Application of the 2006 WHO growth standard from birth to 4 years to Pacific Island children.

BACKGROUND: Pacific adults and children have very high rates of obesity. OBJECTIVE: Body size at birth, 2- and 4 years for the whole cohort, compliant (not smoking and breastfed) and non-compliant children was compared to the 2006 World Health Organization (WHO) growth standard using z-scores. DESIGN: Longitudinal data (n=659) from the 2000 Pacific Island family birth cohort study of weight at birth and weight and height at 2- and 4 years was analysed. RESULTS: At birth the average child was 3.673+/-0.501 kg; z-score 0.605 units higher (P<0.000001) than the WHO standard. At 2- and 4 years, average z-scores for weight and body mass index (BMI) were significantly different from 0 (mean z-scores for weight +1.062 and +1.688, for BMI +1.701 and +1.969 respectively, P<0.000001). Mean height was significantly lower (P<0.000001) z-score=-0.232 at 2 years but higher (P<0.000001) at 4 years, z-score=+0.626. Over 4 years, the daily weight gain was 11.2 g day(-1) compared with 8.9 g day(-1) for the WHO child. Compliant (n=287) compared to non-compliant (n=372) weighed less and were slightly shorter at 2- and 4 years measurement points. Non-compliant children categorized as non-smoking (n=229) weighed more than smoking mothers' (n=143) children at birth, 2- and 4 years. CONCLUSION: Pacific children are born heavy, over 4 years increase in weight is faster and between 2- and 4 years increase in height is faster than the reference breastfed child, independent of pre- and postnatal factors. Smoking decreases the rate of weight gain and children who are not breastfed gain weight faster. Interventions to limit weight gain need to start with the family before conception.

Calibration of densitometers for indicator dye dilution.

A systematic investigation was undertaken to determine which factors affect the calibration of a Gilford monochromatic densitometer used for recording indicator-dilution curves with indocyanine green. Calibration was not influenced by variation of withdrawal speeds from 6.4 to 20.6 cm3/min but varied with differing sampling systems. Variation in haemoglobin from 10 to 17.5 g-dl-1 or in haematocrit from 30 to 60% did not affect calibration. Calibration lines showed both curvature and hysteresis. The opitcal properties of indocyanine green were not affected by storage of diluted dye in the dark for 24 hours but were altered by the presence of contrast media used in angiography. No systematic error resulted from the substitution of stored ACD blood for patient's blood in calibration although random error was increased. Recommendations based on these findings are made for a simple calibration technique which avoids systematic error.

Energy expenditure of young Polynesian and European women in New Zealand and relations to body composition.

BACKGROUND: Reduced energy expenditure and excessive energy intake have been hypothesized to cause obesity. New Zealanders of Polynesian origin have a higher prevalence of obesity than do those of European origin. OBJECTIVE: We investigated relations between components of energy expenditure and body composition. DESIGN: We measured total energy expenditure (TEE) and resting metabolic rate (RMR) in 80 young women [40 New Zealand (NZ) Polynesian and 40 NZ European] aged 18-27 y by the doubly labeled water method and indirect calorimetry, respectively. Each group was partitioned into nonobese and obese on the basis of percentage body fat. RESULTS: TEE and body weight were highly correlated in nonobese NZ Europeans (n = 23, r = 0.76, P < 0.001), obese NZ Europeans (r = 0.58, P = 0.016), and nonobese NZ Polynesians (n = 25, r = 0.59, P = 0.002) but not in obese NZ Polynesians (r = 0.11, P = 0.70). Activity energy expenditure (AEE = TEE - RMR) was similar in obese Polynesians and Europeans (mean+/-SD: 5.5+/-2.2 and 5.2+/-1.9 MJ/d, respectively), but significantly higher in nonobese Polynesians (5.7+/-2.5 MJ/d) than in their European counterparts (3.8+/-1.9 MJ/d, P = 0.005). Similar trends were seen when AEE adjusted for body weight and TEE/RMR were compared among the subgroups. Body weight and RMR together accounted for 66% of the variation in TEE for the European group but only 17% for the Polynesian group. CONCLUSION: Care should be taken in applying "Caucasian norms" relating to energy expenditure to NZ Polynesian people.

