A Whole-Grain Diet Reduces Cardiovascular Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial.

BACKGROUND: Increased dietary whole-grain intake may protect against cardiovascular disease (CVD). OBJECTIVE: The objective was to evaluate the efficacy of whole grains compared with refined grains on body composition, hypertension, and related mediators of CVD in overweight and obese adults. METHODS: We conducted a double-blind, randomized, controlled crossover trial in 40 overweight or obese men and women aged <50 y with no known history of CVD. Complete whole-grain and refined-grain diets were provided for two 8-wk periods, with a 10-wk washout between diets. Macronutrient composition was matched, except for the inclusion of either whole grains or refined grains (50 g/1000 kcal in each diet). Measurements included blood pressure, body composition, blood lipids and adiponectin, and markers of inflammation and glycemia. RESULTS: Thirty-three participants (6 men and 27 women) completed the trial [mean ± SD age: 39 ± 7 y; mean ± SD body mass index (in kg/m2): 33.1 ± 4.3]. Decreases in diastolic blood pressure were -5.8 mm Hg (95% CI: -7.7, -4.0 mm Hg) after the whole-grain diet and -1.6 mm Hg (95% CI: -4.4, 1.3 mm Hg) after the control diet (between effect, P = 0.01). Decreases in plasma adiponectin were -0.1 (95% CI: -0.9, 0.7) after the whole-grain diet and -1.4 (95% CI: -2.6, -0.3) after the control diet (between effect, P = 0.05). Decreases in diastolic blood pressure correlated with the circulating adiponectin concentration (r = 0.35, P = 0.04). Substantial reductions in body weight, fat loss, systolic blood pressure, total cholesterol, and LDL cholesterol were observed during both diet periods, with no relevant difference between them. CONCLUSIONS: The improvement in diastolic blood pressure was >3-fold greater in overweight and obese adults when they consumed a whole-grain compared with a refined-grain diet. Because diastolic blood pressure predicts mortality in adults aged <50 y, increased whole-grain intake may provide a functional approach to control hypertension. This may benefit patients at risk of vascular-related morbidity and mortality. This trial was registered at clinicaltrials.gov as NCT01411540.

Postactivation potentiation enhances swim performance in collegiate swimmers.

This study examined postactivation potentiation (PAP) and its effect on performance during sprint swimming. After maximal muscular contraction, the muscles are in both a potentiated and fatigued state. However, fatigue dissipates faster than potentiation, creating a window of opportunity for possible performance enhancement. We observed 30 collegiate swimmers (15 men and 15 women) performing 2 swim trials in a randomized order. The control trial involved a standard swim warm-up, followed by a 6-minute rest and by a maximal 100-m freestyle swim effort. The PAP trial involved the same protocol; however, a PAP loading protocol involved the subjects completing 4 maximal 10-m swims at a 1-minute interval while attached to a resistive power rack and was completed before the 6-minute rest. Fifty-meter splits and blood lactates were also analyzed. There was a significant improvement in 100-m freestyle swim time (0.54 seconds) for the PAP trial vs. the control trial (p = 0.029). Both men and women improved during the PAP trial compared with the control trial, and there was no significant gender interaction. We conclude that PAP substantially enhances 100-m freestyle performance in collegiate swimmers and presents a valid technique for competitive performance enhancement.

A Whole-Grain Diet Increases Whole-Body Protein Balance Compared with a Macronutrient-Matched Refined-Grain Diet.

