-
1.
Associations between plant-based dietary patterns and risks of type 2 diabetes, cardiovascular disease, cancer, and mortality - a systematic review and meta-analysis.
Wang, Y, Liu, B, Han, H, Hu, Y, Zhu, L, Rimm, EB, Hu, FB, Sun, Q
Nutrition journal. 2023;22(1):46
-
-
-
Free full text
Plain language summary
According to the World Health Organization, type 2 diabetes (T2D), cardiovascular disease (CVD), and cancer account for nearly one in every two deaths globally. These diseases have significant clinical and public health implications. This study's aim was to assess the association of adherence to plant-based dietary patterns and changes in them with risks of major chronic diseases, including T2D, CVD, and cancer, and mortality. This study was a systematic review and meta-analysis of 55 prospective studies. Results showed that greater adherence to a plant-based dietary pattern was inversely associated with risks of T2D, CVD, cancer and all-cause mortality. Associations for T2D, CVD, and cancer were strengthened when the plant-based diets further emphasised healthful plant-based foods, such as vegetables, fruits, whole grains, and legumes. Authors concluded that their findings support the current recommendations that emphasise consuming high-quality plant-based foods for achieving optimal health.
Abstract
BACKGROUND Plant-based dietary patterns are gaining more attention due to their potential in reducing the risk of developing major chronic diseases, including type 2 diabetes (T2D), cardiovascular disease (CVD), cancer, and mortality, while an up-to-date comprehensive quantitative review is lacking. This study aimed to summarize the existing prospective observational evidence on associations between adherence to plant-based dietary patterns and chronic disease outcomes. METHODS We conducted a systematic review and meta-analysis of evidence across prospective observational studies. The data sources used were PubMed and MEDLINE, Embase, Web of Science, and screening of references. We included all prospective observational studies that evaluated the association between adherence to plant-based dietary patterns and incidence of T2D, CVD, cancer, and mortality among adults (≥ 18 years). RESULTS A total of 76 publications were identified, including 2,230,443 participants with 60,718 cases of incident T2D, 157,335 CVD cases, 57,759 cancer cases, and 174,435 deaths. An inverse association was observed between higher adherence to a plant-based dietary pattern and risks of T2D (RR, 0.82 [95% CI: 0.77-0.86]), CVD (0.90 [0.85-0.94]), cancer (0.91 [0.87-0.96]), and all-cause mortality (0.84 [0.78-0.92]) with moderate to high heterogeneity across studies (I2 ranged: 47.8-95.4%). The inverse associations with T2D, CVD and cancer were strengthened when healthy plant-based foods, such as vegetables, fruits, whole grains, and legumes, were emphasized in the definition of plant-based dietary patterns (T2D: 0.79 [0.72-0.87]; CVD: 0.85 [0.80-0.92]; cancer: 0.86 [0.80-0.92]; I2 ranged: 53.1-84.1%). Association for mortality was largely similar when the analyses were restricted to healthy plant-based diets (0.86 [0.80-0.92], I2 = 91.9%). In contrast, unhealthy plant-based diets were positively associated with these disease outcomes. Among four studies that examined changes in dietary patterns, increased adherence to plant-based dietary patterns was associated with a significantly reduced risk of T2D (0.83 [0.71-0.96]; I2 = 71.5%) and a marginally lower risk of mortality (0.95 [0.91-1.00]; I2 = 0%). CONCLUSIONS Better adherence to plant-based dietary patterns, especially those emphasizing healthy plant-based foods, is beneficial for lowering the risks of major chronic conditions, including T2D, CVD, cancer, as well as premature deaths. REGISTRATION OF REVIEW PROTOCOL This review was registered at the PROSPERO International Prospective Register of Systematic Reviews ( https://www.crd.york.ac.uk/PROSPERO/ ) with the registration number CRD42022290202.
-
2.
Sleep-Opt-In: A Randomized Controlled Pilot Study to Improve Sleep and Glycemic Variability in Adults With Type 1 Diabetes.