Prediction of percentage body fat from anthropometric measurements: comparison of New Zealand European and Polynesian young women.

The prediction of total body fat from simple anthropometric measurements was examined in 42 white (New Zealand European and 40 Polynesian women aged 18-27 y. Percentage body fat (%BF) was determined from measurements of total body water (TBW) by 18O dilution. Mean (+/- SD) body mass index (BMI; in kg/m2) averaged 29.2 +/- 7.9 (range: 16.5-48.0) for the New Zealand European group and 31.2 +/- 7.9 (range: 19.8-51.8) for the Polynesian group, %BF calculated from TBW was similar in the two groups (40.5 +/- 9.9% for the New Zealand European compared with 39.1 +/- 7.5% for the Polynesian group). BMI was significantly correlated with height in the Polynesian group but not in the New Zealand European group. The relation between BMI and %BF was curvilinear for both groups. At a fixed %BF, BMI was higher in the Polynesian group than in the New Zealand European group. A BMI of 30 for the New Zealand European group corresponded to a BMI of 34 for the Polynesian group at an equivalent %BF (42%). Prediction equations for %BF developed from skinfold thicknesses or girth measurements were ethnicity dependent. We conclude that the BMI criterion for obesity in whites requires revision for use in Polynesians.

Estimation of body fatness from body mass index and bioelectrical impedance: comparison of New Zealand European, Maori and Pacific Island children.

OBJECTIVE: To compare percentage body fat (%BF) for a given body mass index (BMI) among New Zealand European, Maori and Pacific Island children. To develop prediction equations based on bioimpedance measurements for the estimation of fat-free mass (FFM) appropriate to children in these three ethnic groups. DESIGN: Cross-sectional study. Purposive sampling of schoolchildren aimed at recruiting three children of each sex and ethnicity for each year of age. Double cross-validation of FFM prediction equations developed by multiple regression. SETTING: Local schools in Auckland. SUBJECTS: Healthy European, Maori and Pacific Island children (n=172, 83 M, 89 F, mean age 9.4+/-2.8(s.d.), range 5-14 y). MEASUREMENTS: Height, weight, age, sex and ethnicity were recorded. FFM was derived from measurements of total body water by deuterium dilution and resistance and reactance were measured by bioimpedance analysis. RESULTS: For fixed BMI, the Maori and Pacific Island girls averaged 3.7% lower %BF than European girls. For boys a similar relation was not found since BMI did not significantly influence %BF of European boys (P=0.18). Based on bioimpedance measurements a single prediction equation was developed for all children: FFM (kg)=0.622 height (cm)(2)/resistance+0.234 weight (kg)+1.166, R(2)=0.96, s.e.e.=2.44 kg. Ethnicity, age and sex were not significant predictors. CONCLUSIONS: A robust equation for estimation of FFM in New Zealand European, Maori and Pacific Island children in the 5-14 y age range that is more suitable than BMI for the determination of body fatness in field studies has been developed.

Estimation of body fat in caucasian and Polynesian women from anthropometric measurements.

Girth measurements provide a simple method for estimation of total body fat that can be used over a wide range of percentage body fat (%BF). Well-established equations for determining %BF from girth measurements were applied to 42 Caucasian and 40 Polynesian women. %BF was determined from total body water measurement using oxygen-18 dilution. The relationship between the criterion measurement of %BF and that calculated from girth measurements differed significantly between the two ethnic groups. Assessment of body fat using girth measurements should use ethnicity-specific equations.

Vitamin B12: one carbon metabolism, fetal growth and programming for chronic disease.

