Taste development in Chinese newborns - World Journal of Pediatrics

Taste development in Chinese newbornsTaste development in Chinese newbornsLan Zhang, Hai-Qi LiChongqing, ChinaBackground: Baby facial action coding system(FACS) is a standard instrument created by Oster andRosenstein. Many researchers used it to study the tastedevelopment in infants of different countries. This studywas undertaken to investigate the facial responses ofnewborns to four basic tastes as well as the gender-relatedtaste sensitivity.Methods: Sixty-two newborns (31 females and 31males) were tested at 90 minutes after birth in responseto four tastes including 25% sucrose (sweet), 5% sodiumchloride (salt), 1.43% citric acid (sour), and 0.025%berberine (bitter). The mothers of the newborns hadnormal pregnancy and spontaneous delivery. Thenewborns were full-term with Apgar scores ≥8 at 1 and5 minutes. The facial responses to the four tastes wereclassified into nine facial action units and expressionsfrom A1 to C3, which also represented as the 1-9 gradesof intensity. Cry was defined as intensity of grade 9 andnausea as grade 10. The expressions of the newbornswere recorded by video. The chi-square test and theWilcoxon's rank-sum test were used for statisticalanalyses.Results: Most of the newborns showed absence ofmouth action or sucking while the sucrose solution wasgiven (P0.01). The lip pursing withbrow and middle face actions was a major response tothe sour solution (citric acid) (P

World Journal of PediatricsOriginal articleMethodsThe modified Rosenstein's solutions [8] included 25%sucrose (sweet), 5% sodium chloride (salt), 1.43%citric acid (sour), and 0.025% berberine (bitter). Thesolutions and room temperatures were kept at 37ºCand 28ºC respectively.TestingThe newborns were tested at 90 minutes after birth.About 0.2 ml each of the four taste solutions was droppedat the central portion of the dorsal surface of the infant'stongue. Then distilled water (0.4 ml) was used as a rinseto minimize carry-over effects from one solution toanother for 90 seconds. During testing, the newbornsshould be held upright facing forward. All the expressionsof the newborns were recorded by video. Testing sessionsconsisted of two consecutive 30-second presentations ofeach of the four solutions, separated by two 90-secondwater rinses. The order of the four solutions wasdetermined by a modified Latin square design.Data analysisThe data were analyzed by the statistical analysissystem 8.1. Frequency and intensity of the facial actionunits recorded were analyzed. The chi-square test andWilcoxon's rank-sum test were used for statistical analysis.P

Taste development in Chinese newbornsfrequency of A1 expression was lower in sour responsethan in other taste responses (3.23%) (P0.01 0.2277 >0.01C2 - - 0.2277 >0.01 - - 11.1589 0.01 0.0094 >0.01 5.8612 >0.01Original articleTable 3. Intensity of the facial expressions to the four tastes in the newbornsA1grade 1A2grade 2A3grade 3B1grade 4B2grade 5B3grade 6C1grade 7C2grade 8C3 or crying nauseagrade 9Sweet 58 0 3 0 0 1 0 0 0 0Salt 17 5 7 0 6 5 1 1 17 3Sour 2 3 0 5 10 16 3 0 16 7Bitter 13 9 11 2 1 0 2 6 17 1Nauseagrade 10Table 4. The frequency of facial action units to the four tastes in male newbornsSweet Salt Sour BitterNo. Frequency (%) No. Frequency (%) No. Frequency (%) No. Frequency (%)A1* 27 87.10 8 25.81*2 6.45 7 22.58A2 0 1 3.23 3 9.68 1 3.23A3 3 9.68 7 22.58 0 6 19.35B1 0 0 2 6.45 1 3.23B2 0 1 3.23 5 8.06 3 9.68B3 1 3.23 7 22.58* 11 35.48 0C1 0 0 1 3.23 2 6.45C2 0 0 0* 4 12.90C3 0 7 22.58 7 22.58 7 22.58*: P0.01 3.4039 >0.01 0.0695 >0.01A3 0.3827 >0.01 3.4444 >0.01 - - 1.5309 >0.01B1 - - - - 2.8466 >0.01 0.1139 >0.01B2 - - 0.9984 >0.01 4.8322 >0.01 0.3594 >0.01B3 4.6617 >0.01 1.6782 >0.01 15.5795 0.01 2.8466 >0.01C2 - - - - - - 12.400 0.01 0.9364 >0.01 0.9364 >0.01World J Pediatr, Vol 3 No 3 . August 15, 2007 . www.wjpch.com

