Barbara A Gower

University of Alabama at Birmingham, Birmingham, Alabama, United States

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Publications (222)934 Total impact

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    ABSTRACT: Vascular endothelial function declines with advancing age, due in part to increased oxidative stress and inflammation, and this age-related vascular dysfunction has been identified as an independent risk factor for cardiovascular diseases. This double-blind, placebo-controlled trial investigated the effects of a dietary supplement containing β-hydroxy-β-methylbutyrate (HMB), glutamine and arginine on endothelial-dependent vasodilation of older adults. A total of 31 community-dwelling men and women aged 65-87 years were randomly assigned to two groups. The treatment group received two doses of the supplement daily (totaling 3 g HMB, 14 g glutamine and 14 g arginine) for 6 months, whereas the control group received an isocaloric placebo. At baseline and week 24, vascular endothelial function was measured by flow-mediated dilation of the brachial artery, and fasting blood samples were obtained to measure high-sensitivity C-reactive protein (hsCRP) and tumor necrosis factor-α (TNF-α). Paired sample t-tests revealed a 27% increase in flow-mediated dilation among the treatment group (P=0.003), whereas no change was observed in the placebo group (P=0.651). Repeated-measures analysis of variance verified a significant time by group interaction (P=0.038). Although no significant changes were observed for hsCRP or TNF-α, a trend was observed for increasing hsCRP among the placebo group only (P=0.059). These results suggest that dietary supplementation of HMB, glutamine and arginine may favorably affect vascular endothelial function in older adults. Additional studies are needed to elucidate whether reduced inflammation or other mechanisms may underlie the benefits of supplementation.European Journal of Clinical Nutrition advance online publication, 26 August 2015; doi:10.1038/ejcn.2015.137.
    European journal of clinical nutrition 08/2015; DOI:10.1038/ejcn.2015.137 · 2.71 Impact Factor
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    ABSTRACT: The objective of the study was to assess the agreement of the Lunar Prodigy with the newer Lunar iDXA dual-energy X-ray absorptiometer for determining total body and regional (arms, legs, trunk) bone mineral density (BMD), bone mineral content (BMC), fat mass (FM), lean tissue mass (LTM), total body mass, and percent fat. Ninety-two healthy adult males (n = 36) and females (n = 56) were scanned consecutively on the iDXA and the Prodigy dual-energy X-ray absorptiometers. For iDXA, relative to Prodigy, paired t tests indicated significantly lower estimates for total body and regional BMD and BMC (p < 0.001). Measures of total body and trunk FM, LTM, and percent fat did not differ between the instruments. In regional analyses, estimates of FM and percent fat were greater, and that of LTM was lower, in the arms (p < 0.001). In contrast, iDXA estimates of LTM were higher in the legs (p < 0.001). All body composition measures were significantly correlated (p < 0.001). Bland-Altman analyses indicated that significant bias existed between iDXA and Prodigy for total body and regional BMD estimates (p < 0.001) such that iDXA underestimated BMD to a greater extent in persons with higher values. In addition, iDXA overestimation bias existed for FM in total body, arms, and legs, and the overestimation was primarily observed in participants with greater body fat (p < 0.001). When combining or comparing data from iDXA with those from Prodigy, investigators should be aware that certain total body and regional estimates are significantly different. The greatest percent differences were observed for arm BMD, FM, and percent fat. Copyright © 2015 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.
    Journal of Clinical Densitometry 07/2015; DOI:10.1016/j.jocd.2015.06.003 · 2.03 Impact Factor
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    ABSTRACT: The reports regarding the associations between childhood maltreatment (CM) and body fat composition remain heterogeneous in humans although they are indicated in preclinical studies. In addition, the effects of CM subtypes on different types of body fat are unclear. Thus, in this study, the associations between CM and its subtypes with body fat were determined and the potential pathways were explored. The participants were assessed for a history of CM by the Childhood Trauma Questionnaire and were divided into the CM group (with CM exposures) and non-CM group (without CM exposures). Body composition was measured by dual-energy X-ray absorptiometry. Salivary and blood samples were provided by the subjects. Compared with the non-CM group, subjects with a history of CM had greater visceral fat mass (1,136 ± 160 vs. 836 ± 116 g, P < 0.05) but not total body fat, android fat, body mass index, or waist-to-hip ratio. In addition, subjects with CM had a blunted cortisol awakening response and elevated inflammatory factors. Correlation analysis indicated that CM subtypes had differential effects on visceral adiposity and cortisol awakening response. It is suggested by our results that CM exposure is linked with increased visceral fat deposition, and the perturbation of the hypothalamic-pituitary-adrenal axis activity and activation of the immune system may be two potential pathways through which this relationship is explained. © 2015 The Obesity Society.