Martyn-Nemeth, P, Duffecy, J, Quinn, L, Steffen, A, Baron, K, Chapagai, S, Burke, L, Reutrakul, S
The science of diabetes self-management and care. 2023;49(1):11-22
-
-
-
Free full text
-
Plain language summary
Insufficient sleep (insufficient total sleep time) and irregular sleep timing (variability in the occurrence of sleep within a 24-hour period) are increasingly recognized as important contributors to glycaemic control and variability in type 1 diabetes (T1D). The aims of this study were to evaluate the feasibility and acceptability of a sleep intervention (Sleep-Opt-In) targeted for adults with type 1 diabetes with short or irregular sleep and to examine the effects of Sleep-Opt-In on sleep duration and regularity, glucose indices, and patient-reported outcomes. This study was a randomised controlled parallel trial design. Participants (n=14) were randomly assigned to either the Sleep-Opt-In intervention or a Healthy Living attention control group. Results showed that: - Sleep-Opt-In was feasible and acceptable to the target population. - participants with objectively confirmed short or irregular sleep, sleep irregularity improved by 25 minutes on average, whereas sleep duration improved only negligibly (8 minutes). - the control group experienced an increase in sleep duration but no change in sleep regularity. Authors conclude that Sleep-Opt-In is feasible, acceptable, and promising for further evaluation to improve sleep duration or regularity, glucose parameters and important patient reported outcomes of diabetes distress, daytime sleepiness, fatigue and depressive mood in the T1D population.
Abstract
PURPOSE The purpose of this study was to evaluate the feasibility and acceptability of a technology-assisted behavioral sleep intervention (Sleep-Opt-In) and to examine the effects of Sleep-Opt-In on sleep duration and regularity, glucose indices, and patient-reported outcomes. Short sleep duration and irregular sleep schedules are associated with reduced glycemic control and greater glycemic variability. METHODS A randomized controlled parallel-arm pilot study was employed. Adults with type 1 diabetes (n = 14) were recruited from the Midwest and randomized 3:2 to the sleep-optimization (Sleep-Opt-In) or Healthy Living attention control group. Sleep-Opt-In was an 8-week, remotely delivered intervention consisting of digital lessons, sleep tracker, and weekly coaching phone calls by a trained sleep coach. Assessments of sleep (actigraphy), glucose (A1C, continuous glucose monitoring), and patient-reported outcomes (questionnaires for daytime sleepiness, fatigue, diabetes distress, and depressive mood) were completed at baseline and at completion of the intervention. RESULTS Sleep-Opt-In was feasible and acceptable. Those in Sleep-Opt-In with objectively confirmed short or irregular sleep demonstrated an improvement in sleep regularity (25 minutes), reduced glycemic variability (3.2%), and improved time in range (6.9%) compared to the Healthy Living attention control group. Patient-reported outcomes improved only for the Sleep-Opt-In group. Fatigue and depressive mood improved compared to the control. CONCLUSIONS Sleep-Opt-In is feasible, acceptable, and promising for further evaluation as a means to improve sleep duration or regularity in the population of people with type 1 diabetes.
-
3.
Weight Loss and Exercise Differentially Affect Insulin Sensitivity, Body Composition, Cardiorespiratory Fitness, and Muscle Strength in Older Adults With Obesity: A Randomized Controlled Trial.
