Wed, 19 Dec 2012 11:07 UTC
These formulas are not only second best but are becoming outright toxic to infants. According to a new study by University of California, San Diego bioengineers, free fatty acids created during the digestion of infant formula cause cellular death and severe intestinal conditions.
Breast milk is the perfect food for baby, with numerous advantages over baby formula, especially in the first four months or so. Infant formula has no DHA, cholesterol, lipase, lactoferrin, lysozyme, lactose, vital oligosaccharides, living cells and almost no immunoglobins. All of these components are essential to a newborn's health yet absent in infant formula.
Babies fed a dairy-based formula grow up to have higher blood pressure than babies who are breast-fed, British researchers reported.
Babies fed enriched bottle milk are also more likely to be obese by the age of five.
Human milk oligosaccharides, or HMO, produce short-chain fatty acids that feed a beneficial microbial population in the infant gut. Not only that, the bacterial composition adjusts as the baby grows older and its needs change.
Earlier studies have shown that breast milk lowers the incidence of diarrhea, influenza and respiratory infections during infancy, while protecting against the later development of allergies, type 1 diabetes, multiple sclerosis and other illnesses. As scientists have learned more about the role intestinal flora plays in health, they have gained appreciation for how an infant's early diet can affect this beneficial microbial universe.
The report by San Diego bioengineers was based on in vitro tests comparing the digestion of fresh human breast milk and nine different infant formulas. It was online in the journal Pediatric Research. Scientists have long known that premature infants fed formula are more likely to develop necrotizing enterocolitis (cellular death of intestinal tissue) than those fed breast milk. The condition is the leading cause of death from gastrointestinal diseases in premature infants, but the underlying mechanism has not been understood. Alexander Penn, a research scientist working in the Microcirculation Laboratory of bioengineering Professor Geert Schmid-Schonbein from the UC San Diego Jacobs School of Engineering, believes they have come closer to an answer.
Penn and others had previously determined that the partially digested food in a mature, adult intestine is capable of killing cells, due to the presence of free fatty acids which have a "detergent" capacity that damages cell membranes. The intestines of healthy adults and older children have a mature mucosal barrier that may prevent damage due to free fatty acids. However, the intestine is leakier at birth, particularly for preterm infants, which could be why they are more susceptible to cellular death of intestinal tissue.
Therefore, the researchers wanted to know what happens to breast milk as compared to infant formula when they are exposed to digestive enzymes. They "digested," in vitro, infant formulas marketed for full term and preterm infants as well as fresh human breast milk using pancreatic enzymes or fluid from an intestine. They then tested the formula and milk for levels of free fatty acids. They also tested whether these fatty acids killed off three types of cells involved in necrotizing enterocolitis: epithelial cells that line the intestine, endothelial cells that line blood vessels, and neutrophils, a type of white blood cell that is a kind of "first responder" to inflammation caused by trauma in the body.
Overwhelmingly, the digestion of formula led to cellular death, or cytotoxicity -- in less than 5 minutes in some cases -- while breast milk did not. For example, digestion of formula caused death in 47 percent to 99 percent of neutrophils while only 6 percent of them died as a result of milk digestion. The study found that breast milk appears to have a built-in mechanism to prevent cytotoxicity. The research team believes most food, like formula, releases high levels of free fatty acids during digestion, but that breast milk is digested in a slower, more controlled, process.
Toxic Soy and Aluminum Levels
The aluminum content of a range of the most popular brands of infant formulas remains high, and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies.
The permeability of the gastrointestinal tract of the infant is quite great, as protective mechanisms have not yet fully developed. It is this very fact that allows many of the substances in human mother's milk to systemically permeate the body of the infant.
Unfortunately, the same lack of protection seriously impairs an infant who consumes infant formula, especially soy formulas, and bovine (cow) milk. Whether the pasteurization process (aluminum vats and piping) contributes to the amount of aluminum in milk, or it involves the feed the animal is eating, is unknown.
Research indicates that aluminum concentrations in most cow milk is 20 times greater than human breast milk (5-20 mcg/l) and 100 times greater in soy-based formulas.
More than 35 percent of formula-fed babies in the United States consume soy formula. Babies on soy formula appear to grow with many problems associated with the gastrointestinal tract. These formulas contain very high concentrations of genistein, from 32 to 45 milligrams, which is higher than the amount found to affect menstrual cycles in women. Soy formulas also contain other soy isoflavones that likely affect genistein's actions in the intestine.
A study by a team at Keele University in Staffordshire, led by Dr Chris Exley with Shelle-Ann M Burrell, demonstrating the vulnerability of infants to early exposure to aluminum serves to highlight an urgent need to reduce the aluminum content of infant formulas to as-low-a-level as is practically possible.
Currently, many neonatal intensive care units are moving towards formula-free environments, but breastfeeding a premature infant can be challenging or physically impossible and supplies of donor breast milk are limited. To meet the demand if insufficient breast milk is available, less cytotoxic milk replacements will need to be designed in the future that pose less risk for cell damage.
This may be of benefit not only to premature infants, but also to full-term infants at higher risk for disorders that are associated with gastrointestinal problems and leakier intestines, such as autism spectrum disorder. Dr. Sharon Taylor, a professor of pediatric medicine at UC San Diego School of Medicine and a pediatric gastroenterologist at Rady Children's Hospital-San Diego, said the study offers more support to an already ongoing push by hospitals, including neonatal intensive care units, to encourage breastfeeding even in more challenging circumstances in the NICU. For patients who are too premature or frail to nurse, Dr. Taylor said hospital staff should provide consultation and resources to help mothers pump breast milk that can be fed to the baby through a tube.
Natasha Longo has a master's degree in nutrition and is a certified fitness and nutritional counselor. She has consulted on public health policy and procurement in Canada, Australia, Spain, Ireland, England and Germany.