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Original
research
Nutrient intakes of Australian adolescents from different socioeconomic
backgrounds
Katrina Giskes, Gavin Turrell, Carla Patterson and Beth Newman
Abstract
Objectives: To determine whether adolescents from different socioeconomic
backgrounds differ in their intakes of nutrients implicated in the aetiology
of adult chronic disease.
Design: Secondary analyses of the data obtained from adolescents participating
in the cross-sectional 1995 Australian National Nutrition Survey. Dietary
information had been obtained by 24-hour dietary recalls administered
to participants or their parents by qualified nutritionists. The participants'
socioeconomic position was classified using their mother's and father's
occupation and gross annual household income.
Subjects: Males and females aged 13 to 17 years (n = 793).
Setting: Data had been collected by household interview (61% response
rate) for adolescents from all Australian states and territories.
Main outcome measures: Intakes of total fat, saturated fat, monounsaturated
fat, polyunsaturated fat, vitamin A, folate and vitamin C.
Statistical analyses: Mean nutrient intakes for each socioeconomic group
were compared using a general linear model procedure that adjusted for
age and energy intake.
Results: Significant differences by socioeconomic classification were
observed for total fat, saturated fat, vitamin A, folate and vitamin C.
These differences, however, were few in number and small in magnitude,
and the pattern of results did not suggest that adolescents from disadvantaged
backgrounds had less optimal intakes of nutrients.
Conclusion: The results are inconsistent with Australian research showing
large socioeconomic differences in mortality for chronic disease among
adults. Future research, utilising larger sample sizes and longer dietary
recall periods, may help to elucidate the complex relationship between
diet, socioeconomic position and health. (Nutr Diet 2002;59:79-86)
Key words: socioeconomic position, social class, occupation, income, nutrient
intake
Original research
Benefits of a year-long workplace weight loss program on cardiovascular
risk factors
Janet E. Pritchard, Caryl A. Nowson, Timothy Billington and John D. Wark
Abstract
Objective: To assess the effectiveness of a year-long workplace weight
loss program in reducing risk factors of coronary heart disease.
Design: A randomised, controlled study of low fat (25% of dietary energy)
diet- and/or moderate exercise-induced weight loss interventions in free-living,
middle-aged men. Compliance was monitored from food and activity diaries
at monthly blood pressure measurement sessions. Blood was sampled and
body composition determined from dual energy X-ray absorptiometry before
and after 12 months.
Subjects and setting: Fifty-eight overweight men (mean ± SD age:
43.4 ± 5.7 years; BMI 29.0 ± 2.6 kg/m2), recruited from
a national corporation, were instructed into diet (n = 18) exercise (n
= 21) or control (n = 19) groups over 12 months; 16 control subjects combined
diet and exercise (n = 16) for the subsequent 12 months.
Main outcome measures: At 12 months, weight, total and regional fat and
lean mass, dietary energy and percentage dietary fat intake, physical
activity indices, systolic and diastolic blood pressure, serum insulin,
blood lipids and lipoproteins.
Statistical analyses: Differences between groups were tested using analysis
of variance with Scheffé post hoc test. Differences between pre-
and post-intervention variables were tested using Students' paired t-tests.
Pearson's correlation coefficient and univariate linear regression identified
association between dependent variables, multiple stepwise regression
identified specific predictors.
Results: Weight loss with either diet or exercise resulted in a reduction
in systolic blood pressure (-3.3 ± 1.7%), diastolic blood pressure
(-4.8 ± 1.3%) and LDL cholesterol (-3.9 ± 2.8%), a rise
in HDL cholesterol (+10.0 ± 3.8%) and a change in the LDL/HDL ratio
(-8.9 ± 3.5%). Abdominal fat loss (-26.8 ± 3.6% after diet;
-16.6 ± 4.5% after exercise; -21.0 ± 4.7% after diet and
exercise) was the strongest predictor of change in blood pressure: twenty
percent abdominal fat loss predicted a percentage fall of 2.4 ±
0.05% in systolic blood pressure and 5.4 ± 0.07% in diastolic blood
pressure. Greater abdominal fat loss was associated with the greatest
decrease in serum insulin (P < 0.05).
Conclusion: Modest changes in diet and exercise effected by a low cost
workplace-based education program achieved weight loss, loss of abdominal
fat, reduced blood pressure and serum insulin and improved blood lipid
concentrations.