Brennan, AM, Standley, RA, Anthony, SJ, Grench, KE, Helbling, NL, DeLany, JP, Cornnell, HH, Yi, F, Stefanovic-Racic, M, Toledo, FGS, et al
The journals of gerontology. Series A, Biological sciences and medical sciences. 2022;77(5):1088-1097
-
-
-
Free full text
-
Plain language summary
Aging is marked by increased risk for type 2 diabetes, reduced muscle mass and strength (ie, sarcopenia), decreased physical function and cardiorespiratory fitness, ectopic fat deposition, and insulin resistance all of which increase the risk for physical disability, morbidity, and mortality. These adverse health consequences associated with advanced age are exacerbated with obesity and physical inactivity. The aim of this study was to investigate the effects of weight loss with or without exercise on skeletal muscle insulin sensitivity, exclusively in obese older adults. This study is a 2-site, 6-month randomized controlled trial with a parallel group design. Eighty-six older (60–80 years of age), physically inactive men and women with obesity were randomised into one of the 3 treatments (1:1:1 allocation ratio): control (health education), calorie restriction-induced weight loss, and weight loss with exercise. Results suggest that weight loss via calorie restriction alone is insufficient to significantly improve skeletal muscle insulin sensitivity and requires the addition of exercise to incur benefit, which was also true for clinical measures of insulin resistance including haemoglobin A1C [a blood test that measures the average blood sugar levels over a period of 3 months] and fasting insulin. Authors conclude that regular exercise should be considered as a useful and manageable adjunct to traditional weight loss therapies for older adults with obesity to mitigate risk for chronic disease and maintain functional independence and quality of life.
Abstract
BACKGROUND Aging-related disease risk is exacerbated by obesity and physical inactivity. It is unclear how weight loss and increased activity improve risk in older adults. We aimed to determine the effects of diet-induced weight loss with and without exercise on insulin sensitivity, VO2peak, body composition, and physical function in older obese adults. METHODS Physically inactive older (68.6 ± 4.5 years) obese (body mass index 37.4 ± 4.9 kg/m2) adults were randomized to health education control (HEC; n = 25); diet-induced weight loss (WL; n = 31); or weight loss and exercise (WLEX; n = 28) for 6 months. Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, body composition by dual-energy X-ray absorptiometry and MRI, strength by isokinetic dynamometry, and VO2peak by graded exercise test. RESULTS WLEX improved (p < .05) peripheral insulin sensitivity (+75 ± 103%) versus HEC (+12 ± 67%); WL (+36 ± 47%) versus HEC did not reach statistical significance. WLEX increased VO2peak (+7 ± 12%) versus WL (-2 ± 24%) and prevented reductions in strength and lean mass induced by WL (p < .05). WLEX decreased abdominal adipose tissue (-16 ± 9%) versus HEC (-3 ± 8%) and intermuscular adipose tissue (-15 ± 13%) versus both HEC (+9 ± 15%) and WL (+2 ± 11%; p < .01). CONCLUSIONS Exercise with weight loss improved insulin sensitivity and VO2peak, decreased ectopic fat, and preserved lean mass and strength. Weight loss alone decreased lean mass and strength. Older adults intending to lose weight should perform regular exercise to promote cardiometabolic and functional benefits, which may not occur with calorie restriction-induced weight loss alone.
-
4.
Linoleic Acid-Rich Oil Alters Circulating Cardiolipin Species and Fatty Acid Composition in Adults: A Randomized Controlled Trial.
Cole, RM, Angelotti, A, Sparagna, GC, Ni, A, Belury, MA
Molecular nutrition & food research. 2022;66(15):e2101132
-
-
-
Free full text
-
Plain language summary
Dietary polyunsaturated fatty acid intake is associated with reduced cardiometabolic disease risk. In addition, higher linoleic acid (LA) biomarkers have been associated with a reduced risk for cardiometabolic diseases and conditions. The main aim of this study was to determine whether a modest addition of an oil rich in LA could change the LA content in plasma, erythrocytes, and peripheral blood mononuclear cells (PBMCs). The secondary aim was to determine if the LA-rich oil could alter cardiolipin species in PBMCs. This study is a randomised double-masked placebo-controlled study of 84 participants who were randomly assigned to one of the two groups: either the high-oleate-cookie (n = 42) or LA-cookie groups (n = 42). Results show that dietary supplementation with less than one serving of LA-rich oil per day increases LA in PBMC cardiolipin as well as LA levels. Authors conclude that patients with obesity, cardiometabolic disease, and other conditions related to mitochondrial dysfunction could be a future cohort that should be studied.
