The role of protein intake in the relationship between egg consumption and body composition in young adults. A mediation analysis

Background & aimsTo date, the literature examining the effects of whole-egg consumption on health outcomes focuses primarily on cardiovascular health markers; however, a significant gap exists in the literature about how egg consumption may influence body composition indicators. The aim of this study was to estimate the association between egg consumption and body composition indicators and to examine whether this relationship is mediated by protein intake in young adults.MethodsA cross-sectional study was conducted involving 355 first-year university students (aged 18–30 years) from a Spanish public university. Body composition was measured using bioimpedance and dual-energy X-ray absorptiometry (DXA) and fitness components were determined using the course-navette test. Egg consumption and protein intake (both in g/day/kg of body weight) were determined using a 137-item Food-Frequency Questionnaire. ANCOVA models were used to test the mean differences in body composition indicators (body mass index [BMI], ratio waist circumference/height [WC/height], body fat mass percentage, and body lean mass percentage) by egg consumption categories (<1 egg/week, 1–4 eggs/week, ≥5 eggs/week). Hayes's PROCESS macro was used for mediation analyses.ResultsParticipants reporting high egg consumption (≥5 eggs/week) showed significantly lower BMI, WC/height and body fat mass percentage values and higher body lean mass percentage values than those reporting low egg consumption (<1 egg/week) (p < 0.05). However, these relationships were not maintained after adjusting for protein intake. Protein intake acted as a full mediator of the relationships of egg consumption with BMI (indirect effect [IE] = ?1.19; 95% CI [?3.33; ?0.36]), WC/height (IE = ?0.01; 95% CI [?0.04; ?0.01]) and body lean mass percentage (IE = 2.99; 95% CI [1.26; 5.73]) as a partial mediator of the relationship be-tween egg consumption and body fat mass percentage (IE = ?2.19; 95% CI [?4.92; ?0.46]).ConclusionsThe association between egg consumption and body composition is mediated by protein intake. This finding is important from a public health perspective, suggesting that higher egg consumption (≥5 eggs/week) may lead to a healthier body composition, especially due to higher protein intake.     

The role of adiposity,diet and inflammation on the discordance between LDL-C and apolipoprotein B

Background and aimsWhile low-density lipoprotein cholesterol (LDL-C) is a good predictor of atherosclerotic cardiovascular disease, apolipoprotein B (ApoB) is superior when the two markers are discordant. We aimed to determine the impact of adiposity, diet and inflammation upon ApoB and LDL-C discordance.Methods and resultsMachine learning (ML) and structural equation models (SEMs) were applied to the National Health and Nutrition Examination Survey to investigate cardiometabolic and dietary factors when LDL-C and ApoB are concordant/discordant. Mendelian randomisation (MR) determined whether adiposity and inflammation exposures were causal of elevated/decreased LDL-C and/or ApoB. ML showed body mass index (BMI), dietary saturated fatty acids (SFA), dietary fibre, serum C-reactive protein (CRP) and uric acid were the most strongly associated variables (R² = 0.70) in those with low LDL-C and high ApoB. SEMs revealed that fibre (b = ?0.42, p = 0.001) and SFA (b = 0.28, p = 0.014) had a significant association with our outcome (joined effect of ApoB and LDL-C). BMI (b = 0.65, p = 0.001), fibre (b = ?0.24, p = 0.014) and SFA (b = 0.26, p = 0.032) had significant associations with CRP. MR analysis showed genetically higher body fat percentage had a significant causal effect on ApoB (Inverse variance weighted (IVW) = Beta: 0.172, p = 0.0001) but not LDL-C (IVW = Beta: 0.006, p = 0.845).ConclusionOur data show increased discordance between ApoB and LDL-C is associated with cardiometabolic, clinical and dietary abnormalities and that body fat percentage is causal of elevated ApoB.     

Central and peripheral body fat distribution: Different associations with low-grade inflammation in young adults?

