HICT对超重人群身体成分、心肺功能及代谢指标的影响

为了揭示12周高强度循环训练(high-intensity circuit training, HICT)对于超重肥胖男性的身体组成、心肺功能及代谢症候指标的影响,本研究将23位中年超重男性随机分配至HICT组((45.7±4.0) yrs,(172.1±5.1) cm,(76.6±10.2) kg, n=13)和控制组((47.8±4.8) yrs,(173.5±4.8) cm,(76.6±8.5) kg, n=10)。运动干预前、后分别测量受试者的各项指标。HICT组进行每周6次,为期12周(共72次)的高强度循环训练,即最大努力完成12个动作,运动30 s,休息15 s;控制组则维持日常身体活动。研究显示,相较于控制组,HICT组的体脂肪百分比由(25.1±5.1)%降至(23.2±4.1)%、体脂肪重由(19.5±5.7) kg降至(17.5±4.4) kg;体力指数由63.9±14.1升至72.4±16.9,腰围由(88.2±8.6) cm降至(84.2±8.1) cm、臀围由(99.5±5.1) cm降至(96.7±4.1) cm、收缩压由(136.1±11.8) mmHg降至(120.9±9.4) mmHg、舒张压由(88.9±9.3) mmHg降至(80.6±8.1) mmHg、空腹血糖由(105.9±25.0) mg/d L降至(97.1±22.1) mg/dL、血浆甘油三脂(triglyceride, TG)浓度由(101.5±61.7) mg/dL降至(117.5±50.3) mg/dL、胆固醇(total cholesterol, TC)浓度(161.9±20.0) mg/dL降至(117.5±50.3) mg/dL、高密度脂蛋白(high-density lipoproteincholesterol, HDL-C)浓度由(161.9±20.0) mg/dL升至(148.9±21.8) mg/dL,低密度脂蛋白胆固醇(low-density lipoprotein cholesterol, LDL-C)浓度由(105.1±25.0) mg/dL降至(97.2±23.5) mg/dL,实验前后,HITC组与控制组后测数值具有显著差异(p<0.05)。本研究表明,每周运动时间约60 min,为期12周共72次的高强度循环训练可有效改善中年超重肥胖男性的身体成分、心肺功能和代谢症候指标。     

Effects of Two Conjugated Linoleic Acid Isomers on Body Fat Mass in Overweight Humans

Objective: To examine the effects of two different conjugated linoleic acid (CLA) isomers at two different intakes on body composition in overweight humans. Research Methods and Procedures: Eighty‐one middle‐aged, overweight, healthy men and women participated in this bicentric, placebo‐controlled, double‐blind, randomized study. For 6 weeks (run‐in period), all subjects consumed daily a drinkable dairy product containing 3 g of high oleic acid sunflower oil. Volunteers were then randomized over five groups receiving daily either 3 g of high oleic acid sunflower oil, 1.5 g of cis‐9, trans‐11 (c9t11) CLA, 3 g of c9t11 CLA, 1.5 g of trans‐10, cis‐12 (t10c12) CLA, or 3 g of t10c12 CLA administrated as triacylglycerol in a drinkable dairy product for 18 weeks. Percentage body fat mass and fat and lean body mass were assessed at the end of the run‐in and experimental periods by DXA. Dietary intake was also recorded. Results: Body fat mass changes averaged 0.1 ± 0.9 kg (mean ± SD) in the placebo group and ?0.3 ± 1.4, ?0.8 ± 2.1, 0.0 ± 2.3, and ?0.9 ± 1.7 kg in the 1.5‐g c9t11, 3‐g c9t11, 1.5‐g t10c12, and 3‐g t10c12 groups, respectively. Changes among the groups were not significantly different (p = 0.444). Also, lean body mass and dietary intake were not significantly different among the treatments. Discussion: A daily consumption of a drinkable dairy product containing up to 3 g of CLA isomers for 18 weeks had no statistically significant effect on body composition in overweight, middle‐aged men and women.     

Tissue-Specific Lipoprotein Lipase: Relationships to Body Composition and Body Fat Distribution in Normal Weight Humans

Twenty-six normal weight subjects (22 female, 4 male) were studied to determine the relationships of fasting levels of lipoprotein lipase in gluteal adipose tissue (ATLPL) and skeletal muscle (SMLPL) to body composition and body fat distribution. No relationship was found between fasting gluteal ATLPL and percent (%) body fat There was, however, an inverse relationship between fasting SMLPL (from the vastus lateralis) and %body fat (p=0.005). A strong inverse correlation was also seen between fasting ATLPL and waist/hip ratio (p=0.0006), a measurement of body fat distribution. These relationships existed with or without the male subjects included. The tissue-specific relationships of lipoprotein lipase to body composition and body fat distribution could relate to the development of obesity or the maintenance of normal body weight by the effects of the lipase on the partitioning of lipoprotein triglyceride fatty acids.     

