Journal of the New Zealand Medical Association, 02-June-2006, Vol 119 No 1235
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.
Sample—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).
The 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
This 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: email@example.com
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