Cow's milk is the perfect food for babies. For baby cows, that is. If you want to feed cow's milk to human babies, you have to change it. You have to process it, make it more digestible and load it with vitamins. Even after you modify it into "formula," it won't be as good for human babies as human milk.
"We are talking about two different species," says Dr. Gary Chan, sounding amused. Chan is a neonatologist at the University of Utah Medical Center. He is not the only expert to sound amused when asked why scientists haven't been able to come up with a perfect formula for formula.However, after having a little chuckle, Chan goes on to talk about the latest in formula research. He himself is working on a study into how to boost the immunological properties of formula. There ought to be good news within a year, he says. In other research, doctors and dietitians are working on absorption fat content - problems of nutrition.
Just because formula will never be perfect doesn't mean formula manufacturers aren't trying to make it better.
And why should we care about their research? Because even though three-fourths of all Utah mothers start out by nursing their babies, fewer than 40 percent of them are still nursing when baby is 6 months old. Since pediatricians don't recommend cow's milk until after a baby's first birthday, that means perhaps around 70 to 80 percent of Utah babies will get formula at some time in their lives.
Several weeks ago, pediatrician Dr. Lillian Beard came to Utah to talk about some new formulas for formula. Beard works for Carnation (Nestle USA Inc.), the manufacturer of Good Start formula. Not surprisingly, while she was talking about formula research in general, she was also touting her company's product.
At the same time Beard was speaking on the radio about formula, a nutritionist named Cathy Breedon was in town to speak to the nurses and dietitians who work for the state's Women, Infant and Child (WIC) nutrition program. Breedon also talked about the latest in formula research.
Breedon considers herself a translator. Because she has a doctorate in nutrition, she can read the research, understand it and explain it to the people who work with mothers and babies.
Both Breedon and Beard spoke about casein and whey.
Milk, all milk, is made up of casein protein and whey protein. One difference between human milk and cow's milk is in the ratio of casein to whey. Differences between baby formulas can also be found in that ratio.
Cow's milk protein is 82 percent casein and 18 percent whey. Human milk is 40 percent casein and 60 percent whey. An additional disparity: The casein and whey in human milk have a different structure than the protein in cow's milk.
Human milk protein is more easily absorbed and more fully absorbed by little human babies. The proof is in their stools. Breast-fed babies average four bowel movements a day and their stools are mustard-colored, watery, and fairly odorless. Bottle-fed babies have fewer bowel movements and their stools are harder, darker and not as innocent-smelling.
Lately, different manufacturers have been tinkering with the percentages of whey and casein in an effort to make their formulas more digestible. According to Breedon, Enfamil (manufactured by Meade Johnson) now has a casein to whey ratio of 40 to 60 percent. The casein to whey ratio in Similac (by Ross) has been the same as the cow's milk on which it's based. However, the new Similac is 51 percent casein, 49 percent whey.
Good Start is all whey. And the whey is hydrolized. Hydrolized means broken down into shorter peptides, or smaller pieces of protein. And that, according to Beard, makes it almost as digestible as human milk. (Other researchers believe that whey might be the more allergenic of the two cow's milk proteins and thus an all-casein formula might be better for some babies.) In frequency and consis-tency, the bowel movements of Good Start babies are more like those of breast-fed babies, Beard says.
But there's digestible and then there's digestible. Like all formulas, Good Start still has to have vitamins added. Babies can't absorb the nutrients as well from formula as from breast milk.
Breedon's message is that all commercial formulas are fine. She never recommends one over another, although she will occasionally suggest a mother try a different formula if a baby seems to have tummy aches on one brand.
She says, "The Infant Formula Act governs what can be made. So there is not a lot of difference between formulas. But companies want to highlight their differences - that's a marketing tool."
Casein and whey are only a small part of the research that's going on now, says Breedon.
The American Academy of Pediatrics established a range of acceptable nutrients and calories for formula. If you compare formulas with breast milk, you'll see the difference. (See chart on C1.) Breast milk has less protein and a few more calories per liter and actually fewer vitamins.
Human milk has 38 percent of its calories from carbohydrates, 7 percent from protein and 55 percent from fat. Formulas are allowed to have varying percentages of calories obtained from carbohydrates, proteins and fat, and they are usually manufactured to offer more protein and less fat.
A typical formula might offer 16 percent of its calories from protein and only 30 percent from fat (some blend of corn, palm, soy, safflower and other vegetable oils). If it seems like human milk has a lot of fat and not much protein, Breedon says, we must remember that breast milk is so perfectly suited to a baby's digestive tract that it is perfectly utilized.
Chan talks about "growing babies." The formula manufacturers have studied the way breast-fed babies grow - that being the standard for perfection - and come up with formulas that mimic the growth patterns of breast-fed babies.
All American Academy of Pediatrics-approved formulas "grow babies" that are healthy. And without a bunch of extra vitamins that would add "metabolic stress" to the baby that's trying to digest them.