(Nutr Diet 2002;59:87-96)
Key words: workplace weight loss program, body weight, abdominal fat,
blood pressure, blood lipids, lipoproteins, DXA
Original research
Relationship between serum ferritin concentration and established risk
factors among men in a population with a high mortality from cardiovascular
disease
Hedley G. Peach and Nicole E. Barnett
Abstract
Objectives: To determine whether reported associations between serum ferritin
and cardiovascular risk factors are due to confounding by diet.
Design: Cross-sectional survey in which exercise and smoking habits were
collected by a questionnaire; BMI, waist to hips ratio and blood pressure
were measured; blood was taken for measurement of lipids, glucose and
ferritin; and nutrient and beverage intake were assessed using a validated
food and beverage frequency questionnaire.
Subjects: Men randomly selected from the electoral rolls who had agreed
to participate, had fasted and did not have diabetes, ischaemic heart
disease or haemochromatosis. 165 men were selected of whom 154 participated
and 131 had fasted and were free of disease.
Setting: A regional Australian city.
Main outcome measures: Blood pressure and plasma cholesterol, HDL cholesterol,
triglycerides and glucose concentrations.
Statistical analyses: Correlation and multiple linear regression coefficients
were calculated between serum ferritin and cardiovascular risk factors,
correcting for: age; intake of specific nutrients and alcohol; anthropometry;
smoking and exercise.
Results: There were significant correlations between serum ferritin and
both BMI and waist to hips ratio (r = 0.28, P = 0.001 and r = 0.26, P
= 0.003 respectively). When regressed against ferritin with confounders,
only waist to hips ratio was associated with ferritin (B = 1.61, P = 0.046).
Serum ferritin was also correlated with plasma cholesterol (r = 0.28,
P = 0.00), HDL cholesterol (r = -0.22, P = 0.01), triglycerides (r = 0.25,
P = 0.00) and glucose (r = 0.18, P = 0.04). When ferritin was regressed
against each variable with confounders, only the association with triglycerides
remained just significant (B = 0.12, P = 0.04).
Conclusion: Confounding by diet explained most of the associations between
serum ferritin and cardiovascular risk factors.
Nutr Diet 2002;59:97-102
Key words: ferritin, cardiovascular disease, risk factors, body mass index,
cholesterol, HDL cholesterol, confounding
Original research
What Australians eat for breakfast: an analysis of data from the 1995
National Nutrition Survey
Peter Williams
Abstract
Objective: To analyse data on the patterns of food consumption at breakfast
reported in the 1995 National Nutrition Survey.
Design: The Australian Bureau of Statistics was commissioned to undertake
additional analysis of data on food intake collected using 24-hour recall
interviews, a food frequency questionnaire and a food habits questionnaire.
Subjects: Nationally representative sample of 13 858 Australians, from
age two years, surveyed in the 1995 National Nutrition Survey.
Main outcome measures: Characteristics of people eating breakfast regularly,
mean amount of food groups consumed at breakfast, the percentage of respondents
consuming each food item, and the mean serving sizes.
Statistical analyses: Data are presented as frequencies and mean intakes.
Pearson's chi-square tests were used for comparisons of consumption of
breakfast by household income, special diet and use of vitamin and mineral
supplements.
Results: People on special diets, those taking vitamin or mineral supplements,
and people in the lowest quintile of household income were more likely
to eat breakfast regularly. Breakfast was mostly eaten at home, although
15% of 19- to 24-year-old adults obtained breakfast away from home. Cereals,
bread and milk were the most popular breakfast foods and less than 10%
of Australians ate a cooked breakfast. Sugar added to cereals contributed
less than 2% of the total sugar intake over the day in all age groups.
Conclusion: The high proportion of adolescents and young adults who miss
breakfast regularly is of concern. The most popular breakfast food items
are consistent with dietary guidelines for Australians that promote consumption
of cereals and bread and adequate intakes of dairy foods. There is an
opportunity to increase fruit intake by promoting its consumption at the
breakfast occasion. Nutr Diet 2002;59:103-112
Key words: breakfast, National Nutrition Survey, dietary intake
Review article
What does research on families and food tell us? Implications for nutrition
and dietetic practice
John Coveney
Abstract This review
examines research on food and family life. The evidence suggests that
the dynamics of family relationships crucially affects individuals' food
choices, the healthiness of their choices and the social patterns that
evolve from family food events. Food choices change as reciprocal responsibilities
develop when couples establish relationships and cohabit. The arrival
of children also changes family dynamics. Food preferences are influenced
by family rule-setting as adults attempt to shape food choices of children.
