Introducing babies and toddlers to a wide variety of fruit and vegetable tastes and textures early on pays dividends, say Alison Fildes and Dr Lucy Cooke.
Dr Lucy Cooke, Senior Research Associate and Alison Fildes, MA, Research Assistant Health Behaviour Research Centre, UCL
- Fruit and vegetable intakes in UK children are low and less than a quarter of UK children consume their recommended five-a-day
- The first four to seven months of life is a critical window of opportunity to maximise acceptance of different flavour and textures. Beyond seven months, the infant is more likely to reject new flavours and textures especially bitter flavours
- To optimise fruit and vegetable acceptance an early introduction to a great: variety of fruit and vegetables should take place
- Perseverance is important with previously rejected flavours, especially vegetables - an infant may need to be exposed to the flavour of a food several times before finally accepting.
Balanced nutrition in infancy and early childhood is essential for both short-term and future health, as dietary habits established in childhood are likely to track into later life1, 2. A substantial body of evidence indicates that a diet rich in fruits and vegetables is associated with multiple health benefits in childhood and beyond, including lower blood pressure3, greater bone mass4 and protection against certain cancers5. Despite these findings and the recent "Five-a-Day" campaign, children in the UK are consuming too few fruits and vegetables (FV). Less than a quarter of UK children are eating the recommended five daily portions of FV6 and a recent cohort study examining the diets of 18-month-olds found that 15.9 per cent of the toddlers ate no fruit and 8.4 per cent ate no vegetables over a three day period7. We investigate the evidence for best weaning practice to help optimise acceptance of FV for the infant, toddler and beyond.
When to wean
The period of infancy when solid foods are first introduced provides an unparalleled opportunity to positively influence a child's diet. Complementary feeding (CF) describes the transitional process that occurs between the period of exclusive breast or formula feeding and ultimately the consumption of family foods. This process often involves the introduction of purees and finger foods before moving onto "lumpier" foods.
Four key factors to consider before commencing CF8:
i) The capacity of an exclusively milk diet to meet an infant's nutritional requirements
ii) The infant's motor development
iii) The maturity of the infant's digestive system
iv) Risk of allergies and food sensitisation.
The current UK Department of Health (DH) guidelines recommend exclusive milk feeding for the first six months of life. Delaying the introduction of solids until six months is in line with the World Health Organization (WHO) guidelines, based on the 2001 expert consultation report9 and WHOcommissioned systematic review10, and was adopted by the UK in 2003. The health implications of delaying CF until six months in the UK, in terms of the risk of specific food sensitisation, allergies and coeliac disease remain inconclusive9,10,11,12. The DH recommends that CF should ideally not begin before six months and advises parents to consult a health professional when considering introducing solids before this age. However the British Dietetic Association (BDA) place greater emphasis on an "individual" weaning age, driven by child specific developmental signs13. Most researchers and health professionals do agree that CF should not begin before four months (17 weeks) or after six months because of an increased risk of nutrient and energy deficiencies. The DH and BDA both provide guidelines on developmental cues that indicate an infant's readiness to eat solids13,14.
A variety of flavours
Early exposure to a wide variety of foods and flavours has been shown to be predictive of later dietary intake2,15,16. The acceptance of novel flavours is enhanced in younger infants17 and earlier introduction of FV during CF has been associated with greater intake in later childhood16. There is some evidence of a critical period for flavour acceptance between four and seven months, when infants are particularly receptive to new tastes17,19. It is important to capitalise on this window of opportunity by introducing a wide variety of FV during the period of CF. As CF progresses it is also important for infants to move on from smooth purees to lumpier foods and varied textures. Research suggests in addition to experiencing a variety of flavours during CF, exposure to a variety of textures assists with the transition to an adult diet20. Exposure to lumpier foods between the ages of six and nine months has been associated with reduced feeding problems and greater fruit and vegetable consumption in later childhood18,20.
Focus on fruit and vegetables
The main predictor of children's FV consumption is enjoyment of these foods21,22 and when listing their favourite foods, older children rate fatty and sugary foods the highest and vegetables the lowest23. Children generally prefer fruits to vegetables, reflecting an innate preference for sweet tastes and dislike of sour or bitter tastes24, but some studies have shown that before seven months, infants will consume more of an unfamiliar bitter taste19,25. It may therefore, be beneficial for parents to offer vegetables before fruits during CF to capitalise on this. Children also learn food preferences through experience. In a series of studies looking at preschool children's food preferences, Birch and colleagues found the two major determinants of liking were sweetness and familiarity26,28. The simplest way to increase children's preferences for new foods is to increase familiarity by giving them repeated opportunities to taste small quantities of the food and this has been shown to increase both liking and intake24,29. Research has shown that while initial rejection of a novel vegetable is not uncommon in six to 10-month-old infants, 70 per cent will eat it after eight tastings28, but it seems that mothers typically offer an initially rejected vegetable to their infant less than five times before giving up30. Parents generally judge their infant's liking by their facial expression while eating31, but infants' facial responses to foods may not accurately indicate their willingness to continue eating. If parents focus the infant's willingness to eat, and persistently offer small tastes of a vegetable on multiple occasions, both liking and intake may be increased, even for initially rejected foods28,31. Whilst repeated exposure to a single vegetable flavour increases acceptance, a lack of variety risks "sensory specific satiety" - literally boredom with the taste. A study of infants during period of CF, found those who were offered a variety of different vegetables over nine days ate more of a novel food than those fed only potatoes or carrots32.
There is also evidence to suggest that daily changes in the vegetables offered to infants leads to immediate increases in preference and intake and decreases in rejection of unfamiliar tastes30,31,34. It is often assumed that infants should only be given the blandest of foods to taste (eg. rice or potatoes) but there is no reason to avoid the more bitter tasting green vegetables during CF. Evidence suggests the maximum benefits on food acceptance are achieved by exposing infants to vegetables with a range of sensory properties, ie. lots of different colours, tastes and textures, during CF. Vegetables can be simply cooked and pureed and frozen in ice cube trays for these first tastes and, later on, crunchy raw vegetables make great snacks and teething aids.
Parents should be encouraged to introduce their infants to a wide variety of vegetables (and following that, fruits) as first foods. Infants' negative facial responses to novel foods should not automatically be interpreted as "dislike" and parents should continue to offer rejected foods on future occasions. Repeatedly exposing infants to the tastes and textures of these foods which are most commonly rejected by young children can having a lasting impact on vegetable acceptance with attendant health benefits both in the short and longer term.
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