Improvements In Metabolic Health Research Articles

GLP-1 and PYY3-36 reduce high-fat food preference additively after Roux-en-Y gastric bypass in diet-induced obese rats

BackgroundRoux-en-Y gastric bypass (RYGB) modifies various aspects of eating behavior in morbidly obese individuals to cause marked and lasting weight loss and improvements in metabolic health, but the underlying mechanisms remain poorly understood. ObjectivesTo assess the relative contributions of the gut hormones glucagon-like peptide 1 (GLP-1) and peptide tyrosine tyrosine 3-36 (PYY3-36), whose circulating levels are enhanced by RYGB, in the reduced high-fat (HF) food preference that develops postoperatively. SettingUniversity hospital, Würzburg, Germany. MethodsHF diet–induced obese male Wistar rats underwent RYGB (n = 11) or sham (n = 7) surgeries and were subsequently maintained on a choice of low-fat (10% calories from fat) and HF (60% calories from fat) diets. From postoperative weeks 4 to 6, acute feeding studies were performed in which the selective GLP-1 receptor antagonist exendin-9 (30 μg/kg), the second-generation selective Y2 receptor antagonist JNJ-31020028 (10 mg/kg), or a combination of both drugs was administered intraperitoneally. ResultsDuring the observational period weight, adiposity and total food intake were lower while postprandial plasma GLP-1 and peptide tyrosine tyrosine levels were higher for RYGB-operated compared with sham-operated rats. There was a gradual shift in preference from HF to low-fat food in RYGB-operated rats by postoperative week 3. Single antagonist treatments had a relatively modest impact on HF food preference in rats from both surgical groups. However, dual antagonist treatment caused a striking increase in HF food preference specifically in RYGB-operated rats. ConclusionsGLP-1 and peptide tyrosine tyrosine 3-36 reduce HF food preference additively after RYGB supporting the use of gut hormone combination strategies for healthier feeding behavior.

Absolute Weight Loss, and Not Weight Loss Rate, Is Associated with Better Improvements in Metabolic Health.

Objective To determine if the rate of weight loss (WL) is associated with metabolic changes independent of the absolute WL. Methods WL and health changes were assessed in 11,281 patients attending a publicly funded clinical weight management program over a treatment period of 12.7 months. Early weight loss rate (WLR) in the first 3–6 months and overall WLR were categorized as Fast WLR (≥1 kg/wk), Recommended WLR (0.5 to 0.9 kg/wk), or Slow WLR (<0.5 kg/wk). Results On average, patients attained a 6.6 ± 7.3 kg (5.8 ± 5.7%) WL over 12.8 ± 13.1 months. Prior to adjusting for covariates, patients with Fast WLR (−24.7 ± 13.4 kg) at 3–6 months had a greater overall WL as compared to those with Recommended WLR (−13.3 ± 8.7 kg) and Slow WLR (−5.0 ± 5.4 kg). Fast WLR also had greater improvements in the overall waist circumference and blood pressure than patients with Slow or Recommended WLR. However, after adjustment for absolute WL, Early and overall Recommended and Fast WLR did not differ in the changes in any of the health markers (P > 0.05). Conversely, the absolute WL sustained is significantly associated with changes in metabolic health independent of WLR (P < 0.001). Similar results were observed with WLR over the entire treatment period. Conclusions Faster rates of WL are associated with a greater absolute WL and larger improvements in waist circumference and blood pressure. However, after adjusting for the larger absolute WL sustained, early and overall faster WLR do not appear to have advantages for improving metabolic health markers. Thus, the absolute WL attained may be the most important factor for improving metabolic health.

