An exploratory trial of parental advice for increasing vegetable acceptance in infancy

Abstract

Research suggests that repeatedly offering infants a variety of vegetables during weaning increases vegetable intake and liking. The effect may extend to novel foods. The present study aimed to investigate the impact of advising parents to introduce a variety of single vegetables as first foods on infants' subsequent acceptance of a novel vegetable. Mothers of 4- to 6-month-old infants in the UK, Greece and Portugal were randomised to either an intervention group (n 75), who received guidance on introducing five vegetables (one per d) as first foods repeated over 15 d, or a control group (n 71) who received country-specific 'usual care'. Infant's consumption (g) and liking (maternal and researcher rated) of an unfamiliar vegetable were assessed 1 month post-intervention. Primary analyses were conducted for the full sample with secondary analyses conducted separately by country. No significant effect of the intervention was found for vegetable intake in the three countries combined. However, sub-group analyses showed that UK intervention infants consumed significantly more novel vegetable than control infants (32·8 (sd 23·6) v. 16·5 (sd 12·1) g; P =0·003). UK mothers and researchers rated infants' vegetable liking higher in the intervention than in control condition. In Portugal and Greece, there was no significant intervention effect on infants' vegetable intake or liking. The differing outcome between countries possibly reflects cultural variations in existing weaning practices. However, the UK results suggest in countries where vegetables are not common first foods, advice on introducing a variety of vegetables early in weaning may be beneficial for increasing vegetable acceptance.

Full text

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An exploratory trial of parental advice for increasing vegetable acceptance in infancy.
Alison Fildes1, Carla Lopes3,4, Pedro Moreira4,5George Moschonis2, Andreia Oliveira3,4,
Christina Mavrogianni2, Yannis Manios2, Rebecca Beeken1, Jane Wardle1, Lucy Cooke1
1Health Behaviour Research Centre, Department of Epidemiology and Public Health,
University College London, Gower Street, London WC1E 6BT, United Kingdom. [AF, RB,
JW and LC]
2Department of Nutrition and Dietetics, Harokopio University, Greece, 70, El. Venizelou,
Kallithea 17671, Athens, Greece [GM, CM, YM]
3Department of Clinical Epidemiology, Predictive Medicine and Public Health, University of
Porto Medical School, Porto, Portugal [CL, AO]
4Institute of Public Health, University of Porto, Portugal [CL, PM AO]
5Faculty of Nutrition and Food Sciences, University of Porto, Portugal [PM]
Corresponding author/requests for reprints:
Lucy Cooke PhD. Health Behaviour Research Centre, Department of Epidemiology and
Public Health, University College London, Gower Street, London WC1E 6BT, UK.
Tel. +44(0)20 7679 1720; fax: +44(0)20 7679 8354; E-mail: lucy.cooke@ucl.ac.uk
In the UK this trial is registered as ISRCTN85048101
Running title: Trial of vegetable exposure in infancy
Keywords: Vegetables, weaning, infancy, food preferences, children, exposure.

2
Abstract1
Research suggests repeatedly offering infants a variety of vegetables during weaning2
increases vegetable intake and liking. The effect may extend to novel foods. The present study3
aimed to investigate the impact of advising parents to introduce a variety of single vegetables4
as first foods on infants’ subsequent acceptance of a novel vegetable. Mothers of four-six5
month old infants in the UK, Greece and Portugal were randomised to either an intervention6
group (n=75), who received guidance on introducing five vegetables (one per day) as first7
foods repeated over 15 days, or a control group (n=71) who received country-specific ‘usual8
care’. Infant’s consumption (grams) and liking (maternal and researcher rated) of an9
unfamiliar vegetable were assessed one month post–intervention. Primary analyses were10
conducted for the full sample with secondary analyses conducted separately by country. No11
significant effect of the intervention was found for vegetable intake in the three countries12
combined. However sub-group analyses showed UK intervention infants consumed13
significantly more novel vegetable than control infants (32.8g ± 23.6g vs. 16.5g ± 12.1;14
p=0.003). UK mothers and researchers rated infants’ vegetable liking higher in the15
intervention than control condition. In Portugal and Greece there was no significant16
intervention effect on infants’ vegetable intake or liking. The differing outcome between17
countries possibly reflects cultural variations in existing weaning practices. However, the UK18
results suggest in countries where vegetables are not common first foods, advice on19
introducing a variety of vegetables early in weaning may be beneficial for increasing20
vegetable acceptance.21

