ost of us have heard about the benefits of breast milk, and two recent studies are pointing to new reasons why breast is better than bottle. One study, by Harvard researchers, showed that the longer infants were breast-fed, the less likely they were to be overweight in adolescence. The second study, by government researchers, indicates that breast-fed infants tend to be leaner between the ages of three to five than formula-fed infants. The studies are published in the May 16 issue of the Journal of the American Medical Association.
But there are a number of reasons why some mothers are unable, or choose not to breast feed. Below, pediatrician Dr. Steven Schwarz offers parents some infant formula advice.
Commercial infant formula manufacturers have come very close to providing a similar content of amino acids (the building blocks of protein) fats and carbohydrate, to human breast milk. However, these human milk substitutes lack many compounds found in human milk, such as natural anti-infective agents, enzymes that aid in the digestion of nutrients, and trophic factors, which are proteins that stimulate cell growth and division.
Breast-fed infants have been shown to have a lower incidence of certain infections than formula-fed infants, and they may also have fewer allergies later in life. Clearly, breast is best. However, if you decide to use formula for your baby, commercially available products will support normal growth and development.
Choosing The Right Formula For Your Baby
Casein, whey, soy, hydrolyzed, lactose, sucrose, disaccharide-free, lactose-free, hypoallergenic-these are but a few of the unfamiliar words on formula labels. The vast majority of babies fed a human milk substitute are given modified cow milk or soy protein-based formula.
Cow milk protein contains two major componentscasein and whey. Remember the childhood fable, "Little Miss Muffett, sat on a tuffet, eating her curds and whey?" Well, she was eating cottage cheese. The "curds" are actually casein, and the more digestible "whey" is the liquid protein that floats on top.
Health
Soy protein is significantly different in composition from cow milk protein, but both are modified to more closely resemble the amino acid content of human milk (human milk protein is actually 40 percent casein and 60 percent whey). The carbohydrate in whole cow milk-based formulas is lactose. This disaccharide, which is comprised of two basic carbohydrate units, is the naturally occurring sugar in all mammalian milks, including human milk. Lactose, in addition to providing an important energy source, also enhances the absorption of calcium. Soy formulas generally contain either sucrose (table sugar) or corn syrup. Fats in all formulas are "engineered" from a variety of sources.
Cow milk or soy?
So the question is, should you decide not to breast feed, which formula should you give your baby? In most cases, I recommend cow milk protein-based formula, either Similac (Ross Laboratories) or Enfamil (Mead Johnson).
Soy formula really has little use as the primary source of infant feeding. First, in those infants who are allergic to cow milk, soy protein cross-reacts immunologically with cow milk protein in 5 to 30 percent of all cases, causing the same allergic reaction that results from cow milk protein. Therefore, it really has no place in the initial management, or prevention, of milk allergy. Second, lactose, which is absent in soy formula, is the best carbohydrate source for normal infants.
Low iron formulas
Iron deficiency anemia probably represents the most commonly encountered nutritional problem during infancy and childhood. Babies who are not breast-fed are at significant risk of developing iron deficiency. This occurs for two reasons: first, commercial formulas are extremely low in iron content (unless the formula is supplemented with iron), and second, because the intestinal absorption of dietary iron is much greater in breast-fed infants than it is in bottle-fed infants. I therefore recommend that all formula-fed babies receive an iron-supplemented preparation. These formulas are completely safe, and will prevent anemia that may need to be treated in the future. An overload of iron may cause constipation, but the vast majority of infants tolerate supplemented formulas without difficulty.
How Much? How Often?
Determining how much to give a breast-fed infant is easy-babies will nurse until they are satisfied, and the volume of intake is impossible to measure. Formula-fed infants, however, are often encouraged to drain the bottle. Not uncommonly, I see a one month-old baby consuming six or more ounces every four hours!
As a general rule, you should add three ounces to your baby's age in months, to determine the amount of formula consumed every four hours (until she sleeps through the night). So at one month your baby will take four ounces, at two months five ounces, and so on. When your baby wants to consume more than thirty-two ounces of formula per day (usually by four to five months), she should be ready to supplement her diet with solid foods. Whole cow's milk should not be introduced until at least ten months of age.
Summary
Despite significant advances in infant formula design and manufacture, breast milk remains the optimal choice for infant nutrition. Nevertheless, these human milk substitutes provide nutrients sufficient to assure the normal growth and development of your baby.
Should you choose formula instead of nursing, try to pick one of the cow milk protein-based preparations (unless your pediatrician recommends otherwise), then stick with it! Some parents switch formulas at the slightest indication of any problem. This generally makes matters worse. If you are concerned about formula intolerance, speak to your pediatrician or family doctor before changing you baby's routine. Finally, avoid whole cow's milk until your baby is at least ten months old. I recommend holding off until twelve months. Remember, cow's milk was designed for calves, not for babies.