Conversely, children can also influence adult food choice in families.
The role of social class and single parent status play an important role
in food choice. Most research addressing family food choice is not situated
within a social setting which limits its usefulness markedly. Since nutritionists
and dietitians deal with individuals and groups for whom family life is
an important influence, they would benefit from more evidence about food
choices within this important social context. (Nutr Diet 2002;59:113-119)
Key words: food choice, families, surveys, social environment, Pierre
Bourdieu
Original research
A comparison of bioelectrical impedance and near infra-red interactance
with dual energy
x-ray absorptiometry for the determination of body fat
Marijka Batterham, Linda C. Tapsell and Arthur Jenkins
Abstract
Objective: To compare measurements of percentage body fat obtained using
bioelectrical impedance and near infra-red interactance assessments to
those obtained using dual energy x-ray absorptiometry, a reference technique.
Design: Cross-sectional, cross-validation study. Percentage body fat was
assessed using bioelectrical impedance analysis (Bodystat 1500, Tanita
TBF-622 foot-to-foot analysers with proprietary equations and the equation
of Kotler and colleagues) and near infra-red interactance (Futrex 1000).
Results were compared with a Norland XR-26 dual energy x-ray absorptiometry
scanner.
Subjects: Thirteen males (mean age 35 ± 14 years) and 17 females
(mean age 33 ± 11 years).
Setting: University of Wollongong, New South Wales, Australia.
Main outcome measures: Assessment of percentage body fat using the different
techniques.
Statistical analysis: Bias and limits of agreement using paired t tests
and correlation coefficients. Independent samples t test to assess differences
between sexes.
Results: Bioelectrical impedance performed well. The foot-to-foot scales
(mean 24.44 ± 8.53%), the Bodystat 1500 (mean 26.27 ± 8.57%)
and the equation of Kotler et al. (mean 26.33 ± 7.79%) all gave
mean values for percentage body fat that were similar to the mean value
for dual energy x-ray absorptiometry (mean 24.86 ± 8.01%, P >
0.05). Near infra-red interactance gave an estimate of percentage body
fat (30.37 ± 5.38%) significantly different from the dual energy
x-ray absorptiometry value (P < 0.001).
Conclusion: Bioelectrical impedance analysis is an accurate, inexpensive
method of assessing body composition. Further research is required before
near infra-red interactance could be recommended for use in this subject
population. (Nutr Diet 2002;59:120-126)
Key words: Body fat, adult, bioelectrical impedance, near infra-red interactance,
dual energy x-ray absorptiometry, nutritional assessment
Original research
Performance of a research diet history for use in clinical studies involving
pregnant women with and without gestational diabetes mellitus in the Illawarra
region, New South Wales
Linda C. Tapsell, Suzie Daniells, Gina S. Martin, Sallyanne Knights and
Robert G. Moses
Abstract
Objective: To assess the validity and reliability of a research diet history
for use in clinical studies of gestational diabetes mellitus (GDM) in
the Illawarra region, New South Wales.
Design: Diet history interviews conducted at the diabetes service for
women with GDM and the prenatal clinic for matched normal glucose tolerant
women. The glucose tolerant women provided a repeat diet history two weeks
later along with a seven-day weighed food record.
Subjects: Fourteen women with GDM and 19 normal glucose tolerant women
provided a diet history. Seventeen glucose tolerant women provided food
records, and 17 glucose tolerant women provided a repeat diet history.
Setting: Illawarra area diabetes service and prenatal clinic, Wollongong
hospital, NSW.
Main outcome measures: Reported energy and macronutrient intakes.
Statistical analysis: Differences in under-reporting in GDM and normal
glucose tolerant women assessed by Chi square analysis. Reliability and
relative validity assessed using paired t-tests and Pearson's product
moment correlation. The number and percent of paired diet history-food
record values with > 20% discrepancy were examined. Bland-Altman plots
were established to view agreement between diet history and food record
data and subsequent regression analysis was applied to assess the extent
of systematic bias.
Results: The data from the first diet history were plausible. There was
no difference between energy and macronutrient data (P > 0.05) and
there were correlations between measures (P < 0.05) from repeat diet
histories and between diet history and food record data. The degree of
discrepancy between diet history and food record data pairs was reasonable.
