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Concept: Blood sugar

201

Over-nutrition has fuelled the global epidemic of type 2 diabetes, but the role of individual macronutrients to the diabetogenic process is not well delineated. We aimed to examine the impact of dietary fatty acid intake on fasting and 2-hour plasma glucose concentrations, as well as tissue-specific insulin action governing each. Normoglycemic controls (n = 15), athletes (n = 14), and obese (n = 23), as well as people with prediabetes (n = 10) and type 2 diabetes (n = 11), were queried about their habitual diet using a Food Frequency Questionnaire. All subjects were screened by an oral glucose tolerance test (OGTT) and studied using the hyperinsulinemic/euglycemic clamp with infusion of 6,62H2-glucose. Multiple regression was performed to examine relationships between dietary fat intake and 1) fasting plasma glucose, 2) % suppression of endogenous glucose production, 3) 2-hour post-OGTT plasma glucose, and 4) skeletal muscle insulin sensitivity (glucose rate of disappearance (Rd) and non-oxidative glucose disposal (NOGD)). The %kcal from saturated fat (SFA) was positively associated with fasting (β = 0.303, P = 0.018) and 2-hour plasma glucose (β = 0.415, P<0.001), and negatively related to % suppression of hepatic glucose production (β = -0.245, P = 0.049), clamp Rd (β = -0.256, P = 0.001) and NOGD (β = -0.257, P = 0.001). The %kcal from trans fat was also negatively related to clamp Rd (β = -0.209, P = 0.008) and NOGD (β = -0.210, P = 0.008). In contrast, the %kcal from polyunsaturated fat (PUFA) was negatively associated with 2-hour glucose levels (β = -0.383, P = 0.001), and positively related to Rd (β = 0.253, P = 0.007) and NOGD (β = 0.246, P = 0.008). Dietary advice to prevent diabetes should consider the underlying pathophysiology of the prediabetic state.

Concepts: Unsaturated fat, Fat, Blood sugar, Saturated fat, Glucose tolerance test, Diabetes mellitus, Insulin, Nutrition

189

The study investigated cross-sectional associations of total amount and patterns of sedentary behaviour with glucose metabolism status and the metabolic syndrome.

Concepts: Insulin resistance, Blood sugar, Diabetes mellitus type 2, Diabetes mellitus, Hypertension, Obesity, Nutrition, Insulin

189

BACKGROUND: This study compared the effects of ingesting water (W), a flavored carbohydrate-electrolyte (CE) or a flavored non-caloric electrolyte (NCE) beverage on mood, ratings of perceived exertion (RPE), and sprint power during cycling in recreational exercisers. METHODS: Men (n = 23) and women (n = 13) consumed a 24-h standardized diet and reported 2–4 h post-prandial for all test sessions. After a familiarization session, participants completed 50 min of stationary cycling in a warm environment (wet bulb globe temperature = 25.0[degree sign]C) at ~60-65% of heart rate reserve (146 +/- 4 bpm) interspersed with 5 rest periods of 2 min each. During exercise, participants consumed W, CE, or NCE, served in a counterbalanced cross-over design. Beverage volume was served in 3 aliquots equaling each individual’s sweat losses (mean 847 +/- 368 mL) during the familiarization session. Profiles of Mood States questionnaires (POMS) were administered and blood glucose levels were determined pre- and post- sub-maximal cycling. Following sub-maximal exercise, participants completed 3 30-s Wingate anaerobic tests (WAnT) with 2.5 min rest between tests to assess performance. RESULTS: Blood glucose was higher (p < 0.05) after 50 min of submaximal cycling just prior to the WAnT for CE (6.1 +/- 1.7 mmol/L) compared to W (4.9 +/- 1.5 mmol/L) and NCE (4.6 +/- 1.2 mmol/L). Nonetheless, there were no differences among treatments in peak (642 +/- 153, 635 +/- 143, 650 +/- 141 watts for W, NCE, and CE, respectively; p = 0.44) or mean (455 +/- 100, 458 +/- 95, 454 +/- 95 watts for W, NCE, and CE, respectively; p = 0.62) power for the first WAnT or mean (414 +/- 92, 425 +/- 85, 423 +/- 82 watts, respectively; p = 0.13) power output averaged across all 3 WAnT. Likewise, RPE during submaximal exercise, session RPE, and fatigue and vigor assessed by POMS did not differ among beverage treatments (p > 0.05). CONCLUSIONS: Carbohydrate ingestion consumed by recreational exercisers during a 1-h, moderate-intensity aerobic workout did not alter mood or perceived exertion, nor did it affect subsequent anaerobic performance under the conditions of this study. Drinking caloric sport beverages does not benefit recreational exercisers in a non-fasted state.