Weight loss and metabolic health effects from energy-restricted Mediterranean and Central-European diets in postmenopausal women: A randomized controlled trial

We conducted a randomized controlled trial to examine the effect of two energy-restricted diets on body weight (BW), visceral fat (VF) loss, and the risk factors for metabolic syndrome. A total of 144 centrally obese postmenopausal women were assigned to the moderate in fat Mediterranean diet (MED) or to the Central European diet (CED), which is moderate in carbohydrates and high in dietary fiber (DF), for 16 weeks. BW, waist circumference and VF were significantly reduced by 8.8%, 7.0%, and 24.6%, respectively, over the trial (P < 0.001), with no difference between groups. A similar trend was seen for total cholesterol, triglycerides, glucose, and blood pressure. Within each diet group, the more adherent participants lost significantly more BW than did their less adherent counterparts. VF was significantly reduced only in women who were more adherent to the CED, and the reduction in VF correlated with an increase in the proportion of DF. Short-term dietary treatment with the CED or the MED was associated with similar improvements in some anthropometric, lipid, and nonlipid parameters; however, adequate adherence to the prescribed diet is important in weight loss success and in achieving improvements in metabolic health.

Remission of loss of control eating and changes in components of the metabolic syndrome.

Pediatric loss of control (LOC) eating prospectively predicts the worsening of metabolic syndrome components. However, it is unknown if remission of LOC eating is associated with improvements in metabolic health. Therefore, we conducted a secondary analysis of a trial that enrolled adolescent girls with LOC eating, examining whether LOC remission (vs. persistence) at end-of-treatment was associated with changes in metabolic syndrome components at 6-month follow-up. One hundred three adolescent girls (age 14.5±1.7years; BMI-z 1.5±0.3; 56.3% non-Hispanic White, 24.3% non-Hispanic Black) with elevated weight (75th-97th BMI %ile) and reported LOC eating were assessed for metabolic syndrome components at baseline and again six months following the interventions. The main effects of LOC status at end-of-treatment (persistence vs. remission) on metabolic syndrome components (waist circumference, lipids, glucose, and blood pressure) at 6-month follow-up were examined, adjusting for baseline age, depressive symptoms, LOC frequency, fat mass, and height, as well as race, change in height, change in fat mass, and the baseline value of each respective component. Youth with LOC remission at end-of-treatment had lower glucose (83.9±6.4 vs. 86.5±5.8mg/dL; p=.02), higher high-density lipoprotein cholesterol (50.3±11.8 vs. 44.8±11.9mg/dL; p=.01), and lower triglycerides (84.4±46.2 vs. 96.9±53.7mg/dL; p=.02) at 6-month follow-up when compared with youth with persistent LOC, despite no baseline differences in these components. No other component significantly differed by LOC eating status (ps>.05). Reducing LOC eating in adolescent girls may have a beneficial impact on some components of the metabolic syndrome.

Performance and Health Benefits of Dietary Nitrate Supplementation in Older Adults: A Systematic Review.

Supplementation with nitrate (NO3−)-rich beetroot juice has been shown to improve exercise performance and cardiovascular (CV) responses, due to an increased nitric oxide (NO) availability. However, it is unclear whether these benefits are greater in older adults who have an age-related decrease in NO and higher risk of disease. This systematic review examines 12 randomised, crossover, control trials, investigating food-based NO3− supplementation in older adults and its potential benefits on physiological and cognitive performances, and CV, cerebrovascular and metabolic health. Four studies found improvements in physiological performance (time to exhaustion) following dietary NO3− supplementation in older adults. Benefits on cognitive performance were unclear. Six studies reported improvements in CV health (blood pressure and blood flow), while six found no improvement. One study showed improvements in cerebrovascular health and two found no improvement in metabolic health. The current literature indicates positive effects of dietary NO3− supplementation in older adults on physiological performance, with some evidence indicating benefits on cardiovascular and cerebrovascular health. Effects on cognitive performance were mixed and studies on metabolic health indicated no benefit. However, there has been limited research conducted on the effects of dietary NO3− supplementation in older adults, thus, further study, utilising a randomised, double-blind, control trial design, is warranted.

