Formulating Baby’s Best Menu

While most of us think of breast milk as food, “that is a real misconception,” says Judy Hopkinson, Ph.D., associate professor of pediatrics, Baylor College of Medicine, Houston. Referring to breastfeeding as the “fourth trimester” of pregnancy, she says: “This is a physiologic link that continues, and it’s very important, particularly in the first 4 to 6 months after delivery.” Breast milk is unique in its suitability to a baby’s specific nutritional, developmental and immune needs. “The nutrients that are in human milk are the same things that provide the immunologic protection,” she says. “The proteins in human milk are the immunoglobulins. They are the factors that coat the gut. They are part and parcel of the live cells in the milk. They have multiple roles in addition to nutrition.”

Besides the benefits of these antibodies and enzymes, the lactose, fats, and whey and casein proteins in breast milk are easier for Baby to digest. “And it changes with the mother’s environment,” Hopkinson adds. “There’s an interaction going on with the baby, so the mother will be putting into her milk on a daily basis immunoglobulins that are designed to protect against the pathogens in her environment and, hopefully, in her baby’s environment.”

For manufacturers of infant formula, Mom’s a tough act to follow. But, while vitamin and mineral fortification is standard in infant formulas, feeding studies and technological breakthroughs are allowing manufacturers to bring their products closer to the human ideal than ever before. “The pace of new ingredient additions in infant formula has been perhaps slower than in other categories, due to the highly regulated nature of the product,” admits Sharon Gerdes, technical support consultant, Dairy Management Inc.™ (DMI), Rosemont, IL. But that hasn’t stopped formulators from keeping their eyes on the horizon.

For example, baby formulas better replicate Mom’s milk through the inclusion of probiotic Lactobacillus bifidus cultures. Could the next step be adding prebiotics to feed those good bugs? “Formula companies are already doing that,” says Hopkinson. And the oligosaccharide prebiotics commonly used serve other functions, as well. Noting that “there’s quite a bit of fiber in human milk,” she points out that “these are not fibers like Metamucil. These are a whole variety of components that have very specific action in preventing serious illness in a child.” Some appear to block pathogen binding sites in the baby’s digestive tract, she says. “The other mechanism through which they work is to bind to that part of the pathogen that’s capable of attaching to the mucosa and invading.” Either way, they offer an exciting avenue for product designers to explore.

From a protein standpoint, most infant formulas get theirs from ingredients like nonfat milk and milk-protein concentrates. But, in a bid to come even closer to human breast milk, “perhaps the most-common dairy ingredient in infant formulas is whey protein,” says Gerdes. The ratio of whey to casein in mature human milk is roughly 60:40, while cow’s milk’s stands at near 20:80. Whey enrichment is an excellent strategy for readjusting those proportions closer to the model. According to “U.S. Whey Product and Child Nutrition,” a monograph from the U.S. Dairy Export Council, Arlington, VA, 42% of a formula’s total protein is to come from whey. In other words, “approximately 6 grams of whey protein would need to be added to 9 grams of cow’s-milk protein in a typical cow’s milk–based formula delivering 15 grams of protein per liter,” the paper says.

A higher whey-to-casein ratio also benefits the infant’s amino-acid balance. The plasma amino-acid profiles of breast-fed infants are markedly different from those of infants fed cow’s milk, or even predominantly whey protein–based formulas. Thus, some formula manufacturers have shown interest in formulating with alpha-lactalbumin-enriched whey because its high concentrations of cystine and tryptophan resemble the amounts found in human milk. Manufacturers of formulas for premature infants target a 60:40 whey-to-casein ratio, as well, since casein-dominant formulas yield excessive plasma concentrations of tyrosine and phenylalanine.

When working with whey proteins, formulators should note that the presence and levels of di- and polyvalent ions, buffer salts like citrates and phosphates, and emulsifiers and stabilizers all affect formula stability, as will homogenization temperature and pressure. What’s more, the more whey protein you add to a formula, the more water-soluble vitamins and some minerals—chiefly calcium—you’ll also need to add to satisfy Codex Alimentarius standards for infant formula.

Fats serve a function

As for the fat composition of infant formulas, two long-chain polyunsaturated fatty acids (LC-PUFAs)—docosahexaenoic acid (DHA) and arachidonic acid (ARA)—are receiving heightened attention, too. DHA, an omega-3, and ARA, an omega-6, are the two most-prevalent LC-PUFAs in breast milk and in the structural fat of the baby’s brain, retina and nerves. During the second trimester, as well as during Baby’s first two years, these structures’ development reaches peak levels, making these critical times for DHA and ARA accumulation.

Humans can synthesize DHA and ARA from the alpha-linolenic acid (ALA) and linoleic acid (LA) precursors, respectively, found in foods—including infant formulas. However, a baby’s conversion rates—especially a preemie’s—cannot meet their growing system’s needs. Thus, formula-fed babies may lack DHA and ARA compared to breast-fed babies, whose brains and retinas show high concentrations of the fats. For this and other reasons, expert panels from the World Health Organization, Geneva, and the Child Health Foundation, Columbia, MD, recommend adding DHA and ARA to infant formulas. FDA approved their use in 2002, but has left their addition up to the manufacturer.