The growth pattern of bottle-fed babies is still slightly different, however. They start out the same size as breast-fed babies but after about six months they are taller and heavier. By two years, all the growth differences have disappeared.
Nutritionists aren't sure whether the growth differences are caused by differences between formula and breast milk or because parents who feed babies a bottle tend to encourage the baby to drain the bottle. Breast-fed babies tend to eat just until they are full. Bottle-fed babies might actually be eating more.
There is recent information to show that breast-fed babies have higher development quotients, says Chan. But there are so many other variables - what if mothers who breast feed play with their babies more, encouraging them to get stronger and turn over? - that he hesitates to compare the developmental rates of breast-fed to bottle-fed babies.
As for other rates, bottle-fed babies get sick more often than breast-fed babies do. When they get sick, they stay sick longer.
So some of the most interesting research going on with formulas is studying the immunological properties of breast milk.
Breedon explains that most of the immunities mothers pass on to their babies come in the form of "live cells." Cows don't carry immunities to many human diseases in the first place, but even if they did, pasteurization kills all the live cells in their milk.
Thus formula is never going to offer the same number and kinds of immunities that breast milk can.
Then there is the matter of nucleotides. Nucleotides, explains Breedon, are the building blocks of RNA and DNA. Since the digestive and immune systems are the places where RNA and DNA need to replicate the fastest, mother's milk, containing nucleotides, seems to help babies develop strong immune systems and healthy digestive tissue.
So the research that is going on now is looking at adding nucleotides to formula.
There are more formulas in the world than most consumers are aware of. Breedon gave the WIC employees a list of 70 different formulas - in addition to those dozen varieties commonly found on the grocery shelves. There are corn-free formulas and lysine-and-tryptophan-removed formulas and a formula specifically for babies with an inborn metabolic problem called maple syrup urine disease.
For the vast majority of babies, however, breast milk is the best food. Breast feeding is the goal for all the women who come through the door of WIC, according to Janet Heins, dietitian and breast-feeding coordinator for the Utah health department WIC program.
WIC programs provide nutritional advice and supplements to low-income women. Nationally, WIC helps about 30 percent of all new mothers. Because they help so many people, says Heins, they had to take some of the responsibility when, during the 1980s, breast-feeding rates began to drop.
Today, they are under a Department of Agriculture mandate to spend some of their budget on promotion of breast feeding. They provide peer counselors and education and, as a result, Heins says, breast-feeding rates are about back to the all time high of the 1970s.
Formula manufacturers took some heat as well. In the 1980s, manufacturers found themselves in the midst of a public relations nightmare - they'd been promoting formula in Third World countries and were being accused of making a profit at the expense of the lives and health of babies.
Thus it is that when someone like Beard comes to town, she is careful to begin each speech with a disclaimer: Breast milk is the perfect food. But if a mother isn't going to nurse, for some reason . . . .
And then she goes on to talk about what's new in the formula of formulas.
Janet Heins is kind of chuckling as she says it, an ironic little laugh. What's wrong with this picture? she asks. What we are saying, as health professionals, is that breast milk is perfect. But when we want to know how we are doing at getting that message out, at encouraging mothers to nurse, we don't have any public health studies to rely on. We find out about the numbers of nursing mothers from none other than . . . the formula companies.
Look at it this way, Breedon says: Formulas are good products and they produce healthy babies and, in their attempt to more closely mimic breast milk, these companies are doing important research that helps us understand infant nutrition.
*****
ADDITIONAL INFORMATION
Milk remaining in the stomach - after 2 hours
Breast milk 19%
Formula - high in whey 25%
Formula - high in casein 38%
*****
Even though the casein and whey content of breast milk and some formulas are the same, absorption is different. Breast milk contains less protein and more calories than formula. Formula-fed babies tend to be larger than breast-fed babies until age 2.
Formula-fed babies tend to experience more constipation.
Formula
Similac: 51% casein 49% whey
Enfamil: 40% casein 60% whey
Good Start: 100% whey
Cow's milk
82% casein 18% whey
Breast milk and digestion
40% casein 60% whey
*****
Formula vs. breast milk
Formulas have to fortify their ingredients to equal the nutritional value of breast milk. Most nutrients are not easily absorbed (as is breast milk) and flushed through the baby's digestive system.
...............Breast milk Starter formula*
Protein 1.50g 2.45g
Fat 5.40g 5.46g
Carbo. 10.00g 10.30g
Iron 0.04mg 1.80mg
Sodium 24mg 44mg
Potassium 73mg 108mg
Niacin 208mcg 1350mcg
Folic acid 7mcg 15mcg
VITAMINS:
A 310iu 300iu
D 3.05iu 60.00iu
E .32iu 2.50iu
C 6mg 9mg
B1 29mcg 60mcg
B2 49mcg 90mcg
*Isomil