Effect of supramaximal exercise training on metabolic outcomes in obese adults

ABSTRACTThe purpose of this study was to evaluate the effects of 6 weeks of supramaximal exercise training (SET) on performance variables and metabolic changes in sedentary obese adults.Twenty-four obese adults were randomly allocated into a non-trained (NT) [n = 12; body mass index (BMI) = 33(3)] and SET group [n = 12; BMI = (33(2)]. After baseline metabolic and fitness measurements, the participants completed a 6-week SET intervention. Metabolic, anthropometric, and fitness assessments were repeated post-intervention.For SET, fasting glucose (4.64(0.15) vs. 4.32(0.22) mmol · l–1; P < 0.01), insulin (23.2(4.6) vs. 13.8(3.3) µmol · ml–1; P < 0.01), homoeostasis model assessment-insulin resistance index (4.78(1.2) vs. 2.65(1.5); P < 0.01) and systolic blood pressure (127(3) vs. 120(3) mmHg; P < 0.01) were significantly lower 24-h post-intervention than at baseline and for the NT group, and these changes remained significant at 72-h and 2-weeks post-intervention (P < 0.01, respectively). Interestingly, nonesterified fatty acids (0.62(0.09) vs. 0.71(0.11) mmol · l–1; P < 0.01) and resting fat oxidation rate (57(11) vs. 63(4)%; P < 0.01) increased significantly from baseline 24-h post-intervention in the SET group and from baseline at 72-h (P < 0.01, respectively) and 2-weeks post-intervention (P < 0.01, respectively). Six weeks of SET improved a number of metabolic and vascular risk factors in obese, sedentary adults, highlighting the potential of SET to provide an alternative exercise model for the improvement of metabolic health in this population.

Combatting type 2 diabetes by turning up the heat.

In our westernised society, the level of physical activity is low. Interventions that increase energy expenditure are generally associated with an improvement in metabolic health. Exercise and exercise training increase energy metabolism and are considered to be among the best strategies for prevention of type 2 diabetes mellitus. More recently, cold exposure has been suggested to have a therapeutic value in type 2 diabetes. At a cellular level, there is evidence that increasing the turnover of cellular substrates such as fatty acids is associated with preventive effects against lipid-induced insulin resistance. Cellular energy sensors may underlie the effects linking energy turnover with metabolic health effects. Here we review data supporting the hypothesis that increasing energy and substrate turnover has beneficial effects on insulin sensitivity and should be considered a target for the prevention and treatment of type 2 diabetes.Electronic supplementary materialThe online version of this article (doi:10.1007/s00125-016-4068-3) contains a slideset of the figures for download, which is available to authorised users.

Supramaximal Exercise Training Enhances several Health-Related Outcomes in Obese Adults

Studying the effects of exercise training on health- and performance-related outcomes may be the best approach to describing its beneficial effects among obese individuals. PURPOSE: The present study evaluates the effects of six weeks of supramaximal exercise training (SET) on performance variables and metabolic changes in sedentary obese adults. METHODS: Twenty-four obese adults were randomized into a non-trained (NT) [n=12; body mass index (BMI)=33(3)] and SET group [n=12; BMI=(33(2)]. After baseline metabolic, anthropometric, and fitness measurements, the participants completed a 6-week SET intervention comprising 18 sessions of 6 repeats of 6-second supramaximal sprints on an electromagnetically braked cycle ergometer, with 2-minute recovery between each repetition. Metabolic, anthropometric, and fitness assessments were repeated post-intervention. RESULTS: Neither anthropometrics nor maximal oxygen uptake differed between the groups after 6 weeks of SET. For SET, fasting glucose (4.64(0.15) vs 4.32(0.22) mmol/l; p<0.01), insulin (23.2(4.6) vs 13.8(3.3) μmol/ml; p<0.01), HOMA-IR (4.78(1.2) vs 2.65(1.5); p<0.01), and systolic blood pressure (127(3) vs 120(3) mmHg; p<0.01) were significantly lower 24-hours post-intervention than at baseline and for the NT group, and these changes remained significant at 72-hours and two-weeks post-intervention (p<0.01, respectively). Interestingly, NFEA (0.62(0.09) vs 0.71(0.11) mmol/l; p<0.01) and resting fat oxidation rate (57(11) vs 63(4) %; p<0.01) increased significantly from baseline 24-hours post-intervention in the SET group and decreased significantly from baseline at 72-hours (p<0.01, respectively) and two-weeks post-intervention (p<0.01, respectively). CONCLUSIONS: Although there were no changes in the participants’ anthropometric and aerobic fitness variables, six weeks of SET improved a number of metabolic and vascular risk factors in obese, sedentary adults, highlighting the potential of SET to provide an alternative exercise model for the improvement of metabolic health in this population.