BACKGROUND: There are limited data from randomized control trials to support or refute the contention that whole-grains can enhance protein metabolism in humans. OBJECTIVES: To examine: 1) the clinical effects of a whole-grain diet on whole-body protein turnover; 2) the cellular effects of whole-grains on protein synthesis in skeletal muscle cells; and 3) the population effects of whole-grain intake on age-related muscle loss. METHODS: Adults with overweight/obesity (n = 14; age = 40 ± 7 y; BMI = 33 ± 5 kg/m2) were recruited into a crossover, randomized controlled trial (NCT01411540) in which isocaloric, macronutrient-matched whole-grain and refined-grain diets were fully provisioned for two 8-wk periods. Diets differed only in the presence of whole-grains (50 g/1000 kcal). Whole-body protein kinetics were assessed at baseline and after each diet in the fasted-state (13C-leucine) and integrated over 24 h (15N-glycine). In vitro studies using C2C12 cells assessed global protein synthesis by surface sensing of translation and anabolic signaling by Western blot. Complementary epidemiological assessments using the NHANES database assessed the effect of whole-grain intake on muscle function assessed by gait speed in older adults (n = 2783). RESULTS: Integrated 24-h net protein balance was 3-fold higher on a whole-grain diet compared with a refined-grain diet (P = 0.04). A whole-grain wheat extract increased submaximal rates of global protein synthesis (27%, P < 0.05) in vitro. In a large sample of older adults, whole-grain intake was associated with greater muscle function (OR = 0.92; 95% CI: 0.86, 0.98). CONCLUSIONS: Consuming 50 g/1000 kcal whole-grains per day promotes greater protein turnover and enhances net protein balance in adults. Whole-grains impact skeletal muscle at the cellular level, and are associated with greater muscle function in older adults. Collectively, these data point to a new mechanism whereby whole-grain consumption favorably enhances protein turnover and improves health outcomes.This clinical trial is registered on clinicaltrials.gov (identifier: NCT01411540).

Foregut Exclusion Enhances Incretin and Insulin Secretion After Roux-en-Y Gastric Bypass in Adults With Type 2 Diabetes.

INTRODUCTION: Patients with type 2 diabetes experience resolution of hyperglycemia within days after Roux-en-Y gastric bypass (RYGB) surgery. This is attributed, in part, to enhanced secretion of hindgut factors following exclusion of the gastric remnant and proximal intestine during surgery. However, evidence of the mechanisms of remission remain limited due to the challenges of metabolic evaluation during the early postoperative period. The purpose of this investigation was to determine the role of foregut exclusion in the resolution of type 2 diabetes after RYGB. METHODS: Patients with type 2 diabetes (n = 15) undergoing RYGB had a gastrostomy tube (G-tube) placed in their gastric remnant at time of surgery. Patients were randomized to receive a mixed meal tolerance test via oral or G-tube feeding immediately prior to and 2 weeks after surgery in a repeated measures crossover design. Plasma glucose, insulin, C-peptide, incretin responses, and indices of meal-stimulated insulin secretion and sensitivity were determined. RESULTS: Body weight, fat mass, fasting glucose and insulin, and circulating lipids were significantly decreased 2 weeks after surgery. The glycemic response to feeding was reduced as a function of total area under the curve but not after adjustment for the reduction in fasting glucose. Oral feeding significantly enhanced insulin and incretin secretion after RYGB, which was entirely ablated by G-tube feeding. CONCLUSION: Foregut exclusion accounts for the rise in incretin and insulin secretion but may not fully explain the early improvements in glucose metabolism after RYGB surgery.

Efficacy of whole-body suspension training on enhancing functional movement abilities following a supervised or home-based training program.

BACKGROUND: The purpose of this study was to determine the effects of suspension training on functional movement and body composition, and to compare the effectiveness of home-based training to supervised training. METHODS: Seventeen healthy subjects (8 males, 9 females, age=21.8±3.4 y) with no recent history of resistance training were randomly assigned to a home-based or supervised training group. Subjects performed an 8-week suspension training program consisting of 10 exercises targeting major muscle groups, twice per week for the duration of the study. Pre- and post-intervention testing included body composition using air displacement plethysmography, and a functional movement screen (FMS) to measure functional movement abilities. RESULTS: The 8-week training program significantly improved total FMS scores across the whole sample of subjects (Pre=16.4; Post=17.5; P=0.004), with no differences in improvements between groups. When compared separately, only the supervised group significantly improved FMS scores. There was also a significant increase in lean mass across the total sample of subjects (Pre=52.4 kg; Post=53.3 kg; P=0.03) with no differences between groups. But when compared independently, neither group exhibited a significant increase in lean mass. CONCLUSIONS: When completed as a whole-body exercise program over an 8-week period, suspension training can improve functional ability and increase lean mass in both a supervised and a home-based setting.