World Journal of PediatricsOriginal articlenewborns respond as grades 1 and 2 intensity. 20 and 23newborns responded to the salt and the sour solutions asgrades 9 and 10 of intensity, respectively (Table 3).The sex differentiation in facial responsesTo the sucrose solution, 27 male newborns (87.10%)showed expression A1, which was the highest frequencyof expression A1 among the four tastes (P0.01).To the sour solution, 6.45% of the male newbornsshowed expression A1, which was the lowest frequencyof expression A1 among the four tastes, and 75.80%showed expression B and C, including 35.48% withexpression B3, which was higher than the B3 frequencycompared to the non-sour solutions (P0.01 - -C2 - - 0.6776 >0.01 0.6776 >0.01 0.2335 >0.01C3 - - 1.8419 >0.01 0.6631 >0.01 5.9679 >0.01Table 8. The frequency of the intensity to the four tastes in the male newbornsA1grade 1A2grade 2A3grade 3B1grade 4B2grade 5World J Pediatr, Vol 3 No 3 . August 15, 2007 . www.wjpch.comB3grade 6C1grade 7C2grade 8C3 or cryinggrade 9Sweet 27 0 3 0 0 1 0 0 0 0Salt 8 1 6 0 1 4 0 0 9 2Sour 2 3 0 0 4 6 3 0 9 4Bitter 7 1 6 1 1 0 2 5 7 1Table 9. Intensity of facial action units to the four tastes in the female newbornsA1grade 1A2grade 2A3grade 3B1grade 4B2grade 5B3grade 6C1grade 7C2grade 8C3 or cryinggrade 9Sweet 31 0 0 0 0 0 0 0 0 0Salt 9 4 1 0 5 1 1 1 8 1Sour 0 0 0 5 6 10 0 0 7 3Bitter 6 8 5 1 0 0 0 1 10 0Nauseagrade 10Nauseagrade 10

Taste development in Chinese newbornshad expression A, and 12.90% had expression C2(P0.01). Thirteen female newborns (33.87%)demonstrated expression A2 and A3, the frequency ofexpression A was higher than that of the other threesolutions (P0.01) (Tables 4-7).There were significant differences in facial actionunits between male and female newborns respondingto sucrose and bitter solutions (u=-4.7213, P0.05). Tothe bitter solution, 19 female newborns showed 1-3 gradeof intensity of the facial action units, and 14 of the malenewborns showed 1-3 grade of intensity (u=-2.0522,P

World Journal of PediatricsOriginal article208that to accept sour, and the newborns could distinguishthe four basic tastes.Bartoshuk et al [11]found that women have morefungiform papillae and taste buds than men. Chen's [12]studies showed that 25% of men and 6.1% of women hadno taste to bitter, with a statistical difference. In our study,newborns had sex difference in facial responses to sweetand bitter solutions. Expression A1 appeared in 100%of the female newborns and 87.10% of male newbornswhen the sweet solution was given. 53.22% of the femalenewborns were insensitive to bitter, and 45.16% of the malenewborns had the expression A to bitter flavor. Thesefindings suggest that male newborns are more sensitiveto sweet and bitter than the female newborns. All thefemale newborns were more sensitive to sour than malenewborns.There are so many dietary customs around the world.Mennella [3] suggested that early flavor experiences mayprovide the foundation for cultural and ethnic differencesin cuisine. Camras et al [10] used the Baby FACS to studyEuropean, American, Japanese and Chinese 11-montholdbabies of emotion-inducing laboratory procedures.Their results suggested that Chinese infants were lessexpressive than European, American and Japaneseinfants. Given the solutions prepared by Rosenstein(25% sucrose, 43% sodium chloride, 25% citric acid,and 25% berberine), most newborns vomited except thesweet solution. This indicated that the concentrationsof the solutions prepared by Rosenstein are not suitablefor Chinese infants. Besides, there is difference in tasteresponses in different countries.Funding: None.Ethical approval: This study was approved by the DataInspectorate of China and by the Committee on Studies InvolvingHuman Beings at the Chongqing University of Medical Sciences,China.Competing interest: None declared.Contributors: ZL wrote the main body of the article under thesupervision of LHQ.References1 Fedor-Freybergh P, Vogel MLV, eds. Prenatal and perinatalpsychology and medicine: encounter with the unborn: acomprehensive survey of research and practice. Park Ridge:Parthenon Publishing Group, 1988.2 Smotherman WP, Robinson SR, eds. Behavior of the Fetus.Caldwell: The Telford Press, 1988.3 Mennella JA. Taste and smell. In: Swaiman KF, Ashwall S,eds. Pediatric Neurology: Principles and Practice, 3rd ed.Philadelphia: CV Mosby Company, 1999: 104-113.4 Hauser GJ, Chitayat D, Berbs L, Braver D, Mulbauer B.Peculiar odours in newborns and maternal prenatal ingestion ofspicy food. 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Ontogeny of taste sense.Indian J Physiol Pharmacol 1997;41:193-203.Received February 26, 2007Accepted after revision April 11, 2007