A role for exercise after bariatric surgery?

Obesity predisposes an individual to develop numerous comorbidities, including type 2 diabetes, and represents a major healthcare issue in many countries worldwide. Bariatric surgery can be an effective treatment option, resulting in profound weight loss and improvements in metabolic health; however, not all patients achieve similar weight loss or metabolic improvements. Exercise is an excellent way to improve health, with well-characterized physiological and psychological benefits. In the present paper we review the evidence to determine whether there may be a role for exercise as a complementary adjunct therapy to bariatric surgery. Objectively measured physical activity data indicate that most patients who undergo bariatric surgery do not exercise enough to reap the health benefits of exercise. While there is a dearth of data on the effects of exercise on weight loss and weight loss maintenance after surgery, evidence from studies of caloric restriction and exercise suggest that similar adjunctive benefits may be extended to patients who perform exercise after bariatric surgery. Recent evidence from exercise interventions after bariatric surgery suggests that exercise may provide further improvements in metabolic health compared with surgery-induced weight loss alone. Additional randomized controlled exercise trials are now needed as the next step to more clearly define the potential for exercise to provide additional health benefits after bariatric surgery. This valuable evidence will inform clinical practice regarding much-needed guidelines for exercise after bariatric surgery.

Abstract 688: Trans-10, Cis-12 Conjugated Linoleic Acid Induces a Lipodystrophic Phenotype and Browning of White Adipose Tissue in a Mouse Model of the Metabolic Syndrome

Trans-10, cis-12 conjugated linoleic acid (10,12 CLA) is a naturally occurring dietary trans fatty acid reported to promote weight loss by unknown mechanisms. 10,12 CLA is associated with reduced adiposity, while simultaneously promoting inflammation, insulin resistance, and dyslipidemia. Commercially available CLA supplements containing 10,12 CLA are used to facilitate weight loss, so opposing effects on body weight and inflammation could put consumers at risk for adverse health effects. We therefore examined how 10,12 CLA reduces adiposity in an obese mouse model of the metabolic syndrome. Ldlr-/- mice consuming a high fat high sucrose diet with added cholesterol (HFHSC) supplemented with 1% 10,12 CLA are resistant to weight gain, have reduced body fat, and express genes associated with fatty acid oxidation in adipose tissue. They exhibit substantial fat loss from subcutaneous but not visceral adipose depots, in stark contrast to weight matched calorically restricted mice that maintain subcutaneous fat. Further, mice consuming 10,12 CLA do not show the expected improvements in glucose metabolism or plasma lipids despite carrying significantly less fat, consistent with what is seen with lipodystrophy. Additionally, subcutaneous and brown adipose tissue contain more macrophages in 10,12 CLA-supplemented mice than in control mice, suggestive of a pro-inflammatory state. Mice supplemented with 10,12 CLA also show signs of white adipose tissue “browning” with better maintenance of core body temperature upon cold exposure, both of which were absent in the weight matched control group. In summary, 10,12 CLA induces a lipodystrophic phenotype in obese mice with fat loss specifically from subcutaneous depots, resulting in negligible improvements in glucose tolerance, plasma lipids, and adipose tissue inflammation compared to weight matched controls. Despite substandard improvements in metabolic health and the lipodystrophic phenotype seen with 10,12 CLA, the notion that such a readily available compound could increase browning of white adipose tissue has therapeutic potential, and future studies could provide insight into mechanisms by which this browning potential could be harnessed while minimizing the detrimental effects of 10,12 CLA.