Concepts: 496, Carbohydrate, Self number, Exercise, Cycling, Aerobic exercise, Wet Bulb Globe Temperature, Blood sugar

187

OBJECTIVE: To highlight the contribution of the gut microbiota to the modulation of host metabolism by dietary inulin-type fructans (ITF prebiotics) in obese women. METHODS: A double blind, placebo controlled, intervention study was performed with 30 obese women treated with ITF prebiotics (inulin/oligofructose 50/50 mix; n=15) or placebo (maltodextrin; n=15) for 3 months (16 g/day). Blood, faeces and urine sampling, oral glucose tolerance test, homeostasis model assessment and impedancemetry were performed before and after treatment. The gut microbial composition in faeces was analysed by phylogenetic microarray and qPCR analysis of 16S rDNA. Plasma and urine metabolic profiles were analysed by (1)H-NMR spectroscopy. RESULTS: Treatment with ITF prebiotics, but not the placebo, led to an increase in Bifidobacterium and Faecalibacterium prausnitzii; both bacteria negatively correlated with serum lipopolysaccharide levels. ITF prebiotics also decreased Bacteroides intestinalis, Bacteroides vulgatus and Propionibacterium, an effect associated with a slight decrease in fat mass and with plasma lactate and phosphatidylcholine levels. No clear treatment clustering could be detected for gut microbial analysis or plasma and urine metabolomic profile analyses. However, ITF prebiotics led to subtle changes in the gut microbiota that may importantly impact on several key metabolites implicated in obesity and/or diabetes. CONCLUSIONS: ITF prebiotics selectively changed the gut microbiota composition in obese women, leading to modest changes in host metabolism, as suggested by the correlation between some bacterial species and metabolic endotoxaemia or metabolomic signatures.

Concepts: Obesity, Glucose tolerance test, Blood sugar, Diabetes mellitus, Nutrition, Metabolism, Gut flora, Bacteria

184

BACKGROUND: To evaluate the effect of lifestyle modifications on metabolic syndrome (MetS) as assessed by its resolution and improved values for its components. METHODS: This was a systematic review and meta-analysis. Searches were performed of MEDLINE and the Cochrane Database from January 1966 to October 2011 to identify randomized controlled trials (RCTs) related to the study objective. The included studies were RCTs restricted to the English language, with a follow-up period of 6 months or more, which reported overall resolution of MetS or values of MetS components (fasting blood glucose, waist circumference, high-density lipoprotein (HDL), triglycerides, and systolic and diastolic blood pressure (SBP, DBP)) . Two investigators independently assessed study eligibility. The effect sizes were the relative proportion of patients with resolved MetS and mean differences in MetS component values from baseline to 1-year follow-up in a lifestyle-modification intervention (LMI) group versus a control (conventional lifestyle education or no treatment) group. Meta-analyses were conducted using a random-effects model. RESULTS: Eleven interventions in eight RCTs were used for the meta-analyses. The relative proportion of patients with resolved MetS in the intervention group was approximately 2.0 (95% CI 1.5 to 2.7) times greater in the intervention group compared with the control group (7 interventions, n = 2.839). LMI (5 interventions, n = 748) significantly reduced mean values for SBP by 6.4 mmHg (95% CI 9.7 to 3.2), DBP by 3.3 mmHg (95% CI 5.2 to 1.4), triglycerides by 12.0 mg/dl ( 95% CI 22.2 to 1.7), waist circumference by 2.7 cm (95% CI 4.6 to 0.9), and fasting blood glucose by 11.5 mg/dl (95% CI 22.4 to 0.6) (5 interventions), but reductions were not significant for HDL (1.3 mg/dl; 95% CI 0.6 to 3.1). CONCLUSIONS: The LMI was effective in resolving MetS and reducing the severity of related abnormalities (fasting blood glucose, waist circumference, SBP and DBP, and triglycerides) in subjects with MetS.

Concepts: Effect size, Blood sugar, Randomized controlled trial, Atherosclerosis, Systematic review, Evidence-based medicine, Meta-analysis, Blood pressure

177

Despite a considerable amount of data available on the relationship between dietary glycemic index (GI) or load (GL) and cardiovascular disease (CVD) risk factors, in aggregate, the area remains unsettled. The aim of the present review was to summarize the effect of diets differing in GI/GL on CVD risk factors, by examining randomized controlled-feeding trials that provided all food and beverages to adult participants. The studies included a low and high GI/GL diet phase for a minimum of four weeks duration, and reported at least one outcome related to CVD risk; glucose homeostasis, lipid profile or inflammatory status. Ten publications representing five trials were identified. The low GI/GL compared to the high GI/GL diet unexpectedly resulted in significantly higher fasting glucose concentrations in two of the trials, and a lower area under the curve for glucose and insulin in one of the two studies during an oral glucose tolerance test. Response of plasma total, low density lipoprotein and high density lipoprotein cholesterol concentrations was conflicting in two of the studies for which data were available. There was either weak or no effect on inflammatory markers. The results of the five randomized controlled trials satisfying the inclusion criteria suggest inconsistent effects of the GI/GL value of the diet on CVD risk factors.

