Insulin Sensitivity In Overweight Adults Research Articles

Impact of resistant starch: Absorption of dietary minerals, glycemic index and oxidative stress in healthy rats

Background & AimsResistant starch (RS) is a prebiotic fiber that has been scientifically shown to control the development of obesity. Prebiotic role of RS has also seen to be very important as it helps gut bacteria to regulate fermentation and fatty acid production. This study aimed to check the different levels of RS on glycemic index, oxidative stress and mineral absorption rate in healthy rat models. To evaluate these objectives, the trial was conducted for 40 days of follow up; 10 days were the adjustment period and the collection period over 30 days. MethodsThirty-six healthy female Wistar rats were divided into 4 groups of (9 animals each) NC (Normal Control: without resistant starch), RS0.20 (resistant starch: 0.20 g/kg body weight), RS0.30 (resistant starch: 0.30g/kg body weight), RS0.40 (resistant starch: 0.40g/kg body weight). All the diets were isocaloric and isonitroginous. ResultsThe impact of different levels of RS on the dry-matter intake (DMI) presented statistically significant results (p ≤ .05): DMI was reduced in RS (0.02) fed rats as compared to NC rats in first 3 weeks; and after 4th and 5th weeks, there was a DMI reduction of 28% in RS (0.04) fed rats. Moreover, there was no significant increase in the nutrient intake in all RS diets. The dry-matter (DM) digestibility was statistically significantly (P≤0·05), which increased in all rats fed with different level of RS. The weight loss showed statistically significant results: RS (0.04) exhibited 19g reduction in weight as compared with NC rats. Significant increase was observed in total oxidant status (TOS), in all the RS fed rats when compared with NC rats. The levels of Mg, Ca, Fe and Zn were shown to be decrease in feces analysis, which proves their better absorbance in gut. Statistically significant increase was observed in antioxidant capacity, whereas significant decrease was observed in the total weight of the animals, showing the role of RS in controlling obesity. ConclusionsOverall, significant results were found in all dosage level of RS but long term administration of the higher dosage level (RS0.40) may need to be studied for enhanced results. RS can help improve insulin sensitivity in overweight adults.

Changes in Food and Nutrient Intake and Diet Quality on a Low-Fat Vegan Diet Are Associated with Changes in Body Weight, Body Composition, and Insulin Sensitivity in Overweight Adults: A Randomized Clinical Trial

BackgroundConsuming different food groups and nutrients can have differential effects on body weight, body composition, and insulin sensitivity. ObjectiveThe aim was to identify how food group, nutrient intake, and diet quality change relative to usual-diet controls after 16 weeks on a low-fat vegan diet and what associations those changes have with changes in body weight, body composition, and measures of metabolic health. DesignSecondary analysis of a randomized clinical trial conducted between October 2016 and December 2018 in four replications. Participants/settingParticipants included in this analysis were 219 healthy, community-based adults in the Washington, DC, area, with a body mass index (BMI) between 28 and 40, who were randomly assigned to either follow a low-fat vegan diet or make no diet changes. InterventionA low-fat, vegan diet deriving approximately 10% of energy from fat, with weekly classes including dietary instruction, group discussion, and education on the health effects of plant-based nutrition. Control group participants continued their usual diets. Main outcome measuresChanges in food group intake, macronutrient and micronutrient intake, and dietary quality as measured by Alternate Healthy Eating Index-2010 (AHEI-2010), analyzed from 3-day diet records, and associations with changes in body weight, body composition, and insulin sensitivity were assessed. Statistical analyses performedA repeated-measure analysis of variance model that included the factors group, subject, and time was used to test the between-group differences throughout the 16-week study. Interaction between group and time was calculated for each variable. Within each diet group, paired comparison t tests were calculated to identify significant changes from baseline to 16 weeks. Spearman correlations were calculated for the relationship between changes in food group intake, nutrient intake, AHEI-2010 score, and changes in body weight, body composition, and insulin sensitivity. The relative contribution of food groups and nutrients to weight loss was evaluated using linear regression. ResultsFruit, vegetable, legume, meat alternative, and whole grain intake significantly increased in the vegan group. Intake of meat, fish, and poultry; dairy products; eggs; nuts and seeds; and added fats decreased. Decreased weight was most associated with increased intake of legumes (r = −0.38; P < 0.0001) and decreased intake of total meat, fish, and poultry (r = +0.43; P < 0.0001). Those consuming a low-fat vegan diet also increased their intake of carbohydrates, fiber, and several micronutrients and decreased fat intake. Reduced fat intake was associated with reduced body weight (r = +0.15; P = 0.02) and, after adjustment for changes in BMI and energy intake, with reduced fat mass (r = +0.14; P = 0.04). The intervention group’s AHEI-2010 increased by 6.0 points on average, in contrast to no significant change in the control group (treatment effect, +7.2 [95% CI +3.7 to +10.7]; P < 0.001). Increase in AHEI-2010 correlated with reduction in body weight (r = 0.14; P = 0.04), fat mass (r = −0.14; P = 0.03), and insulin resistance as measured by the Homeostasis Model Assessment (HOMA-IR; r = −0.17; P = 0.02), after adjustment for changes in energy intake. ConclusionsWhen compared with participants’ usual diets, intake of plant foods increased, and consumption of animal foods, nuts and seeds, and added fats decreased on a low-fat vegan diet. Increased legume intake was the best single food group predictor of weight loss. Diet quality as measured by AHEI-2010 improved on the low-fat vegan diet, which was associated with improvements in weight and metabolic outcomes. These data suggest that increasing low-fat plant foods and minimizing high-fat and animal foods is associated with decreased body weight and fat loss, and that a low-fat vegan diet can improve measures of diet quality and metabolic health.