Effects of Intermittent Pneumatic Compression on Delayed Onset Muscle Soreness (DOMS) in Long Distance Runners.

The purpose of this study was to observe the effectiveness of intermittent pneumatic compression (IPC) on reducing C-reactive protein (CRP) and DOMS after long distance running. Ten distance runners, five males and five females, ages 20-53 years performed two 20-mile runs at 70% VO2 max. Each run was followed by either no treatment (control) or IPC treatment for five consecutive days. For the IPC run, participants were treated for one hour immediately following the run and daily for five more days thereafter. On control runs, participants did not receive any treatment. Serum CRP was measured pre- and post-run, and daily thereafter for five days for both trials. Results indicated no significant difference (p > 0.05) between control and treatment runs in CRP levels. Subjective pain ratings indicated no significant difference in pain between control and treatment runs. In conclusion, there appear to be no substantial benefits of IPC in promoting recovery.

A Whole-Grain Diet Increases Glucose-Stimulated Insulin Secretion Independent of Gut Hormones in Adults at Risk for Type 2 Diabetes.

INTRODUCTION: The effect of whole-grain (WG) versus refined-grain (RG) diets on glucose-stimulated insulin secretion (GSIS) and ß-cell function is unclear. METHODS: In a double-blind crossover randomized controlled trial, 13 prediabetic adults (37.2 ± 1.8 y, BMI: 33.6 ± 1.4 kg m-2 , 2 h glucose: 146.9 ± 11.6 mg dL-1 ) are provided isocaloric-matched WG and RG diets for 8-weeks each, with an 8-10 week washout between diets. Glucose, insulin, and C-peptide are studied over 240 min following a 75 g OGTT. Incretins (GLP-1 and GIP), PYY, and total ghrelin are assessed at 0, 30, and 60 min. Mixed-meal diets for carbohydrate (54%), fat (28%), and protein (18%) contain either WG (50 g/1000 kcal) or equivalent RG. RESULTS: Both diets induce fat loss (≈2 kg). While neither diet impacts early phase GSIS, the WG diet increases total GSIS (iAUC of C-peptide0-240 /Glc0-240 , p = 0.02) and ß-cell function (disposition index; GSIS × insulin sensitivity, p = 0.02). GIP and PYY are unaltered by either diet, but GLP-1 is higher at 30 min following RG versus WG (p = 0.04). Ghrelin levels are higher at 60 min of the OGTT following both interventions (p = 0.01). CONCLUSION: A WG-rich diet increases ß-cell function independent of gut hormones in adults with prediabetes.

A whole-grain diet reduces peripheral insulin resistance and improves glucose kinetics in obese adults: A randomized-controlled trial.

BACKGROUND: Whole-grain intake is associated with lower risk of type 2 diabetes but the mechanisms are unclear. PURPOSE: We tested the hypothesis that a WG diet reduces insulin resistance and improves glucose use in individuals at risk for type 2 diabetes compared with an isocaloric-matched refined-grain diet. METHODS: A double-blind, randomized, controlled, crossover trial of 14 moderately obese adults (Age, 38 ±â€¯2 y; BMI, 34.0 ±â€¯1.1 kg/m2). Insulin resistance and glucose metabolism was assessed using an oral glucose tolerance test combined with isotopic tracers of [6,6-2H2]-glucose and [U-13C]-glucose, and indirect calorimetry. Peripheral and hepatic insulin resistance was assessed as 1/(rate of disposal/insulin), and endogenous glucose rates of appearance (Ra) iAUC60-240 × insulin iAUC60-240, respectively. Both diets met ADA nutritional guidelines and contained either whole-grain (50 g per 1000 kcal) or equivalent refined-grain. All food was provided for 8 wk. with an 8-10 wk. washout period between diets. RESULTS: Post-prandial glucose tolerance, peripheral insulin sensitivity, and metabolic flexibility (insulin-stimulated - fasting carbohydrate oxidation) improvements were greater after whole-grain compared to the refined-grain diet (P < 0.05). Compared to baseline, body fat (~2 kg) and hepatic Ra insulin resistance was reduced by both diets, while fasting glucose and exogenous glucose-meal were unchanged after both interventions. Changes in peripheral insulin resistance and metabolic flexibility correlated with improved glucose tolerance (P < 0.05). CONCLUSION: Whole-grains reduced diabetes risk and the mechanisms appear to work through reduced post-prandial blood glucose and peripheral insulin resistance that were statistically linked to enhanced metabolic flexibility.

