Prospective associations of meat consumption during childhood with measures of body composition during adolescence: results from the GINIplus and LISAplus birth cohorts

Poultry Consumption and Human Cardiometabolic Health-Related Outcomes: A Narrative Review

Poultry meats, in particular chicken, have high rates of consumption globally. Poultry is the most consumed type of meat in the United States (US), with chicken being the most common type of poultry consumed. The amounts of chicken and total poultry consumed in the US have more than tripled over the last six decades. This narrative review describes nutritional profiles of commonly consumed chicken/poultry products, consumption trends, and dietary recommendations in the US. Overviews of the scientific literature pertaining to associations between, and effects of consuming chicken/poultry on, body weight and body composition, cardiovascular disease (CVD), and type II diabetes mellitus (T2DM) are provided. Limited evidence from randomized controlled trials indicates the consumption of lean unprocessed chicken as a primary dietary protein source has either beneficial or neutral effects on body weight and body composition and risk factors for CVD and T2DM. Apparently, zero randomized controlled feeding trials have specifically assessed the effects of consuming processed chicken/poultry on these health outcomes. Evidence from observational studies is less consistent, likely due to confounding factors such as a lack of a description of and distinctions among types of chicken/poultry products, amounts consumed, and cooking and preservation methods. New experimental and observational research on the impacts of consuming chicken/poultry, especially processed versions, on cardiometabolic health is sorely needed.

Childhood nutrient intakes are differentially associated with hepatic and abdominal fats in adolescence: The EPOCH study

OBJECTIVE

The aim of this study was to examine whether nutrient intakes in childhood are associated with abdominal and hepatic fat depots later in adolescence.

METHODS

Using data from 302 participants in the longitudinal Exploring Perinatal Outcomes among CHildren (EPOCH) study, energy partition and nutrient density models were constructed to examine associations of nutrient intakes in childhood (~10 years of age), assessed by food frequency questionnaire, with abdominal subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and hepatic fat in adolescence (~16 years of age).

RESULTS

In energy partition models (energy intake not held constant), total, monounsaturated, and polyunsaturated fat intakes in childhood were associated with higher SAT in adolescence (β [95% CI]: 8.5 [0.1-17.1], 25.1 [2.1-48.1], and 59.7 [16.1-103.3] mm² per 100 kcal/d), higher starch intake was associated with log-hepatic fat (back-transformed β [95% CI]: 1.07 [1.01-1.15] per 100 kcal/d), and, in boys only, higher animal protein intake was associated with VAT (β [95% CI]: 5.3 [0.3-10.3] mm² per 100 kcal/d). Most associations were unchanged when adjusted for energy intake in nutrient density models.

CONCLUSIONS

Childhood nutrient intakes were differentially associated with adolescent body fats; specifically, unsaturated fat intake predicted abdominal SAT, animal protein intake predicted VAT, and starch intake predicted hepatic fat. These nutrient intakes may, therefore, be targets for intervention studies aiming to modify adolescent body fat distribution.

Acute Metabolic Response in Adults to Toddler Milk Formulas with Alternating Higher and Lower Protein and Fat Contents, a Randomized Cross-Over Trial

Protein intake in early life influences metabolism, weight gain, and later obesity risk. As such, a better understanding of the effects of protein intake on the postprandial metabolism and its dynamics over time may elucidate underlying mechanisms. In a randomized crossover study, we observed fasted adults who consumed two isocaloric toddler milk formulas concentrated as meals of 480 kcal with 67 g of carbohydrates 30 g (HP) or 7 g (LP) protein, and 10 g or 20 g fat, respectively. Anthropometry and body plethysmography were assessed, and blood samples collected at baseline and over five hours. Time-specific concentrations, areas under concentration curves (AUC), and maximum values of metabolites were compared by paired t-tests to examine the effects of protein content of toddler milks on postprandial plasma concentrations of insulin, glucose, branched-chain amino acids (BCAA), urea and triglycerides. Twenty-seven men and women aged 26.7 ± 5.0 years (BMI: 22.2 ± 2.5 kg/m²) (mean ± SD) participated. BCAA AUC, and Cmax values were significantly higher with HP than LP (144,765 ± 21,221 vs. 97,089 ± 14,650 µmol·min/L, p < 0.001; 656 ± 120 vs. 407 ± 66 µmol/L, p < 0.001), as were insulin AUC and Cmax values (6674 ± 3013 vs. 5600 ± 2423 µmol·min/L, p = 0.005; 71 ± 37 vs. 55 ± 28 µmol/L, p = 0.001). Higher glucose, urea, and triglyceride concentrations occurred in the late postprandial phase (≥180 min) with HP. In conclusion, we noted that higher milk protein intake induces increased postprandial BCAA concentrations for at least 5 h and led to higher initial insulin secretion. Gluconeogenesis due to an influx of amino acids and their degradation after HP meal might explain the late effects of protein intake on glucose and insulin.