    Obesity 07/2015; 23(8). DOI:10.1002/oby.21143 · 3.73 Impact Factor
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    ABSTRACT: Obesity and late-night food consumption are associated with impaired glucose tolerance. Late-night carbohydrate consumption may be particularly detrimental during late pregnancy because insulin sensitivity declines as pregnancy progresses. Further, women who were obese (Ob) prior to pregnancy have lower insulin sensitivity than do women of normal weight (NW). The aim of this study is to test the hypothesis that night-time carbohydrate consumption is associated with poorer glucose tolerance in late pregnancy and that this association would be exacerbated among Ob women. Forty non-diabetic African American women were recruited based upon early pregnancy body mass index (NW, <25 kg m(-2) ; Ob, ≥30 kg m(-2) ). Third trimester free-living dietary intake was assessed by food diary, and indices of glucose tolerance and insulin action were assessed during a 75-g oral glucose tolerance test. Women in the Ob group reported greater average 24-h energy intake (3055 kcal vs. 2415 kcal, P < 0.05). Across the whole cohort, night-time, but not day-time, carbohydrate intake was positively associated with glucose concentrations after the glucose load and inversely associated with early phase insulin secretion (P < 0.05). Multiple linear regression modelling within each weight group showed that the associations among late-night carbohydrate intake, glucose concentrations and insulin secretion were present only in the Ob group. This is the first study to report an association of night-time carbohydrate intake specifically on glucose tolerance and insulin action during pregnancy. If replicated, these results suggest that late-night carbohydrate intake may be a potential target for intervention to improve metabolic health of Ob women in late pregnancy. © 2015 John Wiley & Sons Ltd.
    Maternal and Child Nutrition 03/2015; DOI:10.1111/mcn.12181 · 3.06 Impact Factor
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    ABSTRACT: To evaluate ictal adipokine levels in episodic migraineurs and their association with pain severity and treatment response. This was a double-blind, placebo-controlled trial evaluating peripheral blood specimens from episodic migraineurs at acute pain onset and 30 to 120 minutes after treatment with sumatriptan/naproxen sodium vs placebo. Total adiponectin (T-ADP), ADP multimers (high molecular weight [HMW], middle molecular weight, and low molecular weight [LMW]), leptin, and resistin levels were evaluated by immunoassays. Thirty-four participants (17 responders, 17 nonresponders) were included. In all participants, pretreatment pain severity increased with every quartile increase in both the HMW:T-ADP ratio (coefficient of variation [CV] 0.51; 95% confidence interval [CI]: 0.08, 0.93; p = 0.019) and resistin levels (CV 0.58; 95% CI: 0.21, 0.96; p = 0.002), but was not associated with quartile changes in leptin levels. In responders, T-ADP (CV -0.98; 95% CI: -1.88, -0.08; p = 0.031) and resistin (CV -0.95; 95% CI: -1.83, -0.07; p = 0.034) levels decreased 120 minutes after treatment as compared with pretreatment. In addition, in responders, the HMW:T-ADP ratio (CV -0.04; 95% CI: -0.07, -0.01; p = 0.041) decreased and the LMW:T-ADP ratio (CV 0.04; 95% CI: 0.01, 0.07; p = 0.043) increased at 120 minutes after treatment. In nonresponders, the LMW:T-ADP ratio (CV -0.04; 95% CI: -0.07, -0.01; p = 0.018) decreased 120 minutes after treatment. Leptin was not associated with treatment response. Both pretreatment migraine pain severity and treatment response are associated with changes in adipokine levels. Adipokines represent potential novel migraine biomarkers and drug targets. © 2015 American Academy of Neurology.