Abstract
SCOPE Higher circulating linoleic acid (LA) and muscle-derived tetralinoleoyl-cardiolipin (LA4 CL) are each associated with decreased cardiometabolic disease risk. Mitochondrial dysfunction occurs with low LA4 CL. Whether LA-rich oil fortification can increase LA4 CL in humans is unknown. The aims of this study are to determine whether dietary fortification with LA-rich oil for 2 weeks increases: 1) LA in plasma, erythrocytes, and peripheral blood mononuclear cells (PBMC); and 2) LA4 CL in PBMC in adults. METHODS AND RESULTS In this randomized controlled trial, adults are instructed to consume one cookie per day delivering 10 g grapeseed (LA-cookie, N = 42) or high oleate (OA) safflower (OA-cookie, N = 42) oil. In the LA-cookie group, LA increases in plasma, erythrocyte, and PBMC by 6%, 7%, and 10% respectively. PBMC and erythrocyte OA increase by 7% and 4% in the OA-cookie group but is unchanged in the plasma. PBMC LA4 CL increases (5%) while LA3 OA1 CL decreases (7%) in the LA-cookie group but are unaltered in the OA-cookie group. CONCLUSIONS LA-rich oil fortification increases while OA-oil has no effect on LA4 CL in adults. Because LA-rich oil fortification reduces cardiometabolic disease risk and increases LA4 CL, determining whether mitochondrial dysfunction is repaired through dietary fortification is warranted.
-
5.
Cardiometabolic Risk Factors and Incident Cardiovascular Disease Events in Women vs Men With Type 1 Diabetes.
Braffett, BH, Bebu, I, El Ghormli, L, Cowie, CC, Sivitz, WI, Pop-Busui, R, Larkin, ME, Gubitosi-Klug, RA, Nathan, DM, Lachin, JM, et al
JAMA network open. 2022;5(9):e2230710
-
-
-
Free full text
-
Plain language summary
In the general population, women have a lower absolute risk of cardiovascular disease (CVD) compared with men. However, among individuals with type 1 or type 2 diabetes, the relative risk of CVD is similar or higher in women compared with men. The aim of this study was to assess sex differences in achieving recommended CVD risk management targets and associations with CVD events. This is a cohort study which included a total of 1441 (men n= 736) participants with type 1 diabetes. Results show that the prevalence and mean levels of most cardiometabolic risk factors (except for pulse rate and haemoglobin A1c) were consistent with a less atherogenic profile among women compared with men. Furthermore, achieving treatment targets for blood pressure, lipids, and glucose was associated with significantly decreased risk of CVD in both women and men. Authors conclude that their findings argue for a recalibration of CVD risk factor stratification in revised clinical care guidelines and therapeutic recommendations by sex for individuals with type 1 diabetes.