This review brings together human and animal studies and reviews that examine the possible role of maternal vitamin B12 (B12) on fetal growth and its programming for susceptibility to chronic disease. A selective literature review was undertaken to identify studies and reviews that investigate these issues, particularly in the context of a vegetarian diet that may be low in B12 and protein and high in carbohydrate. Evidence is accumulating that maternal B12 status influences fetal growth and development. Low maternal vitamin B12 status and protein intake are associated with increased risk of neural tube defect, low lean mass and excess adiposity, increased insulin resistance, impaired neurodevelopment and altered risk of cancer in the offspring. Vitamin B12 is a key nutrient associated with one carbon metabolic pathways related to substrate metabolism, synthesis and stability of nucleic acids and methylation of DNA which regulates gene expression. Understanding of factors regulating maternal-fetal one carbon metabolism and its role in fetal programming of non communicable diseases could help design effective interventions, starting with maternal nutrition before conception.

Preventing vitamin B12 deficiency in South Asian women of childbearing age: a randomised controlled trial comparing an oral vitamin B12 supplement with B12 dietary advice.

BACKGROUND/OBJECTIVES: To examine the effectiveness, acceptability and sustainability of interventions to reduce vitamin B12 (B12) deficiency in South Asian women before conception. SUBJECTS/METHODS: A 6-month randomised controlled trial conducted in Auckland, New Zealand. Participants (62 South Asian women, 18-50 years old) were stratified by dietary practices, then randomised to three treatment groups: B12 Supplement (oral cyanocobalamin 6 µg/day) (n=21), Placebo (n=21), or B12 Dietary Advice (n=20). Primary outcome measures were changes in B12 biomarkers (serum B12 and holotranscobalamin (holoTC)) at 6 months. Dietary B12 intake was estimated from a B12 food-specific frequency questionnaire (B12FFQ). Intention-to-treat analysis was applied using 'last observation carried forward' method. Changes in B12 biomarkers by treatment were compared using analysis of variance. Pearson's correlations tested relationships between dietary B12 intake and B12 biomarkers. RESULTS: At baseline, 48% of women tested as insufficient or deficient in serum B12 (<222 pmol/l) and 51% as insufficient or deficient in holoTC (<45 pmol/l). B12 status was moderately correlated with dietary B12 intake (r=0.5, 95% confidence interval (CI) (0.3-0.7)) and 44% of women reported insufficient dietary intake (<2.4 µg/day). B12 Supplement was the only treatment group to record a significant increase in B12 biomarkers over 6 months: serum B12 by 30% (95% CI (11-48%)) and holoTC by 42% (12-72%). CONCLUSIONS: The prevalence of B12 insufficiency among Auckland South Asian women is high and moderately correlated with inadequate intake of foods that contain B12. Cyanocobalamin supplementation (6 µg/day) was associated with improved B12 biomarkers, with a potential to improve preconception B12 status in South Asian women.

Water: neglected, unappreciated and under researched.

Water, an essential nutrient, is often ignored in reports of dietary surveys and nutrition. Although it is ubiquitous in foods and beverages, the attention is often focused on the minerals or calorific values of the fluids imbibed rather than the water per se. Water is often taken for granted by many in Western countries due to its abundant availability through water systems. In developing countries, however, water and sanitation raise significant problems. This review overviews (i) the global perspective of the potable water supply, (ii) human rights and water, (iii) dietary guidelines and sources of water and (iv) the physiology of water balance. Gaps in knowledge and understanding around hydration and water requirements are also discussed. Nutritionists are urged to look at the bigger picture of the global water supply and to use good judgement and common sense when advising on water requirements.

Bioimpedance prediction of fat-free mass from dual-energy X-ray absorptiometry in a multi-ethnic group of 2-year-old children.

