Anke L. B. Günther

Dietary Protein Intake throughout Childhood Is Associated with the Timing of Puberty

Early puberty onset is associated with hormone-related cancers, but whether diet in childhood influences pubertal timing is controversial. We examined the association of protein intake in early and mid-childhood with the ages at take-off of the pubertal growth spurt (ATO), peak height velocity (APHV), and menarche in girls and voice break in boys using data from the longitudinal Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Among participants who provided 3-d weighed dietary records at 12 mo, 18-24 mo, 3-4 y, and 5-6 y, 112 had sufficient anthropometric measurements between 6 and 13 y to allow estimation of ATO. Life-course plots were used to identify critical periods of total, animal, and vegetable protein intake (percentage of total energy intake) for pubertal timing. At these ages, the association between tertiles of protein intake (T1-T3) and the outcomes was investigated using multiple linear regression analysis. A higher total and animal protein intake at 5-6 y was related to an earlier ATO. In the highest tertile of animal protein intake at 5-6 y, ATO occurred 0.6 y earlier than in the lowest [(mean, 95% CI) T1: 9.6, 9.4-9.9 vs. T2: 9.4, 9.1-9.7 vs. T3: 9.0, 8.7-9.3 y; P-trend = 0.003, adjusted for sex, total energy, breast-feeding, birth year, and paternal university degree]. Similar findings were seen for APHV (P-trend = 0.001) and the timing of menarche/voice break (P-trend = 0.02). Conversely, a higher vegetable protein intake at 3-4 and 5-6 y was related to later ATO, APHV, and menarche/voice break (P-trend = 0.02-0.04). These results suggest that animal and vegetable protein intake in mid-childhood might be differentially related to pubertal timing.

Association of DASH Diet With Cardiovascular Risk Factors in Youth With Diabetes Mellitus The SEARCH for Diabetes in Youth Study

Background— We have shown that adherence to the Dietary Approaches to Stop Hypertension (DASH) diet is related to blood pressure in youth with type 1 and type 2 diabetes mellitus. We explored the impact of the DASH diet on other cardiovascular disease risk factors. Methods and Results— Between 2001 and 2005, data on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, low-density lipoprotein particle density, apolipoprotein B, body mass index, waist circumference, and adipocytokines were ascertained in 2130 youth aged 10 to 22 years with physician-diagnosed diabetes mellitus. Dietary intake was assessed by food frequency questionnaire, categorized into the DASH food groups, and assigned an adherence score. Among youth with type 1 diabetes mellitus, higher adherence to the DASH diet was significantly and inversely associated with low-density lipoprotein/high-density lipoprotein ratio and A1c in multivariable-adjusted models. Youth in the highest adherence tertile had an estimated 0.07 lower low-density lipoprotein/high-density lipoprotein ratio and 0.2 lower A1c levels than those in the lowest tertile adjusted for confounders. No significant associations were observed with triglycerides, low-density lipoprotein particle density, adipocytokines, apolipoprotein B, body mass index Z score, or waist circumference. Among youth with type 2 diabetes mellitus, associations were observed with low-density lipoprotein particle density and body mass index Z score. Conclusions— The DASH dietary pattern may be beneficial in the prevention and management of cardiovascular disease risk in youth with diabetes mellitus.

The influence of habitual protein intake in early childhood on BMI and age at adiposity rebound: results from the DONALD Study

Objective:To analyse the influence of habitual protein intake in early childhood on age and body mass index (BMI) at adiposity rebound (AR), a potential critical period for the development of obesity.Subjects:A total of 313 children (161 boys, 152 girls) participating in the Dortmund Nutritional and Anthropometric Longitudinally Designed Study.Methods:Weighted summary indices were created reflecting habitual, energy-adjusted protein intake (expressed as % of energy) and protein intake per kg reference body weight per day (g/kg RBW/day) between the age of 12 and 24 months. Body mass index standard deviation scores (BMI-SDS), age at AR and covariates (mothers BMI, gestational age, breastfeeding and siblings) were included in the final models.Results:After adjusting for potential confounders, girls in the highest tertile (T3) of habitual energy-adjusted protein intake had a significantly higher BMI-SDS at AR than those in T1 (T1: −0.61 (95% CI: −0.90; −0.31), T2: −0.49 (−0.79; −0.20), T3: −0.08 (−0.36; 0.20), P for difference=0.01). A comparable association existed with habitual protein intake expressed as g/kg RBW/day (T1: −0.64 (−0.93; −0.36), T2: −0.22 (−0.52; 0.09), T3: −0.25 (−0.54; 0.04), P=0.04). In boys, there were no differences in BMI-SDS at AR between tertiles of habitual protein intake (% of energy or g/kg RBW/day) (P>0.05). Boys in the lowest tertile of habitual energy-adjusted protein intake tended to experience a later AR (T1: 6.0 (5.6; 6.4), T2: 5.5 (5.1; 5.9), T3: 5.4 (5.0; 5.9) years, P=0.07). But neither in girls nor in boys was age at AR significantly different between tertiles of habitual protein intake (% of energy or g/kg RBW/day) (P>0.05).Conclusion:A higher habitual protein intake between the age of 12 and 24 months was associated with a higher BMI-SDS at AR in girls, but not in boys. There was no consistent relation between habitual protein intake in early childhood and timing of AR.