There was no evidence of systematic bias between the diet history and
seven-day weighed food record for energy and macronutrient intake measurements.
Conclusions: In the absence of dietary counselling, the diet history in
this setting was reliable and provided valid results relative to seven-day
weighed food record data and with reference to cut-off limits for plausible
reporting of energy intakes. (Nutr Diet 2002;59:127-134)
Key words: diabetes, gestational; diet surveys; reproducibility; validity
Original research
The type and frequency of consumption of carbohydrate-rich foods may play
a role in the clinical expression of insulin resistance during pregnancy
Lynda Gillen, Linda C. Tapsell, Gina S. Martin, Suzie Daniells, Sallyanne
Knights and
Robert G. Moses
Abstract
Objectives: To assess differences in patterns of carbohydrate consumption
between women diagnosed with gestational diabetes mellitus (GDM) and a
group of glucose tolerant pregnant women.
Design: A cross-sectional survey of the usual dietary intakes of a sample
of women with GDM, newly diagnosed and taken at the first clinic visit,
and a sample of women without GDM, matched for age and prepregnancy weight,
at the beginning of the third trimester of pregnancy.
Subjects: 16 women newly diagnosed with GDM and 24 healthy pregnant women.
Subjects with a diagnosis of GDM in a previous pregnancy and other risk
factors for GDM were not excluded.
Setting: The Illawarra area health service, Diabetes service and prenatal
clinic at the Wollongong hospital.
Main outcome measures: Reported patterns of carbohydrate consumption in
terms of total intakes, amounts of carbohydrate-rich food groups and foods
grouped according to glycaemic index (GI) values. These were expressed
as energy (kJ) or amount of carbohydrate (g), and frequency of consumption.
An average diet GI score was calculated.
Statistical analyses: Differences in dietary intake variables between
groups were assessed using independent two tailed t-tests.
Results: There were no significant differences between the two groups
for total intakes of carbohydrate in kJ or g. Women with GDM, however,
reported significantly less carbohydrate (g) from pasta, fruit juice and
milk products (P < 0.05) and from foods with low GI values (P <
0.05). The GDM group reported less frequent intakes of foods with higher
GI values (P < 0.05). The average diet GI was significantly higher
for the GDM group when adjusted for total energy intake (P < 0.05).
Conclusions: This small qualitative study of the food habits of free-living
pregnant women assessed patterns of carbohydrate consumption not readily
identifiable using a nutrient approach. Compared to glucose tolerant pregnant
controls, women with GDM reported lower intakes of carbohydrate-rich foods
with low GI values and a reduced frequency of consumption of foods with
higher GI values. These 'non-beneficial' patterns of intake likely impact
on blood glucose control and have implications for the dietary management
of this group. (Nutr Diet 2002;59:135-143)
Insight
Original case study
Hyperemesis gravidarum-A serious complication of pregnancy
Kerryn Roem
Abstract This case
study reports on a 28-year-old female who presented ten weeks gestation
into her pregnancy with twins, with a four-week history of nausea and
vomiting. At 12 weeks gestation she had lost 14% of her prepregnancy body
weight and antiemetic medications had failed. Nasogastric feeding was
commenced and successfully alleviated her nausea and vomiting within 24
hours. Marginal thiamin deficiency was subsequently diagnosed and she
was treated with 100 mg intramuscular thiamin and discharged on 100 mg
oral thiamin daily. Nasogastric feeding continued until 16 weeks gestation
at which time the tube dislodged and the patient refused to have it reinserted.
She continued to vomit once per day but otherwise tolerated an oral diet.
At 28 weeks gestation she was delivered by emergency caesarian due to
foetal distress. Both babies died of complications of prematurity. This
case highlights the need for early and aggressive nutritional intervention
to prevent weight loss and nutritional deficiencies. Nasogastric feeding
offers a safe and effective means of nutritional support and is able to
alleviate nausea and vomiting. Furthermore it is recommended that women
with hyperemesis have their thiamin concentrations monitored and in cases
of severe intractable hyperemesis women may require thiamin supplements.
Key words: pregnancy, hyperemesis gravidarum, nasogastric feeding, thiamin,
refeeding syndrome
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Nutrition & Dietetics, Volume 59, Number 2, June 2002