The American journal of clinical nutrition最新文献

{"title":"Body composition and mortality in chronic obstructive pulmonary disease.","authors":"Annemie M W J Schols,&nbsp;Roelinka Broekhuizen,&nbsp;Clarie A Weling-Scheepers,&nbsp;Emiel F Wouters","doi":"10.1093/ajcn.82.1.53","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.53","url":null,"abstract":"<p><strong>Background: </strong>Survival studies have consistently shown significantly greater mortality rates in underweight and normal-weight patients with chronic obstructive pulmonary disease (COPD) than in overweight and obese COPD patients.</p><p><strong>Objective: </strong>To compare the contributions of low fat-free mass and low fat mass to mortality, we assessed the association between body composition and mortality in COPD.</p><p><strong>Design: </strong>We studied 412 patients with moderate-to-severe COPD [Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) stages II-IV, forced expiratory volume in 1 s of 36 +/- 14% of predicted (range: 19-70%). Body composition was assessed by using single-frequency bioelectrical impedance. Body mass index, fat-free mass index, fat mass index, and skeletal muscle index were calculated and related to recently developed reference values. COPD patients were stratified into defined categories of tissue-depletion pattern. Overall mortality was assessed at the end of follow-up.</p><p><strong>Results: </strong>Semistarvation and muscle atrophy were equally distributed among disease stages, but the highest prevalence of cachexia was seen in GOLD stage IV. Forty-six percent of the patients (n = 189) died during a maximum follow-up of 5 y. Cox regression models, with and without adjustment for disease severity, showed that fat-free mass index (relative risk: 0.90; 95% CI: 0.84, 0.96; P = 0.003) was an independent predictor of survival, but fat mass index was not. Kaplan-Meier and Cox regression plots for cachexia and muscle atrophy did not differ significantly.</p><p><strong>Conclusions: </strong>Fat-free mass is an independent predictor of mortality irrespective of fat mass. This study supports the inclusion of body-composition assessment as a systemic marker of disease severity in COPD staging.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"53-9"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.53","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25176097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioelectrical impedance analysis: population reference values for phase angle by age and sex.","authors":"Maria Cristina G Barbosa-Silva,&nbsp;Aluísio J D Barros,&nbsp;Jack Wang,&nbsp;Steven B Heymsfield,&nbsp;Richard N Pierson","doi":"10.1093/ajcn.82.1.49","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.49","url":null,"abstract":"<p><strong>Background: </strong>Phase angle is an indicator based on reactance and resistance obtained from bioelectrical impedance analysis (BIA). Although its biological meaning is still not clear, phase angle appears to have an important prognostic role.</p><p><strong>Objective: </strong>The aim of this study was to estimate population averages and SDs of phase angle that can be used as reference values.</p><p><strong>Design: </strong>BIA and other methods used to evaluate body composition, including hydrodensitometry and total body water, were completed in 1967 healthy adults aged 18-94 y. Phase angle was calculated directly from body resistance and reactance, and fat mass (FM) was estimated from the combination of weight, hydrodensitometry, and total body water by using the 3-compartment Siri equation. Phase angle values were compared across categories of sex, age, body mass index (BMI), and percentage FM.</p><p><strong>Results: </strong>Phase angle was significantly (P < 0.001) smaller in women than in men and was lower with greater age (P < 0.001). Phase angle increased with an increase in BMI and was significantly inversely associated with percentage fat in men. Phase angle was significantly predicted from sex, age, BMI, and percentage FM in multiple regression models.</p><p><strong>Conclusions: </strong>Phase angle differs across categories of sex, age, BMI, and percentage fat. These reference values can serve as a basis for phase angle evaluations in the clinical setting.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"49-52"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.49","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25176096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alcohol intake and methylenetetrahydrofolate reductase polymorphism modify the relation of folate intake to plasma homocysteine.","authors":"Stephanie E Chiuve,&nbsp;Edward L Giovannucci,&nbsp;Susan E Hankinson,&nbsp;David J Hunter,&nbsp;Meir J Stampfer,&nbsp;Walter C Willett,&nbsp;Eric B Rimm","doi":"10.1093/ajcn.82.1.155","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.155","url":null,"abstract":"<p><strong>Background: </strong>Folate intake increases plasma folate and reduces total homocysteine (tHcy) concentrations, which may lower coronary artery disease (CAD) and cancer risks. Folate metabolism may be altered by alcohol intake and 2 common polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, 677C-->T and 1298A-->C.