Short-term aerobic exercise training improves gut peptide regulation in nonalcoholic fatty liver disease.

Obesity-related nonalcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease. Exercise and diet are uniformly prescribed treatments for NAFLD; however, there are limited empirical data on the effects of exercise training on metabolic function in these patients. The purpose of this study was to investigate the fasting and glucose-stimulated adaptation of gut peptides to short-term aerobic exercise training in patients with NAFLD. Twenty-two obese subjects, 16 with NAFLD [body mass index (BMI), 33.2 ± 1.1 (SE) kg/m(2)] and 6 obese controls (BMI, 31.3 ± 1.2 kg/m(2)), were enrolled in a supervised aerobic exercise program (60 min/day, 85% of their heart rate maximum, for 7 days). Fasting and glucose-stimulated glucagon-like peptide-1 (GLP-17-36) and peptide tyrosine tyrosine (PYYTotal) concentrations in plasma were assessed before and after the exercise program. Initially, the NAFLD group had higher fasting PYY (NAFLD = 117 ± 18.6, control = 47.2 ± 6.4 pg/ml, P < 0.05) and GLP-1 (NAFLD = 12.4 ± 2.2, control = 6.2 ± 0.2 pg/ml, P < 0.05) and did not significantly increase GLP-1 or PYY in response to glucose ingestion. After the exercise program, fasting GLP-1 was reduced in the NAFLD group (10.7 ± 2.0 pg/ml, P < 0.05). Furthermore, exercise training led to significant increase in the acute (0-30 min) PYY and GLP-1 responses to glucose in the NAFLD group, while the total area under the glucose-stimulated GLP-1 response curve was reduced in both NAFLD and controls (P < 0.05). In summary, 7 days of vigorous aerobic exercise normalized the dynamic PYY and GLP-1 responses to nutrient stimulation and reduced the GLP-1 response in NAFLD, suggesting that exercise positively modulates gut hormone regulation in obese adults with NAFLD.

A Community-Based Exercise and Support Group Program Improves Quality of Life in African-American Breast Cancer Survivors: A Quantitative and Qualitative Analysis.

African-American (AA) breast cancer (BCa) survivors have higher mortality rates, more comorbidities and are less likely to meet national physical activity guidelines after diagnosis compared to Caucasian BCa survivors. We previously reported that a 20-week resistance exercise intervention coupled with a support group and home walking program, conducted using facilities and personnel at a community cancer support center, in Stage I-III AA BCa survivors improved strength, fitness and circulating C-peptide levels. Here, we report our findings on changes in quality of life (QoL) and other behavioral measures associated with this 20-week intervention and, discuss findings from a qualitative analysis of semi-structured patient interviews. We found a clinically relevant improvement in QoL using the Functional Assessment of Cancer Therapy for Breast Cancer (FACT-B) (Baseline, B: 101.1 ± 21.5; End-of-Intervention, EOI: 108.5 ± 21.6; p = 0.05) and, a significant decrease in depression using the Beck Depression Inventory-II (B: 11.9 ± 8.1; EOI: 9.0 ± 5.5; p = 0.03). Our analysis of the patient interviews support improvements in these behavioral measures in that participants stated that they "feel better", were "more motivated" and "uplifted" after the program. The patient interviews also provided insights to the primary motivators (e.g., social support, improvements in strength and function, weight loss) and barriers (e.g., family and health issues) in adhering to the program and provided suggestions for improving the program (e.g., incorporating nutritional and treatment related side-effect discussions). Our results suggest that community-based lifestyle interventions may improve QoL and depression in AA BCa survivors and lend insights for improving future programs.

