Nurturing a Healthy Generation of Children: Research Gaps and Opportunities. Группа авторов

acceptance was associated with a higher acceptance of vegetables at the age of 1 year [30].

Concerning flavors, we similarly explored the acceptance of foods bearing specific odors and evaluated whether their acceptance was related to the acceptance of the corresponding odors (presented alone in scented bottles). We found that at 12 months rejection of the odor of trimethylamine and dimethyl disulfide was related to the rejection of fish and sulfurous cheeses between 12 and 15 months, respectively [31]. Therefore, in the case of olfaction, the flavor-food acceptance associations concerned foods with strong, unpleasant flavors at 12 months only, suggesting that the olfactory system acts as an “alarm” system during this period of food transition.

Eating behavior in children is characterized by its evolution as far as food neophobia is concerned. By the end of the second year, neophobic reactions start happening and can also be designated as picky eating behavior. This developmental phase concerns most children, but we were interested in evaluating whether neophobic reactions could be related to differences in taste and smell acceptance. To evaluate this aspect, we considered taste differential reactivity by computing within-subject variability across tastes as well as flavor differential reactivity by computing within-subject variability across flavors. We found that at 20 months, food neophobia was associated to flavor differential reactivity but not to taste differential reactivity [32], stressing the importance of olfaction in the development of neophobic reactions.

Finally, we have developed a working model of chemosensory, experiential, and environmental factors likely to influence food likes at the age of 2 years (Fig. 2). In this model, we included parental feeding practices and feeding style in the environmental and experiential factors likely to influence likes. The evaluation of this model showed that most of the factors hypothesized to influence liking for vegetables at the age of 2 years had a significant influence, but not the variety of early flavor exposure (in utero and in mother’s milk), when all factors are taken into account in the same model [30].

Fig. 2. Working model of the various early factors which are likely to influence the development of food likes at the age of 2 years. Among the putative factors, it was previously shown that exposure to food-related flavors (in utero or in breast milk) may impact acceptance of new foods at the time of onset of complementary feeding (CF), because the amniotic fluid or breast milk may be flavored by the flavors from the mother’s diet. The reactivity of the infant to sensory stimuli, in particular food-related tastes and odors, is also likely to modulate his/her acceptance of new foods. At the onset of CF, repeated exposure to a given food was shown to strongly impact its acceptance; moreover, exposure to a variety of foods within a given category impacts the acceptance of other new foods from this category. Tracking of eating habits was previously shown but did not necessarily cover well the very early period. Finally, beyond the impact of the family feeding practices, it was previously shown that parental feeding style is also likely to impact food likes in young children.

      Conclusions

      It was shown that children are born with the ability to taste, smell, and discriminate foods, and also to learn to like a new food and its sensory properties. However, marked reactions to taste and olfactory inputs may hinder the learning processes and may be associated with the rejection of specific foods with pronounced tastes and/or flavors. Through the effect of eating experience, taste and olfactory cues acquire a biological significance in relation to the foods they are associated with. Observation of the development of taste and flavor preferences in children shows that learning abilities are high between the onset of complementary feeding and the age of 2 years. This period clearly appears as a window of opportunity to introduce foods from the family diet, particularly vegetables. Learning processes also happen in interaction with parental feeding style and practices, which have to be taken into account to fully understand the development of children’s eating behavior. The research on the early development of food preferences in relation to taste and flavor exposure is still in its infancy. Much more has to be learned: the type of exposure that is more likely to alter food preferences further, the most important periods for this chemosensory exposure, and the conditions under which they may resist to the influence of other factors which are also likely to influence the development of eating behavior and food preferences.

      Practical Implications

      The present results may have practical implications in terms of child feeding in the early years. Encouraging mothers to eat a variety of foods during pregnancy may help to imprint their child’s liking of healthy foods through the exposure to the flavors of such foods in utero. Similarly, breastfeeding until the start of complementary feeding may enhance the acceptance of new foods offered at this transitional stage in child feeding. Parents should also be aware that when tasting or smelling new foods, children are more likely to display negative facial expressions than positive ones, but they may also continue eating. Thus, parents should be encouraged to continue offering new foods to their children for sensory learning to take place, even if they feel that their child’s initial reactions to these foods are not very positive. Such advices should be particularly enforced in parents of children who are very sensitive to taste and odors, and who may be more likely to display neophobic reactions. Parents should be patient and ready to persist in their willingness to offer new foods without forcing their child to eat.

      Acknowledgments

      The authors wish to thank all the children and their parents who took part in the OPALINE study as well as their colleagues who participated in the OPALINE data collection and analysis: Claire Chabanet, Christine Lange, Pascal Schlich, Caroline Laval, Valérie Feyen, Emilie Szleper, Vincent Boggio, Sandra Wagner, Camille Divert, and Wen Lun Yuan.

      Disclosure Statement

      The OPALINE cohort was supported by grants of the Regional Council of Burgundy, of IFR92, of PRNH-INRA-INSERM, and of the “ANR — The French National Research Agency” under the “Programme National de Recherche en Alimentation et nutrition humaine”, project “ANR-06-PNRA-028, OPALINE”; and of Blédina, Nestlé, Symrise, Cedus and Valrhona; labelled by Vitagora^®. S.N. received stipend from Nestlé Nutrition Insitute for participation in the 91st NNI workshop. Other authors have no financial relationship to disclose.

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