3
Introduction22
An important predictor of children’s fruit and vegetable consumption is their23
enjoyment of these foods(1, 2). Innate preferences for sweet tastes and dislike of sour or bitter24
tastes mean that fruit is readily accepted, but that liking for vegetables may be harder to25
achieve. However, innate preferences can be modified through pre- and post-natal26
experiences(3). Flavours become more acceptable as they grow in familiarity and there is27
unequivocal evidence in young children that intake and liking for unfamiliar foods can be28
increased through repeated exposure, i.e. providing repeated opportunities to taste small29
quantities of the food(4-10).30
Between the ages of 4-7 months, infants are highly receptive to new flavours and31
textures, requiring fewer exposures than older children to increase acceptance(11-14). Exposing32
children to the taste of commonly rejected foods, such as vegetables, may be most effective in33
early infancy before the onset of food neophobia or pickiness (a normal developmental stage34
during the second year of life)(14). Since food preferences develop early and have been shown35
to track through later childhood and into adulthood(15, 16), early intervention is likely to reap36
the greatest benefit.37
While repeated exposure to a single vegetable flavour increases infants’ acceptance,38
the speed with which they acquire preferences means that a lack of sufficient variety might39
result in a ‘monotony’ effect – the infant becoming bored with the taste(17). Daily changes in40
the vegetables offered to infants during the transition to solid foods have been shown to lead41
to immediate increases in preference and intake, and a generalization of the effect to42
acceptance of novel tastes(17-19). In a group of formula-fed infants, the effect of offering a43
variety of different vegetables versus carrots alone, or potatoes alone over a period of nine44
days was evaluated(17). Infants in both the variety and carrot groups significantly increased45
their intake of carrots compared with infants fed potatoes, but only the infants exposed to a46
variety of tastes ate more of a novel food at the end of the exposure period. More recently it47
has been suggested that the variety of vegetables from meal to meal offered to weaning48
infants is more important than the overall number of vegetables offered. For example,49
increased intake of novel foods was observed in weaning-age infants experiencing daily50
changes in the vegetables offered compared to infants fed three vegetables, each for three51
consecutive days(18), suggesting the beneficial effect of variety is maximized by daily52
changes. In addition, a more varied diet during the weaning period has been linked to greater53
dietary diversity in later childhood(20, 21).54

4
The benefits of repeated and varied exposure early in the complementary feeding55
period have been previously described(18, 19, 22, 23), suggesting promising opportunities for56
increasing children’s vegetable intake. However, no studies to date have tested the procedures57
in the form of an easily disseminable intervention comprising simple, practical guidance to58
parents for introducing a variety of vegetables as first foods. Furthermore, no previous study59
of variety exposure in infants has included a no-treatment control group in which mothers60
receive only the current standard weaning advice offered by their national health service.61
Finally, although current weaning recommendations and practices vary across Europe, no62
study to date has examined cross-cultural differences in the effectiveness of such an63
intervention.64
The present study is an exploratory trial of an intervention comprising guidance to65
parents on the introduction of a variety of vegetables at the first stages of weaning. The66
primary outcome was infants’ consumption of a novel vegetable, offered one month after the67
start of complementary feeding. The secondary outcome was infant’s ‘liking’ for the novel68
vegetable, rated by both researchers and mothers. The same procedure was followed by69
researchers in the United Kingdom, Greece and Portugal in order to examine the effect of the70
intervention compared with usual care in the different countries.71
72
Subjects and Methods73
Trial design74
A multicentre, individually randomized (ratio; 1:1), parallel-group study design was75
adopted for this exploratory trial conducted in the UK, Greece and Portugal between February76
2011 and July 2012.77
Sample size78
Estimating effect size was difficult because few comparable studies have been79
published. The closest study in the literature(17) achieved an extremely large effect on vegetable80
intake (d = 4.0) from a brief but intensive exposure-based intervention, with outcomes measured81
in the laboratory. A second parent-led, exposure-based intervention with 2-6 year olds showed82
a significant, but smaller effect (d = 0.2) on children’s vegetable consumption(4). Outcomes in83
previous studies have therefore ranged from small to very large, with larger effects in a younger84
age-group which is most comparable to the present study. The sample size for the current trial85

