Breast-Feeding Best Bet for Babies by Rebecca D. Williams
New parents want to give their babies the very best. When it comes to nutrition, the best first food for babies is breast milk.
More than two decades of research have established that breast milk is perfectly suited to nourish infants and protect them from illness. Breast-fed infants have lower rates of hospital admissions, ear infections, diarrhea, rashes, allergies, and other medical problems than bottle-fed babies.
"There are 4,000 species of mammals, and they all make a different milk. Human milk is made for human infants and it meets all their specific nutrient needs," says Ruth Lawrence, M.D., professor of pediatrics and obstetrics at the University of Rochester School of Medicine in Rochester, N.Y., and spokeswoman for the American Academy of Pediatrics.
The academy recommends that babies be breast-fed for six to 12 months. The only acceptable alternative to breast milk is infant formula. Solid foods can be introduced when the baby is 4 to 6 months old, but a baby should drink breast milk or formula, not cow's milk, for a full year.
"There aren't any rules about when to stop breast-feeding," says Lawrence. "As long as the baby is eating age-appropriate solid foods, a mother may nurse a couple of years if she wishes. A baby needs breast milk for the first year of life, and then as long as desired after that."
In 1993, 55.9 percent of American mothers breast-fed their babies in the hospital. Only 19 percent were still breast-feeding when their babies were 6 months old. Government and private health experts are working to raise those numbers.
The U.S. Food and Drug Administration is conducting a study on infant feeding practices as part of its ongoing goal to improve nutrition in the United States. The study is looking at how long mothers breast-feed and how they introduce formula or other foods.
Health experts say increased breast-feeding rates would save consumers money, spent both on infant formula and in health-care dollars. It could save lives as well.
"We've known for years that the death rates in Third World countries are lower among breast-fed babies," says Lawrence. "Breast-fed babies are healthier and have fewer infections than formula-fed babies."
Human Milk for Human Infants
The primary benefit of breast milk is nutritional. Human milk contains just the right amount of fatty acids, lactose, water, and amino acids for human digestion, brain development, and growth.
Cow's milk contains a different type of protein than breast milk. This is good for calves, but human infants can have difficulty digesting it. Bottle-fed infants tend to be fatter than breast-fed infants, but not necessarily healthier.
Breast-fed babies have fewer illnesses because human milk transfers to the infant a mother's antibodies to disease. About 80 percent of the cells in breast milk are macrophages, cells that kill bacteria, fungi and viruses. Breast-fed babies are protected, in varying degrees, from a number of illnesses, including pneumonia, botulism, bronchitis, staphylococcal infections, influenza, ear infections, and German measles. Furthermore, mothers produce antibodies to whatever disease is present in their environment, making their milk custom-designed to fight the diseases their babies are exposed to as well.
A breast-fed baby's digestive tract contains large amounts of Lactobacillus bifidus, beneficial bacteria that prevent the growth of harmful organisms. Human milk straight from the breast is always sterile, never contaminated by polluted water or dirty bottles, which can also lead to diarrhea in the infant.
Human milk contains at least 100 ingredients not found in formula. No babies are allergic to their mother's milk, although they may have a reaction to something the mother eats. If she eliminates it from her diet, the problem resolves itself.
Sucking at the breast promotes good jaw development as well. It's harder work to get milk out of a breast than a bottle, and the exercise strengthens the jaws and encourages the growth of straight, healthy teeth. The baby at the breast also can control the flow of milk by sucking and stopping. With a bottle, the baby must constantly suck or react to the pressure of the nipple placed in the mouth.
Nursing may have psychological benefits for the infant as well, creating an early attachment between mother and child. At birth, infants see only 12 to 15 inches, the distance between a nursing baby and its mother's face. Studies have found that infants as young as 1 week prefer the smell of their own mother's milk. When nursing pads soaked with breast milk are placed in their cribs, they turn their faces toward the one that smells familiar.
Many psychologists believe the nursing baby enjoys a sense of security from the warmth and presence of the mother, especially when there's skin-to-skin contact during feeding. Parents of bottle-fed babies may be tempted to prop bottles in the baby's mouth, with no human contact during feeding. But a nursing mother must cuddle her infant closely many times during the day. Nursing becomes more than a way to feed a baby; it's a source of warmth and comfort.
Benefits to Mothers
Breast-feeding is good for new mothers as well as for their babies. There are no bottles to sterilize and no formula to buy, measure and mix. It may be easier for a nursing mother to lose the pounds of pregnancy as well, since nursing uses up extra calories. Lactation also stimulates the uterus to contract back to its original size.