    Neurology 03/2015; 84(14). DOI:10.1212/WNL.0000000000001443 · 8.29 Impact Factor
  • Barbara A Gower · Amy M Goss
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    ABSTRACT: Obesity, particularly visceral and ectopic adiposity, increases the risk of type 2 diabetes. The aim of this study was to determine if restriction of dietary carbohydrate is beneficial for body composition and metabolic health. Two studies were conducted. In the first, 69 overweight/obese men and women, 53% of whom were European American (EA) and 47% of whom were African American (AA), were provided with 1 of 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 43%, 18%, and 39%, respectively) for 8 wk at a eucaloric level and 8 wk at a hypocaloric level. In the second study, 30 women with polycystic ovary syndrome (PCOS) were provided with 2 diets (lower-fat diet: 55%, 18%, and 27% of energy from carbohydrate, protein, and fat, respectively; lower-carbohydrate diet: 41%, 19%, and 40%, respectively) at a eucaloric level for 8 wk in a random-order crossover design. As previously reported, among overweight/obese adults, after the eucaloric phase, participants who consumed the lower-carbohydrate vs. the lower-fat diet lost more intra-abdominal adipose tissue (IAAT) (11 ± 3% vs. 1 ± 3%; P < 0.05). After weight loss, participants who consumed the lower-carbohydrate diet had 4.4% less total fat mass. Original to this report, across the entire 16-wk study, AAs lost more fat mass with a lower-carbohydrate diet (6.2 vs. 2.9 kg; P < 0.01), whereas EAs showed no difference between diets. As previously reported, among women with PCOS, the lower-carbohydrate arm showed decreased fasting insulin (-2.8 μIU/mL; P < 0.001) and fasting glucose (-4.7 mg/dL; P < 0.01) and increased insulin sensitivity (1.06 arbitrary units; P < 0.05) and "dynamic" β-cell response (96.1 · 10(9); P < 0.001). In the lower-carbohydrate arm, women lost both IAAT (-4.8 cm(2); P < 0.01) and intermuscular fat (-1.2 cm(2); P < 0.01). In the lower-fat arm, women lost lean mass (-0.6 kg; P < 0.05). Original to this report, after the lower-carbohydrate arm, the change in IAAT was positively associated with the change in tumor necrosis factor α (P < 0.05). A modest reduction in dietary carbohydrate has beneficial effects on body composition, fat distribution, and glucose metabolism. This trial was registered at as NCT00726908 and NCT01028989. © 2015 American Society for Nutrition.
    Journal of Nutrition 01/2015; 145(1):177S-83S. DOI:10.3945/jn.114.195065 · 3.88 Impact Factor
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    ABSTRACT: The role of vitamin D in cardiovascular health remains debated as results have been inconsistent. Previous studies have not considered the bioavailability of 25-hydroxy vitamin D [25(OH)D]. Objectives of our study were to investigate the association between serum concentrations of total, free and bioavailable 25(OH)D and independent predictors of cardiovascular risk such as flow mediated dilatation (FMD) and augmentation index (AIx). This cross-sectional study included 47 post-menarchal, adolescent females [31 African American (AA) and 16 European American (EA)]. AIx was standardized to a heart rate of 75 beats/min (AIx75). Free and bioavailable 25(OH)D concentrations were calculated from standard formulas. Mean age of the participants was 15.8±1.4 years and mean body mass index was 23.1±4.0 kg/m2. Serum total 25(OH)D was not associated with FMD, but was positively associated with AIx75 in the adjusted model (rho = 0.4, P = 0.03). AIx75 was positively associated with bioavailable 25(OH)D (rho = 0.4, P = 0.004) and free 25(OH)D (rho = 0.4, P = 0.009) and the associations persisted after adjusting for covariates. In race-specific analyses, total, free and bioavailable 25(OH)D were strongly positively associated with AIx75 in AA (rho = 0.5, 0.4, 0.4, respectively), which persisted even after adjusting for covariates. Whereas in EA there was an inverse association between total 25(OH)D and AIx75 in EA (rho = -0.6), which attenuated after adjusting for covariates. Circulating total, free and bioavailable 25(OH)D were associated with arterial stiffness in adolescent girls, and these associations were race dependent. Notwithstanding, the implications of associations between vascular function indices and 25(OH)D remains unclear.