Diet Quality in Childhood Is Prospectively Associated with the Timing of Puberty but Not with Body Composition at Puberty Onset

We examined whether the diet quality of healthy children prior to the pubertal growth spurt was associated with age and body composition at puberty onset. Multivariate regression analyses were performed using data from 222 Dortmund Nutritional and Anthropometric Longitudinally Designed Study participants (mean age +/- SD at baseline: 7.4 +/- 1.3 y) with 3-d weighed dietary records and anthropometric data at baseline, i.e. the visits 2 and 3 y before the onset of pubertal growth spurt [defined as age at take-off (ATO)]. Diet quality at baseline was determined using the nutrient density-based Nutritional Quality Index (NQI) and the food group and nutrient-based Revised Childrens Diet Quality Index (RC-DQI). Based on their distribution, 3 NQI or RC-DQI categories were created to indicate lower, moderate, and higher diet quality. Parameters describing body composition at ATO were age- and gender-specific Z-scores of BMI, fat mass/height(2), and fat-free mass/height(2). Children with lower diet quality indicated by lower NQI scores entered puberty approximately 0.4 y earlier than children with higher NQI scores {ATO in lower and higher NQI categories were [mean (95% CI)] 9.2 y (9.0-9.4), and 9.6 y (9.4-9.9), adjusted for sex, maternal overweight, baseline energy intake, and baseline BMI Z-score} (P-value = 0.02). A similar association of the RC-DQI with ATO was largely explained by baseline energy intakes. Our data suggest that diet quality was not independently associated with body composition at ATO. Children with lower diet quality according to a nutrient density-based index appear to enter puberty at an earlier age, independently of prepubertal body composition.

Current trends of 24-h urinary iodine excretion in German schoolchildren and the importance of iodised salt in processed foods

Worldwide, the iodisation of salt has clearly improved iodine status. In industrialised countries, iodised salt added to processed food contributes most to iodine supply. Yet it is unclear as to what extent changes in the latter may affect the iodine status of populations. Between 2004 and 2009, 24-h urinary iodine excretions (UIE) were repeatedly measured in 278 German children (6 to 12 years old) of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study (n 707). Na excretion measurements and simultaneously collected 3-d weighed dietary records provided data on intakes of the most important dietary sources of iodine in the childrens diet. Actual trends of UIE (2004-9) and contributions of relevant food groups were analysed by mixed linear regression models. Longitudinal regression analysis showed a plateau of UIE in 2004-6; afterwards, UIE significantly decreased till 2009 (P = 0·01; median 24-h UIE in 2004-6: 85·6 μg/d; 2009: 80·4 μg/d). Median urinary iodine concentration fell below the WHO criteria for iodine sufficiency of 100 μg/l in 2007-9. Salt, milk, fish and egg intake (g/d) were significant predictors of UIE (P < 0·005); and the main sources of iodine were salt and milk (48 and 38 %, respectively). The present data hint at a beginning deterioration in the iodine status of German schoolchildren. A decreased use of iodised salt in industrially produced foods may be one possible reason for this development. Because of the generally known risks for cognitive impairment due to even mild iodine deficits in children, a more widespread use of iodised salt, especially in industrially processed foods, has to be promoted.

Renal Net Acid Excretion Capacity Is Comparable in Prepubescence, Adolescence, and Young Adulthood but Falls with Aging

OBJECTIVES: To evaluate whether renal net acid excretion capacity (NAEC) varies across different age groups and, specifically, whether it falls in elderly people.