</p><p><strong>Objective: </strong>We examined whether the associations between folate intake and plasma folate and tHcy concentrations were modified by alcohol intake or variations in the MTHFR gene.</p><p><strong>Design: </strong>We conducted a cross-sectional analysis among 988 women by using multivariate linear regression models to estimate mean plasma tHcy and folate concentrations. Folate intake was the sum of food and supplemental sources.</p><p><strong>Results: </strong>We observed an inverse association between folate intake and tHcy, which was modified by alcohol intake (P for interaction = 0.04) and MTHFR677 genotype (P for interaction = 0.05) but not by MTHFR1298 genotype (P for interaction = 0.97). In the lowest quintile of folate intake, moderate drinkers (>/=15 g alcohol/d) had significantly higher tHcy concentrations (15.2 +/- 2.9 nmol/mL) than did light drinkers (11.3 +/- 0.7 nmol/mL) and nondrinkers (11.0 +/- 0.8 nmol/mL). However, the reduction in tHcy between the highest and lowest quintiles of folate intake was significantly greater in moderate drinkers (-6.6 nmol/mL) than in light drinkers (-2.3 nmol/mL) and nondrinkers (-2.1 nmol/mL). The elevated tHcy in women with low folate intake who also consumed moderate amounts of alcohol was even higher (22.4 +/- 4.8 nmol/mL) in the presence of the variant MTHFR677 allele. The positive association between folate intake and plasma folate was somewhat modified by alcohol intake (P for interaction = 0.08) but not by either MTHFR genotype.</p><p><strong>Conclusions: </strong>Moderate alcohol intake and low MTHFR activity have adverse effects on tHcy, but those effects may be overcome by sufficient folate intake.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"155-62"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25177082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association of physical activity with body-composition indexes in children aged 6-8 y at varied risk of obesity.","authors":"Kirsten L Rennie,&nbsp;M Barbara E Livingstone,&nbsp;Jonathan C K Wells,&nbsp;A McGloin,&nbsp;W Andrew Coward,&nbsp;Andrew M Prentice,&nbsp;Susan A Jebb","doi":"10.1093/ajcn.82.1.13","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.13","url":null,"abstract":"<p><strong>Background: </strong>Physical inactivity increases the risk of obesity, but the relations between reported levels of physical activity (PA) and measures of body fatness (BF) in children are remarkably inconsistent.</p><p><strong>Objective: </strong>We examined the relation between objective measures of PA and body-composition indexes in nonobese children.</p><p><strong>Design: </strong>A cross-sectional study was conducted in 100 children aged 6-8 y who were recruited according to their risk of future obesity: high-risk children had >/=1 obese parent [body mass index (BMI; in kg/m(2)): >30] and low-risk children had 2 nonobese biological parents (BMI: <30). Free-living activity energy expenditure (AEE) and PA level were calculated from 7-d doubly labeled water measurements, time spent in light-intensity activity was assessed by heart rate monitoring, and body composition was determined from isotopic dilution. To adjust for body size, fat mass and fat-free mass were normalized for height and expressed as fat mass index (FMI) and lean mass index (LMI), respectively.</p><p><strong>Results: </strong>High-risk children had significantly higher BMI, LMI, and FMI than did low-risk children, but no group differences in PA were found. AEE and PA level were positively associated with LMI and, after adjustment for sex and fat-free mass, negatively associated with FMI but not with BMI. Boys who spent more than the median time in light-intensity activities had significantly higher FMI than did less sedentary boys. This difference was not observed in girls.</p><p><strong>Conclusions: </strong>AEE and PA level were negatively associated with BF in nonobese children. Accurate measures of body composition are essential to appropriate assessment of relations between PA and obesity risk.