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Lan Zhang, Hai-Qi Li
Chongqing, China
Author Affiliations: Department of Primary Child Care, Children's Hospital of Chongqing University of Medical Sciences, Chongqing 400014, China (Zhang L, Li HQ)
Corresponding Author: Lan Zhang, MD, Department of Primary Child Care, Children's Hospital of Chongqing University of Medical Sciences, Chongqing 400014, China (Tel: 86-13982156971; Email: zlan7487@126.com)
Background: Baby facial action coding system (FACS) is a standard instrument created by Oster and Rosenstein. Many researchers used it to study the taste development in infants of different countries. This study was undertaken to investigate the facial responses of newborns to four basic tastes as well as the gender-related taste sensitivity.
Methods: Sixty-two newborns (31 females and 31 males) were tested at 90 minutes after birth in response to four tastes including 25% sucrose (sweet), 5% sodium chloride (salt), 1.43% citric acid (sour), and 0.025% berberine (bitter). The mothers of the newborns had normal pregnancy and spontaneous delivery. The newborns were full-term with Apgar scores ¡İ8 at 1 and 5 minutes. The facial responses to the four tastes were classified into nine facial action units and expressions from A1 to C3, which also represented as the 1-9 grades of intensity. Cry was defined as intensity of grade 9 and nausea as grade 10. The expressions of the newborns were recorded by video. The chi-square test and the Wilcoxon's rank-sum test were used for statistical analyses.
Results: Most of the newborns showed absence of mouth action or sucking while the sucrose solution was given (P<0.01). No special expressions were seen when the salt solution was fed (P>0.01). The lip pursing with brow and middle face actions was a major response to the sour solution (citric acid) (P<0.01). The expressions responding to the bitter solution were mouth gaping with brow and middle face actions (P<0.01). Male newborns were more sensitive to the sweet and bitter solutions than female ones (P<0.01). There were no sex differences in the intensities of facial responses to the salt and sour solutions (P>0.05).
Conclusions: Newborns can present distinct responses to the four basic tastes (sweet, salt, sour, and bitter). Male newborns are more sensitive to sweet and bitter solutions than female newborns.
Key words: neonates; taste; development
World J Pediatr 2007;3(3):203-208
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