Metabolic Responses to Endurance Electrical Stimulation Training in Persons with Spinal Cord Injury

Persons with spinal cord injuries are at high risk for metabolic and cardiovascular disease due to reductions in physical activity. Improvements in metabolic health may be possible in this population with the use of electrical stimulation exercise. PURPOSE: Measure metabolic changes in response to 4 months of home-based electrical stimulation endurance training of the quadriceps muscles. METHODS: Oral glucose tolerance test (OGTT), lipid panel, and NIRS-measured mitochondrial capacity assessments were performed before and after electrical stimulation training in 14 persons with motor complete SCI, ranging from C4-T9. RESULTS: Baseline homeostatic model assessment-insulin resistance (HOMA-IR) was 4.3 ± 2.5. On average, glucose and insulin responses to OGTT did not improve after electrical stimulation exercise, p > 0.05. Glucose at 120 min pre: 123.1 ± 34.5 mg/dL vs. post 126.3 ± 36.7 mg/dL and insulin at 120 min pre: 221.1 ± 205 vs. post 195.4 ± 263.3 IU/L. On average, mitochondrial capacity in the vastus lateralis improved by 120% (range: -14 to 387%, p = 0.019). CONCLUSION: Endurance electrical stimulation training of the vastus lateralis muscles was not sufficient to elicit whole-body changes in glucose metabolism, although muscle specific changes in mitochondrial capacity occurred. Future studies should consider training additional muscles, as well as incorporating nutritional interventions. Supported by NIH RO1HD039676.

Inflammatory and Metabolic changes following Bariatric Surgery

Bariatric surgery is beneficial not only in inducing significant weight loss but also improving insulin sensitivity thereby reducing morbidity and mortality. However, the exact mechanisms are not fully understood yet. We hypothesize that bariatric surgery results in metabolic improvements and decreased inflammation, leading to reduced obesity related co-morbidities. To test this, we recruited patients undergoing Roux En Y gastric bypass and serum was collected during surgery, 2 weeks and 6 months post-surgery. As expected, leptin, a marker of adiposity and other circulating pro-inflammatory adipokines such as Tumor Necrosis Factor-α and Monocyte Chemotractant Protein-1 showed decreasing trends over time indicating reduced inflammation. Free fatty acids were also significantly reduced post-surgery. Metabolomic analyses performed using Nuclear Magnetic Resonance spectrometry showed that branched chain amino acids (BCAA: Isoleucine, Leucine and Valine), and 2-hydroxybutyrate were significantly reduced 6 months post-surgery compared to time of surgery. These metabolic changes indicate alterations in fatty acid and amino acid metabolism and suggest possible reductions in oxidative stress and insulin resistance. In depth analyses of metabolic profiles and pathways pre vs post- surgery are currently underway. In conclusion, our studies demonstrate significant improvements in metabolic health and reduced inflammation that may contribute to enhanced insulin sensitivity following bariatric surgery. Physician's Medical Education & Research Foundation, Knoxville,TN & Texas Tech University

Bariatric surgery in adolescents: what do we know so far?

Obesity represents a vast and rapidly increasing global burden. Bariatric surgery is the only intervention achieving sustained weight loss, among its wide-ranging benefits. In this article, we describe the growing challenges presented by adolescents with severe obesity and review the literature on surgical and other treatment options. Outcomes in terms of weight loss, metabolic and quality of life improvement, reversal of obstructive sleep apnea, insulin resistance, type II diabetes mellitus, hypertension, and dyslipidemia appear comparable to those seen in adults. However, long-term data on safety and sustainability are lacking. There is a growing acceptance of the need for surgery as a treatment for the morbidly obese adolescent population, and the number of studies reporting outcomes after adolescent bariatric surgery is increasing. Accumulating evidence suggests that the benefits seen in adult bariatric surgery can be reproduced in adolescents. Thus, adolescent bariatric surgery appears to be safe and effective in achieving benefits desired in terms of weight control and improvements in metabolic health and quality of life. However, particular care must be taken when treating a young population, and long-term outcomes are awaited to properly define indications and limitations.

The nonhuman primate as a model for type 2 diabetes

Although rodent models provide insight into the mechanisms underlying type 2 diabetes mellitus (T2DM), they are limited in their translatability to humans. The nonhuman primate (NHP) shares important metabolic similarities with the human, making it an ideal model for the investigation of type 2 diabetes and use in preclinical trials. This review highlights the key contributions in the field over the last year using the NHP model. The NHP has not only provided novel insight into the normal and pathological processes that occur within the islet, but has also allowed for the preclinical testing of novel pharmaceutical targets for obesity and T2DM. Particularly, administration of fibroblast growth factor-21 in the NHP resulted in weight loss and improvements in metabolic health, supporting rodent studies and recent clinical trials. In addition, the NHP was used to demonstrate that a novel melanocortin-4 receptor agonist did not cause adverse cardiovascular effects. Finally, this model has been used to provide evidence that glucagon-like peptide-1-based therapies do not induce pancreatitis in the healthy NHP. The insight gained from studies using the NHP model has allowed for a better understanding of the processes driving T2DM and has promoted the development of well tolerated and effective treatments.