5
(n=120) was therefore designed to provide 80% power to detect a medium effect size (d = 0.5)86
at p = .05 (24) on intake of a novel vegetable in a taste test.87
Recruitment of participants88
Women in the final trimester of their pregnancy and mothers of infants less than 689
months old were recruited from antenatal clinics (n=327), primary care, paediatricians, and90
hospitals in London (UK), Athens (Greece), and Porto (Portugal) to a larger study exploring91
children’s fruit and vegetable acceptance during weaning. Mothers were eligible to participate92
if they were over 18 years old at recruitment, they were sufficiently proficient in each93
country’s respective native language to understand the study materials and their infant was94
born after 37 weeks gestation, without diagnosed feeding problems. Mothers who volunteered95
to participate were asked to complete a consent form and baseline questionnaire following96
recruitment. A sub-sample of these participants was randomly selected to take part in the97
current trial and invited to meet with a researcher or health professional immediately prior to98
the initiation of complementary feeding. All participants were advised that they were free to99
withdraw from the study at any point. The flow of participants through the trial in each of the100
three countries is illustrated in Figure 1.101
Randomization102
An independent statistician at University College London generated a block103
randomization matrix that was used in all three countries. Individual participants were104
randomly assigned to an intervention or control (‘usual care’) condition following an initial105
interview to establish feeding method. As research has shown that breast-fed infants accept106
new foods more readily than their formula-fed counterparts(25, 26), equal representation of107
breast-fed and formula-fed infants were ensured across the groups, and within each Country,108
using block randomization. Allocation was revealed to the researcher. Because of the nature109
of the intervention, parents in the intervention arm and researchers delivering the intervention110
were not blind. However parents were unaware of the randomized controlled design and111
therefore neither the control nor the intervention group knew of the existence of the other.112
Ethical approval113
This study was conducted according to the guidelines laid down in the Declaration of114
Helsinki and all procedures involving human subjects/patients were approved by the relevant115
ethical committees in each participating country. In the UK, ethical approval was granted by116

6
the NHS Central London Research Ethics Committee (10/H0718/54), research and117
development approval by NHS University College Hospital and NHS North Central London118
Research Consortium. In Greece, ethical approval was granted by the Ethical Committee of119
Harokopio University of Athens (session no. 27/14-07-2010). In Portugal, ethical approval120
was granted by the local ethical committee (Ethical committee for Health of the São João121
Hospital/ University of Porto Medical School – 29.JUL10-12951). Written informed consent122
was obtained from the subjects.123
124
Intervention125
All participants met with a researcher or health professional immediately prior to the126
initiation of complementary feeding (i.e. introducing solid foods). Visits took place either at127
the participants’ home or a paediatrician’s office and the mothers determined the precise128
timing of these visits (which in some instances was up to 4 weeks prior to the initiation of129
complementary feeding).130
In the intervention group, a researcher or health professional explained to the131
participant ; (i) the importance of introducing vegetables early in the weaning process, (ii) the 132
beneficial effects of offering different single vegetables each day, (iii) the techniques of133
exposure feeding, (iv) interpreting infants’ facial reactions to food, and (v) the need for134
persistence when an infant initially rejects a food. A leaflet reinforcing these messages135
(standardised across countries) was given to participants, who were then asked to complete a136
short questionnaire about their infant’s early milk-feeding experiences.137
In consultation with mothers (and paediatricians in the Portuguese sample), five138
vegetables were selected as the first foods to be introduced. Mothers were provided with a139
small number of commercially available vegetable purees to use, but were told that they could140
prepare their own foods if they preferred. They were asked to offer the five vegetables in a141
sequence over 15 days as follows: A,B,C,D,E, A,B,C,D,E, A,B,C,D,E and to record progress142
on a chart provided. For a further five days, participants were told to continue to offer143
vegetables, but in addition, to start to introduce additional age-appropriate foods.144
Participants in the control group completed the same questionnaire as intervention145
mothers. However control mothers were not offered any specific guidance, instructions or146
information on weaning with vegetables. Instead the control group received ‘usual care’147
which varies between European countries.148

7
In the UK, the recommendations are to introduce fruits, vegetables and baby rice or149
cereal as first foods, but the information provided to mothers is inconsistent and the advice150
available may vary by local health authority. In Greece, paediatricians provide parents with151
guidance on appropriate first foods, commonly baby rice, cereals or fruits. In Portugal, the152
guidelines for weaning are not prescriptive and health professionals are advised to adapt153
international and national recommendations (e.g.. from WHO, ESPGHAN and Portuguese154
Paediatric Society), to the needs and circumstances of individual infants(27). Recently there155
has been a move towards advice to introduce vegetable soups or purees as first foods.156
Outcome Measures157
Mothers in both control and intervention groups completed questionnaires about158
themselves and their infant prior to the intervention and at follow-up (one month after the159
introduction of solid foods), which included items on demographics and feeding practices.160
Mothers reported their date of birth, parity, marital status and educational qualifications.161
Mothers reported separately on the frequency of fruit and vegetable servings they had162
consumed in the past week and the data was recoded to provide an estimation of the total163
number each of fruit and vegetable portions consumed daily. Self-reported height and weight164
was used to calculate maternal BMI (kg/m2) and maternal age was calculated at the time of165
child’s birth. Maternal age and BMI were treated as continuous variables, while education166
was dichotomized as ‘university level’ vs. ‘below university level’. Mothers were also asked167
to record their child's date of birth, sex, birth weight (in kg), and the number of weeks’168
gestation at birth, to provide an estimate of gestational age. Feeding method was assessed169
with the question ‘Which feeding methods did you use in the first three months’, with170
response options: ‘entirely breastfeeding’; ‘mostly breastfeeding with some bottle-feeding’;171
‘equally breastfeeding and bottle-feeding’; ‘mostly bottle-feeding and some breastfeeding’;172
‘almost entirely bottle-feeding (only tried breastfeeding a few times)’; ‘entirely bottle-feeding173
(never tried breastfeeding)’; and ‘other’. Infant age at the time of introduction to solids was174
calculated in weeks by using the child’s date of birth and the date on which mother’s reported175
that they had offered solid food for the first time.176
At follow-up, taste tests were administered in which an unfamiliar vegetable177
(artichoke puree) was offered to participating infants. The primary outcome was intake (g) of178
the novel vegetable. Infant liking for the vegetable (independently rated by mothers and179
researchers) was also recorded. The procedure was then repeated with a novel fruit (peach180