Abstract
IMPORTANCE The lower risk of cardiovascular disease (CVD) among women compared with men in the general population may be diminished among those with diabetes. OBJECTIVE To evaluate cardiometabolic risk factors and their management in association with CVD events in women vs men with type 1 diabetes enrolled in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study. DESIGN, SETTING, AND PARTICIPANTS This cohort study used data obtained during the combined DCCT (randomized clinical trial, conducted 1983-1993) and EDIC (observational study, conducted 1994 to present) studies through April 30, 2018 (mean [SD] follow-up, 28.8 [5.8] years), at 27 clinical centers in the US and Canada. Data analyses were performed between July 2021 and April 2022. EXPOSURE During the DCCT phase, patients were randomized to intensive vs conventional diabetes therapy. MAIN OUTCOMES AND MEASURES Cardiometabolic risk factors and CVD events were assessed via detailed medical history and focused physical examinations. Blood and urine samples were assayed centrally. CVD events were adjudicated by a review committee. Linear mixed models and Cox proportional hazards models evaluated sex differences in cardiometabolic risk factors and CVD risk over follow-up. RESULTS A total of 1441 participants with type 1 diabetes (mean [SD] age at DCCT baseline, 26.8 [7.1] years; 761 [52.8%] men; 1390 [96.5%] non-Hispanic White) were included. Over the duration of the study, compared with men, women had significantly lower body mass index (BMI, calculated as weight in kilograms divided by height in meters squared; β = -0.43 [SE, 0.16]; P = .006), waist circumference (β = -10.56 cm [SE, 0.52 cm]; P < .001), blood pressure (systolic: β = -5.77 mm Hg [SE, 0.35 mm Hg]; P < .001; diastolic: β = -3.23 mm Hg [SE, 0.26 mm Hg]; P < .001), and triglyceride levels (β = -10.10 mg/dL [SE, 1.98 mg/dL]; P < .001); higher HDL cholesterol levels (β = 9.36 mg/dL [SE, 0.57 mg/dL]; P < .001); and similar LDL cholesterol levels (β = -0.76 mg/dL [SE, 1.22 mg/dL]; P = .53). Women, compared with men, achieved recommended targets more frequently for blood pressure (ie, <130/80 mm Hg: 90.0% vs 77.4%; P < .001) and triglycerides (ie, <150 mg/dL: 97.3% vs 90.5%; P < .001). However, sex-specific HDL cholesterol targets (ie, ≥50 mg/dL for women, ≥40 mg/dL for men) were achieved less often (74.3% vs 86.6%; P < .001) and cardioprotective medications were used less frequently in women than men (ie, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker: 29.6% [95% CI, 25.7%-33.9%] vs 40.0% [95% CI, 36.1%-44.0%]; P = .001; lipid-lowering medication: 25.3% [95% CI, 22.1%-28.7%] vs 39.6% [95% CI, 36.1%-43.2%]; P < .001). Women also had significantly higher pulse rates (mean [SD], 75.2 [6.8] beats per minute vs 71.8 [6.9] beats per minute; P < .001) and hemoglobin A1c levels (mean [SD], 8.3% [1.0%] vs 8.1% [1.0%]; P = .01) and achieved targets for tighter glycemic control less often than men (ie, hemoglobin A1c <7%: 11.2% [95% CI, 9.3%-13.3%] vs 14.0% [95% CI, 12.0%-16.3%]; P = .03). CONCLUSIONS AND RELEVANCE These findings suggest that despite a more favorable cardiometabolic risk factor profile, women with type 1 diabetes did not have a significantly lower CVD event burden than men, suggesting a greater clinical impact of cardiometabolic risk factors in women vs men with diabetes. These findings call for conscientious optimization of the control of CVD risk factors in women with type 1 diabetes.
-
6.
Longitudinal association of dietary carbohydrate quality with visceral fat deposition and other adiposity indicators.
Zamanillo-Campos, R, Chaplin, A, Romaguera, D, Abete, I, Salas-Salvadó, J, Martín, V, Estruch, R, Vidal, J, Ruiz-Canela, M, Babio, N, et al
Clinical nutrition (Edinburgh, Scotland). 2022;41(10):2264-2274
-
-
-
-
Free full text
Plain language summary
Abdominal obesity, measured by waist circumference, a proxy of visceral fat, is increasing at an even greater rate than overall obesity alone. Diet plays a key role in body fat accumulation; however, recent evidence also indicates that, beyond quantity, the quality of certain nutrients may have an independent effect. The aim of this study was to determine the dynamic association between changes in overall dietary carbohydrate quality and changes in objectively measured visceral and overall adiposity distribution This study is a prospective cohort study based on data collected during the first year of the PREDIMED-Plus (PREvencion con DIeta MEDiterranea Plus) randomised controlled trial. In the PREDIMED-Plus trial, a total of 6874 people were randomly allocated in a 1:1 ratio to either the intervention or control group. Results show that a carbohydrate quality index increase was associated with a decrease in regional and overall adiposity. The observed associations were mostly driven by fibre and the wholegrains/total grains ratio. Authors conclude that the promotion of fibre-rich foods, including fruits, vegetables, legumes and nuts, and the substitution of refined grains by wholegrains, may be important dietary recommendations to adopt in clinical practice to promote a healthier body composition.