Interactions between Growth of Muscle and Stature: Mechanisms Involved and Their Nutritional Sensitivity to Dietary Protein: The Protein-Stat Revisited

Childhood growth and its sensitivity to dietary protein is reviewed within a Protein-Stat model of growth regulation. The coordination of growth of muscle and stature is a combination of genetic programming, and of two-way mechanical interactions involving the mechanotransduction of muscle growth through stretching by bone length growth, the core Protein-Stat feature, and the strengthening of bone through muscle contraction via the mechanostat. Thus, growth in bone length is the initiating event and this is always observed. Endocrine and cellular mechanisms of growth in stature are reviewed in terms of the growth hormone-insulin like growth factor-1 (GH-IGF-1) and thyroid axes and the sex hormones, which together mediate endochondral ossification in the growth plate and bone lengthening. Cellular mechanisms of muscle growth during development are then reviewed identifying (a) the difficulties posed by the need to maintain its ultrastructure during myofibre hypertrophy within the extracellular matrix and the concept of muscle as concentric "bags" allowing growth to be conceived as bag enlargement and filling, (b) the cellular and molecular mechanisms involved in the mechanotransduction of satellite and mesenchymal stromal cells, to enable both connective tissue remodelling and provision of new myonuclei to aid myofibre hypertrophy and (c) the implications of myofibre hypertrophy for protein turnover within the myonuclear domain. Experimental data from rodent and avian animal models illustrate likely changes in DNA domain size and protein turnover during developmental and stretch-induced muscle growth and between different muscle fibre types. Growth of muscle in male rats during adulthood suggests that "bag enlargement" is achieved mainly through the action of mesenchymal stromal cells. Current understanding of the nutritional regulation of protein deposition in muscle, deriving from experimental studies in animals and human adults, is reviewed, identifying regulation by amino acids, insulin and myofibre volume changes acting to increase both ribosomal capacity and efficiency of muscle protein synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) and the phenomenon of a "bag-full" inhibitory signal has been identified in human skeletal muscle. The final section deals with the nutritional sensitivity of growth of muscle and stature to dietary protein in children. Growth in length/height as a function of dietary protein intake is described in the context of the breastfed child as the normative growth model, and the "Early Protein Hypothesis" linking high protein intakes in infancy to later adiposity. The extensive paediatric studies on serum IGF-1 and child growth are reviewed but their clinical relevance is of limited value for understanding growth regulation; a role in energy metabolism and homeostasis, acting with insulin to mediate adiposity, is probably more important. Information on the influence of dietary protein on muscle mass per se as opposed to lean body mass is limited but suggests that increased protein intake in children is unable to promote muscle growth in excess of that linked to genotypic growth in length/height. One possible exception is milk protein intake, which cohort and cross-cultural studies suggest can increase height and associated muscle growth, although such effects have yet to be demonstrated by randomised controlled trials.

Association between protein-rich dietary patterns and anthropometric measurements among children aged 6 years

AIM

The associations between types of dietary protein intake and child anthropometric measurements have not been fully studied. Therefore, we examined dietary protein pattern in relation to anthropometric indicators among 6-year-old children.

METHODS

We carried out a cross-sectional study of 788 randomly selected children from health centres in Tehran, Iran. Dietary intake was assessed using a food frequency questionnaire completed by the mothers. Anthropometric measurements were based on standard protocols. Principle component analysis was performed to identify different dietary protein patterns. We used multivariate logistic regression to evaluate how these patterns were associated with child anthropometry.