8
puree), which acted as a control food and to provide an indication of whether the intervention181
had the unintended side effect of reducing acceptance of foods other than vegetables.182
Taste tests took place in the infant’s home or paediatrician’s office and test foods were183
fed to infants by mothers in the presence of the researcher. The researcher present at the taste184
test was the same individual who delivered the intervention and was not therefore able to be185
blinded to condition. Taste tests were conducted at the child’s mealtime in order to ensure that186
they were hungry. Mothers were provided with two 130g jars of artichoke puree, the contents187
of which were weighed prior to the start of the taste test. Artichoke puree was selected on the188
basis that it is an unfamiliar and rarely consumed vegetable among young children across189
Europe(8, 28) and not available as a commercial baby food in any of the three participating190
countries. Mothers were instructed to feed their infant as normal and at their usual pace until191
the infant refused the food on three or more occasions, or had finished two full jars. Refusal192
was defined as keeping the mouth closed, turning the head away, pushing the spoon away,193
crying, or playing(19). Conditions were kept as naturalistic as possible; with mothers using194
any techniques (i.e. facial expressions, verbal encouragements, etc.) they would normally195
employ to encourage their infant to eat in a mealtime situation. On completion of the test, all196
spilled food was returned to the bowl/jar which was weighed again to calculate the weight of197
food consumed(19). Immediately after each feeding session, the mother and researcher198
separately and independently rated the infant’s apparent liking for the food on a 9-point scale,199
ranging from 1 = ’dislikes very much‘, to 9 = ’likes very much‘ with a central point of200
5 = ’neither likes nor dislikes‘(22, 29). The entire process was then repeated with the unfamiliar201
test fruit (peach puree). The vegetable was always offered first followed by the fruit202
approximately ten minutes later.203
Statistical analyses204
Participants with complete data on the primary outcome (intake at the taste test) were205
included in the analyses. ANCOVAs were conducted to compare intervention and control206
groups by weight of vegetable consumed, and researcher’s and mother’s rating of vegetable207
liking at the taste test while controlling for country. These analyses were repeated for fruit208
intake and the researcher’s and mother’s rating of fruit liking at the taste test. As typical209
weaning practices in the three participating nations varied secondary analyses were then210
performed comparing intake and liking ratings between intervention and control groups for211
each country separately.212

9
Results213
The flow of participants through the trial is illustrated in Figure 1. In total, 139214
families completed the trial including the taste tests 1 month post-intervention (53, 31 and 55215
families in the UK, Greece and Portugal respectively). Sample demographics are presented in216
Table 1. The first solid foods consumed by the infants in the three countries, provided by217
experimental condition, are shown in Table 2.218
Completed intervention charts were returned by 86% of intervention families (UK;219
100% [28/28], Greece; 100% [16/16], Portugal; 63% [17/27]). Completed charts revealed that220
over the 15 day intervention period parents recorded their infants consuming vegetables on221
89% (mean=13.3, SD=3.0) of the 15 possible eating occasions (UK; [86%] mean=12.8,222
SD=3.4, Greece; [95%], mean=14.2, SD=1.8, Portugal [88%], mean=13.1, SD=3.0). Infants223
were recorded as eating nothing on 7% (mean=1.0, SD=1.8) of the 15 intervention days (UK;224
[6%] mean=1.1, SD=2.4, Greece; [5%], mean=0.8, SD=1.8, Portugal; [8%], mean=1.2,225
SD=1.7). Data on infants’ willingness to eat during the intervention period was missing for226
5% of the total eating occasions (UK; 8%, Greece; 0%, Portugal; 5%).227
The results of the taste tests by experimental condition are shown in Table 3. The228
mean intake of the unfamiliar vegetable puree was almost 10g higher among intervention229
group infants (38.91g) compared to the control group (29.84g). However the primary analyses230
examining the effect of the intervention in the three countries combined (n = 139) revealed no231
significant main effect of the intervention on vegetable intake, controlling for the effect of232
country (F (1, 135) = 3.49, p = 0.064). Infants in the intervention group were rated by233
researchers as liking the unfamiliar vegetable significantly more than control infants (F234
(1,135) = 4.70, p < 0.032) but a similar trend observed for maternal ratings of infants'235
vegetable liking did not reach significance (F (1,135) = 3.84, p = 0.052), while controlling for236
the effect of country in the pooled sample. No main effect of the intervention was found for237
either intake or liking ratings for fruit.238
Separate analyses by country revealed a significant effect of the intervention on intake239
of the novel vegetable in the UK, with intervention infants eating on average 16g more240
artichoke puree than control infants (32.8g vs. 16. 5g; t(51) = 3.10; p = 0.003) (see Table 4).241
This group difference in vegetable intake represented a large effect size (Cohen’s d = 0.8) (13).242
UK intervention infants were also rated as liking the puree significantly more than control243
infants by mothers (6.7 vs. 4.3; t(51) = 4.51; p < 0.001) and researchers (6.7 vs. 4.6; t(51) =244

