PHILADELPHIA—Infants exposed early to starchy, salty foods will develop a greater preference for salty taste, by as early as 6 months of age, than will infants who have not been given salty foods, according to a new study published in the American Journal of Clinical Nutrition.
Researchers from the Monell Chemical Senses Center found the exposed infants consumed 55% more salt during a preference test than did infants not yet introduced to starchy foods. At preschool age, the same infants were more likely to consume plain salt, demonstrating the enduring influence of early dietary exposure.
“More and more evidence is showing us that the first months of life constitute a sensitive period for shaping flavor preferences. In light of the health consequences of excess sodium intake, we asked if the effect of early experience extended to salt," said lead author Leslie J. Stein, Ph.D., a physiological psychologist at Monell.
For the study, salt preference of 61 infants was tested at both 2 and 6 months of age. At each age, the infant was allowed to drink from three bottles for two minutes each. One bottle contained water, another contained a moderate concentration of salt (one percent, about the saltiness of commercial chicken noodle soup) and the third bottle had a higher concentration of salt (two percent, which tastes extremely salty to adults). Preference for salty taste was calculated at each age by comparing the amount the infant consumed of a given salt solution to the amount of water it consumed. If the infant drank more of the 1% salt solution than water, it was considered to have a preference for the 1% solution.
Two-month-old infants were either indifferent to (1%) or rejected (2%) the salt solutions. At 6 months, salty taste preference of the same infants was related to previous exposure to starchy table food. The 26 infants already eating starchy foods preferred both salt solutions to water, while the 35 babies who had not yet been introduced to these foods remained indifferent to or continued to reject the salt solutions.
The researchers focused on starchy table foods because they include processed foods, such as breakfast cereals, bread and crackers, which frequently are used as beginning foods and often contain added salt. Exposure to other types of table foods, such as fruit, was not associated with an increased preference for the taste of salt.
To explore whether the early effect extended into childhood, 26 of the children returned at preschool age. Mothers completed questionnaires about the children’s dietary behaviors, which revealed that the 12 children who were introduced to starchy table foods before 6 months of age were more likely to lick salt from foods and also were likely to eat plain salt.
The findings suggest that the early dietary exposure was related to an increased affinity for the taste of salt several years later.