BACKGROUND/OBJECTIVES: Bioimpedance analysis (BIA) is a simple, convenient and widely used tool for the measurement of body composition in population surveys and surveillance. Prediction equations based on BIA applicable to preschool children are available but are based on total body water estimation and have not been developed across multiple ethnic groups. Our aim was to develop a BIA-based equation in a multi-ethnic sample of 2-year old using fat-free mass (FFM) from dual-energy X-ray absorptiometry (DXA) as criterion measure. SUBJECTS/METHODS: Single-frequency hand-to-foot BIA (model BIM4, Impedimed) and whole-body DXA measurements were carried out in 77 (35 boys, 42 girls; 27 European, 20 Polynesian, 30 Asian and other) healthy preschool children (age range 22-38 months). Body mass index s.d. scores were 0.41 ± 1.23 for boys and 0.61 ± 1.09 for girls. The performance of published equations applicable to this age group was assessed. The predicted residual sum of squares method was used to develop and cross-validate a multiple regression equation relating FFM to BIA measures. RESULTS: Published equations performed poorly for estimating FFM in this group of children. The prediction equation developed in all 77 children was: FFM (kg)=0.367 height(cm)(2)/resistance+0.188 weight (kg)+0.077 height (cm)+0.273 sex (male=1, female=0)-2.490, R(2)=0.89, standard error of estimate=0.50 kg. Ethnicity and age did not add significantly to the model. CONCLUSIONS: We have developed an equation that may have application for prediction of FFM in 2-3-year-old children, which does not require determination of hydration factors. Further work should be carried out using DXA scanning to extend the applicable age range.

Child's homocysteine concentration at 2 years is influenced by pregnancy vitamin B12 and folate status.

Longitudinal studies investigating vitamin B12 and folate status of mothers and their offspring will provide a better understanding of intergenerational nutrition. During pregnancy and 2 years (2y) after delivery, we measured plasma vitamin B12 and folate concentrations in 118 women [aged (mean ± s.d.) 22.9 ± 3.9y] who attended a rural (n = 68) or an urban (n = 50) antenatal clinic in Pune, India. Cord blood vitamin B12 and folate were measured, and when the child was 2y total homocysteine (tHcy) was also measured. Demographic and diet measurements were recorded using standard methods. Pregnancy plasma vitamin B12 concentration at 34 weeks was low [median (25th, 75th), 115 (95, 147) pm]; 75% had low status (<150 pm). Plasma folate was high (mean ± s.d., 33 ± 21 nm); one had a folate concentration <7 pm. Cord plasma vitamin B12 and folate concentrations were higher than and positively associated with maternal concentrations. In stepwise regression, higher child vitamin B12 at 2y was predicted (total R 2 15.7%) by pregnancy vitamin B12 (std ß 0.201, R 2 7.7%), current consumption of cow's milk (std ß 0.194, R 2 3.3%) and whether breast feeding was stopped before 2y (std ß -0.234 R 2 7.2%). Child's 2y tHcy concentration was high (11.4 ± 3.6 µm) and predicted by lower pregnancy vitamin B12 (std ß -0.206, R 2 4.1%), lack of vitamin supplementation (std ß -0.256, R 2 5.6%) in pregnancy and whether currently breastfed (std ß 0.268, R 2 8.4%). Low maternal vitamin B12 status in pregnancy and prolonged breast-feeding results in disturbed one-carbon metabolism in offspring at 2y. Supplementation of women of child-bearing age, particularly during pregnancy and lactation, may improve the homocysteine status of these children.

Vitamin B12 and folate during pregnancy and offspring motor, mental and social development at 2 years of age.

Insufficiency of vitamin B12 (B12) and folate during pregnancy can result in low concentrations in the fetus and have adverse effects on brain development. We investigated the relationship between maternal B12 and folate nutrition during pregnancy and offspring motor, mental and social development at two years of age (2 y). Mothers (n = 123) and their offspring (62 girls, 61 boys) from rural and middle-class urban communities in and around Pune city were followed through pregnancy up to 2 y. Maternal B12 and folate concentrations were measured at 28 and 34 weeks of gestation. At 2 y, the Developmental Assessment Scale for Indian Infants was used to determine motor and mental developmental quotients and the Vineland Social Maturity Scale for the social developmental quotient. Overall, 62% of the mothers had low B12 levels (<150 pmol/l) and one mother was folate deficient during pregnancy. Maternal B12 at 28 and 34 weeks of gestation was associated with offspring B12 at 2 y (r = 0.29, r = 0.32, P < 0.001), but folate was not associated with offspring folate. At 2 y, motor development was associated with maternal folate at 28 and 34 weeks of gestation. Mental and social development quotients were associated positively with head circumference and negatively with birth weight. In addition, pregnancy B12 and folate were positively associated with mental and social development quotients. Maternal B12 and folate during intrauterine life may favorably influence brain development and function. Pregnancy provides a window of opportunity to enhance fetal psychomotor (motor and mental) development.