No effect of resveratrol supplementation after 6 months on insulin sensitivity in overweight adults: a randomized trial

ABSTRACTBackgroundEffects of resveratrol on metabolic health have been studied in several short-term human clinical trials, with conflicting results. Next to dose, the duration of the clinical trials may explain the lack of effect in some studies, but long-term studies are still limited.ObjectivesThe objective of this study was to investigate the effects of 6-mo resveratrol supplementation on metabolic health outcome parameters.MethodsForty-one overweight men and women (BMI: 27–35 kg/m2; aged 40–70 y) completed the study. In this parallel-group, double-blind clinical trial, participants were randomized to receive either 150 mg/d of resveratrol (n = 20) or placebo (n = 21) for 6 mo. The primary outcome of the study was insulin sensitivity, using the Matsuda index. Secondary outcome measures were intrahepatic lipid (IHL) content, body composition, resting energy metabolism, blood pressure, plasma markers, physical performance, quality of life, and quality of sleep. Postintervention differences between the resveratrol and placebo arms were evaluated by ANCOVA adjusting for corresponding preintervention variables.ResultsPreintervention, no differences were observed between the 2 treatment arms. Insulin sensitivity was not affected after 6 mo of resveratrol treatment (adjusted mean Matsuda index: 5.18 ± 0.35 in the resveratrol arm compared with 5.50 ± 0.34 in the placebo arm), although there was a significant difference in postintervention glycated hemoglobin (HbA1c) between the arms (P = 0.007). The adjusted means showed that postintervention HbA1c was lower on resveratrol (35.8 ± 0.43 mmol/mol) compared with placebo (37.6 ± 0.44 mmol/mol). No postintervention differences were found in IHL, body composition, blood pressure, energy metabolism, physical performance, or quality of life and sleep between treatment arms.ConclusionsAfter 6 mo of resveratrol supplementation, insulin sensitivity was unaffected in the resveratrol arm compared with the placebo arm. Nonetheless, HbA1c was lower in overweight men and women in the resveratrol arm. This trial was registered at Clinicaltrials.gov as NCT02565979.

Effects of a Low-Fat Vegan Diet on Gut Microbiota in Overweight Individuals and Relationships with Body Weight, Body Composition, and Insulin Sensitivity. A Randomized Clinical Trial.

Diet modulates gut microbiota and plays an important role in human health. The aim of this study was to test the effect of a low-fat vegan diet on gut microbiota and its association with weight, body composition, and insulin resistance in overweight men and women. We enrolled 168 participants and randomly assigned them to a vegan (n = 84) or a control group (n = 84) for 16 weeks. Of these, 115 returned all gut microbiome samples. Gut microbiota composition was assessed using uBiome Explorer™ kits. Body composition was measured using dual energy X-ray absorptiometry. Insulin sensitivity was quantified with the predicted clamp-derived insulin sensitivity index from a standard meal test. Repeated measure ANOVA was used for statistical analysis. Body weight decreased in the vegan group (treatment effect −5.9 kg [95% CI, −7.0 to −4.9 kg]; p < 0.001), mainly due to a reduction in fat mass (−3.9 kg [95% CI, −4.6 to −3.1 kg]; p < 0.001) and in visceral fat (−240 cm3 [95% CI, −345 to −135 kg]; p < 0.001). PREDIcted M, insulin sensitivity index (PREDIM) increased in the vegan group (treatment effect +0.83 [95% CI, +0.48 to +1.2]; p < 0.001). The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (+5.1% [95% CI, +2.4 to +7.9%]; p < 0.001) and correlated negatively with changes in weight (r = −0.24; p = 0.01), fat mass (r = −0.22; p = 0.02), and visceral fat (r = −0.20; p = 0.03). The relative abundance of Bacteroides fragilis decreased in both groups, but less in the vegan group, making the treatment effect positive (+18.9% [95% CI, +14.2 to +23.7%]; p < 0.001), which correlated negatively with changes in weight (r = −0.44; p < 0.001), fat mass (r = −0.43; p < 0.001), and visceral fat (r = −0.28; p = 0.003) and positively with PREDIM (r = 0.36; p < 0.001), so a smaller reduction in Bacteroides fragilis was associated with a greater loss of body weight, fat mass, visceral fat, and a greater increase in insulin sensitivity. A low-fat vegan diet induced significant changes in gut microbiota, which were related to changes in weight, body composition, and insulin sensitivity in overweight adults, suggesting a potential use in clinical practice.