Yet, even without a mandate, companies have been quick to incorporate the fatty acids. Davis notes that 96% to 97% of infant formulas on the U.S. market include DHA and ARA, as reams of studies testify to their value. Among the findings that Martek presents on its website: Breastfed infants weaned to formula supplemented with DHA and ARA demonstrated higher visual acuity than breast-fed infants who transitioned to unsupplemented formula; infants fed formula containing recommended levels of DHA and ARA showed improved mental development and scored seven points higher on the Bayley Mental Development Index; and the blood pressure of babies fed formula with DHA and ARA was significantly lower than that of babies fed unsupplemented formula, yet similar to blood pressure of breast-fed infants.

Researchers haven’t yet settled on optimum addition levels. According to the American Academy of Pediatrics, Elk Grove Village, IL, expert panels from Life Sciences Research Office, Inc., Bethesda, MD, recommend neither a minimum nor a maximum for either fatty acid in term infant formulas, although they set a maximum in preterm formulas of 0.35% and 0.60% total fatty-acid intake for DHA and ARA, respectively. Davis, for her part, suggests that, for term infants ages 0 to 6 months, at least 0.20% of fatty acids should come from DHA, and up to twice that much from ARA.

Menu no-nos

With so much focus on what babies need, it’s easy to lose sight of what they don’t need. Yet, antsy parents, combined with complex, sometimes conflicting food-safety recommendations, have product developers acting with an abundance of caution when adding ingredients to baby foods.

For one thing, we couldn’t add honey even if we wanted to. Because children younger than 1 year don’t yet have the intestinal flora to prevent Clostridium botulinum spores in honey from hatching active bacteria, regulations prohibit manufacturers from using it in commercially prepared baby foods. And, while some links have emerged between corn syrup and similar illnesses, the corn syrup in processed baby foods and formulas undergoes heat treatment sufficient to serve as a kill step.

Seemingly innocuous vegetables like beets, carrots, collards, spinach and turnips can also pose a threat of causing methemoglobinemia, a serious form of anemia in young children, if grown in high-nitrate soil or water. This should give pause to moms and dads eager to process their own puréed baby foods; while manufacturers can extensively test their vegetables or contract with growers whom they know not to use high-nitrate soil or water, the lay parent cannot.

Allergens are always a concern in immunologically immature babies. Indeed, one of the reasons experts recommend not feeding Baby anything other than human milk or formula for the first four to six months is that babies are so prone to developing reactions. Once Baby does start on solid foods, however, the general scheme for identifying and avoiding allergies involves, first, not feeding any notorious allergens during the first few months on solids, and then introducing new foods one by one, usually for three days to a week at a time, to observe any reactions and narrow them to a particular culprit.

This is why baby-food manufacturers should focus on single-ingredient formulations for their first-stage products and avoid the usual offending suspects. “The most common is cow’s milk,” says Guy H. Johnson, Ph.D., principal, Johnson Nutrition Solutions LLC, Kalamazoo, MI. Formula manufacturers can sidestep this by using hydrolyzed cow’s-milk proteins, which are effectively predigested for the infant. Some brands follow this approach, while others eliminate the proteins entirely. Eggs are also considered a no-no until late in the first year, as are other common allergens, including wheat, corn, citrus, tomatoes, seafood, peanuts and tree nuts.

These last two are inadvisable for another, completely different reason: They’re choking hazards. So are hot dogs sliced into coin shapes, peanut butter, caramels and other viscous or sticky foods, whole grapes, large chunks of firm fruits like apples or hard pears, similarly firm vegetables, big pieces of meat, popcorn, sunflower seeds, raisins, and even soft breads that turn into a pasty bolus that could lodge in Baby’s throat. The issue of choking is particularly important in the context of snacks, which baby usually eats in a slightly less-supervised manner, and which are usually delivered in individual units that, if not designed correctly, can be a choking hazard waiting to happen. “You want something that the baby can chew and that will pretty much dissolve in their mouths,” Johnson says. “The classic is that people will give their toddlers Cheerios because they taste good and they’re appropriate to eat.” He suggests toast or items with a biscuit or crackerlike texture, too, not to mention small bits of cooked fruit or carrots.

Kimberly J. Decker, a California-based technical writer, has a B.S. in Consumer Food Science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay area, where she enjoys eating and writing about food. You can reach her at kim@decker.net.

Web resources

Building Blocks for Baby Food

Code of Federal Regulations, Title 21, Section 107.3—Infant Formula

FDA Infant Formula Overview

Standard For Infant Formula And Formulas For Special Medical Purposes Intended For Infants

Other resources

Essential Fatty Acids

Prebiotics

Probiotics

Whey and Whey Products