Previous Exposure To Flavors Improves Infants' Food Acceptance - Brief Article

Nutrition Research Newsletter, July, 2001

A major concern of parents of infants is the timing and order of introduction to solid foods (beikost). Typically, parents are instructed by pediatricians to first complement milk feedings with a grain product and then to gradually introduce other foods such as pureed fruit, vegetables, and meats. There is some controversy among health care professionals as to whether or not foods should be introduced in a particular order. Some feel that vegetables should be offered before fruit because infants have an inherent preference for sweet tastes, which may interfere with the acceptance of vegetables. The ultimate goal is to encourage children to eat a varied diet that will meet the nutritional needs of growth. Research in both human and animal models suggests that acceptance of solid foods by infants during weaning is enhanced by early exposure to flavor variety.

Researchers at the NIH tested the hypotheses that exposing formula-fed infants to a variety of flavors at the time when beikost is first introduced could enhance the acceptance of new foods by the infants. They also hypothesized that infants who had previously consumed fruit would be less likely to reject vegetables at the time of first exposure than would infants who had never been exposed to fruit. Forty-eight formula-fed infants who had begun consuming cereal during the previous month were recruited to serve as subjects. None of the infants had consumed vegetables or meats prior to enrollment in the study; however, 32% were previously fed pureed fruit, fruit juices, or both at least daily; 16% were fed fruit occasionally; and the remaining 50% of infants had never been exposed to fruit. Mothers were given masks to wear during the testing to eliminate any potential influence of their facial or verbal responses on the infants' behaviors and to minimize the effects of maternal responses to the food odors. The mothers were instructed to refrain from introducing additional foods or beverages to their infants before and during the 12-day experimental period. Mothers brought their infants to the testing center on days 1,11, and 12. The mothers were videotaped feeding their infants pureed carrots on days 1 and 11 and pureed chicken on day 12. The content of three jars was the maximum amount of food offered during each session. The amount of food consumed was measured by weighing each jar of baby food immediately before and after each feeding session. Following the feeding session, mothers were asked to rate their infants' enjoyment of the food on a five-point scale. The infants' experiences during the nine-day home exposure period were different. Mothers and infants were randomly assigned to one of three experimental groups: the carrot group was fed carrots only; the potato group was fed potatoes only; and the variety group was fed a variety of vegetables that did not include carrots.

After data analysis, it was found that infants fed either carrots or a variety of vegetables during the home exposure period ate significantly more of the carrots after the exposure period than did the infants who were fed potatoes during the home exposure period. Previous exposure to a variety of vegetables also increased the acceptance of the novel food, pureed chicken. Daily exposure to fruit also enhanced the infants' initial acceptance of carrots.

Through this research the investigators demonstrated that exposure to a variety of flavors enhances acceptance of novel foods in formula-fed infants.

C. Gerrish, J. Mennella. Flavor variety enhances food acceptance in formula-fed infants. Am J Clin Nutr; 73:1080-1085 (June 2001) [Correspondence: JA Mennella, 3500 Market Street, Philadelphia, PA 19104-3308. E-mail: mennella@monell.org].