756-P: Changes in Gut Microbiota in Response to a Plant-Based Diet Are Related to Changes in Weight, Body Composition, and Insulin Sensitivity: A 16-Week Randomized Clinical Trial

Background: This study tested the effect of a 16-week plant-based diet on gut microbiota composition, body weight, body composition, and insulin resistance in overweight adults with no history of diabetes. Methods: Participants (n=148) were randomized to follow a low-fat vegan diet (n=73) or to make no diet changes (n=75) for 16 weeks. At baseline and 16 weeks, gut microbiota composition was assessed, using uBiome kits. Dual energy X-ray absorptiometry was used to measure body composition. PREDIM index was used to assess insulin sensitivity. Repeated measure ANOVA was used for statistical analysis. Results: Body weight was reduced significantly in the vegan group (treatment effect -5.8 kg [95% CI, -6.9 to -4.7 kg]; p&amp;lt;0.001), particularly due to a reduction in fat mass (treatment effect -3.9 kg [95% CI, -4.6 to -3.1 kg]; p&amp;lt;0.001) and in visceral fat (treatment effect -172 cm3 [95% CI, -308 to -37 kg]; p=0.01). PREDIM increased significantly (p&amp;lt;0.001) in the vegan group (treatment effect +0.88 [95% CI, +0.5 to +1.2]; p&amp;lt;0.001). The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (treatment effect +4.8% [95% CI, +1.97 to +7.58%]; p=0.001). Relative changes in Faecalibacterium prausnitzii correlated negatively with changes in body weight (r=-0.26; p=0.008), fat mass (r=-0.26; p=0.008), and visceral fat (r=-0.25; p=0.01). The relative abundance of Bacteoides fragilis increased in the vegan group (treatment effect +19.5% [95% CI, +14.7 to +24.3%]; p&amp;lt;0.001). Relative changes in Bacteroides Fragilis correlated negatively with changes in body weight (r=-0.48; p&amp;lt;0.001), fat mass (r=-0.48; p&amp;lt;0.001), visceral fat (r=-0.24; p=0.02), and positively with changes in PREDIM (r=0.36; p=0.0004). Conclusions: A 16-week low-fat vegan dietary intervention induced changes in gut microbiota that were related to changes in weight, body composition and insulin sensitivity in overweight adults. Disclosure H. Kahleova: None. A. Tura: None. N. Barnard: None. Funding Physicians Committee for Responsible Medicine

Effects of low doses of fish and milk proteins on glucose regulation and markers of insulin sensitivity in overweight adults: a randomised, double blind study.

To examine whether supplementation with low doses of fish or milk proteins would affect glucose regulation and circulating lipid concentrations in overweight healthy adults. Ninety-three overweight adults were assigned to receive 2.5g protein/day from herring (HER), salmon (SAL), cod (COD) or milk (CAS, a casein-whey mixture as positive control) as tablets for 8weeks. Seventy-seven participants were included in the analyses. HER and SAL did not affect glucose and insulin concentrations. COD significantly reduced within-group changes in 90 and 120min postprandial glucose concentrations but changes were not different from HER and SAL groups. CAS supplementation significantly reduced the area under the curve for glucose concentrations (- 7%), especially when compared to SAL group, and reduced postprandial insulin c-peptide concentration (- 23%). Reductions in acetoacetate (- 24%) and β-hydroxybutyrate (- 29%) serum concentrations in HER group were more prominent compared to SAL and COD groups, with no differences between fish protein groups for α-hydroxybutyrate. Serum concentrations of α-hydroxybutyrate (- 23%), acetoacetate (- 39%) and β-hydroxybutyrate (- 40%) were significantly reduced within CAS group, and the decreases were significantly more pronounced when compared to SAL group. Serum lipid concentrations were not altered in any of the intervention groups. Findings indicate that 2.5g/day of proteins from fish or milk may be sufficient to improve glucose regulation in overweight adults. The effects were most pronounced after supplementation with proteins from cod, herring and milk, whereas salmon protein did not affect any of the measurements related to glucose regulation. This trial was registered at clinicaltrials.gov as NCT01641055.

