

LDL levels were similar for teens who only had formula as babies and teens who were fed a combination of formula and breast milk.

But exclusively breastfed babies had lower LDL and total cholesterol, and lower levels of triglycerides, or fats, compared to babies only fed formula.

Overweight teens tended to have higher total and LDL cholesterol levels than adolescents at healthy weights.

The study wasn’t a controlled experiment designed to prove whether or how breast milk might directly impact teens’ cholesterol levels, or why exclusive breastfeeding but not mixed feeding appeared to influence cholesterol levels.

Even so, the results add to the evidence that early nutritional exposures – even in the first weeks or months of life – may modify so-called cardiovascular risk factors like cholesterol levels, said Christopher Owen of the Population Health Research Institute at St George’s University of London.

“Breast milk is high in cholesterol content and babies who are breast fed have much higher blood cholesterol compared to those formula fed,” Owen, who wasn’t involved in the study, said by email.

“This early exposure to the high cholesterol content of breast milk may program fat metabolism, improving the body’s ability to metabolize fat in later life,” Owen added. “Mothers should be encouraged and supported to breast feed where possible.”

SOURCE: Pediatrics, online April 9, 2019.