    PLoS ONE 12/2014; 9(12):e114689. DOI:10.1371/journal.pone.0114689 · 3.23 Impact Factor
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    ABSTRACT: We conducted a study designed to evaluate whether the benefits of intentional weight loss exceed the potential risks in a group of community-dwelling obese older adults who were at increased risk for cardiometabolic disease. The CROSSROADS trial used a prospective randomized controlled design to compare the effects of changes in diet composition alone or combined with weight loss with an exercise only control intervention on body composition and adipose tissue deposition (Specific Aim #1: To compare the effects of changes in diet composition alone or combined with weight loss with an exercise only control intervention on body composition, namely visceral adipose tissue), cardiometabolic disease risk (Specific Aim #2: To compare the effects of a change in diet composition alone or combined with weight loss with an exercise only control intervention on cardiometabolic disease risk), and functional status and quality of life (Specific Aim #3: To compare the effects of a change in diet composition alone or combined with weight loss with an exercise only control intervention on functional status and quality of life). Participants were randomly assigned to one of three groups: Exercise Only (Control) Intervention, Exercise + Diet Quality + Weight Maintenance Intervention, or Exercise + Diet Quality + Weight Loss Intervention. CROSSROADS utilized a lifestyle intervention approach consisting of exercise, dietary, and behavioral components. The development and implementation of the CROSSROADS protocol, including a description of the methodology, detailing specific elements of the lifestyle intervention, assurances of treatment fidelity, and participant retention; outcome measures and adverse event monitoring; as well as unique data management features of the trial results, are presented in this article.
    Journal of Nutrition in Gerontology and Geriatrics 11/2014; 33(4):376-400. DOI:10.1080/21551197.2014.965993
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    The Journal of Headache and Pain 09/2014; 15(Suppl 1):E25-E25. DOI:10.1186/1129-2377-15-S1-E25 · 2.80 Impact Factor
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    ABSTRACT: The inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk, or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines. The benefits of carbohydrate restriction in diabetes are immediate and well documented. Concerns about the efficacy and safety are long term and conjectural rather than data driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss), and leads to the reduction or elimination of medication. It has never shown side effects comparable with those seen in many drugs. Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term randomized controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed. (C) 2015 The Authors. Published by Elsevier Inc.
    Nutrition 07/2014; 31(1). DOI:10.1016/j.nut.2014.06.011 · 2.93 Impact Factor
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    ABSTRACT: Objective To determine if consumption of a reduced-carbohydrate (CHO) diet would result in preferential loss of adipose tissue under eucaloric conditions, and whether changes in adiposity were associated with changes in postprandial insulin concentration. Methods In a crossover-diet intervention, 30 women with PCOS consumed a reduced-CHO diet (41:19:40%energy from CHO:protein:fat) for 8 weeks and a standard diet (55:18:27) for 8 weeks. Body composition by DXA and fat distribution by CT were assessed at baseline and following each diet phase. Insulin AUC was obtained from a solid meal test (SMT) during each diet phase. Results Participants lost 3.7% and 2.2% total fat following the reduced-CHO diet and STD diet, resp. (p< 0.05 for difference between diets). The reduced-CHO diet induced a decrease in subcutaneous-abdominal, intra-abdominal, and thigh-intermuscular adipose tissue (-7.1%, -4.6%, and -11.5%, resp.), and the STD diet induced a decrease in total lean mass. Loss of fat mass following the reduced CHO diet arm was associated with lower insulin AUC (p< 0.05) during the SMT. Conclusions In women with PCOS, consumption of a diet lower in CHO resulted in preferential loss of fat mass from metabolically harmful adipose depots, whereas a diet high in CHO appeared to promote repartitioning of lean mass to fat mass.
    Metabolism 07/2014; 63(10). DOI:10.1016/j.metabol.2014.07.007 · 3.89 Impact Factor
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    ABSTRACT: To test the hypothesis that a breakfast meal with high carbohydrate/low fat results in an earlier increase in postprandial glucose and insulin, a greater decrease below baseline in postprandial glucose, and an earlier return of appetite, compared to a low carbohydrate/high fat meal. Overweight but otherwise healthy adults (n=64) were maintained on one of two eucaloric diets: high carbohydrate/low fat (HC/LF; 55:27:18% kcals from carbohydrate: fat: protein) versus low carbohydrate/high fat (LC/HF; 43:39:18% kcals from carbohydrate: fat: protein). After 4 weeks of acclimation to the diets, participants underwent a meal test during which circulating glucose and insulin and self-reported hunger and fullness, were measured before and after consumption of breakfast from their assigned diets. The LC/HF meal resulted in a later time at the highest and lowest recorded glucose, higher glucose concentrations at 3 and 4 hours post-meal, and lower insulin incremental area under the curve. Participants consuming the LC/HF meal reported lower appetite 3 and 4 hours following the meal, a response that was associated with the timing of the highest and lowest recorded glucose. Modest increases in meal arbohydrate content at the expense of fat content may facilitate weight gain over the long-term by contributing to an earlier rise and fall of postprandial glucose concentrations and an earlier return of appetite.