Effects of Exercise Training and Weight Loss on Plasma Fetuin-A Levels and Insulin Sensitivity in Overweight Older Men

Aerobic exercise training and weight loss (AEX+WL) improves insulin sensitivity in overweight adults; however, the underlying pathways are incompletely understood. Fetuin-A, a hepatokine that inhibits insulin signaling, may be involved in the salutary effects of AEX+WL. Therefore, we examined the effects of 6-month AEX+WL on plasma fetuin-A levels (36–48 hours after the last bout of exercise), aerobic capacity (VO2max), body composition, glucose tolerance, and insulin sensitivity (M) in 16 sedentary, overweight-obese older men (age = 60 ± 2 years, BMI = 31 ± 1 kg/m2) with no history of cardiovascular disease or diabetes. At baseline, fetuin-A levels correlated directly with adiposity and had a borderline inverse correlation with M. After AEX+WL, body weight decreased by ~10 kg, while both VO2max and M increased by 16% (P < 0.005 for all). Contrary to our hypothesis, plasma fetuin-A levels increased after AEX+WL (1.16 ± 0.10 g/L versus 1.70 ± 0.19 g/L, P = 0.006). This increase was unrelated to changes in body composition or glucose metabolism, but directly correlated with changes in VO2max (r = 0.57, P < 0.05). Thus, in overweight-to-obese older men, AEX+WL appears to increase plasma fetuin-A levels. Although not associated with improvements in insulin sensitivity, this increase in fetuin-A was related to improvements in aerobic capacity and could be representative of the cardioprotective effects of AEX+WL in older men.

Moderate protein intake improves total and regional body composition and insulin sensitivity in overweight adults

A high protein intake (~40% of energy intake) combined with aerobic and resistance exercise training is more closely associated with improved body composition and cardiovascular risk profile than a traditional protein intake (~15% of intake) combined with moderate-intensity aerobic exercise. However, there is concern that such high-protein diets may adversely affect health. We therefore tested the hypothesis that moderate protein intake (~25% of energy intake) would elicit similar benefits on body composition and metabolic profile as high protein intake. Twenty-four overweight/obese men and women (body mass index [BMI] = 32.2 ± 3.4, percentage of body fat [%BF] = 37.3 ± 8.0) were matched for BMI and %BF and randomly assigned to one of 3 groups for a 3-month nutrition/exercise training intervention: (1) high-protein diet (~40% of energy intake) and combined high-intensity resistance and cardiovascular training (HPEx, n = 8, 5 female and 3 male), (2) moderate-protein diet (~25% of energy intake) and combined high-intensity resistance and cardiovascular training (MPEx, n = 8, 5 female and 3 male), or (3) high-protein diet only (HPNx, n = 8, 5 female and 3 male). Total and regional body composition (dual-energy x-ray absorptiometry), insulin sensitivity (insulin sensitivity index to the oral glucose tolerance test), insulin-like growth factor–1 (IGF-1), IGF binding protein–1 (IGFBP-1), IGF binding protein–3 (IGFBP-3), and blood lipids were measured at baseline and after the intervention. All groups experienced significant ( P < .05) and similar losses of body weight, BMI, and total and abdominal %BF, and similar improvements in insulin sensitivity (HPEx, 6.3 ± 1.2 vs 9.5 ± 0.98; MPEx, 6.2 ± 1.4 vs 8.4 ± 1.6; HPNx, 3.7 ± 1.1 vs 7.0 ± 1.1; insulin sensitivity index to the oral glucose tolerance test; P < .05) and leptin levels. Furthermore, the HPEx group demonstrated decreases in total cholesterol (TC) and triglycerides, and increases in IGF-1 and IGFBP-1. The MPEx group experienced decreases in TC, whereas the HPNx group had increases in high-density lipoprotein cholesterol, TC to high-density lipoprotein, IGF-1, and IGFBP-1. In conclusion, moderate protein intake elicits similar benefits in body composition and insulin sensitivity as a high-protein diet. These findings may have practical implications for individuals interested in diets containing elevated dietary protein.