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| Journal of the New Zealand Medical Association,
02-June-2006, Vol 119 No 1235
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Dietary patterns of New Zealand European preschool children
Reremoana Theodore, John Thompson, Clare Wall, David
Becroft, Elizabeth Robinson, Phillipa Clark, Jan Pryor, Chris Wild, Ed
Mitchell
Diet during the early childhood years is important for
growth, development, and health. Studies have found that undernutrition and
vitamin deficiencies can lead to developmental problems including lower
cognitive functioning1–3 and poor growth.4,5
Studies have also suggested that diets high in fat and sugar
are related to increasing rates of obesity and obesity-related diseases in
children and adolescents.6,7 The prevalence of overweight and obesity has
increased worldwide in children and adolescents over the last 30
years.8–10 Lack of physical activity, as well as dietary patterns, are
considered to be likely contributors to this global rise.11,12 Furthermore,
childhood dietary habits are associated with later adult diet and
health.13–15
Nutritional research in New Zealand has focused on the first
2 years of life,16 or on children over 5
years of age.17 Little is known about what preschool New Zealand children eat.
The New Zealand Ministry of Health (MOH) recommendations for preschool children
include daily consumption of a variety of fruits and vegetables, lean meats and
pulses, breads and cereals, and milk and dairy products.18 There is no
information, however, on whether preschool children’s dietary patterns
meet with MOH recommendations.
The aim of this study was to describe the dietary patterns
of preschool children and compare these with the recommended daily intakes of
key food groups.18 Dietary patterns of children in this study will be discussed
in relation to the findings from the NZ 2002 National Children’s Nutrition
Survey (CNS) on school-aged children.
MethodsSample—Children
in the study were those enrolled in the Auckland Birthweight Collaborative (ABC)
study, which was principally a case-control study of risk factors related to
being born small-for-gestational age
(SGA). The ABC study design has been
previously described in detail.19
In brief, approximately half of the children in the
study were born SGA, weighing less than, or equal to, the sex-specific 10th
percentile for gestational age.20 Controls were born appropriate-for-gestational
age (AGA), weighing greater than the sex-specific 10th percentile for
gestational age. All children were born at term, defined as 37 or more weeks of
completed gestation.
Children were born between October 1995 and November
1997. The ABC study is a longitudinal study. At birth, 1714 mothers and children
enrolled in the study. In data collected when the children were born, 871
mothers identified as being New Zealand European. Data have been collected at
birth (Phase 1), at 1 year of age (Phase 2) and 3.5 years of age (Phase 3).
At
Phase 3 of the study, 550 NZ European mothers and children were interviewed. The
response rate for Māori, Pacific Island, and other non-European
participants was low at 3.5 years. Analysis of the results of children in these
groups was considered to be unrepresentative of children in the overall
population. Analysis was therefore restricted to NZ European participants
attending at Phase 3.
The ABC study was approved by the North Health Research
Ethics Committee.
Food frequency
information—An interviewer-administered food frequency
questionnaire (FFQ) examining the frequency of consumption of a wide variety of
commonly eaten foods was completed. The FFQ had been previously validated
against a 4-day weighed food record and biochemical measures and showed good
short-term repeatability.21 The FFQ was then adapted for children at 3.5 years
of age and was comparable to the FFQ used in the CNS.
The majority of the questionnaire examined how often a
child had eaten a food in the previous four-week period.
Response options were:
Information was also
collected on the number of consumed daily standard servings of fruit and
vegetables. Serving size examples used in the study were comparable to serving
sizes defined in the NZ Ministry of Health guidelines—e.g., 1 apple,
½ cup of stewed fruit.18 Data collection over a 2-year period allowed for
the seasonal variability in intake of food.
Statistical
analysis—Analyses of the total sample employed weighting to adjust
for the disproportionate sampling of children born SGA. The weighting accounts
for the unequal selection probabilities of the SGA and AGA infants in this
study, thus making the results representative of the total population of New
Zealand European children aged 3.5 years. Food frequency information on 88
individual foods or drinks was converted to times eaten per month and combined
to create overall food groups (e.g. fruit).