    Appetite 05/2014; 80. DOI:10.1016/j.appet.2014.04.031 · 2.69 Impact Factor
  • Amy C Ellis · Jessica A Alvarez · Barbara A Gower · Gary R Hunter
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    ABSTRACT: Previous studies suggest that circulating 25(OH)D may favorably influence cardiorespiratory fitness and fat oxidation. However, these relationships have not been examined in older adult women of different ethnic groups. The objectives of this study were to determine whether serum 25(OH)D is related to cardiovascular fitness (VO2max) in sedentary women ages ≥60 years and to determine whether these associations differ between African Americans (AA) and European Americans (EA). A secondary aim was to determine whether serum 25(OH)D is correlated with respiratory quotient (RQ) during submaximal exercise. This cross-sectional analysis included 67 AA and EA women ages 60-74 years. VO2max was measured by a modified Bruce graded treadmill protocol, and measurements were adjusted for percent fat and lean body mass assessed by air displacement plethysmography. Indirect calorimetry was used to measure RQ at rest and during four submaximal exercise tests. Fasting blood samples were obtained to quantify serum 25(OH)D. Serum 25(OH)D was associated with VO2max (ml/kg LBM/min) independent of percent body fat (r = 0.316, p = 0.010). However, subgroup analysis revealed that this relationship was specific to AA (r = 0.727, p = 0.005 for AA; r = 0.064, p = 0.643 for EA). In all subjects combined, 25(OH)D was inversely correlated (p < 0.01) with all measures of submaximal RQ. Higher serum 25(OH)D was associated with greater cardiorespiratory fitness in older adult AA women. Among both AA and EA, inverse associations between serum 25(OH)D and RQ suggest that women with higher levels of circulating vitamin D also demonstrated greater fat oxidation during submaximal exercise.
    Endocrine 02/2014; 47(3). DOI:10.1007/s12020-014-0210-5 · 3.88 Impact Factor
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    ABSTRACT: Context: We hypothesized that similar to the coordinated homeostatic regulation of most hormones, the concentration of free and bioavailable 25-hydroxy vitamin D [25(OH)D] will be tightly controlled by total 25(OH)D and vitamin D binding protein (VDBP); and, that the VDBP concentrations will be associated with insulin resistance status. Objective: Our primary objective was to investigate associations between total, free and bioavailable 25(OH)D and VDBP. We also evaluated the relationships of VDBP with insulin resistance indices. Study design was cross sectional in the setting of a University children's hospital. The relative concentration of bioavailable 25(OH)D to total 25(OH)D [bioavailable 25(OH)D /total 25(OH)D was expressed as a percentage [% bioavailable 25(OH)D]. Results: Subjects were 47, post menarchal, female adolescents, mean age 15.8 ± 1.4 years, mean BMI 23.1 ± 4.0 kg/m(2). Total 25(OH)D was strongly associated with VDBP (rho = 0.57, P = <0.0001). At lower total 25(OH)D concentrations, the concentration of bioavailable 25(OH)D relative to total 25(OH)D was higher (23.8% vs. 14.9%, P<0.0001), whereas the relative concentration of free 25(OH)D was similar (P=0.44). VDBP was inversely associated with fasting insulin (rho=-0.51, P=0.0003) and HOMA-IR (rho=-0.45, P=0.002), and positively with WBISI (rho=0.33, P=0.02); these relationships were persisted after adjusting for percent fat and attenuated after adjusting for race. Conclusion: Our data suggest that, VDBP concentrations are regulated by total 25(OH)D levels to maintain adequate concentrations of bioavailable 25(OH)D. VDBP concentrations are inversely associated with hyperinsulinemia and insulin resistance.Background.