Concepts: Insulin resistance, Diabetes mellitus, Blood sugar, Cardiovascular disease, Glycemic index, Atherosclerosis, Nutrition, Low-density lipoprotein

172

OBJECTIVE We tested the hypothesis of an independent cross-sectional association between obstructive sleep apnea (OSA) severity and glycated hemoglobin (HbA(1c)) in adults without known diabetes. RESEARCH DESIGN AND METHODS HbA(1c) was measured in whole-blood samples from 2,139 patients undergoing nocturnal recording for suspected OSA. Participants with self-reported diabetes, use of diabetes medication, or HbA(1c) value ≥6.5% were excluded from this study. Our final sample size comprised 1,599 patients. RESULTS A dose-response relationship was observed between apnea-hypopnea index (AHI) and the percentage of patients with HbA(1c) >6.0%, ranging from 10.8% for AHI <5 to 34.2% for AHI ≥50. After adjustment for age, sex, smoking habits, BMI, waist circumference, cardiovascular morbidity, daytime sleepiness, depression, insomnia, sleep duration, and study site, odds ratios (95% CIs) for HbA(1c) >6.0% were 1 (reference), 1.40 (0.84-2.32), 1.80 (1.19-2.72), 2.02 (1.31-3.14), and 2.96 (1.58-5.54) for AHI values <5, 5 to <15, 15 to <30, 30 to <50, and ≥50, respectively. Increasing hypoxemia during sleep was also independently associated with the odds of HbA(1c) >6.0%. CONCLUSIONS Among adults without known diabetes, increasing OSA severity is independently associated with impaired glucose metabolism, as assessed by higher HbA(1c) values, which may expose them to higher risks of diabetes and cardiovascular disease.

Concepts: Blood sugar, Medical conditions related to obesity, Hypopnea, Glycated hemoglobin, Sleep, Diabetes mellitus, Obstructive sleep apnea, Sleep apnea

171

Hypoglycemia is a common complication of insulin treatment in type 1 diabetes mellitus and can occur in any patient with diabetes when glucose consumption exceeds supply. Many studies have been done to elucidate those factors that predict severe hypoglycemia: younger age, longer duration of diabetes, lower HgbA1c, higher insulin dose, lower Body Mass Index, male gender, Caucasian race, underinsurance or low socioeconomic status, and the presence of psychiatric disorders. Hypoglycemia can affect patients' relationships, occupation, and daily activities such as driving. However, one of the greatest impacts is patients' fear of severe hypoglycemic events, which is a limiting factor in the optimization of glycemic control. Therefore, the importance of clinicians' ability to identify those patients at greatest risk for hypoglycemic events is two-fold: 1) Patients at greatest risk may be counseled as such and offered newer therapies and monitoring technologies to prevent hypoglycemic events. 2) Patients at lower risk may be reassured and encouraged to improve their glycemic control. Since the risk of long-term complications with poor blood glucose control outweighs the risks of hypoglycemia with good blood glucose control, patients should be encouraged to aim for glucose concentrations in the physiologic range pre- and post-prandially. Advancements in care, including multiple daily injection therapy with analog insulin, continuous subcutaneous insulin infusion, and continuous glucose monitoring, have each subsequently improved glycemic control and decreased the risk of severe hypoglycemia.

Concepts: Glucagon, Obesity, Diabetes mellitus type 1, Diabetes, Hypoglycemia, Blood sugar, Insulin, Diabetes mellitus

169

This study was designed to evaluate accuracy, performance, and safety of the Dexcom (San Diego, CA) G4(®) Platinum continuous glucose monitoring (CGM) system (G4P) compared with the Dexcom G4 Platinum with Software 505 algorithm (SW505) when used as adjunctive management to blood glucose (BG) monitoring over a 7-day period in youth, 2-17 years of age, with diabetes.

Concepts: Nutrition, Glucose tolerance test, Diabetes, Glucose, Insulin, Blood glucose monitoring, Blood sugar, Diabetes mellitus

169

The leaves of the white mulberry tree (Morus alba L.) are used worldwide in traditional medicine as anti-diabetics. Various constituents of mulberry leaves, such as iminosugars (i.e. 1-deoxynojirimicin), flavonoids and related compounds, polysaccharides, glycopeptides and ecdysteroids, have been reported to exert anti-diabetic activity, but knowledge about their contribution to the overall activity is limited. The objective of the present work was to determine the in vivo anti-diabetic activity of an extract of mulberry leaves (MA), and to examine to what extent three major constituents, chlorogenic acid, rutin and isoquercitrin, might contribute to the observed activity. Quantities of the three constituents of interest in the extract were determined by using HPLC-DAD. Activity was determined by using a type II diabetic rat model. After 11 days of per os administration of 250 or 750 mg/kg of MA or the corresponding amounts of each individual compound, a dose dependent decrease of non-fasting blood glucose levels were found for MA, chlorogenic acid and rutin, but not for isoquercitrin. Based on our results, chlorogenic acid and rutin might account for as much as half the observed anti-diabetic activity of MA, hence they can be considered as excellent markers for the quality control of mulberry products.

Concepts: Diabetes mellitus type 2, Moraceae, Nutrition, Diabetes mellitus, Moreae, Blood sugar, Morus, Morus alba