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"13-20"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.13","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25175548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Economics of Obesity","authors":"A. Drewnowski, P. Eichelsdoerfer","doi":"10.1016/B978-0-12-374387-9.00058-1","DOIUrl":"https://doi.org/10.1016/B978-0-12-374387-9.00058-1","url":null,"abstract":"","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114069026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The satiating power of protein--a key to obesity prevention?","authors":"Arne Astrup","doi":"10.1093/ajcn.82.1.1","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.1","url":null,"abstract":"","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"1-2"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25175545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations.","authors":"David S Weigle,&nbsp;Patricia A Breen,&nbsp;Colleen C Matthys,&nbsp;Holly S Callahan,&nbsp;Kaatje E Meeuws,&nbsp;Verna R Burden,&nbsp;Jonathan Q Purnell","doi":"10.1093/ajcn.82.1.41","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.41","url":null,"abstract":"<p><strong>Background: </strong>Ad libitum, low-carbohydrate diets decrease caloric intake and cause weight loss. It is unclear whether these effects are due to the reduced carbohydrate content of such diets or to their associated increase in protein intake.</p><p><strong>Objective: </strong>We tested the hypothesis that increasing the protein content while maintaining the carbohydrate content of the diet lowers body weight by decreasing appetite and spontaneous caloric intake.</p><p><strong>Design: </strong>Appetite, caloric intake, body weight, and fat mass were measured in 19 subjects placed sequentially on the following diets: a weight-maintaining diet (15% protein, 35% fat, and 50% carbohydrate) for 2 wk, an isocaloric diet (30% protein, 20% fat, and 50% carbohydrate) for 2 wk, and an ad libitum diet (30% protein, 20% fat, and 50% carbohydrate) for 12 wk. Blood was sampled frequently at the end of each diet phase to measure the area under the plasma concentration versus time curve (AUC) for insulin, leptin, and ghrelin.</p><p><strong>Results: </strong>Satiety was markedly increased with the isocaloric high-protein diet despite an unchanged leptin AUC. Mean (+/-SE) spontaneous energy intake decreased by 441 +/- 63 kcal/d, body weight decreased by 4.9 +/- 0.5 kg, and fat mass decreased by 3.7 +/- 0.4 kg with the ad libitum, high-protein diet, despite a significantly decreased leptin AUC and increased ghrelin AUC.</p><p><strong>Conclusions: </strong>An increase in dietary protein from 15% to 30% of energy at a constant carbohydrate intake produces a sustained decrease in ad libitum caloric intake that may be mediated by increased central nervous system leptin sensitivity and results in significant weight loss. This anorexic effect of protein may contribute to the weight loss produced by low-carbohydrate diets.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"41-8"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.41","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25176095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional foods for coronary heart disease risk reduction: a meta-analysis using a multivariate approach.","authors":"Inar A Castro,&nbsp;Lúcia P Barroso,&nbsp;Patricia Sinnecker","doi":"10.1093/ajcn.82.1.32","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.32","url":null,"abstract":"<p><strong>Background: </strong>It has been difficult to identify the appropriate bioactive substance for the development of new functional foods associated with coronary heart disease, because the results of many clinical studies are contradictory.</p><p><strong>Objective: </strong>The objective of this study was to use the multivariate statistical approach known as principal component analysis (PCA) followed by a mixed model to process data obtained from a meta-analysis aimed at evaluating simultaneously the effect of ingestion of 1 of 3 types of bioactive substances (n-3 fatty acids, soluble fibers, and phytosterols) on 1 or more of 4 biomarkers (plasma total cholesterol, triacylglycerol, LDL cholesterol, and HDL cholesterol).</p><p><strong>Design: </strong>Five independent variables (number of patients per study, dose, age, body mass index, and treatment length) and 4 dependent variables (percentage change in blood total cholesterol, LDL, HDL, and triacylglycerol) from 159 studies and substudies were organized into a matrix. The original values were converted to linear correlation units, which resulted in a new matrix.</p><p><strong>Results: </strong>Two principal components were enough to explain 63.73% and 84.27% of the variance in the independent and dependent variables, respectively. Phytosterols and soluble fibers had a hypocholesterolemic effect, whereas n-3 fatty acids lowered triacylglycerol and increased total, LDL, and HDL cholesterol. The PCA and mixed model showed that this behavior was independent of dose, number of patients per study, age, and body mass index but was associated with treatment length.