Background and aimsEvidence regarding the impact of regional body fat distribution on low-grade inflammation is limited. The current study examined the association of central and peripheral body fat distribution and low-grade inflammation levels in young adults, considering collinearity between variables.Methods and resultsA cross-sectional analysis of 809 adults (aged 27 years) was conducted as part of the EPITeen cohort, Porto, Portugal. Regional body fat was measured by dual-energy X-ray absorptiometry scan (DXA) and serum high-sensitivity C-reactive protein (hsCRP) was measured in a fasting blood sample. OLS (ordinary least squares) and LASSO (least absolute shrinkage and selection operator) regression models were fitted to estimate the association of trunk and peripheral fat with hsCRP, stratified by sex. Using OLS regression, trunk fat in females was positively associated with ln(hsCRP) (β₁ = 0.064, 95% CI 0.018; 0.109). The effect of peripheral fat on ln(hsCRP) was shown not to be significantly different from trunk fat (β₂ = −0.011, 95% CI −0.110; 0.089), but no statistically significant association was observed (β₃ = 0.053, 95% CI −0.004; 0.110) between peripheral fat and ln(hsCRP). In males, trunk fat also showed a positive association with ln(hsCRP) (β₁ = 0.104, 95% CI 0.055; 0.154), and the effect of peripheral fat on ln(hsCRP) was shown to be significantly different from trunk fat (β₂ = −0.124, 95% CI −0.237;−0.011). However, the association between peripheral fat and ln(hsCRP) did not reach statistical significance (β₃ = −0.020, 95% CI −0.086; 0.046). The results of OLS were confirmed by LASSO regression.ConclusionA higher fat deposited in the trunk was positively associated with hsCRP, whereas no statistically significant effect was observed for peripheral fat.     

Effectiveness to promote weight loss maintenance and healthy lifestyle habits of a group educational intervention program in adults with obesity: IGOBE program

BackgroundTo achieve sustainable weight loss and healthy lifestyle changes is a huge challenge in the fight against obesity. The objective of this study was to evaluate the effectiveness to promote weight loss maintenance and healthy lifestyle habits of a group educational intervention program, Group Intervention in OBEsity (IGOBE), compared with a usual care therapy to lose weight.MethodsPatients with obesity (n = 437; 18.5% men, 18–77 years and 40.4 ± 6.7 kg/m²) were randomised into two groups to follow a prospective interventional real-life study: a control group (CG), treated with usual clinical practice, and an intervention group (IG), in which the patients participate in a group intervention program on healthy lifestyle habits with weekly sessions for six weeks, after which a re-evaluation was made at six months and at 12 months of follow-up. After finishing the study dropout rates were 44.6% in CG and 43.4% in IG. Anthropometric, dietetic habits and body composition data were analysed in both groups at the pre-intervention and post-interventions of the subjects by completer’s analysis.ResultsAt 12 months of following IGOBE program, the IG achieved greater weight loss (–7.1% of the initial weight) than the CG, which exhibited a weight gain (3.0% of the initial weight). The body weight change induced in the IG was accompanied by a reduction in fat mass, particularly visceral fat and waist circumference. Relevantly, the IG adhered to a healthy dietary pattern and changed its eating habits, which correlated with the improvement in body weight.ConclusionsIntensive educational group treatment that induces a change of eating habits and adherence to healthy dietary pattern is more effective in a long-term to counteract obesity traits than a standard treatment performed individually. The IGOBE program could be a cost-effective practice in the clinical management of obesity.     

Relationship of a Body Shape Index and Body Roundness Index with carotid atherosclerosis in arterial hypertension