COL6A3 Is Regulated by Leptin in Human Adipose Tissue and Reduced in Obesity

Fibrosis of adipose tissue (AT) increases AT rigidity, reduces its expandability, and contributes to metabolic dysfunction. Collagen type VI, α3 (COL6A3) encodes 1 subunit of a fibrotic extracellular matrix protein highly expressed in rodent AT. Knockout of collagen VI in rodent AT led to a significant improvement in metabolic health in obese, diabetic ob/ob mice. However, it is unknown whether this collagen has the same metabolic significance in human AT. We therefore aimed to undertake a comprehensive assessment of COL6A3 in relation to human AT and obesity. Characterization of COL6A3 in human AT showed 5-fold higher expression in the stromalvascular fraction compared with adipocyte expression and significantly higher expression in subcutaneous AT (SCAT) than omental AT. In both depots, COL6A3 expression appeared to be lowered in obesity, whereas diet- and surgery-induced weight loss increased COL6A3 expression in SCAT. Leptin treatment caused a dose-dependent decrease in COL6A3 expression, although no effect was seen with insulin or glucose treatment and no difference observed in subjects with diabetes. In addition, we found that the collagen expression profile in humans differs significantly from rodents, because COL6A3 does not appear to be the predominant collagen in adipose, muscle, or liver. Our findings oppose those initially seen in rodent studies and, most importantly, demonstrate a direct regulation of COL6A3 by leptin. This highlights the importance of a paracrine leptin signaling pathway in human AT and suggests an additional mechanism by which leptin can regulate extracellular matrix composition and, with it, AT expandability.

Improvements in hippocampal-dependent memory and microglial infiltration with calorie restriction and gastric bypass surgery, but not with vertical sleeve gastrectomy

Much recent evidence suggest that obesity and related comorbidities contribute to cognitive decline, including the development of non age-related dementia and Alzheimer's disease. Obesity is a serious threat to public health, and few treatments offer proven long-term weight loss. In fact, bariatric surgery remains the most effective long-term therapy to reduce weight and alleviate other aspects of the metabolic syndrome (MetS). Unlike the demonstrated benefits of caloric restriction to prevent weight gain, few if any studies have compared various means of weight loss on central nervous system function and hippocampal-dependent cognitive processes. Our studies comprise the first direct comparisons of caloric restriction to two bariatric surgeries (Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG)) on cognitive function. Weight loss following caloric restriction, RYGB and VSG was associated with generalized improvements in metabolic health and hippocampal-dependent learning, as measured in the radial arm maze and spontaneous alternation tests. However, VSG-treated rats exhibited deficits on spatial learning tasks in the Morris water maze. In addition, whereas VSG animals had elevated hippocampal inflammation, comparable to that of obese controls, RYGB and calorie-restricted (pair-fed, PF) controls exhibited an amelioration of inflammation, as measured by the microglial protein ionized calcium binding adaptor molecule 1 (IBA1). We also assessed whether GHR (ghrelin) replacement would attenuate hippocampal inflammation in VSG, as post-surgical GHR levels are significantly reduced in VSG relative to RYGB and PF rats. However, GHR treatment did not attenuate the hippocampal inflammation. Although VSG was comparably effective at reducing body weight and improving glucose regulation as RYGB, VSG did not appear to confer an equal benefit on cognitive function and markers of inflammation.

Cardiometabolic Health in Bipolar Disorder.