    The Journal of Clinical Endocrinology and Metabolism 10/2013; 99(1). DOI:10.1210/jc.2013-2452 · 6.21 Impact Factor
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    ABSTRACT: Little is known about early coincidental changes in bone and vascular properties, particularly in the context of skeletal anabolism (puberty) versus relative equilibrium (young adulthood). We aimed to determine if subclinical markers of vascular function were associated with bone mineral content (BMC) and to evaluate the contribution of systemic factors in healthy females ages 14-42 years. Endothelial function was assessed by flow mediated dilatation (FMD), arterial stiffness by pulse wave velocity (PWV) and augmentation index (AIx), blood pressure (BP) by sphygmomanometer, BMC by DXA, and systemic factors by fasting blood draw. General linear models controlled for age, race and height indicated a positive association between systolic BP (SBP) and BMC independent of systemic factors. When stratified by age using 19 years as a cut-point, there was an inverse relationship between AIx75 in adolescents with insulin (P<0.10) or inflammatory markers (P<0.10) in statistical models. Conversely, there was a positive relationship between BMC and both PWV and AIx75 in young adults (P<0.05). The link between bone and the vasculature may be life stage-dependent. In the context of a less dynamic microenvironment in young adult females, metabolic factors appear to moderate less of an effect of hemodynamic properties on the skeleton relative to adolescents.
    09/2013; 1(3). DOI:10.4248/BR201303007
  • Barbara A Gower · Krista Casazza
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    ABSTRACT: Historically, obesity was thought to be advantageous for maintaining healthy bones due to the greater bone mineral density observed in overweight individuals. However, recent observations of increased fracture in some obese individuals have led to concern that common metabolic complications of obesity, such as type 2 diabetes, metabolic syndrome, impaired glucose tolerance, insulin resistance, hyperglycemia, and inflammation may be associated with poor bone health. In support of this hypothesis, greater visceral fat, a hallmark of insulin resistance and metabolic syndrome, is associated with lower bone mineral density. Research is needed to determine if and how visceral fat and/or poor metabolic health are causally associated with bone health. Clinicians should consider adding a marker metabolic health, such as waist circumference or fasting plasma glucose concentration, to other known risk factors for osteoporosis and fracture.
    Journal of Clinical Densitometry 09/2013; 16(4). DOI:10.1016/j.jocd.2013.08.010 · 2.03 Impact Factor
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    ABSTRACT: Qualitative aspects of diet may affect body composition and propensity for weight gain or loss. We tested the hypothesis that consumption of a relatively low glycemic load (GL) diet would reduce total and visceral adipose tissue under both eucaloric and hypocaloric conditions. Participants were 69 healthy overweight men and women. Body composition was assessed by DXA and fat distribution by CT scan at baseline, after 8 weeks of a eucaloric diet intervention, and after 8 weeks of a hypocaloric (1000 kcal/day deficit) diet intervention. Participants were provided all food for both phases, and randomized to either a low GL diet (<45 points per 1000 kcal; n = 40) or high GL diet (>75 points per 1000 kcal, n = 29). After the eucaloric phase, participants who consumed the low GL diet had 11% less intra-abdominal fat (IAAT) than those who consumed the high GL diet (P < 0.05, adjusted for total fat mass and baseline IAAT). Participants lost an average of 5.8 kg during the hypocaloric phase, with no differences in the amount of weight loss with diet assignment (P = 0.39). Following weight loss, participants who consumed the low GL diet had 4.4% less total fat mass than those who consumed the high GL diet (P < 0.05, adjusted for lean mass and baseline fat mass). Consumption of a relatively low GL diet may affect energy partitioning, both inducing reduction in IAAT independent of weight change, and enhancing loss of fat relative to lean mass during weight loss.