A nursing mother is forced to get needed rest. She must sit down, put her feet up,and relax every few hours to nurse. Nursing at night is easy as well. No one has to stumble to the refrigerator for a bottle and warm it while the baby cries. If she's lying down, a mother can doze while she nurses.
Nursing is also nature's contraceptive--although not a very reliable one. Frequent nursing suppresses ovulation, making it less likely for a nursing mother to menstruate, ovulate, or get pregnant. There are no guarantees, however. Mothers who don't want more children right away should use contraception even while nursing. Hormone injections and implants are safe during nursing, as are all barrier methods of birth control. The labeling on birth control pills says if possible another form of contraception should be used until the baby is weaned.
Breast-feeding is economical also. Even though a nursing mother works up a big appetite and consumes extra calories, the extra food for her is less expensive than buying formula for the baby. Nursing saves money while providing the best nourishment possible.
When Formula's Necessary
There are very few medical reasons why a mother shouldn't breast-feed, according to Lawrence.
Most common illnesses, such as colds, flu, skin infections, or diarrhea, cannot be passed through breast milk. In fact, if a mother has an illness, her breast milk will contain antibodies to it that will help protect her baby from those same illnesses.
A few viruses can pass through breast milk, however. HIV, the virus that causes AIDS, is one of them. Women who are HIV positive should not breast-feed.
A few other illnesses--such as herpes, hepatitis, and beta streptococcus infections--can also be transmitted through breast milk. But that doesn't always mean a mother with those diseases shouldn't breast-feed, Lawrence says.
"Each case must be evaluated on an individual basis with the woman's doctor," she says.
Breast cancer is not passed through breast milk. Women who have had breast cancer can usually breast-feed from the unaffected breast. There is some concern that the hormones produced during pregnancy and lactation may trigger a recurrence of cancer, but so far this has not been proven. Studies have shown, however, that breast-feeding a child reduces a woman's chance of developing breast cancer later.
Silicone breast implants usually do not interfere with a woman's ability to nurse, but if the implants leak, there is some concern that the silicone may harm the baby. Some small studies have suggested a link between breast-feeding with implants and later development of problems with the child's esophagus. Further studies are needed in this area. But if a woman with implants wants to breast-feed, she should first discuss the potential benefits and risks with her child's doctor.
If a woman is unsure whether she wants to nurse, she can try it for a few weeks and switch if she doesn't like it. It's very difficult to switch to breast-feeding after bottle-feeding is begun.If she plans to breast-feed, a new mother should learn as much as possible about it before the baby is born. Obstetricians, pediatricians, childbirth instructors, nurses, and midwives can all offer information about nursing. But perhaps the best ongoing support for a nursing mother is someone who has successfully nursed a baby.
La Leche League, a national support organization for nursing mothers, has chapters in many cities that meet regularly to discuss breast-feeding problems and offer support.
"We encourage mothers to come to La Leche League before their babies are born," says Mary Lofton, a league spokeswoman. "On-the-job training is hard to do. It's so important to learn how to breast-feed beforehand to avoid problems."
Interested women or couples are welcome to attend La Leche League meetings without charge. League leaders offer advice by phone as well. To find a convenient La Leche League chapter, call (1-800) LA-LECHE.
Rebecca D. Williams is a writer in Oak Ridge, Tenn.
Tips for Breast-Feeding Success
It's helpful for a woman who wants to breast-feed to learn as much about it as possible before delivery, while she is not exhausted from caring for an infant around-the-clock. The following tips can help foster successful nursing:
- Get an early start: Nursing should begin within an hour after delivery if possible, when an infant is awake and the sucking instinct is strong. Even though the mother won't be producing milk yet, her breasts contain colostrum, a thin fluid that contains antibodies to disease.
- Proper positioning: The baby's mouth should be wide open, with the nipple as far back into his or her mouth as possible. This minimizes soreness for the mother. A nurse, midwife, or other knowledgeable person can help her find a comfortable nursing position.
- Nurse on demand: Newborns need to nurse frequently, at least every two hours, and not on any strict schedule. This will stimulate the mother's breasts to produce plenty of milk. Later, the baby can settle into a more predictable routine. But because breast milk is more easily digested than formula, breast-fed babies often eat more frequently than bottle-fed babies.
- No supplements: Nursing babies don't need sugar water or formula supplements. These may interfere with their appetite for nursing, which can lead to a diminished milk supply. The more the baby nurses, the more milk the mother will produce.
- Delay artificial nipples: It's best to wait a week or two before introducing a pacifier, so that the baby doesn't get confused. Artificial nipples require a different sucking action than real ones. Sucking at a bottle could also confuse some babies in the early days. They, too, are learning how to breast-feed.