Although bipolar disorder is characterized by adverse effects on mood and social functioning, it is also associated with poor physical health. Some of the most prevalent comorbidities affecting individuals with bipolar disorder include those of a cardiometabolic nature, such as obesity, insulin resistance, and cardiovascular disease.1,2 In addition to detracting from physical wellbeing, there is growing awareness that comorbid medical conditions in people with bipolar disorder contribute to poorer psychiatric treatment outcomes and are associated with more severe mood symptoms.3–5 These comorbid conditions may arise from overlapping biological pathways that promote the development of both mood dysregulation and altered metabolism. In this article, the scope of cardiometabolic health concerns in bipolar disorder will be reviewed, including the prevalence of modifiable risk factors, pathophysiological correlates linking metabolic dysregulation and mood, and potential genetic vulnerabilities that contribute to the development of cardiometabolic illness and mood disorders. Novel treatment approaches that target improvement of metabolic health as a means of improving mood, cognition, and other psychiatric symptoms will also be discussed.

Randomized Controlled Trial to Improve Adiposity, Inflammation, and Insulin Resistance in Obese African‐American and Latino Youth

The purpose of this study was to examine ethnic differences in the metabolic responses to a 16-week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African-American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre- and postintervention: strength, dietary intake, body composition (dual-energy X-ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. -32.3% vs. -6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. -14.2% vs. -13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: -27.3% vs. -4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor-1 (PAI-1) (-38.3% vs. +1.0%, P < 0.01) and resistin (-18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2-h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (P's < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.

Obesity and chronic disease in younger people

In your editorial on obesity,1 Yates et al talk in apocalyptic terms about the rise in its prevalence. Their description of its ‘devastating consequences’ is amplified to an impressive degree by the repeated use of figures referring to relative rather than absolute risk. They propose an ‘urgent need for high quality research’ and go on to comment approvingly on the paper from the Bristol team,2 concluding that it provides evidence that ‘primary care can be used to engage effectively with, and manage, childhood obesity’. To be honest, I'm not that good at analysing research papers but I felt it would be worthwhile seeing whether the paper delivered on this promise. Unless I am missing something, the main results I can see from this paper are as follows: Of 152 eligible patients at the start of the trial, only 39 of them (25%) made it through to the end of the 12-month intervention period. Reductions in body mass index (BMI) seen in those who did last the course (in both the primary and secondary care groups) were modest to say the least — and the authors comment that the mean change in BMI ‘is too small to be certain of an improvement in metabolic health’. There is no follow up beyond the 12-month trial period to see if there is any sustained reduction in BMI. A more realistic conclusion, therefore, is that this model of an obesity clinic is equally ineffective in primary and secondary care. Something perhaps to bear in mind before we rush to provide such services as part of the ‘re-focusing of healthcare priorities’ that your editorial recommends.

Effects of a high-protein, low-carbohydrate v. high-protein, moderate-carbohydrate weight-loss diet on antioxidant status, endothelial markers and plasma indices of the cardiometabolic profile

There are concerns that weight-loss (WL) diets based on very low carbohydrate (LC) intake have a negative impact on antioxidant status and biomarkers of cardiovascular and metabolic health. Obese men (n 16) participated in a randomised, cross-over design diet trial, with food provided daily, at approximately 8.3 MJ/d (approximately 70 % of energy maintenance requirements). They were provided with two high-protein diets (30 % of energy), each for a 4-week period, involving a LC (4 % carbohydrate) and a moderate carbohydrate (MC, 35 % carbohydrate) content. Body weight was measured daily, and weekly blood samples were collected. On average, subjects lost 6.75 and 4.32 kg of weight on the LC and MC diets, respectively (P < 0.001, SED 0.350). Although the LC and MC diets were associated with a small reduction in plasma concentrations of retinol, vitamin E (α-tocopherol) and β-cryptoxanthin (P < 0.005), these were still above the values indicative of deficiency. Interestingly, plasma vitamin C concentrations increased on consumption of the LC diet (P < 0.05). Plasma markers of insulin resistance (P < 0.001), lipaemia and inflammation (P < 0.05, TNF-α and IL-10) improved similarly on both diets. There was no change in other cardiovascular markers with WL. The present data suggest that a LC WL diet does not impair plasma indices of cardiometabolic health, at least within 4 weeks, in otherwise healthy obese subjects. In general, improvements in metabolic health associated with WL were similar between the LC and MC diets. Antioxidant supplements may be warranted if LC WL diets are consumed for a prolonged period.