Validation of protein intake assessed from weighed dietary records against protein estimated from 24 h urine samples in children, adolescents and young adults participating in the Dortmund Nutritional and Longitudinally Designed (DONALD) Study

OBJECTIVE To date, only a few nutritional assessment methods have been validated against the biomarker of urinary-N excretion for use in children and adolescents. The aim of the present study was to validate protein intake from one day of a weighed dietary record against protein intake estimated from a simultaneously collected 24 h urine sample. DESIGN Cross-sectional analyses including 439 participants of the Dortmund Nutritional and Longitudinally Designed (DONALD) Study from four age groups (3-4, 7-8, 11-13 and 18-23 years). Mean differences, Pearson correlation coefficients (r), cross-classifications and Bland-Altman plots were used to assess agreement between methods. RESULTS Weighed dietary records significantly underestimated mean protein intake by -6.4 (95 % CI -8.2, -4.7) g/d or -11 %, with the difference increasing across the age groups from -0.6 (95 % CI -2.7, 1.5) g/d at age 3-4 years to -13.5 (95 % CI -18.7, -8.3) g/d at age 18-23 years. Correlation coefficients were r = 0.7 for the total study sample and ranged from r = 0.5 to 0.6 in the different age groups. Both methods classified 85 % into the same/adjacent quartile for the whole study group (83-86 % for the different age groups) and 2.5 % into the opposite quartile (1.9-3.1 % for the different age groups). Bland-Altman plots for the total sample indicated that differences in protein intake increased across the range of protein intake, while this bias was not obvious within the age groups. CONCLUSIONS Protein intake in children and adolescents can be estimated with acceptable validity by weighed dietary records. In this age-heterogeneous sample, validity was lower among adolescents and young adults.

Prospective relevance of dietary patterns at the beginning and during the course of primary school to the development of body composition.

Primary school years seem to represent a critical period for the development of overweight and obesity. However, only a few studies have analysed the prospective relationship between dietary patterns and weight status in children. The aims of the present study were to identify dietary patterns at the beginning of and during the primary school period and to examine their relevance to the development of body composition. Nutritional and anthropometric data from 371 participants of the Dortmund Nutritional and Longitudinally Designed (DONALD) Study at the beginning (ages 6 and 7 years) and end (ages 10 and 11 years) of the primary school period were used. Principal component analyses (PCA) were conducted to identify dietary patterns, which were regressed on changes in BMI and fat mass index (FMI) between ages 6 and 7 years and ages 10 and 11 years. Reduced rank regression (RRR) was used to directly extract patterns explaining variation in changes in BMI and FMI between ages 6 and 7 years and ages 10 and 11 years. PCA yielded interpretable patterns of dietary changes at the beginning of and during the primary school period, which were not related to changes in body composition. Conversely, RRR allowed identifying predictive patterns: higher baseline intakes of white bread and lower baseline intakes of whole-grain products as well as increases in the consumption of savoury snacks, sausages and cheese during primary school years independently predicted increases in BMI and FMI during the primary school period. In conclusion, selection of unfavourable carbohydrate sources at the beginning of the primary school period and increases in the consumption of processed savoury foods during primary school years may adversely affect the development of body composition during the course of primary school.

Prospective association of protein intake during puberty with body composition in young adulthood

To examine the association of habitual animal and plant protein intake during the potentially critical period of puberty with body composition in young adulthood.

Prospective associations of dietary insulin demand, glycemic index, and glycemic load during puberty with body composition in young adulthood.

Background:Puberty is a so-called critical period for overweight development and is characterized by physiological insulin resistance during mid-puberty. This study addressed the hypothesis that habitual consumption of a diet inducing higher levels of postprandial glycemia or insulinemia during puberty may have an unfavorable effect on the body composition in young adulthood.Methods:Multivariate regression analysis was performed on 262 participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study with at least two 3-day weighed dietary records during puberty (baseline: girls 9–14 years; boys 10–15 years) and anthropometric measurements in young adulthood (18–25 years). A published dietary glycemic index was assigned to each carbohydrate-containing food. Similarly, each food was assigned a food insulin index (insulinemic response to a 1 MJ portion of food relative to 1 MJ of glucose) using 121 values measured at Sydney University.Results:Dietary glycemic index or glycemic load during puberty was not related to body composition in young adulthood. In contrast, a higher dietary insulin index and a higher dietary insulin load during puberty were associated with higher levels of percentage of body fat (%BF) in young adulthood, even after adjustment for early life, socioeconomic and nutritional factors; %BF in energy-adjusted tertiles of dietary insulin index were 22.9 (95% confidence intervals (CI): 21.6, 24.1), 24.5 (23.2, 25.7), 24.7 (23.5, 25.9) %, P for trend=0.01; %BF in energy-adjusted tertiles of dietary insulin load were 22.8 (95% CI: 21.5, 24.0), 24.5 (23.2, 25.7), 24.8 (23.6, 26.0) %, P for trend=0.01. Adjustment for baseline %BF attenuated these relationships (P for trend=0.1 and=0.08, respectively). Dietary insulin demand was not related to body mass index.Conclusion:This study suggests a prospective adverse influence of dietary insulin demand during puberty on %BF in young adulthood. Postprandial increases in insulinemia rather than increases in glycemia appear to be implicated in an unfavorable development of body composition.