- Air dry: In the early postpartum period or until her nipples toughen, the mother should air dry them after each nursing to prevent them from cracking, which can lead to infection. If her nipples do crack, the mother can coat them with breast milk or other natural moisturizers to help them heal. Vitamin E oil and lanolin are commonly used, although some babies may have allergic reactions to them. Proper positioning at the breast can help prevent sore nipples. If the mother's very sore, the baby may not have the nipple far enough back in his or her mouth.
- Watch for infection: Symptoms of breast infection include fever and painful lumps and redness in the breast. These require immediate medical attention.
- Expect engorgement: A new mother usually produces lots of milk, making her breasts big, hard and painful for a few days. To relieve this engorgement, she should feed the baby frequently and on demand until her body adjusts and produces only what the baby needs. In the meantime, the mother can take over-the-counter pain relievers, apply warm, wet compresses to her breasts, and take warm baths to relieve the pain.
- Eat right, get rest: To produce plenty of good milk, the nursing mother needs a balanced diet that includes 500 extra calories a day and six to eight glasses of fluid. She should also rest as much as possible to prevent breast infections, which are aggravated by fatigue.
Breastfeeding is good for every part of baby's body--from the brain to the diaper area. Here's a list:
- Brain. Higher IQ in breastfed children. Cholesterol and other types of fat in human milk support the growth of nerve tissue.
- Eyes. Visual acuity is higher in babies fed human milk.
- Ears. Breastfed babies get fewer ear infections.
- Mouth. Less need for orthodontics in children breastfed more than a year. Improved muscle development of face from suckling at the breast. Subtle changes in the taste of human milk prepare babies to accept a variety of solid foods.
- Throat. Children who are breastfed are less likely to require tonsillectomies.
- Respiratory system. Evidence shows that breastfed babies have fewer and less severe upper respiratory infections, less wheezing, less pneumonia and less influenza.
- Heart and circulatory system. Evidence suggests that breastfed children may have lower cholesterol as adults. Heart rates are lower in breastfed infants.
- Digestive system. Less diarrhea, fewer gastrointestinal infections in babies who are breastfeeding. Six months or more of exclusive breastfeeding reduces risk of food allergies. Also, less risk of Crohn's disease and ulcerative colitis in adulthood.
- Immune system. Breastfed babies respond better to vaccinations. Human milk helps to mature baby's own immune system. Breastfeeding decreases the risk of childhood cancer.
- Endocrine system. Reduced risk of getting diabetes.
- Kidneys. With less salt and less protein, human milk is easier on a baby's kidneys.
- Appendix. Children with acute appendicitis are less likely to have been breastfed.
- Urinary tract. Fewer infections in breastfed infants.
- Joints and muscles. Juvenile rheumatoid arthritis is less common in children who were breastfed.
- Skin. Less allergic eczema in breastfed infants.
- Growth. Breastfed babies are leaner at one year of age and less likely to be obese later in life.
- Bowels. Less constipation. Stools of breastfed babies have a less-offensive odor.
Milk is milk, right? Mammals make it (humans are mammals) and babies drink it. There's more to the story than that. Each species of mammal makes a unique kind of milk, which meets all the nutritional requirements of its offspring at the beginning of life. Each species' milk has specific qualities that insure the survival of the young in a particular environment. This principle is known as the biological specificity of milk. Mother seals, for example, make a high-fat milk because baby seals need lots of body fat to survive in cold water. Since brain development is crucial to the survival of humans, human milk provides nutrients for rapid brain growth.
No matter what animal it comes from, milk contains the basic nutritional elements of fats, proteins, carbohydrates, vitamins, and minerals. Let's look at each one of these nutrients in human milk, comparing them to the same nutrients in formula or cow milk, so you can further appreciate how your milk is custom-made to meet the needs of your baby.
Unique nutrition for unique humans. As hormones levels change in the days after birth, the mother's body starts to make more plentiful amounts of milk. Colostrum gradually changes into mature milk--the stuff babies have been thriving on for thousands of years. Milk's basic ingredients are fat, proteins, lactose, vitamins, minerals, and water. This is true of milk from all kinds of mammals. Yet, the proportions of these ingredients differ, as do the kinds of protein and fat. This is what makes each species' milk uniquely suited to its young. It's also why cow's milk and cow's milk-based formulas are not the ideal food for human infants.