10
4.37; p < 0.001) separately (see Table 4). A large intervention effect size was observed for245
both maternal and researcher ratings of liking (Cohen’s d = 1.2 for both). No group246
differences were found between UK intervention and control infants for intake (27.9g vs.247
40.7g) or liking ratings of the unfamiliar fruit.248
In the Greek sample, mean intake in the intervention group was on average 13g higher249
than in the control group (36.3g versus 23.6g) although this difference was not statistically250
significant. Intervention infants were also given slightly higher vegetable liking ratings in the251
taste test by both mothers (4.3 vs. 3.3) and researchers (4.6 vs. 3.4) in Greece but again these252
differences were not significant.253
In Portugal, no significant intervention effect on infants’ intake of the artichoke puree254
was observed at follow-up with intervention infants consuming only an average of 2g more255
than control infants (46.9g vs. 45.1g). Similarly there was no effect of the intervention on256
mothers’ or researchers’ vegetable liking ratings for the Portuguese infants (4.6 vs. 5.2 and257
4.5 v. 5.0 respectively).258
There were no significant group differences in intake or either mother’s or researcher’s259
ratings of the infants liking of the unfamiliar fruit puree in any of the three countries (see260
Table 4).261
Discussion262
No significant main effect of the intervention on children’s intake of a novel vegetable263
was found in the full sample. Children in the intervention group were rated by researchers as264
liking the unfamiliar vegetable more than the control group but this was not the case for265
maternal ratings. However, UK intervention infants ate significantly more of an unfamiliar266
vegetable and were rated by both mothers and researchers as liking the vegetable more than267
infants in the control group one month after the introduction of solid foods. In the Greek and268
Portuguese samples, there was no significant effect of the intervention on either intake or269
liking of an unfamiliar vegetable. However, observations of the raw data in Greece did270
suggest a positive trend towards higher consumption among the intervention infants.271
The UK findings provide support for previous research showing repeated exposure to272
vegetables during complementary feeding can impact positively on infants’ vegetable273
acceptance(22, 30, 31) and daily changes in the variety of vegetables consumed increase274
acceptance of a novel food(17, 18). The differences in the outcomes observed across the three275
study sites may be partly explained by cultural variations in typical weaning practices in these276

11
countries. Recent research has revealed that Portuguese school-children have among the277
highest levels of vegetable intake in Europe(32). In addition, the Euro-Growth study,278
examining infant feeding practices and the introduction of complementary foods across279
Europe, found that fruit was the most common first food offered to infants in both Greece and280
the UK, while in Portugal it was cereal or vegetables(33). This suggests that normal weaning281
practices in Portugal more closely resemble those advocated in the present study, potentially282
minimizing differences between intervention and control groups. The observation that over283
70% of the Portuguese control infants in the present study were given vegetable-based soups284
as their first food supports this assertion. In contrast, only 32% of the UK control infants and285
just 7% of the Greek control infants received vegetables as their first foods. Instead, baby rice286
or cereals were the most common first foods consumed by control infants in the UK (56%)287
and Greece (73%). This is also reflected in the raw intake data from the taste test in which288
Portuguese control infants ate more of the unfamiliar vegetable puree than UK and Greek289
Intervention infants.290
No group differences in fruit intake or liking were observed in the taste test in any of291
the 3 countries. This suggests that introducing single vegetables as first foods, and not292
offering fruit for the first 15 days does not reduce fruit preference in young infants. This is293
reassuring but unsurprising given infants’ innate preferences for sweet tastes(34, 35). The294
finding that vegetable exposure does not affect fruit acceptance also supports a recent study295
that found infants who had been exposed to 5 days of rice flour porridge, followed by 19 days296
of vegetables, ate on average the same amount of a novel fruit immediately post-intervention297
as infants who had no exposure yet to either fruits or vegetables and had only received 5 days298
of rice flour porridge(30).299
Alternative explanations for the group differences in novel vegetable acceptance300
observed for UK infants should be acknowledged. It is possible that the intervention infants301
received less energy as a result of consuming vegetables only for the first 15 days of weaning302
and were therefore hungrier than control infants during this period. However there is no clear303
reason why this phenomenon should be unique to UK infants. Additionally, first solid foods304
are ‘complementary’ to the continuation of milk feeding and most infants continue to305
consume a large proportion of their energy via breast or formula milk during this early306
weaning period, particularly if solids are introduced prior to 6 months as was common in the307
present study. As the intervention feeding plan lasted 15 days and the taste tests were308
conducted one month after the introduction of solids it is particularly unlikely that309