To convert data on foods into groups, the mid-point of
the frequency options was taken for options such as 1–3 times per month,
which was calculated as 2 times per month.
The percentage of children consuming (or not consuming)
the New Zealand Ministry of Health (MOH) recommended intake for fruits and
vegetables based on serving sizes was calculated.18
The percentage of children consuming the following food
groups in line with MOH recommendations were calculated: breads and cereals
(including rice and pasta); meat, fish, chicken or eggs; milk and dairy
products. For other food groups, the percentage of children eating from a food
group daily or weekly was calculated.
The most commonly eaten type of food (e.g. potatoes) in
overall food groups (e.g. vegetables) was calculated by ranking the percentage
of children consuming each food per week. To assess the different variety of
fruit and vegetable eaten weekly, individual fruits or vegetables eaten at least
weekly were added.
The differences in food frequency between SGA and AGA
children, between genders, and between those children taking, and not taking,
vitamin and/or mineral supplements daily were assessed for 40 food variables,
listed in Table 2, using χ2 statistics. The procedure
‘surveyfreq’ in SAS v9.1 (SAS Institute, Cary,
NC) was used for analyses. Proc surveyfreq
can be used for single-stage or multistage designs, with or without unequal
weighting, and with or without stratification. This procedure uses the Taylor
expansion method to estimate sampling errors of estimators based on complex
sample designs (SAS statistics online manual).
ResultsThe anthropometric characteristics of the children at Phase
3 are shown in Table 1. Characteristics of the parents have been described
previously.19 In brief, for mothers who attended Phase 3 of the study, mean
maternal age at birth of the subject was 32 years of age; 14% of mothers smoked
during pregnancy; mean maternal height was 166.4 cm (SE=0.35); mean maternal
weight was 64.7 kg (SE=0.70); and mean maternal BMI was 23.2 (SE=0.24).
Table 1. Physical characteristics of the children in
the study
*Weighted
to account for disproportionate sampling; BMI=Body mass index
(kg/m2).
There was no difference in food frequency between SGA and
AGA children for major food groups. SGA children were significantly less likely
than AGA children to eat processed meats weekly (SGA 30% vs AGA 51%,
χ2 = 7.85, p=0.005) and to drink
water two or more times per day (SGA 22% vs AGA 36%,
χ2 = 4.46, p=0.03). Food frequency
results are shown for the total sample of children adjusted for disproportionate
sampling.
Seventy-three percent of preschool children were reported as
eating the recommended two or more servings of fruit per day, not including
fruit juice (Table 2). In relation to food frequency information, 68% of
preschool children ate fruit two or more times a day (Table 2). The MOH
recommended vegetable servings of two or more a day were consumed by 46% of all
children (Table 2). Males were significantly less likely than females to consume
two or more servings of vegetables per day (males 41% vs females 52%,
χ2 = 3.98, p=0.05). In relation to
food frequency, 77% of preschool children had vegetables two or more times a day
(Table 2). Males were significantly less likely than females to eat two or more
vegetables per day (males 71% vs female 81%, χ2 = 4.96, p=0.03).
Table 2. The percentage of children consuming specific
types of foods or drinks by frequency
* Does not include fruit
juice;
† MOH recommended number of servings ‡ Liver, beef/pork/lamb as part of a dish, beef/pork/lamb as main dish, corned beef § Bacon/ham, processed meats (e.g. luncheon, salami), hamburger ║ Fish fillets (fresh or frozen, with or without crumbs), shellfish, all fish under the category ‘oily’ fish ** Canned tuna in water/brine, canned tuna in oil, dark fish (salmon, sardines – fresh or tinned in brine/water), tinned salmon or sardines in oil †† Drinking milk, milk on cereals ‡‡ Reduced-fat (1.5% fat) and low-fat (0.5% fat) milk §§ Cheese, yoghurt, ice cream ║║ Chips, candy bars, muesli bars, biscuits, and cakes *** General multivitamins, vitamin C, iron supplements, halibut oil ††† Walnuts, almonds, and other nuts Eighty-eight percent of children ate meat, fish, eggs, or
chicken at least daily, as recommended by MOH (Table 2). Seventy-three percent
of children had red meat at least twice weekly.