</p><p><strong>Conclusions: </strong>PCA is useful for summarizing available scientific information in examinations of health claims for foods and supplements.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"32-40"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.32","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25175551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Folic acid supplementation for 3 wk reduces pulse pressure and large artery stiffness independent of MTHFR genotype.","authors":"Carolyn Williams,&nbsp;Bronwyn A Kingwell,&nbsp;Kevin Burke,&nbsp;Jane McPherson,&nbsp;Anthony M Dart","doi":"10.1093/ajcn.82.1.26","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.26","url":null,"abstract":"<p><strong>Background: </strong>Folic acid reduces plasma homocysteine and may be an important therapy for preventing cardiovascular disease. A key mechanism may be the reduction of arterial stiffness.</p><p><strong>Objective: </strong>The effect of folic acid supplementation on blood pressure and large artery stiffness was examined in relation to methylenetetrahydrofolate reductase (MTHFR) genotype.</p><p><strong>Design: </strong>Forty-one asymptomatic men with normal or high-normal ambulatory blood pressure (systolic: >130 to <145 mm Hg; diastolic: >80 to <90 mm Hg) participated. The study had a randomized, placebo-controlled, double-blind, crossover design that incorporated 3-wk treatments with 5 mg folic acid/d or matching placebo; each treatment was separated by a 4-wk washout phase.</p><p><strong>Results: </strong>Folic acid reduced brachial pulse pressure by 4.7 +/- 1.6 mm Hg (P < 0.05) without changing mean arterial pressure. Systemic arterial compliance increased by 0.15 +/- 0.03 mL/mm Hg (P < 0.05) after folic acid treatment but did not change after placebo treatment. These responses did not significantly correlate with either homocysteine or folate plasma concentrations. MTHFR genotype CC homozygotes (without the 677C-->T polymorphism) with normal blood pressure had a larger reduction in homocysteine concentrations in response to folic acid than did T allele carriers. Blood pressure and arterial stiffness responses were independent of MTHFR genotype.</p><p><strong>Conclusion: </strong>Folic acid is a safe and effective supplement that targets large artery stiffness and may prevent isolated systolic hypertension.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"26-31"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.26","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25175550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactive effects of iron and zinc on biochemical and functional outcomes in supplementation trials.","authors":"Christa Fischer Walker,&nbsp;Katarzyna Kordas,&nbsp;Rebecca J Stoltzfus,&nbsp;Robert E Black","doi":"10.1093/ajcn.82.1.5","DOIUrl":"https://doi.org/10.1093/ajcn.82.1.5","url":null,"abstract":"<p><p>Iron and zinc are essential micronutrients for human health. Deficiencies in these 2 nutrients remain a global problem, especially among women and children in developing countries. Supplementation with iron and zinc as single micronutrients enhances distinct and unique biochemical and functional outcomes. These micronutrients have the potential to interact when given together; thus, it is important to assess the biochemical and functional evidence from clinical trials before supplementation policies are established. We reviewed randomized trials that assessed the effects of iron and zinc supplementation on iron and zinc status. On the basis of this review, zinc supplementation alone does not appear to have a clinically important negative effect on iron status. However, when zinc is given with iron, iron indicators do not improve as greatly as when iron is given alone. In most of the studies, iron supplementation did not affect the biochemical status of zinc, but the data are not clear regarding morbidity outcomes. Although some trials have shown that joint iron and zinc supplementation has less of an effect on biochemical or functional outcomes than does supplementation with either mineral alone, there is no strong evidence to discourage joint supplementation. Supplementation programs that provide iron and zinc together are an efficient way to provide both micronutrients, provided the benefits of individual supplementation are not lost. Further research is needed before health policies on joint supplementation programs can be established.</p>","PeriodicalId":315016,"journal":{"name":"The American journal of clinical nutrition","volume":" ","pages":"5-12"},"PeriodicalIF":7.1,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/ajcn.82.1.5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25175547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}