Dietary patterns and vitamin B(12) status of migrant Indian preadolescent girls.

BACKGROUND: Inter-generational dietary patterns are implicated in the development of adult disease and have a critical role in cell division, growth and development. OBJECTIVE: The assessment of B(12) status in six meat-eating (ME) and six non-meat-eating (NME) 9-11 years old, Tanner stage 1, migrant Indian girls. DESIGN: B(12) status was assessed by haematology, fasting B(12), folate, methyl malonic acid (MMA) and 7-day-diet-diary analysis. RESULTS: Red cell and iron measurements were within reference ranges for all girls. Reported B(12) intake correlated with serum B(12) (r=0.74, P=0.006). Serum B(12) was lower in NME girls compared with ME girls (232+/-95 vs 543+/-201 pmol l(-1), P=0.01). Two NME girls were deficient in vitamin B(12) (B(12)<170 pmol l(-1), MMA>0.26 micromol l(-1)). Overall serum B(12) was low (388+/-221 pmol l(-1)) and serum folate intake high (27+/-8 pmol l(-1); 342+/-269 microg day(-1)). CONCLUSIONS: Asymptomatic B(12) deficiency is present in NME migrant Indian preadolescents in the presence of high folate. Supplementation with B(12) in this group may be necessary to improve future health outcomes.

Indices of fatness and relationships with age, ethnicity and lipids in New Zealand European, Maori and Pacific children.

BACKGROUND/OBJECTIVES: To investigate the relationships between body mass index (BMI), body fatness, ethnicity, age and blood lipids. SUBJECTS/METHOD: In a subsample (N=643) of the 2002 New Zealand Child Nutrition Survey (N=3275, age 5-14 years) consisting Maori (89 boys, 69 girls), Pacific (154 boys, 194 girls) and European (71 boys, 66 girls) ethnic groups, fat-free mass (FFM) was determined by bioimpedance analysis. FFM index (FFMI, FFM/height(2)), fat mass index (FMI, fat mass/height(2)) and percentage body fat (%BF) were derived. Plasma total cholesterol and high-density lipoprotein (HDL) cholesterol were measured in 515 (80%) of these children. RESULTS: For the same BMI, %BF was lower in Pacific Island (P<0.0001) and Maori (P<0.0001) girls compared with European but for boys there were no ethnic differences. Cross-sectional analysis across ages using Hattori charts clearly showed sexual dimorphism with girls having a higher FMI, FFMI and BMI than boys by the age of 13 year. Both Pacific girls and boys showed upward trends in FFMI and FMI with age that were significantly higher than those of the other ethnicities. Adjusting for age, sex and ethnicity, %BF was a better predictor (R(2)=0.090, P=0.0002) of total cholesterol than BMI (R(2)=0.061, P=0.049) or waist (R(2)=0.075, P=0.013) while FFMI was the best predictor of HDL cholesterol (R(2)=0.15, P<0.0001) and waist was the best predictor of the total cholesterol/HDL cholesterol ratio (R(2)=0.17, P<0.0001). CONCLUSIONS: Measurements of body fat and indices of body fatness additional to BMI in multiethnic paediatric populations allow changes in fat mass and FFM to be tracked and improve the ability to predict dyslipidaemia.

BMI, fat and muscle differences in urban women of five ethnicities from two countries.