Protein is a prime example of how human milk is unique nutrition for human babies. Human milk is low in protein, at least when compared with the milk of other species, especially cow's milk. This isn't a nutritional deficiency; there are good reasons for this. Human infants are designed to grow slowly. While it's important for humans to develop strong bodies, even more important is brain development and the learning of social skills. The experiences that shape the brain come from close contact between mother and baby when baby is held and carried. If human infants doubled their birthweight in less than 50 days the way baby calves do, and then continued growing, how could their mothers carry them and talk to them and keep them close? Baby cows need to learn where to find the best grass in the meadow; baby humans need to learn how to work with others so that everyone's needs get met.
Though the protein content of human milk is generally low, the types of amino acids that make up these proteins are important. One particular amino acid, taurine, is found in large amounts in human milk. Studies show that taurine has an important role in the development of the brain and the eyes. The body can't convert other kinds of amino acids into taurine, so its presence in human milk is significant--so significant that some formula manufacturers have begun adding it to artificial baby milks.
If you let milk stand out of the refrigerator and sour, you will see that milk proteins fall into two categories, curds and whey. (Remember Miss Muffet?) The curd portion, the casein proteins, are the white clots; the liquid is the whey. Cow's milk is mostly casein protein, which forms a rubbery, hard-to-digest curd in babies' tummies. Human milk has more whey than curd, and the curds that are formed are softer and more quickly digested. Breastfed babies get hungry sooner than babies who are formula-fed because human milk proteins are digested so efficiently. It doesn't take as much energy to digest human milk as it does to digest formula. Frequent feedings also ensure that human babies get lots of attention from their mothers.
There's another reason why babies digest human milk so quickly: the fat in human milk comes with an enzyme, lipase, that breaks the fat down into smaller globules so this important nutrient can be better absorbed into the bloodstream. Fat is a valuable source of energy for babies, so the presence of lipase makes the fat in human milk more available. This is one of the reasons human milk is so good for premature babies, who need lots of energy to grow but whose digestive systems are very immature.
A changing nutrient for changing needs. The fat content of human milk changes constantly. Typically, fat levels are low at the beginning of a feeding and high at the end. Babies nurse eagerly to get the low-fat, thirst-quenching foremilk, then slow down and linger over the high-fat dessert at the end of their meal. Babies who nurse again soon after the end of the last feeding get more high-fat milk, so babies who breastfeed more frequently during a growth spurt get more calories. Longer intervals between feedings bring down the fat content of the milk stored in the breast. This nutritional fact of human milk is one of the many reasons why the rigid 3 to 4 hour scheduled style of feeding is biologically incorrect.
Smarter fats. The special kind of fat in human milk is important to brain development. As newborn babies grow, the nerves are covered with a substance called myelin which helps the nerves transmit messages to other nerves throughout the brain and body. To develop high-quality myelin, the body needs certain types of fatty acids--linoleic and linolenic--which are found in large amounts in human milk. (See "Breastfeeding Builds Brighter Brains")
The vitamins and minerals listed on the formula can are no match for those in the milk made by mom, even if milligram by milligram comparisions suggest otherwise. When formula researchers want to know how much of a particular vitamin or mineral babies need each day, they look first at how much of that nutrient is present in human milk and how much milk a baby of a given age takes in a day. But just doing the math doesn't tell the whole story. More important than the amounts of nutrients in the milk is the amount that is available for the infant to use, a nutrient principle called bioavailability. The bioavailability of a nutrient is influenced by many factors, including its chemical form and the presence of other substances.
The three important minerals calcium, phosphorus, and iron are present in breastmilk at lower levels than in formula, but in breastmilk these minerals are present in forms that have high bioavailability. For example, 50 to 75 percent of the iron in breastmilk is absorbed by the baby. With formula, as little as four percent of the iron is absorbed into baby's bloodstream. To make up for the low bioavailability of factory-added vitamins and minerals, formula manufactures raise the concentrations. Sounds reasonable, right? If only half gets absorbed by the body, put twice as much into the can. Yet, this nutrient manipulation may have a metabolic price.
Baby's immature intestines are required to dispose of the excess. Meanwhile, the excess unabsorbed minerals (especially iron) can upset the "ecology of the gut," interfering with the growth of healthful bacteria and allowing harmful bacteria to flourish. This is another reason formula-fed infants have harder, more unpleasant smelling stools.
To enhance the bioavailability of nutrients, breastmilk contains facilitators - substances that enhance the absorption of other nutrients. For example, vitamin C in human milk increases the absorption of iron. Zinc absorption is also enhanced by other factors in human milk. In an interesting experiment, researchers added equal amounts of iron and zinc to samples of human milk, formula, and cow'd milk, and fed them to adult volunteers. More of the nutrients in the human-milk sample got into the bloodstream compared to the formula and cow's milk. In essence, breastmilk puts nutrients where they belong - in baby's blood, not in baby's bowels.
