Flavour nutrient learning of vegetables

Rationale: Children*s consumption of vegetables is below recommendations. Since
preference is the most important predictor of children*s intake and most
children dislike vegetables, new strategies are needed to increase their
preferences for vegetables. Flavour-nutrient learning is one of the effective
mechanisms to change preferences.

Studies so far have shown the importance of the early years in later food
behaviour (Devine et al., 1998; Maynard et al., 2006; Nicklaus et al., 1991;
Nicklaus et al., 2004 & 2005; Skinner et al., 2002). During the first years of
life, infants and toddlers are learning what, how much, when and how to eat and
different studies have shown that food habits are partly formed as early as the
age of 2-3 years. Nevertheless the more favourable periods for the acquisition
of these long-term healthy food behaviours during early childhood are not known
precisely (Mennella et al., 2004). In this study we want to understand how
children develop food habits and what key learning mechanisms play a role. We
aim in this study at a younger age (two-four years).

Different learning mechanisms (conditioning, simple exposure, imitation, social
interactions in particular within the family) are known to be involved in food
preference forming (Birch, 1999). However, the impact of these learning
mechanisms has only been examined within a few weeks following an experiment
and thus does not provide a real understanding as to the long-term impact of
these mechanisms on food preference development. Moreover the individual*s
susceptibility to the different learning mechanisms has not been studied.

To understand more of the learning principles of vegetable consumption in young
children (2-4 years). The aim of this study is to investigate the effect of
flavour nutrient learning on vegetable preference and intake.

Primary Objective:
To investigate if flavour nutrient learning is an effective mechanism to
increase children*s vegetable intake.
1. is there an effect ?

Secondary Objective(s):
To investigate if there is a long term impact of flavour-nutrient learning on
vegetable preference.
2. if intake increases, is this conditioning effect maintained over time ?

Study design: A randomized (cross over design) with a duration of 8 weeks. The
children will start with two pre-tests of each vegetable puree in the low
energy variant. They will perform an ad libitum consumption session. They will
also do a rank-order preference test with four vegetable products including the
target vegetables. After these pre-tests the conditioning trails starts: one
vegetable product low energy (one flavour A) will be paired with the other
vegetable (flavour B) product high energy in one group. Whereas in the other
group the conditioning starts with a vegetable product (flavour B) low energy
paired with vegetable A high energy. So half of the children will receive
taste A with high-energy and flavour B with low-energy, whereas the reverse is
true for the other 50% of the children. The children will consume these
products (125 gram) randomly for a series of days (minimum 2 times per week),
until both vegetable products have been consumed 7 times each. After these
conditioning trials, the children will do again two post -tests (ad libitum
consumption) with each vegetable product in the low energy variant and a
preference test with three vegetable products including the target vegetables A
and B. The low energy products will be offered again after two months to
investigate the sustainability of the mechanism. In case of an increase on
vegetable intake after 2 months, there will be another post test after six
months.

Participants will receive during the study half of the time a vegetable product
low in energy and the other half a vegetable product high in energy.

Nature and extent of the burden and risks associated with participation,
benefit and group relatedness: This study is group-related and needs the
involvement of children. The mechanism of flavour nutrient learning should be
applied in real-life. Findings in adults cannot be extrapolated to children
(there is evidence that the flavour nutrient learning mechanism is less
effective in adults). The burden for the participants can be considered
minimal. It will not disturb their routine or daily schedule, since the
children will have the vegetable product just before lunchtime offered as an
entrée. The tasting procedure at the start and end of the study will be done in
the same way. The risk for the participants is nihil. The vegetable products
are made with ingredients, which are not harmful for children: fresh
vegetables, salt, rice flour, sunflower oil and maltodextrin. Children with
allergies of the selected vegetables will be excluded from participation. An
alternative will be offered to them so that they can participate in the group
activity but their data will not be used. If the mechanism works in children,
we can help to make vegetables more attractive for children. The higher
vegetable consumption will be a great benefit for children*s future eating
pattern and their health. The study is accompanied with an information program
about taste and nutrition of vegetables.