OBJECTIVE: To investigate body composition differences, especially the relationship between body mass index (BMI) and percent body fat (%BF), among five ethnic groups. DESIGN: Cross-sectional. SUBJECTS: Seven hundred and twenty-one apparently healthy women aged 18-60 years (BMI: 17.4-54.0 kg/m(2)) from South Africa (SA, 201 black, 94 European) and New Zealand (NZ, 173 European, 76 Maori, 84 Pacific, 93 Asian Indian). MEASUREMENTS: Anthropometry, including waist circumference, and total, central and peripheral body fat, bone mineral content and total appendicular skeletal muscle mass (ASMM) derived from dual X-ray absorptiometry. RESULTS: Regression analysis determined that at a BMI of 30 kg/m(2), SA European women had a %BF of 39%, which corresponded to a BMI of 29 for SA black women. For a BMI of 30 kg/m(2) in NZ Europeans, equivalent to 43% body fat, the corresponding BMIs for NZ Maori, Pacific and Asian Indian women were 34, 36 and 26 kg/m(2), respectively. Central fat mass was lower in black SA than in European SA women (P<0.001). In NZ, Pacific women had the lowest central fat mass and highest ASMM, whereas Asian Indian women had the highest central fat mass, but lowest ASMM and bone mineral content. CONCLUSIONS: The relationship between %BF and BMI varies with ethnicity and may be due, in part, to differences in central fatness and muscularity. Use of universal BMI or waist cut-points may not be appropriate for comparison of obesity prevalence among differing ethnic groups, as they do not provide a consistent reflection of adiposity and fat distribution across ethnic groups.

Prediction of fat-free mass by bioimpedance analysis in migrant Asian Indian men and women: a cross validation study.

BACKGROUND: Bioimpedance analysis (BIA) is a fast and convenient field technique for estimation of total body fat-free mass (FFM). However, bioimpedance-based prediction equations have been developed in predominantly white populations and little information is available on their usefulness in Asian Indian populations. OBJECTIVE: To develop a prediction equation for FFM based on BIA measurements applicable to a migrant population of Asian Indians and to investigate the predictive accuracy of published BIA-based equations in this ethnic group. DESIGN: FFM was measured by dual-energy X-ray absorptiometry in 211 healthy adults (110 men, 101 women; age ranges 19-74 year) of Asian Indian ethnicity and used as the reference measure to develop prediction equations based on single-frequency BIA measurements of resistance and reactance. A cross-validation technique was applied. Predictive accuracy of published BIA-based equations was assessed in this sample. RESULTS: Sex-specific equations developed in the entire group included height2/resistance and body weight as predictors (R2=0.84 and 0.70 and standard errors of estimate of 2.8 and 2.0 kg for males and females, respectively; CV: 6%). Of published equations examined, one predicted FFM satisfactorily in men with nonsignificant bias and may be applicable to Asian Indian populations. None of the published equations tested performed satisfactorily in women. CONCLUSIONS: Bioimpedance-based equations for predicting FFM developed specifically in Asian Indians are recommended for field studies designed to measure body composition of this ethnic group.

Resting metabolic rate in young Polynesian and Caucasian women.

OBJECTIVE: To investigate whether resting metabolic rate (RMR) differs between Caucasian and Polynesian women. DESIGN: Cross-sectional comparison. SUBJECTS: Eighty-two (42 Caucasian, 40 Polynesian) healthy women aged between 18 and 27 y. MEASUREMENTS: RMR (indirect calorimetry) and body composition (fat-free mass and fat mass derived from oxygen-18 dilution measurement of total body water). RESULTS: RMR was similar in the Caucasian (6956 +/- 1291 (s.d.) kJ/d) and Polynesian (7125 +/- 1290 kJ/d) groups while fat-free mass was significantly lower in the Caucasian group (45.3 +/- 6.8 vs 51.0 +/- 6.4 kg, P < 0.002). After adjustment for fat-free mass and fat mass, RMR was lower in the Polynesian than the Caucasian groups (6783 +/- 904 vs 7281 +/- 901 kJ/d, P = 0.023). CONCLUSION: The significantly lower relative RMR observed in Polynesian compared to Caucasian women may predispose Polynesian women to eventual onset of obesity.