Every year medical journal articles describe more valuable substances discovered in human milk. Scientists are only beginning to write the story on other factors in human milk that may be important to baby's growth and development. For example, other enzymes besides lipase are available to aid infant digestion. Epidermal growth factor, present in human milk in significant amounts, may promote the development of tissues in the digestive tract and elsewhere. Other hormones in milk may influence a baby's metabolism, growth, and physiology. The effects may be subtle, but they may also have far-reaching implications. Being breastfed has advantages that reach into adulthood. Science is only beginning to learn what these benefits are.
The health benefits of breastfeeding extend far past weaning. As researchers look at the various factors associated with different diseases, they often find that children and adults who were breastfed as infants are less likely to experience problems with chronic diseases. In some cases, even minimal amounts of breastfeeding may provide some protection against disease in later life, but usually the longer a baby is breastfed the greater the protective effect. Here are some of the ways that breastfeeding builds a lifetime of good health:
1. Breastfeeding prevents obesity. Even in infancy, breastfed babies as a group are leaner than their formula-fed peers. Studies have shown that children who are breastfed are less likely to be obese during adolescence, and that longer periods of breastfeeding greatly reduce the risk of being overweight in adulthood. Overweight children are more likely to become overweight adults. Since breastfed babies themselves control how much they eat (aided by the changes in fat levels during a feeding session), children who are breastfed learn to trust their bodies' signals about how much they need to eat and when. This builds healthy eating habits right from the start. Although parents might urge a formula-fed baby to finish up the last ounce or two of milk in the bottle, you can't do this to a breastfed baby. When she's done, she's done!
2. Better teeth. Breastfed babies have better jaw alignment and are less likely to need orthodontic work as they get older. A study of 10,000 children found that those who were breastfed for a year or more were 40 percent less likely to require orthodontic treatment. The sucking action used to breastfeed involves complex motions of the facial muscles and tongue. This improves the development of facial muscles and the shape of the palate. The better jaw alignment associated with breastfeeding can even mean less snoring and a lowered risk for a condition known as obstructive sleep apnea--the blockage of air flow during sleep, which can disturb sleep patterns and lead to other health problems.
3. Lowered risk of heart disease. All the evidence isn't in yet, but some researchers believe that breastfeeding during infancy may lower the risk of heart attacks and strokes in later life. This is due in part to the higher levels of cholesterol in human milk. Some heart researchers theorize that because of the cholesterol content of human milk, a breastfed baby's liver learns to metabolize cholesterol better than formula-fed infants. This leads to lower blood cholesterol levels as adults and thus a lower risk of heart disease. Though limited in number, some studies have shown that adults who were formula-fed as infants tend to have higher blood cholesterol and are more likely to have arterosclerotic plaques than those who were breastfed.
4. Lowered risk of juvenile diabetes. Babies who are breastfed are less likely to develop type 1 diabetes mellitus in childhood. Researchers have attributed this lowered risk of diabetes to the delayed introduction of cow milk in breastfed babies. In addition, researchers have shown a lower insulin release in breastfed infants compared to infants fed formula. This preventive effect is particularly important if you have a family history of diabetes.
5. Lowered risk of multiple sclerosis. Multiple sclerosis, a degenerative muscle disease that strikes adults, may be caused in part by myelin breakdown. However, multiple sclerosis is less common in countries where breastfeeding rates are high. Human milk's contribution to the myelin formation may help to prevent multiple sclerosis in later life.
6. Lowered risk of asthma and allergy. Studies have shown that breastfeeding lowers the chances of a child developing allergies and asthma symptoms. Breastmilk's immune components protect babies from allergens in the first months of life. Breastfeeding also delays the introduction of potentially allergenic foods, such as cow milk and soy protein, into the diet until the baby is older and the immune system is more mature.
7. Other diseases. Research suggests that breastfeeding may also play a role in preventing digestive diseases, such as ulcerative colitis and Crohn's disease, as well as childhood cancers. This makes sense: nourish an infant's body with the unique food designed for it by nature and that body will function in a healthier way, perhaps for the child's entire life.
Breastmilk's influence on health is probably more far-reaching than researchers have even dared to imagine, but studies of factors that affect the development of disease in adults seldom ask their research subjects how they were fed as infants (and many adults would have trouble giving accurate answers to these kinds of questions). New studies of what breastmilk contains suggest that this living biological fluid carries substances that are critical to the optimal development of many systems in the body. This early development may very well affect the progress of many diseases throughout life.
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