Background and aimsA Body Shape Index (ABSI) and Body Roundness Index (BRI) are two new anthropometric adiposity indices that have shown to be associated better than BMI with adipose abdominal tissue, with the onset of diabetes and the risk of premature death. Little is known about the influence of ABSI and BRI on subclinical vascular damage. The study was aimed to assess the relationship between ABSI and BRI with carotid atherosclerosis damage in subjects with arterial hypertension.Methods and resultsA total of 468 patients with arterial hypertension (30–80 years old) were enrolled; adiposity indices were calculated (BMI, WC, ABSI, BRI) and carotid ultrasonographic examination was performed to detect atherosclerotic damage (IMT or atherosclerotic plaque). BRI, but not ABSI, was higher in subjects with IMT> 0.90 mm in comparison to those with a lower IMT (p < 0.001), whereas patients with carotid plaques showed higher values of ABSI (p = 0.001), as well as of BRI (p = 0.003). Linear regression analysis disclosed significant correlation of IMT with ABSI, BRI and BMI (all p < 0.001). In the multivariate analysis, BRI was independently correlated with cIMT (p = 0.015). On the contrary, ABSI did not show any independent association with cIMT. However, ABSI was strongly associated with carotid plaques in multiple logistic regression analysis after adjustment for potential confounding factors. When BRI or BMI replaced ABSI into the multivariate models, they did not show any independent correlation with carotid plaques.ConclusionsABSI may be proposed as a better correlate of carotid atherosclerosis than the traditional measures of adiposity.     

Olanzapine affects locomotor activity and meal size in male rats

Olanzapine is an antipsychotic drug that frequently induces weight gain accompanied by increased fat deposition as a side effect. To investigate how olanzapine affects different aspects of energy balance, we used male rats to determine effects on meal patterns, food preference, locomotor activity and body temperature. In two short-term experiments olanzapine was administered via osmotic minipumps. In the first experiment, we offered rats standard lab chow only. In the second experiment, we offered rats free choice between chow, sucrose and saturated fat. In a third experiment, olanzapine was chronically administered via the drinking water to determine effects on body composition. In each experiment olanzapine decreased locomotor activity and altered meal patterns. Olanzapine caused an increase in average meal size accompanied by reduced meal frequency, without clearly affecting food preference. In the chronic experiment body composition was altered, favoring adipose tissue over lean muscle mass, despite reductions in overall body weight gain. The increase in average meal size implies that the primary effect of olanzapine on feeding is an impairment of the normal satiation process. Furthermore, energy balance is clearly affected by a reduction in locomotor activity. Thus, the effects of olanzapine on adiposity do not depend solely on the presence of hyperphagia.     

Dietary fat plays a major role in obesity: no

The percentage of dietary energy from fat has been suggested to be an important determinant of body fat, and this presumed effect has been invoked to justify the general promotion of low‐fat diets. Dietary fat and the prevalence of obesity are lower in poor countries than in affluent countries. However, these contrasts are seriously confounded by differences in physical activity and food availability; within areas of similar economic development, per capita intake of fat and the prevalence of obesity have not been positively correlated. Randomized trials are the preferable method for evaluating the effect of dietary fat on adiposity because they avoid problems of confounding that are difficult to control in other studies. In short‐term trials, a small reduction in body weight is typically seen in individuals randomized to diets with a lower percentage of calories from fat. In a meta‐analysis of these trials, it was estimated that a decrease in 10% of energy from fat would reduce weight by 16 g d^–1, which would correspond to a 9‐kg weight loss by 18 months. However, compensatory mechanisms appear to operate because in trials lasting one year or longer, fat consumption within the range of 18–40% of energy has consistently had little, if any, effect on body fatness. Moreover, within the United States (US), a substantial decline in the percentage of energy from fat during the last two decades has corresponded with a massive increase in obesity, and similar trends are occurring in other affluent countries. Diets high in fat do not account for the high prevalence of excess body fat in Western countries; reductions in the percentage of energy from fat will have no important benefits and could further exacerbate this problem. The emphasis on total fat reduction has been a serious distraction in efforts to control obesity and improve health in general.     

