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Old 06-14-2006, 05:35 PM   #2
trisherina
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(continued)

Formula manufacturers say infant formula is modeled on breast milk and emphasize that it is the only safe alternative recommended by pediatricians for mothers who cannot, or choose not to, breast-feed.

But while formula tastes the same way at every feeding, advocates of breast-feeding say, the smells and flavors of human breast milk change from day to day, from morning to evening, influenced by the mother's diet. Many nutritionists believe that exposing an infant to this bouquet of flavors early on may make for less fussy eaters who are more flexible about trying new foods and more likely to eat a healthy, varied diet.

"I think of human milk not just as food, but as a sophisticated and intricate infant support system that has evolved over millions of years to provide the infant with nutrition, protection and components of information," said Dr. E. Stephen Buescher, a professor of pediatrics at Eastern Virginia Medical School in Norfolk, who heads the inflammation section in the school's Center for Pediatric Research.

"It isn't just calories," Dr. Buescher said.

The protection that breast-feeding provides against acute infectious diseases including meningitis, upper and lower respiratory infections, pneumonia, bowel infections, diarrhea and ear infections has been among the most extensively studied of its benefits and is well documented, said Dr. Lawrence M. Gartner, chairman of the American Academy of Pediatrics' breast-feeding section.

Breast-fed babies have 50 percent to 95 percent fewer infections than other babies, Dr. Gartner said, adding, "It's pretty dramatic."

One reason for the reduction in the incidence and the severity of infections is the antibodies contained in the mother's milk. "A lot of this has to do with the mother and baby interacting," he explained. "Whatever the baby is exposed to, the mother is exposed to, and the mother will make antibodies within three to four days." The baby absorbs them through breast milk.

Breast milk also protects the baby through other mechanisms. For example, it contains agents that prevent bacteria and viruses from attaching to cells in the baby's body, so the foreign agents are expelled in the stool, Dr. Gartner said.

The protection is not ironclad, so breast-fed babies will often get a mild infection that does not make the baby sick but acts almost like a vaccine. "What we think is that human milk creates an environment where you get your immunity without the cost of an infection, the vomiting and the diarrhea," Dr. Buescher said. "That's a bargain."

Neonatologists are urging the mothers of their tiniest patients to express breast milk because premature and low-birth-weight babies are particularly vulnerable to infections. Studies have found that premature babies who get breast milk are discharged earlier from the hospital and are less likely to develop necrotizing enterocolitis, a potentially deadly disease.

Breast milk has also been shown to lift the cognitive development of premature babies, presumably because it contains certain fatty acids that aid brain development.

Experts say it is possible that human breast milk produces permanent changes in the immune system, in a sense "educating" the baby's immune system, Dr. Gartner suggested. That may explain why children who were breast-fed appear to be at lower risk for autoimmune diseases like Crohn's, asthma and juvenile diabetes. Several studies also indicate that breast-fed children are at reduced risk for the cancers lymphoma and leukemia.

Officials with the International Formula Council say there is not enough evidence to prove a relationship between early feeding and serious chronic diseases.

Dr. Myron Peterson, director of medical affairs for Cato Research, a private independent research organization which reviewed the literature on breast-feeding for the council, said that studies have found a link between nursing and health benefits but that they do not prove a causal relationship. "It's like the old statement about the rooster crowing making the sun come up," he said. "If you did an observational study on that, what would you say?"

An unpublished report the council commissioned from Cato says "it is not scientifically correct to conclude the lack of exclusive breast-feeding plays a causative role in the development of these diseases."

But scientists are so intrigued about the potential to protect children from juvenile diabetes that a large 10-year multinational study called Trigr (for Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk) is under way to find out whether breast-feeding protects at-risk children from developing the disease.

And public health officials, excited about mounting evidence suggesting that children who were breast-fed are at lower risk of being obese, have been promoting breast-feeding as a strategy to combat alarming rates of childhood obesity.

The health benefits of breast-feeding may extend to mothers as well. According to the American College of Obstetricians and Gynecologists, extended breast-feeding reduces the risk of ovarian cancer and breast cancer. New studies have also found that women who breast-feed face a lower risk of adult-onset or Type 2 diabetes, and they seem to be at lower risk for osteoporosis later in life.

Immediately after childbirth, nursing accelerates healing by reducing the amount of bleeding and causing the uterus to contract more rapidly back to its normal size. Making milk burns up to 500 extra calories a day, so nursing mothers get help shedding extra pounds from pregnancy, experts say, especially if they nurse for an extended period.

Experts say lactation also seems to have a calming effect on the mother, which may be an adaptive mechanism to ease the transition to life with a new baby. Every time a mother nurses, she gets a spike in oxytocin, which may have an antianxiety effect and help promote bonding with the new baby, said Kathryn G. Dewey, a professor of nutrition at the University of California, Davis, and an expert on breast-feeding.

Nursing may even produce a euphoric feeling, she said.

Dr. Michael Kramer, a professor of pediatrics and of epidemiology and biostatistics at McGill University's medical school in Montreal who has been studying the health effects of breast-feeding among infants in Belarus, found a strong protective effect against gastrointestinal illnesses and a lesser protective effect against respiratory infections. Dr. Kramer is still analyzing data on obesity, I.Q., behavior and blood pressure.

"It can't do all of the things that are being claimed for it," Dr. Kramer said, injecting a note of caution into the debate. "But it probably does some of them."
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