RESULTS

Three dietary protein patterns were identified: pattern 1 (rich in red and processed meats, dairy products and eggs), pattern 2 (rich in fish and poultry) and pattern 3 (rich in soy and legumes). After adjusting for potential confounders (energy intake, socioeconomic status and physical activity), being in the third compared to the first tertiles of pattern 2 was associated with increased (OR = 1.57; 95% CI: 1.09-2.27; P = .01) and decreased (OR = 0.54; 95% CI: 0.32-0.92; P = .02) risk of overweight/obesity and underweight/wasting, respectively. There was no association between other dietary patterns and risk of overweight/obesity or underweight/wasting.

CONCLUSIONS

The present study showed inverse association between the fish/white meat pattern and underweight/wasting and also a positive association between higher fish/white meat protein intake and higher risk of overweight/obesity. Further studies are needed to confirm these results.

Animal Protein Intake Is Associated with General Adiposity in Adolescents: The Teen Food and Development Study

Protein plays a crucial role in the growth and development of adolescents. However, being a secondary energy source, protein's role in obesity has been sidelined. We examined whether intake of protein (total, animal, plant), branched-chain (BCAAs), and sulfur-containing (SCAAs) amino acids are associated with general body and central obesity and body composition in a cross-sectional study among healthy adolescents. Students aged 12-18 years old (n = 601) in schools near two major Adventist universities in California and Michigan provided dietary data via a validated web-based food frequency questionnaire (FFQ) and anthropometric data during school visits. Intakes of total, animal, and plant proteins, and BCAAs and SCAAs were derived from FFQ data. We defined general body obesity with body-mass-index-for-age (BMIz) z-scores and central obesity with waist-to-height ratios (WHtR). After full adjustment for covariates, multiple regression analyses showed significant positive associations between intakes of total protein (β = 0.101, 95% CI: 0.041, 0.161), animal protein (β = 0.118, 95% CI: 0.057, 0.178), BCAAs (β = 0.056, 95% CI: 0.025, 0.087), and SCAAs (β = 0.025, 95% CI: 0.012, 0.038) with general body adiposity. Animal protein (β = 0.017, 95% CI: 0.001, 0.033) and SCAAs (β = 0.004, 95% CI: 0.000, 0.008) were also associated with central obesity. Total and animal protein and BCAA and SCAA were also significantly associated with fat mass. Our findings suggest that high protein intake may pose a possible detriment to adolescent health. Longitudinal and safety evaluation studies are recommended.

Knowledge, Attitude and Behaviours Related to Weight Control and Body-Image Perceptions among Chinese High School Students

Background

Body-image perception is one of the determinants in weight management, especially among adolescents. This study aimed to assess weight-control knowledge, attitude and behaviours along with body-image perceptions among Chinese high school students in order to compare the weight-control behaviours with those perceptions.

Methods

A cross-sectional study was conducted among 277 Chinese students in Form 1 and Form 2 in Pulau Pinang, Malaysia using convenience sampling. The following outcomes were evaluated: weight-control knowledge, attitude and behaviours (weight-related knowledge and attitude questionnaire; weight control strategies scale) and body-image perceptions (figure rating scale).

Results

Both genders were found to have high weight-control knowledge, with female adolescents scoring significantly higher than male adolescents (P = 0.010). However, only half of the adolescents (50.9%) perceived that obesity is bad for health. Although only 44.4% of adolescents were dissatisfied with their current weight status, 62.8% intended to change their present weight status. Male adolescents significantly engaged more in physical activity (PA) (P = 0.035) and self-monitoring (SM) (P = 0.014) compared to their female counterparts. Furthermore, male adolescents chose their current body size as their ideal body image, but female adolescents preferred a slimmer ideal figure. The percentage of male and female adolescents who desired a smaller body figure was 39.6% and 54.5%, respectively. Lastly, there was no significant difference between weight-control behaviours and adolescents’ body-image perceptions.

Conclusion

Female Chinese adolescents had higher weight-control knowledge and preferred a slimmer body size, yet males were more likely to engage in PA and SM behaviours. Essentially, imprecise attitude towards obesity among half of the Chinese high school students is of particular concern.

Low muscle mass and strength in pediatrics patients: Why should we care?