Thyroid Function and Metabolic Syndrome: A Cross-Sectional Study in Obese and Overweight Patients

Objective: Metabolic syndrome (MetS) is associated with increased risks of developing cardiovascular disease and type 2 diabetes. Thyroid dysfunction is also a known cardiovascular risk factor. In obese patients, serum thyroid-stimulating hormone (TSH) levels tend to be higher than in lean controls. The objective of this study was to assess potential associations between serum TSH levels and MetS as well as individual components of MetS.Methods: This was a cross-sectional observational study of obese and overweight patients seen for initial evaluation at the Boston Medical Center weight-management clinic between February 1, 2013 and February 1, 2014. Demographic, anthropometric, and laboratory data including serum TSH, insulin, glucose, hemoglobin A_1c, and lipid levels were obtained from electronic medical records. Associations between serum TSH levels and presence of MetS and its components were assessed.Results: A total of 3,447 patients, 75.6% female and 38% African American, without known thyroid dysfunction, were included. Mean ± SD age was 46.74 ± 15.11 years, and mean ± SD body mass index was 36.06 ± 9.89 kg/m². Among 1,005 patients without missing data, the prevalence of MetS was 71.84%. In patients with MetS, the median serum TSH was 1.41 μIU/mL, compared with 1.36 μIU/mL in patients without MetS (P = .45). In multivariate models, there was no significant association between serum TSH levels and the presence of MetS, adjusting for age, sex, race, education, socioeconomic status, and smoking. There were also no significant associations between serum TSH and individual components of the MetS.Conclusion: Serum TSH level does not appear to be a potentially modifiable risk factor for MetS in obese and overweight individuals.Abbreviations: BMI = body mass index FT₄ = free thyroxine HDL-C = high-density-lipoprotein cholesterol HbA_1c = hemoglobin A_1c MetS = metabolic syndrome SE = standard error TSH = thyroid-stimulating hormone     

Eating Behaviors and Indexes of Body Composition in Men and Women from the Québec Family Study

Objective: To put into relationship the dietary and anthropometric profile of men and women with their eating behaviors (cognitive dietary restraint, disinhibition, and susceptibility to hunger) and to assess whether gender and obesity status influence these associations. Research Methods and Procedures: Anthropometric measurements (including visceral adipose tissue accumulation), dietary profile (3‐day food record), and eating behaviors (Three‐Factor Eating Questionnaire) were determined in a sample of 244 men and 352 women. Results: Women had significantly higher cognitive dietary restraint and disinhibition scores than men (p < 0.0001). In both genders, scores for disinhibition and susceptibility to hunger, but not for cognitive dietary restraint, were higher in obese subjects than in overweight and nonobese subjects (p < 0.05). Positive correlations were observed between rigid restraint and most of the anthropometric variables studied (0.12 ≤ r ≤ 0.16). Moreover, in women, flexible restraint was negatively associated with body fat and waist circumference (r = ?0.11). Cognitive dietary restraint and rigid restraint were positively related to BMI among nonobese women (0.19 ≤ r ≤ 0.20), whereas in obese men, cognitive dietary restraint and flexible restraint tended to be negatively correlated with BMI (?0.20 ≤ r ≤ ?0.22; p = 0.10). Discussion: Gender could mediate associations observed between eating behaviors and anthropometric profile. It was also found that disinhibition and susceptibility to hunger are positively associated with the level of obesity. On the other hand, cognitive dietary restraint is not consistently related to body weight and adiposity, whereas rigid and flexible restraint are oppositely associated to obesity status, which suggests that it is important to differentiate the subscales of cognitive dietary restraint. Finally, counseling aimed at coping with disinhibition and susceptibility to hunger could be of benefit for the long‐term treatment of obesity.     