Eighty-six percent of children consumed dairy products or
milk at least twice daily, in line with MOH recommendations (Table 2). Milk was
consumed daily by 85% of children and dairy products by 75% of children.
Seven percent of children ate breads, cereals, rice, or
pasta at least four times a day as recommended (Table 2). The percentage of
children eating bread and breakfast cereals at least daily was 79% and 44%
respectively.
Total treat foods (including cakes, biscuits, chips, candy
bars, and muesli bars) were consumed at least daily by 85% of children (Table
2). Twelve percent of children ate treat foods three or more times daily.
Eighty-two percent of children drank water daily (Table
2). Fruit juice and cordial were consumed
daily by 30% and 36% of children respectively. Soft drinks were consumed three
or more times a week by nearly one-quarter of children (24%).
Despite the recommendation that dietary supplements should
not be generally given to children, nearly one-quarter of children (24%) were
taking vitamin and/or mineral supplements daily, and 39% were taking a dietary
supplement at least once a week (Table 2). Children taking dietary supplements
daily were significantly less likely (than those not taking dietary supplements
daily) to consume milk or dairy products at least two times per day (79% vs 88%,
χ2 = 3.71, p=0.05).
The most commonly consumed foods are described in Table 3.
Apples and pears were the most commonly eaten fruit, consumed weekly by 95% of
children (Table 3). The most commonly eaten vegetable was potato (Table 3).
Standard milk (approximately 3% fat) was the most commonly consumed milk drink
(Table 3).
There was no difference between the proportion of male and
females drinking standard milk, however, females were significantly more likely
to drink reduced-fat (1.5% fat) and low-fat (0.5% fat) milk than males (females
12% vs males 6%, χ2 = 4.39, p=0.04).
The mean number of different types of fruit consumed per
week was 4.65 (SE=0.10). The mean number of different types of vegetables eaten
per week was 6.53 (SE=0.16).
Table 3. Food frequency information showing the
percentage of children consuming specific types of foods or drinks at least once
per week
* Does not include
drinking milk
DiscussionThis study provides a unique description of what NZ
preschool children eat, and research has not been previously undertaken on this
scale within this particular age group.
In this study, more than one-quarter of preschool children
were not eating the recommended daily intake of fruit servings, similar to the
number of children reported as not eating fruit two or more times per day. The
small discrepancy between the reported servings of fruit consumed and reported
fruit frequency (5%) may be due to children eating less commonly consumed fruit
that were not listed in the FFQ.
The
proportion of children
in this study eating fruit at least twice daily was higher than that reported
for school-aged NZ European and other children (non-Māori and non-Pacific
Island) in the CNS.17 Our results are consistent with the finding that
younger children consume fruit more regularly than older children.17
More than half of preschool children were not consuming the
recommended daily intake of vegetable servings.18 A higher percentage of
children (77%) were reported as eating two or more vegetables per day based on
food frequency information. This finding suggests that not all children are
consuming whole servings of vegetables.
Of concern is the small proportion of children eating breads
or cereals (including pasta and rice) at recommended levels. These foods are
high in energy and are a significant contributor of dietary folate and iron for
NZ children.17 The CNS found that although bread intake did not vary with age,
the frequency of intake of breakfast cereals declined with age.17
Most children ate meat, fish, chicken, or eggs daily. The
most frequently eaten meat was chicken, a finding consistent with the 2002
nutrition survey.17 Nearly two-thirds of children drank milk daily, a higher
proportion than NZ school-aged children;17 this is consistent with the CNS
finding that milk consumption decreases with age.
