Taste and its influences. How to make vegetables attractive foods for children

From birth, humans show liking for sweet tastes and a dislike of sour or bitter tastes (Beauchamp & Moran 1982) and preferences for salty tastes emerge at around 4 months of age. In a study of the food preferences of over 400 4-5 year old children, we observed strong liking for sweet, starchy and high fat foods, moderate liking for fruit and protein foods and widespread dislike of vegetables (Wardle et al. 2001). Low consumption and dislike of vegetables is a robust finding in community surveys worldwide (Cooke et al. 2004; Skinner et al. 2002).

The only other characteristic of food reliably associated with children’s food preferences is energy density (i.e. calories per gram). Indeed, combined with sweetness, energy density accounts for a substantial proportion of variance in food preferences. The satiating effect of eating high calorie foods produces pleasant feelings of fullness which become associated with their taste, texture or smell and thus a preference is learned. Even amongst fruit and vegetables - which are relatively low in energy density - children have been found to prefer those that are more energy-dense, so that potatoes and bananas are preferred to courgette and melon; and this remains true even after controlling for sweetness (Gibson & Wardle 2003).

A further important determinant of children’s food preferences is familiarity. Put simply, children like to eat foods they know; the more often a food has been tried the more it is liked. The means by which a food becomes familiar is partly direct experience, but may also be through observation of the eating behaviour of others. Research with many animal species shows that watching conspecifics eating and enjoying a novel food encourages the target animal to eat it. Modelling has also been demonstrated with children. These generalities of children’s food preferences probably evolved in the impoverished food environment of the distant past to ensure adequate energy and nutrient intake and avoid accidental poisoning.

Although it is possible to make generalisations about children’s likes and dislikes, there are also wide individual differences. For example, in one study, the number of foods out of 95 that children disliked ranged from none to 45 (Wardle et al. 2001). In addition, children vary widely in their responses; to foods, and to unfamiliar foods in particular. Food fussiness and neophobia (a reluctance to try new foods) are common in preschool aged children and our findings have shown that they impact negatively on consumption of fruit, vegetables and protein foods (Cooke et al. 2006; Cooke et al. 2003).

Variations between children appear to be both genetically and environmentally determined. We have used to twin data to provide estimates of the relative contribution of genetic and environmental factors to preferences for foods in empirically-derived categories (Breen et al. 2006). The - 16 - FOOD IN ACTION 2007 - Abstract Book highest heritability estimate was found for meat/fish (0.78) followed by fruit (0.51), vegetables (0.37) and, lowest of all, desserts (0.20). In another study of these twins, we have established that roughly 78% of the variance in neophobia is attributable to genetic factors (Cooke et al. 2007). However, findings of moderate to high heritability do not indicate that dislikes, especially for vegetables, are intractable since environmental factors also have an important role to play.

The extent to which parents model eating behaviour, the frequency with which they serve particular foods to their children, and the strategies they use to encourage consumption, all influence food acceptance. Whilst strict control and the use of reward may be counter-productive, graduated exposure methods hold considerable promise. In one study, mothers of preschool children were randomised to an exposure condition (encouraging their child to do daily tasting of the target vegetable), information (leaflets and advice on healthy eating) or a control (no treatment) condition. Children were given a pre- and post-intervention test of liking and intake. Only children in the exposure group showed significant increases in liking and intake and these increases were greater than in either of the other two groups (Wardle et al. 2003). Exposure techniques appear to reduce neophobic responses to new foods by requiring only sub-rejection- threshold levels of consumption on any one occasion. However, the long term impact on liking and consumption remains untested at present and should be a focus of future research.

In conclusion, innate taste preferences and predispositions tend to militate against children’s liking for vegetables, but children’s capacity to learn from experience can be harnessed to increase acceptance. Exposure-based interventions hold the most promise and the refinement of interventions and dissemination of improved guidance to parents is a future priority.

References

1. Beauchamp, G. K. & Moran, M. (1982) Dietary experience and sweet taste preference in humaninfants. Appetite, 3, 139-152.

2. Breen, F. M., Plomin, R. & Wardle, J. (2006) Heritability of food preferences in young children. Physiol Behav., 88, 443-447.

3. Cooke, L., Carnell, S. & Wardle, J. Food neophobia and mealtime food consumption in 4-5 year old children. International Journal of Behavioral Nutrition and Physical Activity 2006.

4. Cooke, L., Wardle, J. & Gibson, E. L. (2003) The relationship between child food neophobia and everyday food consumption. Appetite, 41, 95-96.

5. Cooke, L., Wardle, J., Gibson, E. L., Sapochnik, M., Sheiham, A. & Lawson, M. (2004) Demographic, familial and trait predictors of fruit and vegetable consumption by preschool children. Public Health Nutrition, 7, 295-302.

6. Cooke, L. J., Haworth, C. A. & Wardle, J. (2007) Genetic and environmental influences on children’s food neophobia. American Journal of Clinical Nutrition, 86, 428-433.

7. Gibson, E. L. & Wardle, J. (2003) Energy density predicts preferences for fruit and vegetables in 4 year-old children. Appetite, 41, 97-98.

8. Skinner, J. D., Caruth, B. R., Bounds, W. & Ziegler, P. J. (2002) Children’s food preferences: a longitudinal analysis. Journal of the American Dietetic Association, 102, 1638-1647.

9. Wardle, J., Cooke, L., Gibson, E. L., Sapochnik, M., Sheiham, A. & Lawson, M. (2003) Increasing children’s acceptance of vegetables: a randomised trial of guidance to parents. Appetite, 40, 155-162.

10. Wardle, J., Sanderson, S., Gibson, E. L. & Rapoport, L. (2001) Factor-analytic structure of food preferences in four-year-old children in the UK. Appetite, 37, 217-223.