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

ultimately increase the range of nutrients consumed and the likelihood that a well-balanced diet is achieved. In other words, the variety effect may reflect an important adaptive mechanism in the regulation of food intake among omnivores.

      Repeated Exposure

Despite the new freedom to introduce a variety of foods, many infants and young children are still unable to find the optimal nutritional mix. Vegetables may be rejected for a number of different reasons, from their bitter taste, unfamiliar texture, their relatively low energy content to simple lack of access in many families. Infants are born with about 10,000 taste buds and are, so to speak, real supertasters at birth. Although they have a genetic preference for sweets, they also have an aversion to bitterness. Whether fennel, broccoli, or artichoke – even the smallest trace of bitter substances often does not escape the highly sensitive child’s palate. Thus, the following question emerges: Can children learn to like vegetables? What the infant tastes or does not taste is a question of training. Many parents give up here too soon. So, what to do when gourmet babies stubbornly resist something new? The most successful strategy to promote vegetable intake is repeated exposure [1, 12–14]. Repeated exposure to the pure/distinct taste of a vegetable during complementary feeding (on at least 8 occasions) can help infants learn to accept vegetables both immediately and in later childhood [1, 12]. So, if the baby does not eat a certain type of vegetable, it does not automatically mean that they do not like it. At first, they only reject them because they do not know them. This is often misinterpreted. So, patience, patience – parents should not blame the child. It is a fundamental survival instinct that warns the little ones against new things. Patient repetition pays off. Parents should offer a new type of vegetable at least 8 times in a row. So, the baby gets used to its taste and learns to like the disliked vegetable.

      Several research groups have observed that repeated exposure to a new vegetable, even one that is initially disliked, can lead to acceptance of that vegetable [12, 13]. For example, when a well-liked vegetable and an initially disliked vegetable were given to 7-month-old infants on alternate days over 16 days, by the 8th exposure to each, intake and liking of the 2 were similar [12]. In this study, mothers were asked to specify which vegetable purée their infants especially liked during the first months of taking solid foods or rejected so adamantly that the mothers no longer offered these foods to them. The mothers were then asked to offer their infants one vegetable daily – alternating between a vegetable the infants had initially rejected and one they had preferred – for 16 consecutive days. By the 8th exposure, the infants’ liking and intake of both vegetables was almost identical. Nine months later, 63% of the infants were still consuming and liking the previously disliked vegetable [12]. This persistence of increased acceptance was confirmed in children aged 6 years since 57% of the children continued to eat and like the initially disliked vegetable [1]. The importance of this effect has considerable practical implications. In the same regions in Germany and France where the repeated exposure study was conducted, if infants initially disliked a vegetable, most mothers (85%) offered it at no more than 2–3 subsequent meals before giving up and deciding not to offer it again [17]. Among the mothers reporting refusal, 6% said they immediately decided their infant definitively disliked the vegetable, 33% after 2 meals, 57% after 3–5 meals, and only 4% continued trying for longer. The results of those studies suggest that, rather than giving up after 2–3 tries, it is well worth offering an initially disliked vegetable up to 8–10 times without pressuring the child to eat it, because it is likely to be followed by adequate acceptance well into childhood.

      Methods which mothers use to promote the intake of vegetables in their children are numerous. Strategies include seasoning, adding sauces or other liked foods, or even hiding vegetables. There is a lot of literature whether mixing or “masking” vegetables with other foods, a common way of preparing infant meals, enhances or reduces the positive effects of exposure on the development of acceptance for the masked vegetable [13]. Further research is required to explore whether specific combinations of foods and the prominence of the individual vegetable flavors (and visual characteristics) produce different outcomes for preference and intake. There is some evidence from a small sample of mothers that mixing vegetable flavors (purées of cooked vegetable) with milk or baby rice can increase infants’ initial acceptance of vegetables and help bridge the transition from a diet of milk to the introduction of pure vegetable flavors [21].

      Discussion and Conclusion

      The prevalence of childhood obesity is rising, and multiple studies indicate that most of the risk factors develop during the early phases of life. These factors may range from the prenatal to the postnatal period. This brief review shows the importance of complementary feeding as a window of opportunity for the development of eating behaviors that can be maintained throughout childhood. The complementary feeding period is a “window of opportunity” to familiarize infants with a wide variety of foods because at this stage infants’ openness to trying new foods is at its peak, and familiar foods are likely to become preferred foods, and these acquired preferences tend to persist in later childhood.

      Many children do not eat the currently recommended amounts of vegetables, and parents are frequently searching for practical ways to increase vegetable acceptance. The lack of the sweet flavor and the low energy density of many vegetables and some fruits mean that these foods may be rejected by children, and extra efforts may need to be put in place to help them accept these foods. Within this context, strategies to successfully promote better acceptance of vegetables should be identified. In spite of a huge body of literature, practical aspects and the results of their application are still poorly understood. This is due to the high complexity related to physiological mechanisms underlying early sensory experiences and the development of sensory preferences.

      This review shows the effectiveness of breastfeeding, early experiences with vegetable variety during complementary feeding, and repeated experience with an initially disliked vegetable in promoting vegetable acceptance into childhood. The effects are long-lasting and provide the foundation for evidence-based recommendations to help parents promote healthy eating habits to their children. Current infant feeding guidance and practices suggest that this type of approach is not typical in many countries and that there is scope to provide parents and health care professionals with practical advice on encouraging vegetable acceptance during complementary feeding. The findings addressed in this review should be used in the design of future interventions targeting the prevention of childhood obesity.

      Disclosure Statement

      The author has no conflict of interest.

      References

1Maier-Nöth A, Schaal B, Leathwood P, Issanchou S: The lasting influences of early food-related variety experience: a longitudinal study of vegetable acceptance from 5 months to 6 years in two populations. PLoS One 2016;11:e0151356.

2Jones L, Moschonis G, Oliveira A, et al: The influence of early feeding practices on healthy diet variety score among pre-school children in four European birth cohorts.