Expert Review
Conflicts of interest:
None
Take Home Message:
This prospective cohort of older adults with overweight/obesity and MetS, found that improvements in dietary carbohydrate quality over one year was associated with positive changes in visceral and overall fat deposition, largely due to dietary fibre and the wholegrain/total grain ratio.
Evidence Category:
-
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
X
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
Background
Obesity prevalence is increasing worldwide and is associated with a range of metabolic and cardiovascular diseases. Excess visceral fat appears with increasing age but also with unhealthy dietary patterns and lifestyle behaviours, and it contributes to chronic diseases, particularly type 2 diabetes (T2D), insulin resistance, metabolic syndrome (MetS), and cardiovascular diseases (CVD).
Aim
This study determined the association between changes in overall dietary carbohydrate quality and changes in objectively-measured visceral and overall adiposity distribution. Three repeated measurements of diet and adiposity were conducted throughout a 1-year follow-up, using a dual-energy X-ray absorptiometry (DXA) scans for body composition assessment.
The study compared an intensive weight-loss (intervention group) using an energy-reduced Mediterranean Diet (MedDiet), with physical activity (PA), and behavioural support on the prevention of CVD events, compared to usual care and dietary counselling only.
This prospective cohort study analysed a subgroup of 1476 participants (men aged 55-75 years and women aged 60-75 years) enrolled in the PREDIMED-Plus randomized controlled trial. Participants were overweight or obese (BMI>27 kg/m2 and <40 kg/m2) with no previous cardiovascular events and at least three characteristics of metabolic syndrome (MetS): hypertension, hyper-triglyceridemia, lower high-density lipoprotein (HDL) cholesterol, hyperglycemia, or central obesity.
Dietary intake was measured at baseline, 6- and 12-months using a Spanish version of the validated 143-item semi-quantitative food-frequency questionnaire, via face-to-face interviews by trained dietitian-nutritionists. Carbohydrate quality index (CQI) was calculated using four criteria: total dietary fibre, glycemic index, wholegrain/total grain carbohydrate ratio, and solid/total carbohydrate ratio.
Results
Improvements in body composition and lifestyle factors were observed compared to baseline data (both study arms combined) (p < 0.05 for all). A higher Carbohydrate Quality Index CQI (p = 0.024) was observed at both the 6 and 12 month follow-up.
A 3-point increment in CQI over 12-month follow-up was associated with a decrease in visceral fat (β 0.067 z-score, 95% CI -0.088 to -0.046, p<0.001), android-to-gynoid fat ratio* (β -0.038, 95% CI -0.059 to -0.017, p<0.001) (*calculated by dividing the fat mass (g) from the specific regions), and total fat (β -0.064, 95% CI -0.080 to -0.047, p<0.001).
Fibre intake and the ratio of whole grain/total grain showed the strongest inverse associations with all adiposity indicators. Statistically significant differences were observed over time in all CQI components. The most relevant changes were the increase in consumption of carbohydrates from whole-grains and a decrease in refined grains, and an increase in dietary fibre intake. After evaluating each CQI component separately, the study found that fibre intake and the ratio of whole grain/total grain presented the strongest and statistically significant negative associations with all adiposity indicators (all p-values <0.01).
Limitations
Due to the observational nature of the study, causality cannot be inferred. The study population is based on older people with overweight/obesity and MetS from a Mediterranean area, which can limit the generalisability of findings to the general population.
The use of self-reported dietary data is subject to measurement error, where self-reports may be affected by a tendency to respond in a manner to avoid criticism or judgement and to seek social approval.