Several studies have found a positive relationship between
soft-drink consumption and obesity, and body mass index.7,22 Soft-drink
consumption has been found to be positively related to increased daily energy
intake and may displace the consumption of other drinks, such as milk and
juice.22 Of concern, nearly 25% of preschool children in this study were
drinking soft drinks three or more times a week. Limiting the consumption of
these drinks in preschool children may be important given the increasing rates
of childhood obesity in New Zealand.10
NZ guidelines recommend that “treat” foods, such
as muesli bars and potato chips, be eaten only occasionally. Australian
guidelines are more specific for these “extra” foods, recommending
no more than one or two servings per day.23 We found that 12% of preschool
children ate these foods three or more times a day. These foods tend to be
energy dense and low in micronutrients.
In this study, preschool boys were less likely to eat
vegetables at recommended levels than girls. Boys were also less likely than
girls to consume reduced-fat milk and low-fat milk. These gender differences in
dietary patterns are similar to those found in NZ adults.24 SGA children were
less likely than AGA children to eat processed meats weekly and to drink water
two or more times per day. Due to numerous comparisons, caution should be taken
in interpreting these results.
This study found no differences in dietary patterns between
those children taking dietary supplements, and those not taking supplements,
except for milk and dairy product consumption. (Supplements are generally not
recommended for New Zealand children.)25
This study’s limitations need to be addressed.
Firstly, diet is strongly associated with socioeconomic status and parental
education.15,26 Previous ABC study research has found that NZ European mothers
attending at Phase 3 of the study were more likely to have higher socioeconomic
status, a tertiary education, be older, and less likely to have smoked during
pregnancy than non-respondents.27 It is therefore likely that our findings on
food frequency are conservative. The proportion of children in the general
population eating fruit, vegetables, breads, and cereals at recommended levels
is likely to be lower than reported in this study. Secondly, these findings are
restricted to NZ European children. Future research is needed to examine the
diet of New Zealand preschool children of other ethnic groups.
In conclusion, these results suggest that preschool children
are not eating the recommended number of vegetables, fruits, and breads/cereals.
However, there is limited information on preschool nutrition in New Zealand, and
interpretation of these results should be undertaken with some caution until
further studies have been completed.
Assessing and describing the diet and nutrient intakes of
New Zealand preschool children is an area that needs attention, as diet in early
childhood is likely to impact on later adult diet and health.
Author information:
Reremoana F Theodore, PhD Student, Department of Paediatrics, University of
Auckland, Auckland; John M D Thompson, Senior Research Fellow; Department of
Paediatrics, University of Auckland, Auckland; Clare R Wall, Senior Lecturer,
Institute of Food Nutrition and Human Health, Massey University, Albany Campus,
Auckland; David M O Becroft, Paediatric Pathologist, Departments of Paediatrics
and Obstetrics & Gynaecology, University of Auckland, Auckland; Elizabeth
Robinson, Biostatistician, Department of Epidemiology and Biostatistics,
University of Auckland, Auckland; Phillipa M Clark, Senior Lecturer, Department
of Paediatrics, University of Auckland, Auckland; Jan E Pryor, Associate
Professor, Department of Psychology, Victoria University, Wellington; Chris J
Wild, Professor, Department of Statistics, University of Auckland, Auckland; Ed
A Mitchell, Professor, Department of Paediatrics, University of Auckland,
Auckland
Acknowledgments: The
initial study was funded by the Health Research Council of New Zealand. Phase 3
of the study was funded by Child Health Research Foundation, Becroft Foundation,
and Auckland Medical Research Foundation. It was conducted in the
Children’s Research Centre which is supported by the Starship Foundation
and Auckland HealthCare Ltd.
Reremoana Theodore is supported by the Health Research
Council of New Zealand
Māori Health PhD
Scholarship. Professor Ed Mitchell and Dr John Thompson are supported by the
Child Health Research Foundation. We acknowledge the assistance of Gail Gillies
of the Children’s Research Centre in assessing the participants. Lastly,
we sincerely thank the parents and children for participating in these
studies.
Correspondence:
Professor Ed Mitchell, Department of Paediatrics, University of Auckland,
Private Bag 92019, Auckland. Fax: (09) 373 7486; email: e.mitchell@auckland.ac.nz
References:
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