Early lead exposure and childhood adiposity in Mexico city

BackgroundPrenatal and early childhood lead exposures have been associated with reduced weight in infants and young children, while studies that have examined such associations in children during peripubescence are rare.ObjectivesWe investigated the associations of prenatal and early-life exposure to lead with indices of adiposity in peripubertal children living in Mexico City.MethodsMaternal bone lead (as a proxy for cumulative fetal exposure) was assessed at 1 month postpartum. Blood samples were obtained from children annually from 1 to 4 years. Multivariable linear regression models were used to examine the association between each lead biomarker and BMI z-score, waist circumference, sum of skinfolds and body fat percentage in 248 children aged 8–16 years.ResultsAfter adjusting for covariates, maternal patella lead was associated with lower child BMI z-score (β = ?0.02, 95% CI: 0.03, ?0.01, p = 0.004), waist circumference (β = ?0.12 cm, 95% CI: 0.22, ?0.03, p = 0.01), sum of skinfolds (β = ?0.29 mm, 95% CI: 0.50, ?0.08, p = 0.007) and body fat percentage (β = ?0.09%, 95% CI: 0.17, ?0.01, p = 0.03). No significant associations were detected from the postnatal exposure period.ConclusionsWe observed a significant and inverse association of prenatal lead exposure with body composition in Mexican children, suggesting the potential role of early lead exposure in the fetal programming of child growth. Further research on the biological mechanisms underlying these associations is needed.     

Influence of high-fat feeding, diet-induced obesity, and hyperamylinemia on the sensitivity to acute amylin

Obesity results in the increased secretion of various hormones controlling food intake and body weight, such as leptin, and insulin; increased circulating levels of pancreatic amylin have also been described in obese humans and rodents. Because leptin-resistance is present in diet-induced obese (DIO) rats, and because hyperleptinemia seems necessary for the full development of leptin resistance, we tested whether amylin sensitivity is inversely correlated with adiposity, such that DIO reduces the anorectic action of acute amylin. We also determined if hyperamylinemia leads to a change in amylin sensitivity. In the first experiment, rats were chronically exposed to a high fat (HF; 60% fat) diet or fed standard chow for control. The anorectic response to amylin was tested on several occasions over a 14 week observation period. HF feeding led to the expected increase in body adiposity; the response to an acute amylin injection (5 - 50 μg/kg s.c.) was unaltered for 10 weeks of HF feeding. Even after 12 weeks on a HF diet, which clearly caused obesity, acute administration of amylin (5 μg/kg, s.c.) was still able to suppress food intake, although the suppression was not statistically significant. Further experiments using additional doses of amylin will be necessary to demonstrate possible amylin resistance after HF feeding or in DIO rats. In the second experiment, we tested more specifically whether hyperamylinemia that may result from HF feeding and subsequent obesity, reduces the sensitivity of the amylin signaling system. To avoid confounding factors, we chronically infused lean chow fed rats with amylin (5 or 10 μg/kg/day s.c.) to elevate their plasma amylin concentration to levels observed in obese rats (30 - 40 pM). In the absence of obesity, hyperamylinemia did not lead to a reduced sensitivity to acute amylin (5 - 20 μg/kg s.c.) injections; acute amylin reduced eating similarly in all groups of rats. Overall, we concluded that direct diet effects by short term exposure to HF appear to be of little importance for amylin sensitivity; further, long-term maintenance on a HF diet and the resulting obesity only slightly attenuated the anorectic response to acute amylin. Because we observed no marked changes in amylin sensitivity in lean, chow fed rats with induced hyperamylinemia, amylin receptor downregulation in chronic hyperamylinemia does not seem to occur.     

Stephen C. Woods: a precocious scientist

To investigate the early scientific development of Steve Woods, I reviewed his research during the first decade after he received his doctoral degree in 1970. The main parts of his research program were conditioned insulin secretion and hypoglycemia, Pavlovian conditioning of insulin secretion before a scheduled access to food, and basal insulin as a negative-feedback signal from fat mass to the brain. These topics were pursued with experimental ingenuity; the resulting publications were interesting, clear, and rhetorically effective. Although the theoretical framework for his experiments with insulin was homeostatic, by the end of the decade he suggested that classic negative-feedback homeostasis needed to be revised to include learning acquired by lifestyle. Thus, Woods functioned as a mature scientist from the beginning of his research—he was very precocious. This precocity also characterized his teaching and mentoring as recalled by two of his students during that time, Joseph Vasselli and Paul Kulkosky. The most unusual and exemplary aspect of his precocity is that the outstanding performance of his first decade was maintained during the subsequent 30 years.