12
intervention infants were systematically hungrier than control infants at the time of the taste310
tests.311
Necessary variations in the study procedures of the participating countries are likely to312
have impacted on results. In Portugal researchers had to acquire permission from the infants’313
paediatricians/GP in order to conduct the study and in a proportion of cases the advice was314
delivered by health professionals rather than researchers. Although acceptance was generally315
high, health professionals did not comply fully with the intervention even after agreeing to316
participate. Consequently, fidelity of, and adherence to the intervention may have been317
undermined. There is some evidence of lower compliance among Portuguese participants -318
only 67% of the intervention mothers gave their infants an isolated vegetable as their first319
food as requested, compared to 93% in the UK and 100% in Greece. Additionally fewer320
Portuguese intervention parents (63%, compared to 100% in the UK and Greece) returned321
completed study charts, suggesting lower compliance with the intervention procedure. There322
is need to repeat this study in a larger sample within countries where vegetables are not323
already common first foods and future research would benefit from exploring differences in324
outcome when advice is delivered by health professionals compared to researchers. A further325
limitation of this study is that while mothers were unaware of the study hypotheses, neither326
they nor researchers could be “blinded” to treatment which may have influenced preference327
ratings in the taste tests. However, the ecological validity of the experiment; the fact it was328
implemented by mothers themselves in the home is a strength, as is the randomized study329
design and inclusion of a no-treatment control.330
The intervention was received positively by parents who particularly welcomed the331
simple, prescriptive, and unambiguous nature of the instructions at an often anxiety-332
provoking stage of infant development. UK intervention infants showed increased intake and333
liking of an unfamiliar vegetable in the short term but this was not true in Portugal where334
vegetables are commonly given as first foods. It appears that repeated exposure to a variety335
of vegetables at weaning may work to increase vegetable acceptance in the short-term in336
countries where vegetables are not typically provided as first foods. However, the longer337
term impact of the intervention remains to be explored. This intervention is straightforward338
and would be easy to disseminate to mothers during an infants’ first months when parents are339
in frequent contact with health professionals and actively seeking advice about weaning.340

13
Acknowledgement341
The authors would like to thank the families who participated in the study and the healthcare342
providers and staff who assisted with their recruitment.343
344
Financial Support345
This research is supported By: European Community’s Seventh Framework Programme346
(FP7/2007-2013) under the grant agreement n°245012-HabEat. The purees offered to347
participants in this study and the artichoke and peach purees used as a test food were donated348
by Danone Nutricia Research. The funders had no role in the design, analysis or writing of349
this article.350
351
Conflict of Interest352
None of the authors reported a conflict of interest.353
354
Authorship355
The authors’ responsibilities were as follows - LC, CL, PM, YM and JW: designed the356
research; AF, GM, CL, AO and CM: conducted the research; AF, AO, CM and RB analysed357
data; AF, LC, GM, CL, RB, AO, CM, GM and JW: wrote the manuscript; AF: had primary358
responsibility for the final content of the manuscript; and all authors: read and approved the359
final manuscript.360