    Obesity 06/2013; 21(6). DOI:10.1002/oby.20191 · 3.73 Impact Factor
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    ABSTRACT: Context:Animal studies indicate that osteocalcin (OC), particularly the undercarboxylated isoform (unOC), affects insulin sensitivity and secretion, but definitive data from humans are lacking.Objective:To determine if total OC and unOC are independently associated with insulin sensitivity and β-cell response in overweight/obese adults; whether glucose tolerance status affects these associations; and whether associations are independent of bone formation, as reflected in procollagen type 1 amino propeptide (P1NP).Design, Setting, and Participants:This was a cross-sectional study conducted at a University Research Center involving 63 overweight/obese adults with normal (n=39) or impaired fasting glucose (IFG, n=24).Main outcome measures:Serum concentrations of total/undercarboxylated OC and P1NP were assessed by RIA; insulin sensitivity was determined by intravenous glucose tolerance test (SI-IVGTT), liquid meal test (SI-meal), and HOMA-IR; β-cell response to glucose (basal, PhiB; dynamic, PhiD; static, PhiS; and total, PhiTOT) was derived using C-peptide modeling of meal test data; and intra-abdominal adipose tissue (IAAT) was measured using CT scanning.Results:Multiple linear regression, adjusting for IAAT and P1NP, revealed that total OC was positively associated with SI-IVGTT (P<0.01) in the total sample. OC was not associated with SI-meal or HOMA-IR. In participants with IFG, unOC was positively associated with PhiS and PhiTOT (P<0.05) independent of insulin sensitivity.Conclusions:In overweight/obese individuals, total OC may be associated with skeletal muscle but not hepatic insulin sensitivity. unOC is uniquely associated with β-cell function only in individuals with IFG. Further research is needed to probe the causal inference of these relationships, and to determine if indirect nutrient sensing pathways underlie these associations.
    The Journal of Clinical Endocrinology and Metabolism 04/2013; 98(7). DOI:10.1210/jc.2013-1203 · 6.21 Impact Factor
  • Paula C Chandler-Laney · Barbara A Gower · David A Fields
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    ABSTRACT: Excess weight gain during both pre- and postnatal life increases risk for obesity in later life. Although a number of gestational and early life contributors to this effect have been identified, there is a dearth of research to examine whether gestational factors and weight gain velocity in infancy exert independent effects on subsequent body composition and fat distribution. To test the hypothesis that birth weight, as a proxy of prenatal weight gain, and rate of weight gain before 6 months would be associated with total and truncal adiposity at 12 months of age. Healthy, term infants (N = 47) were enrolled in the study and rate of weight gain (g/day) was assessed at 0-3 months, 3-6 months, and 6-12 months. Total and regional body composition were measured by dual-energy X-ray absorptiometry (DXA) at 12 months. Stepwise linear regression modeling indicated that lean mass at 12 months, after adjusting for child length, was predicted by rate of weight gain during each discrete period of infancy (P < 0.05), and by maternal pre-pregnancy BMI (P < 0.05). Total fat mass at 12 months was predicted by rate of weight gain during each discrete period (P < 0.01), and by older maternal age at delivery (P < 0.05). Trunk fat mass at 12 months, after adjusting for leg fat mass, was predicted by rate of weight gain from 0-3 months and 3-6 months (P < 0.05). Results suggest that growth during early infancy may be a critical predictor of subsequent body composition and truncal fat distribution.
    Obesity 03/2013; 21(1):144-8. DOI:10.1002/oby.20236 · 3.73 Impact Factor
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    ABSTRACT: Objective: This study compared BMD relative to body weight following a ∼6-month weight loss program and a 1-year weight maintenance phase in premenopausal women and determined whether African American (AA) and European-American (EA) women's BMD respond similarly during weight loss. Design and methods: Premenopausal women (n = 115, 34 ± 5 years) were evaluated in an overweight state (BMI between 27 and 30 kg/m(2) ), following an 800 kcal/day diet/exercise program designed to reduce BMI<25 kg/m(2) , and 1-year following weight loss. Results: BMD relative to body weight (Z-scores) increased after weight loss, but decreased during the 1-year weight maintenance phase. All 1-year follow-up BMD Z-scores were increased (except L1) compared to baseline measurements (P < 0.05). These sites included the hip neck (+0.088, P = 0.014), total hip (+0.099, P = 0.001), L2 (+0.127, P = 0.013), L3 (+0.135, P = 0.014), and L4 (+0.199, P = 0.002). AAs had significantly higher absolute BMD at all sites (P < 0.05) compared to EAs, but no time by race interactions were evident during weight loss (except in L3). Conclusion: These results may indicate that weight loss is safe with regard to bone health for overweight premenopausal women.
    Obesity 03/2013; 21(3). DOI:10.1002/oby.20052 · 3.73 Impact Factor

Publication Stats

6k Citations
934.00 Total Impact Points


  • 1994–2015
    • University of Alabama at Birmingham
      • Department of Nutrition Sciences
      Birmingham, Alabama, United States
  • 2014
    • Georgia Regents University
      Augusta, Georgia, United States
  • 1993–2011
    • University of Delaware
      • Department of Biological Sciences
      Delaware, United States