Skeletal muscle plays major roles in metabolism and overall health across the lifecycle. Emerging evidence indicates that prenatal (maternal diet during pregnancy and genetic defects) and postnatal factors (physical activity, hormones, dietary protein, and obesity) influence muscle mass acquisition and strength early in life. As a consequence, low muscle mass and strength contributes to several adverse health outcomes during childhood. Specifically, studies demonstrated inverse associations of muscle mass and strength to single and clustered metabolic risk factors. The literature also consistently reports that low muscle mass and strength are associated with reduced bone parameters during growth, increasing the risk of osteoporosis in old age. Furthermore, muscle mass gains are associated with improved neurodevelopment in the first years of life. Given these negative implications of low muscle mass and strength on health, it is crucial to track muscle mass and strength development from childhood to adolescence. Several body composition techniques are currently available for estimation of muscle mass, all with unique advantages and disadvantages. The value of ultrasound as a technique to measure muscle mass is emerging in pediatric research with potential for translating the research findings to clinical settings. For the assessment of muscle strength, the handgrip strength test has been widely employed but without a standardized protocol. Although further research is needed to define normative data and cut points for the low muscle mass and strength phenotype, the use of such non-invasive medical monitoring is a promising strategy to identify early abnormalities and prevent low muscle mass in adulthood.

Associations of protein intake in early childhood with body composition, height, and insulin-like growth factor I in mid-childhood and early adolescence

BACKGROUND

Early protein intake may program later body composition and height growth, perhaps mediated by insulin-like growth factor I (IGF-I). In infancy, higher protein intake is consistently associated with higher IGF-I concentrations and more rapid growth, but associations of protein intake after infancy with later growth and IGF-I are less clear.

OBJECTIVES

Our objective was to examine associations of protein intake in early childhood (median 3.2 y) with height, IGF-I, and measures of adiposity and lean mass in mid-childhood (median 7.7 y) and early adolescence (median 13.0 y), and with changes in these outcomes over time. We hypothesized that early childhood protein intake programs later growth.

METHODS

We studied 1165 children in the Boston-area Project Viva cohort. Mothers reported children's diet using food-frequency questionnaires. We stratified by child sex and examined associations of early childhood protein intake with mid-childhood and early adolescent BMI z score, skinfold thicknesses, dual-energy X-ray absorptiometry (DXA) fat mass, DXA lean mass, height z score, and IGF-I concentration. We adjusted linear regression models for race/ethnicity, family sociodemographics, parental and birth anthropometrics, breastfeeding status, physical activity, and fast food intake.

RESULTS

Mean protein intake in early childhood was 58.3 g/d. There were no associations of protein intake in early childhood with any of the mid-childhood outcomes. Among boys, however, each 10-g increase in early childhood total protein intake was associated with several markers of early adolescent size, namely BMI z score (0.12 higher; 95% CI: 0.01, 0.23), DXA lean mass index (1.34% higher; 95% CI: -0.07%, 2.78%), and circulating IGF-I (5.67% higher; 95% CI: 0.30%, 11.3%). There were no associations with fat mass and no associations with any adolescent outcomes among girls.

CONCLUSIONS

Early childhood protein intake may contribute to programming lean mass and IGF-I around the time of puberty in boys, but not to adiposity development. This study was registered at clinicaltrials.gov as NCT02820402.

Association of Dietary Fatty Acids with Blood Lipids is Modified by Physical Activity in Adolescents: Results from the GINIplus and LISA Birth Cohort Studies

The role of consuming different types of fatty acids (FA) at the expense of carbohydrates (CHO), on the blood lipid profile of adolescents is largely unknown, as is the modulating effect of different levels of physical activity (PA). Children from the GINIplus and LISA birth cohorts, with complete data on dietary FA (assessed by food-frequency questionnaires), objectively-measured PA (assessed by accelerometers) and blood lipids (lipoprotein cholesterol and triglycerides) at age 15 years, were included (N = 837). Sex-stratified associations between dietary FA and blood lipids were assessed by linear regression in substitution models which represented isocaloric replacements of CHO with saturated FA (SFA), monounsaturated FA (MUFA), n-3 polyunsaturated FA (PUFA) or n-6 PUFA. To assess the interactions with PA, analyses were then performed stratified by tertiles of different PA levels (sedentary, lifestyle, moderate-to-vigorous (MVPA)). Both sexes presented a significant inverse association between MUFA and triglycerides, and females a direct association between n-3 PUFA and high-density lipoprotein. Stratifying by PA tertiles, associations were mainly restricted to participants with the lowest levels of lifestyle PA, or the highest time spent sedentary. The effects of dietary FA on the lipid profile vary in an activity-specific manner, emphasizing possible synergistic roles of diet and PA.