A Community-Based Exercise and Support Group Program in African-American Breast Cancer Survivors (ABCs).

African-American (AA) women have higher rates of breast cancer (BCa) mortality than Caucasian women, and a recent study using data from the Surveillance, Epidemiology and End Results (SEER) registry suggests that this disparity may be due, in part, to the poorer health status of AAs at diagnosis and not treatment related issues. Randomized controlled trials involving supervised aerobic and resistance exercise have shown improved body composition and improvement in cancer-related biomarkers in BCa patients and may lead to improved recurrence and survival rates; however, most trials have focused on Caucasians and many have been conducted in academic- and clinic-based settings. We evaluated the feasibility of conducting a 20-week, supervised, resistance training, group exercise intervention coupled with a support group and home walking program utilizing facilities and personnel at a community cancer support center (The Gathering Place, Beachwood, Ohio) in AA Stage I-III BCa survivors who were within 12 months of completing treatment (surgery, chemotherapy, and/or breast irradiation); and, evaluated the potential effects of this intervention on physical measures and cancer-related biomarkers. 27 patients provided informed consent and 19 participated in the program. On average, attendance rates were 70.0% ± 19.1% for the exercise sessions and 63.1% ± 13.8% for the support group. We observed a significant decrease in circulating C-peptide levels (B: 893.9 ± 399.1 pg/mL; EOI: 723.9 ± 319.0 pg/mL; p=0.01). Although we did not observe a significant decrease in weight in the entire sample, there was a significant decrease in waist circumference and percent total body fat among those who attended 70% or more of the exercise sessions. In summary, we demonstrated that conducting lifestyle interventions in AA BCa survivors in a community setting is feasible. Future interventions should invoke strategies to enhance adherence and include a structured dietary intervention to enable greater weight loss.

Improved hepatic lipid composition following short-term exercise in nonalcoholic fatty liver disease.

CONTEXT: Hepatic steatosis, insulin resistance, inflammation, low levels of polyunsaturated lipids, and adiponectin are implicated in the development and progression of nonalcoholic fatty liver disease (NAFLD). OBJECTIVE: We examined the effects of short-term aerobic exercise on these metabolic risk factors. DESIGN AND PARTICIPANTS: Obese individuals (N = 17, 34.3 ± 1.0 kg/m²) with clinically confirmed NAFLD were enrolled in a short-term aerobic exercise program that consisted of 7 consecutive days of treadmill walking at ~85% of maximal heart rate for 60 minutes per day. Preintervention and postintervention measures included hepatic triglyceride content, and a lipid saturation index and polyunsaturated lipid index (PUI) of the liver, obtained by (1)H magnetic resonance spectroscopy (N = 14). Insulin sensitivity was estimated from an oral glucose tolerance test (OGTT), and mononuclear cells were isolated to assess reactive oxygen species production during the OGTT. Circulating glucose, insulin, and high molecular weight (HMW) adiponectin were determined from plasma. MAIN OUTCOME: Short-term aerobic exercise training improved hepatic lipid composition in patients with NAFLD. RESULTS: Exercise training resulted in an increase in liver PUI (P < .05), increased insulin sensitivity (Matsuda Index: P < .05), HMW adiponectin (P < .05), and maximal oxygen consumption (P < .05). Reactive oxygen species production during the OGTT was reduced following exercise training (P < .05). HMW adiponectin was increased after the exercise program and the increase was positively correlated with the increase in liver PUI (r = 0.52, P = .05). Body weight remained stable during the program (P > .05). CONCLUSION: Short-term exercise can target hepatic lipid composition, which may reduce the risk of NAFLD progression. The improvement in hepatic lipid composition may be driven by adiponectin.