Effects of Exercise on Metabolic Risk Variables in Overweight Postmenopausal Women: A Randomized Clinical Trial

Objective: This study examined the effects of exercise on metabolic risk variables insulin, leptin, glucose, and triglycerides in overweight/obese postmenopausal women. Research Methods and Procedures: Sedentary women (n = 173) who were overweight or obese (BMI ≥ 25 kg/m² or ≥24 kg/m² with ≥33% body fat), 50 to 75 years of age, were randomized to 12 months of exercise (≥45 minutes of moderate‐intensity aerobic activity 5 d/wk) or to a stretching control group. Body composition (DXA) and visceral adiposity (computed tomography) were measured at baseline and 12 months. Insulin, glucose, triglycerides, and leptin were measured at baseline and 3 and 12 months. Insulin resistance was evaluated by the homeostasis model assessment formula. Differences from baseline to follow‐up were calculated and compared across groups. Results: Exercisers had a 4% decrease and controls had a 12% increase in insulin concentrations from baseline to 12 months (p = 0.0002). Over the same 12‐month period, leptin concentrations decreased by 7% among exercisers compared with remaining constant among controls (p = 0.03). Homeostasis model assessment scores decreased by 2% among exercisers and increased 14% among controls from baseline to 12 months (p = 0.0005). The exercise effect on insulin was modified by changes in total fat mass (trend, p = 0.03), such that the exercise intervention abolished increases in insulin concentrations associated with gains in total fat mass. Discussion: Regular moderate‐intensity exercise can be used to improve metabolic risk variables such as insulin and leptin in overweight/obese postmenopausal women. These results are promising for health care providers providing advice to postmenopausal women for lifestyle changes to reduce risk of insulin resistance, coronary heart disease, and diabetes.     

Effects of Calcium and Dairy on Body Composition and Weight Loss in African‐American Adults

Objective: Our objective was to determine the effects of dairy consumption on adiposity and body composition in obese African Americans. Research Methods and Procedures: We performed two randomized trials in obese African‐American adults. In the first (weight maintenance), 34 subjects were maintained on a low calcium (500 mg/d)/low dairy (<1 serving/d) or high dairy (1200 mg Ca/d diet including 3 servings of dairy) diet with no change in energy or macronutrient intake for 24 weeks. In the second trial (weight loss), 29 subjects were similarly randomized to the low or high dairy diets and placed on a caloric restriction regimen (?500 kcal/d). Results: In the first trial, body weight remained stable for both groups throughout the maintenance study. The high dairy diet resulted in decreases in total body fat (2.16 kg, p < 0.01), trunk fat (1.03 kg, p < 0.01), insulin (18.7 pM, p < 0.04), and blood pressure (6.8 mm Hg systolic, p < 0.01; 4.25 mm Hg diastolic, p < 0.01) and an increase in lean mass (1.08 kg, p < 0.04), whereas there were no significant changes in the low dairy group. In the second trial, although both diets produced significant weight and fat loss, weight and fat loss on the high dairy diet were ～2‐fold higher (p < 0.01), and loss of lean body mass was markedly reduced (p < 0.001) compared with the low dairy diet. Discussion: Substitution of calcium‐rich foods in isocaloric diets reduced adiposity and improved metabolic profiles in obese African Americans without energy restriction or weight loss and augmented weight and fat loss secondary to energy restriction.     

A Major Gene for Resting Metabolic Rate Unassociated with Body Composition: Results from the Québec Family Study

A major gene hypothesis for resting metabolic rate (RMR) was investigated using segregation analysis (POINTER) of data on families participating in Phase 2 of the Québec Family Study. Complete analyses were conducted on RMR adjusted for age, and also on RMR adjusted for age and other covariates, primarily fat mass (FM) and fat-free mass (FFM). Prior to adjustment for covariates, support for a major gene hypothesis was equivocal — i.e., there was evidence for either a major gene or a multifactorial component (i.e., polygenic and/or familial environment). The multifactorial model was preferred over the major gene model, although the latter did segregate according to Mendelian expectations. However, after the effects of FM and FFM were accounted for, a major gene effect was unambiguous and compelling. The putative locus accounted for 57% of the variance, affected 7% of the sample, and led to high values of RMR. The lack of a significant multifactorial effect suggested that the familial etiology of RMR adjusted for FM and FFM was likely to be entirely a function of the major locus. Comparing the RMR results from pre- and post-adjustment for FM and FFM suggests a plausible hypothesis. We know from earlier studies in this sample that there is a putative major gene for FM and a major non-Mendelian effect for FFM. The current study leads us to speculate that: (1) the gene(s) affecting body size and body composition also may have an effect on RMR, and further (2) removal of the effect of the major gene(s) for body size and composition allowed for detection of an additional major gene affecting only the RMR. Thus, RMR appears to be an oligogenic trait.     

