FRIDAY, May 14, 2004 (HealthDayNews) -- For years, health professionals have been preaching that breast milk is best for baby. Now, a new study says the benefits of breast-feeding may last well past infancy and even affect your risk of heart disease.
The study found teenagers who'd been breast-fed as infants had a lower ratio of bad to good cholesterol and lower levels of C-reactive protein, a possible marker of heart disease, in their blood than teens who had been fed formula as babies.
"What we've shown is that breast-feeding is a beneficial risk factor for heart disease and stroke," said study author Dr. Atul Singhal, deputy director of the MRC Childhood Nutrition Research Center at the Institute for Child Health in London.
Singhal said that means "breast-feeding is not only good for the short-term, but has a huge impact on long-term health as well."
The new study appears in the May 15 issue of The Lancet.
Numerous studies have shown that breast-feeding is beneficial for both baby and mother. Breast milk contains antibodies from the mother that boost immunity in babies, making them less susceptible to infections, allergies and asthma, according to the National Women's Health Information Center. For mothers, breast-feeding helps use up extra calories and may lower the risk of some cancers later in life, research has found.
Between 1982 and 1985, babies born prematurely were recruited from five different centers in the United Kingdom for two different randomized studies on infant nutrition. One study compared breast milk to pre-term formula, while the other compared regular infant formula to pre-term formula that was sometimes supplemented with breast milk.
For the new study, the researchers were able to follow up on 216 of the infants who were now between the ages of 13 and 16. They tested the teens' blood to see if their early nutrition had any effect on their current risk of heart disease.
The researchers found teens who had been fed breast milk had, on average, a 14 percent lower ratio of LDL (bad cholesterol) to HDL (good cholesterol). A lower ratio implies a lower risk of heart disease, according to the researchers.
They also found levels of C-reactive protein were significantly lower in teens who had been breast-fed as infants than those who received formula. C-reactive protein is a marker of inflammation and high levels are believed to be a warning sign for heart disease.
Singhal thinks one of the reasons breast-feeding may lower these heart-risk readings later in life is because breast-fed babies grow more slowly. And that, he believes, affects long-term cardiovascular health.
Dr. Michael Wasserman, a pediatrician at Ochsner Clinic Foundation Hospital in New Orleans, called the study intriguing, adding the research adds to "the whole host of arguments to already be made for breast-feeding."
But, he cautioned, "it's a little bit difficult to say that a four-week period predetermines so many aspects of the biochemistry of your body."
Wasserman said the study had several limitations, chief among them the small size of the sample. He added the study would need to be replicated with a larger sample. Also, he said, the researchers tried to account for factors such as weight, sex and socioeconomic status, but there are a lot of other forces that influence cholesterol levels, such as current diet.
He said pediatricians already recommend that any mother who is able to should breast-feed. But if a woman can't or doesn't want to breast-feed, that doesn't mean she's a bad mother, Wasserman said. There's a lot of guilt associated with choosing not to breast-feed or not being able to, he noted.
Singhal said breast-feeding is "obviously not the most important factor in the development of heart disease, but it is one of the ones you can do something about."
To learn more about the benefits of breast-feeding, visit the American Academy of Pediatrics.