14
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17
Figure 1: Flow of participants through the study
1Reasons for lost to follow up following randomization: In the UK intervention group family non-contactable (n=1); In Portugal intervention group family withdrew from
study (n=1); In Portugal control group family unavailable for visit (n=1).
2Reasons for lost to follow up following first visit: In the UK intervention group baby was unwell so unable to complete taste test (n=1) and family unavailable for visit
(n=1); in the UK control group family unavailable for visit (n=1), family withdrew from study (n=1).
3Families that completed the taste test (the primary outcome).
Allocated to control:
UK: n= 27
Portugal: n=29
Greece: n=15
Total: n=71
Allocated to intervention;
UK: n= 31
Portugal: n=28
Greece: n=16
Total: n=75
Did not complete first visit
1
;
UK: n=1
Portugal: n=1
Greece: n=0
Total: n=2
Did not complete first visit
2
;
UK: n= 0
Portugal: n=1
Greece: n=0
Total: n=1
Completed first visit;
UK: n=27
Portugal: n=28
Greece: n =15
Total: n=70
Completed first visit;
UK: n=30
Portugal: n=27
Greece: n=16
Total: n=73
Completed Follow-up
3
;
UK: n= 28
Portugal: n=27
Greece: n=16
Total: n=71
Mothers and infants selected to current
trial and randomized to group;
UK: n= 58
Portugal: n=57
Greece: n=31
Total: n= 146
Did not complete Follow-up
2
;
UK: n= 2
Portugal: n=0
Greece: n=0
Total: n=2
Did not complete Follow-up
2
;
UK: n=2
Portugal: n=0
Greece: n=0
Total: n=2
Completed Follow-up
3
;
UK: n=25
Portugal: n =28
Greece: n =15
Total: n=68

18
Table 1: Characteristics of mothers and infants by condition and country
Control Intervention
UK
(n=25)
Greece
(n=15)
Portugal
(n=28)
Combined
(n =68)
UK
(n=28)
Greece
(n=16)
Portugal
(n=27)
Combined
(n =71)
Total
(n=139)
Mothers
Age (at child’s birth, years), mean (SD) 34.2 (5.1) 31.5 (4. 7) 32.0 (4.5) 32.7 (4.8) 34.8 (2.9) 33.6 (4.0) 31.3 (5.5) 33.2 (4.5) 33.0 (4.7)
BMI (kg/m
2
), mean (SD) 23.4 (4.3) 22.4 (3.6) 24.1 (6.8) 23.5 (5.4) 21.9 (2.2) 23.3 (4.5) 22.9 (3.4) 22.6 (3.3) 23.0 (2.4)
Primapara, n (%) 16 (64.0) 8 (53.3) 14 (50.0) 38 (55.9) 14 (50.0) 8 (50.0) 17 (62.9) 39 (54.9) 77 (55.4)
Education, n (%)
1
Below University
Undergraduate or above
2 (8.7)
23 (91.3)
6 (40.0)
9 (60.0)
12 (42.9)
16 (57.1)
20 (29.4)
48 (70.6)
2 (7.1)
26 (92.9)
4 (25.0)
12 (75.0)
11 (40.7)
16 (59.3)
17 (23.9)
54 (76.1)
37 (26.6)
102 (73.4)
Marital status, n (%)
Married/cohabiting
Single
24 (96.0)
1 (4.0)
14 (93.3)
1 (6.7)
25 (89.3)
3 (10.7)
63 (92.6)
5 (7.4)
27 (96.4)
1 (3.6)
16 (100.0)
0 (0.0)
24 (88. 9)
3 (11.1)
67 (94.4)
4 (5.6)
130 (93.5)
9 (6.5)
Vegetable intake (serves/day), mean (SD) 2.6 (1.1) 1.0 (0.5) 2.1 (1.5) 2.1 (1.3) 2.6 (1.1) 1.2 (0.6) 1.7 (1.1) 1.9 (1.2) 2.0 (1.2)
Fruit intake (serves/day), mean (SD) 2.6 (1.2) 1.7 (0.9) 2.3 (1.2) 2.3 (1.2) 2.6 (1.1) 1.4 (1.0) 2.1 (1.2) 2.1 (1.2) 2.2 (1.2)
Infants
Sex (male), n (%) 12 (48.0) 10 (66.7) 11 (39.3) 33 (48.5) 16 (57.1) 11 (68.8) 13 (48.2) 40 (56.3) 73 (52.5)
Milk feeding method, n (%)
2
Entirely breastfed
Mixed
Entirely bottle fed
17 (68.0)
5 (20.0)
3 (12.0)
5 (33.3)
10 (66.7)
0 (0.0)
15 (53.6)
10 (35.7)
3 (10.7)
37 (54.4)
25 (36.8)
6 (8.8)
15 (53.6)
11 (39.3)
2 (7.1)
6 (37.5)
10 (62.5)
0 (0.0)
14 (51.9)
10 (37.0)
3 (11.1)
35 (49.3)
31 (43.7)
5 (7.0)
72 (51.8)
56 (40.3)
11 (7.9)
Gestational age (weeks), mean (SD) 39.2 (1.5) 37.9 (2.6) 39.0 (1.7) 38.9 (1.9) 39.7 (1.3) 39.0 (1.9) 38.5 (2.0) 39.1 (1. 8) 39.0 (1.8)
Birth weight (kg), mean (SD) 3.6 (0.6) 3.1 (0.5) 3.1 (0.5) 3.3 (0.6) 3.6 (0.5) 3.2 (0.4) 3.1 (0.4) 3.3 (0.5) 3.3 (0.5)
Age at introduction of solid foods, mean (SD) 5.3 (0.5) 5.1 (0.6) 5.0 (0.7) 5.2 (0.6) 5.4 (0.5) 5.8 (0.3) 5.0 (0.6) 5.3 (0.6) 5.2 (0.6)
1The variables were categorized as follows:

19
Below university: No qualifications, secondary school certificate, technical school, high school certificate, private faculty diploma
Undergraduate +: Undergraduate Degree, Postgraduate Qualification
2The variables were categorized as follows:
Entirely breastfed: Breastfeeding exclusively
Mixed: Mostly breastfeeding with some bottle-feeding, equally breastfeeding and bottle-feeding, mostly bottle-feeding and some breastfeeding
Entirely bottle fed: Almost all bottle-feeding (only tried breastfeeding a few times), Bottle-feeding only (never tried breastfeeding)

20
Table 2: First foods offered to infants by country and experimental condition
Food Categories Countries combined UK Greece Portugal
Control
(n=68)
Intervention
(n=71)
Control
(n=25)
Intervention
(n=28)
Control
(n=15)
Intervention
(n=16)
Control
(n=28)
Intervention
(n=27)
n ( %) n ( %) n ( %) n ( %) n ( %) n ( %) n ( %) n ( %)
Isolated vegetable 10 (14.7) 60 (84.5) 8 (32.0) 26 (92.9) 1 (6.7) 16 (100.0) 1 (3.6) 18 (66.7)
Isolated fruit 7 (10.3) - - 3 (12.0) - - 3 (20.0) - - 1 (3.6) - -
Baby rice or cereal 31 (45.6) 7 (9.9) 14 (56.0) 2 (7.1) 11 (73.3) - - 6 (21.4) 5 (18.5)
Vegetable soup
1
20 (29.4) 4 (5.6) - - - - - - - - 20 (71.4) 4 (14.8)
1Vegetable soups are common weaning foods in Portugal and typically include potato, olive oil and at least two different vegetables (e.g. carrot, pumpkin, onion, garlic, and
leek).

21
Table 3: Taste Test: Vegetable and Fruit intake and liking rating by experimental condition
Control
(n = 68)
Intervention
(n=71)
Mean (SD) Mean (SD) p-value
ANCOVA1
Vegetable (artichoke)
Intake (g) 29.84 (30.12) 38.91 (33.65) 0.064
Maternal rated liking 4.50 (2.63) 5.34 (2.47) 0.052
Researcher rated liking 4.51 (2.37) 5.38 (2.36) 0.032*
Fruit (peach)
Intake (g) 64.23 (65.56) 51.18 (51.76) 0.211
Maternal rated liking 6.57 (2.66) 6.20 (51.76) 0.371
Researcher rated liking 6.46 (2.71) 6.07 (2.45) 0.327
1Effect of condition controlling for Country
* P-values representing significant group differences (< 0.05)

22
Table 4: Taste Test: Vegetable and Fruit intake and liking rating by country and experimental condition
* P-values representing significant group differences (< 0.05)
UK GREECE PORTUGAL
Control
(n = 25)
Intervention
(n=28)
Control
(n = 15)
Intervention
(n=16)
Control
(n = 28)
Intervention
(n=27)
Mean (SD) Mean (SD) p-value
t-test
Mean (SD) Mean (SD) p-value
t-test
Mean (SD) Mean (SD) p-value
t-test
Vegetable (artichoke)
Intake (g) 16.47 (12.09) 32.75 (23.64) 0.003* 23.60 (22.81) 36.25 (28.74) 0.187 45.11 (37.73) 46.89 (43.36) 0.871
Maternal rated liking 4.29 (2.03) 6.69 (1.83) <0.001* 3.33 (2.35) 4.25 (2.44) 0.296 5.21 (3.05) 4.59 (2.49) 0.412
Researcher rated liking 4.58 (1.82) 6.66 (1.63) <0.001* 3.40 (2.20) 4.63 (2.10) 0.123 4.96 (2.74) 4.52 (2.61) 0.540
Fruit (peach)
Intake (g) 40.70 (32.60) 27.93 (30.09) 0.144 58.40 (49.57) 82.50 (68.04) 0.272 88.36 (85.50) 56.74 (48.82) 0.098
Maternal rated liking 7.25 (2.35) 6.69 (2.00) 0.352 5.20 (2.65) 6.00 (2.88) 0.428 6.68 (2.78) 5.85 (2.82) 0.273
Researcher rated liking 7.29 (2.26) 6.97 (1.68) 0.549 5.13 (2.17) 5.88 (2.63) 0.400 6.39 (3.12) 5.30 (2.79) 0.095