Body Composition of African American and White Children: A 2‐Year Follow‐Up of the BAROC Study

Objective: To evaluate the 2‐year changes in body composition of white and African American boys and girls. Research Methods and Procedures: A total of 114 boys and girls ages 12 to 14 years with equal sex and ethnic distribution between African American and white races participated in measurements of body composition using DXA, underwater weighing (densitometry), skinfold thickness, corporal diameters, circumferences, isotope dilution (H₂¹⁸O), and bioelectric impedance. Results: Sixty‐eight of the 114 children advanced from Tanner Stages 1 and 2 to Tanner Stages 3 to 5 over a 2‐year period. More than 50% of the children were in the top 15th percentile according to normative data for body mass index but not for triceps skinfold. All measures except for percentage of fat, density, and four of the six skinfolds increased significantly during the 2 years, with no differences between races, genders, or fat group. The boys who advanced in Tanner Stage reduced their percentage of fat and a number of skinfolds and increased their lean body mass, but the girls did not. The percentage of water was significantly higher in the fatter children and declined significantly over 2 years. Most children remained in the same quartile of body fat, lean body mass, and bone mineral content over 2 years. Discussion: The data are consistent with the hypothesis that over 2 years, growth is the major determinant of changing body composition, with body‐fat group and sexual maturation being additional variables.     

Triglyceride‐to‐HDL‐cholesterol Ratio and Metabolic Syndrome as Contributors to Cardiovascular Risk in Overweight Patients

Insulin resistance increases cardiovascular risk of obese patients. Triglyceride to high‐density lipoprotein cholesterol ratio (TG/HDL) ≥3.0 (in mg/dl) is a marker of insulin resistance in overweight persons. We aimed at assessing cardiovascular risk profile in 301 overweight elderly Neapolitan outpatients, according to TG/HDL ratio and metabolic syndrome (MS), diagnosed by National Cholesterol Education Program (NCEP) and International Diabetes Federation (IDF) criteria. TG/HDL ratio was ≥3.0 in 97 patients (group A) and <3.0 in 204 (group B). Overall, 93–97% of group A patients and 38–51% of group B patients had MS, depending on the diagnostic criterion. Group A patients with MS had significantly higher waist‐to‐hip ratio, total and non‐HDL cholesterol than group B patients with MS. In group B, MS and non‐MS patients had similar waist‐to‐hip ratio, blood pressure, total and non‐HDL cholesterol. Ten year coronary risk, calculated by the Framingham equations (n = 243), was 10.3 ± 5% in group B, non‐MS patients; 13.1 ± 6% in group B, MS patients; 19.9 ± 8% in group A (F = 32.8; P < 0.001). At the multiple regression analysis, TG/HDL ratio was associated with coronary risk (r² = 0.227) more closely than gender, blood pressure, waist‐to‐hip ratio, non HDL cholesterol, and MS considered as a whole. A separate regression analysis showed that the logarithmically transformed TG/HDL ratio, an index of the HDL cholesterol esterification rate, is also associated with coronary risk (r² = 0.252). Thus, TG/HDL ratio could help to characterize high‐risk overweight patients deserving a special therapeutic effort. Cardiovascular risk profile of insulin‐sensitive patients, identified by lower values of this parameter, is only moderately affected by MS.     

Effects of Sibutramine on Resting Metabolic Rate and Weight Loss in Overweight Women

Sibutramine, a monoamine re-uptake inhibitor, has recently been approved by the Food and Drug Administration as a weight loss agent. Sibutramine lowers body-weight in rodents by reducing energy intake and increasing energy expenditure. Sibutramine facilitates weight loss in human subjects, but it is not clear whether it acts on energy intake, energy expenditure, or both. The present study was a randomized clinical trial designed to assess the effects of sibutramine (at 10 or 30 mg/day) on body weight and resting metabolic rate (RMR). Forty-four overweight women were randomized to 1) placebo (n=15); 2) sibutramine at 10 mg/day (n=15) or, 3) sibutramine at 30 mg/day (n=14). All subjects were instructed to consume a 1200 kcal/day diet for 8 weeks while receiving drug or placebo. RMR was assessed by indirect calorimetry at baseline, at 3 hours after the first dose of drug (or placebo), and at the end of the 8-week weight-loss period. Sibutramine reduced body weight-relative to placebo, but there was no difference between weight loss on the two sibutramine doses. No significant differences in RMR between sibutramine and placebo were seen, either 3-hour post dose or after the 8-week weight-loss period. After the weight loss period, all groups were taken off medication and kept weight stable for another 4 weeks. RMR was measured again and was not different among groups. That there was no change in RMR when sibutramine was stopped further suggests that the drug does not directly affect RMR. In summary, while sibutramine was shown to be an effective weightloss agent over 8 weeks, we found no evidence that it increased RMR.