MONDAY, April 5, 2004 (HealthDayNews) -- If you're wondering why you can't resist salty potato chips or even brussels sprouts, ask your parents what they fed you as a baby.
Taste preferences begin to develop as early as 3 or 4 months of age and are very dependent on what is fed during early infancy, said Julie Mennella, a biopsychologist and researcher at the Monell Chemical Senses Center in Philadelphia, a basic research institute. Menella has just completed more research on feeding preferences of infants.
She describes ages 3 and 4 months as "a pretty magical time." For instance, "it is when babies' salt taste -- the ability to detect salt -- appears to peak," she said.
Her team assigned 53 babies whose parents had chosen to formula-feed into one of four groups by the time they were 2 weeks old. One group was fed the milk-based formula Enfamil, while another got Nutramigen, a protein thydrolysate formula that most adults would describe as very unpleasant tasting. The other two groups got three months of protein formula with four months of standard formula, introduced at different times.
After seven months, the researchers videotaped the babies while feeding on three separate days with three different formulas -- the two used in the study and another protein formula called Alimentum. Protein formulas are often fed to babies who suffer from colic, because doctors believe they're allergic to milk-based formulas.
Seven-month old babies who had never had the protein formula rejected it. But those who had eaten it during the study appeared relaxed and happy while feeding on the protein formula, Mennella said.
"If the babies got these formulas when they were young, they continued to accept them," she added. "Some of these flavor experiences during the first year of life are impacting on preferences later in life."
Using the two formulas during the study was not meant to suggest that one is better than another, Mennella noted. "It basically is using this [approach] as a tool to get at the timing [of taste preferences]," she said.
In previous research, Mennella and her colleagues found that breast-fed infants learn to accept and prefer the flavors of their mothers' diets, which are transmitted via the breast milk.
While genetics also plays a role in taste preferences, Mennella's research, which appears in the April issue of the journal Pediatrics, suggests exposure and environment also count.
The goal of the research is to improve diets, to get young children eating more healthfully, she said.
But what persuades babies and the rest of us to like a certain flavor is a complicated question, she said.
"Flavor is both taste and smell, and a lot of it is smell. Smell enables us to distinguish strawberry from cherry Jell-O, for instance," she said. "During childhood, olfactory memories are being formed, which are flavor memories."
"I think that it is some of these experiences occurring during infancy and early childhood that defines comfort food for us," she added.
One practical implication of her current study, Mennella said, is that parents advised to feed their babies the protein formula shouldn't feel as if they are punishing the child by using a formula most adults find unpleasant tasting. If introduced early enough, her research shows, children accept such a formula readily and actually find it palatable.
As more is discovered, Mennella said, the more information parents will have on what foods and formulas they should consider feeding their children to shape the most healthful preferences.
The study lends some science to what pediatricians have assumed for years, said Dr. Frank Greer, a professor of pediatrics at the University of Wisconsin at Madison and a member of the American Academy of Pediatrics' nutrition committee. "This study is a good start to show there's something to it."
A good next step, he said, would be to feed pregnant women or breast-feeding mothers the protein formula and see if their infants were more accepting of the taste.
But he added, "I don't want to promote these formulas for typical milk intolerance." Their optimal role, he said, is only for children with milk allergy.