Clinical practice applications:
Evidence has shown that the quality of dietary carbohydrates, rather than the quantity, may have a greater impact on health and overall mortality.
While visceral fat constitutes only a small proportion of total fat, the available evidence indicates that it plays an important role in certain chronic diseases, such as T2D, MetS, CVD and cancer.
Findings from this study suggest a better CQI via the manipulation of carbohydrate quality may be associated with a decrease in visceral fat, which are independent of changes in total body fat.
Considerations for future research:
Future strategies to decrease visceral fat are warranted.
Robust reference ranges are needed for the interpretation of visceral fat in clinical practice and research settings.
Abstract
BACKGROUND & AIMS The quality of dietary carbohydrates rather than total carbohydrate intake may determine the accumulation of visceral fat; however, to date, few studies have examined the impact of diet on adiposity using specific imaging techniques. Thus, the aim of this prospective study was to investigate the association between concurrent changes in carbohydrate quality index (CQI) and objectively-quantified adiposity distribution over a year. METHODS We analyzed a cohort of 1476 participants aged 55-75 years with overweight/obesity and metabolic syndrome (MetS) from the PREDIMED-Plus randomized controlled trial. Dietary intake information was obtained at baseline, 6- and 12-months from a validated 143-item semi-quantitative food-frequency questionnaire, and CQI (range: 4 to 20) was calculated based on four dietary criteria: total dietary fibre, glycemic index, wholegrain/total grain carbohydrate ratio, and solid/total carbohydrate ratio. Overall and regional adiposity (total body fat, visceral fat and android-to-gynoid fat ratio) was quantified using dual-energy X-ray absorptiometry at all three time points. Multiple adjusted linear mixed-effects models were used to assess associations between concurrent changes in repeatedly measured CQI and adiposity over time. RESULTS After controlling for potential confounding factors, a 3-point increment in CQI over 12-month follow-up was associated with a decrease in visceral fat (β -0.067 z-score, 95% CI -0.088; -0.046, p < 0.001), android-to-gynoid fat ratio (-0.038, -0.059; -0.017, p < 0.001), and total fat (-0.064, -0.080; -0.047, p < 0.001). Fibre intake and the ratio of wholegrain/total grain showed the strongest inverse associations with all adiposity indicators. CONCLUSIONS In this prospective cohort of older adults with overweight/obesity and MetS, we found that improvements in dietary carbohydrate quality over a year were associated with concurrent favorable changes in visceral and overall fat deposition. These associations were mostly driven by dietary fibre and the wholegrain/total grain ratio. TRIAL REGISTRATION The trial was registered at the International Standard Randomized. CONTROLLED TRIAL (ISRCTN http://www.isrctn.com/ISRCTN89898870) with number 89898870 and registration date of 24 July 2014, retrospectively registered.
-
7.
Effect of time restricted eating on body weight and fasting glucose in participants with obesity: results of a randomized, controlled, virtual clinical trial.
Peeke, PM, Greenway, FL, Billes, SK, Zhang, D, Fujioka, K
Nutrition & diabetes. 2021;11(1):6
-
-
-
Free full text
Plain language summary
Time-restricted eating (TRE) has been identified as an effective method of losing weight in the face of rising obesity worldwide. Fasting for at least 12 hours has a beneficial effect on weight management and cardiometabolic health. Overnight fasting longer than 12 hours may result in fat-burning or ketosis. A high-fat, low-protein, low-carbohydrate snack during a 14-hour fast is believed not to raise blood sugar levels and helps with hunger management. This 8-week virtual, pilot, randomised, comparator-controlled clinical trial evaluated the benefits of following a commercial weight loss programme combined with TRE on body weight and fasting blood glucose (FBG) levels. The commercial weight loss programme included calculated calories and macronutrient content in their customised meal plans, as well as coaching and troubleshooting sessions. The participants were randomly assigned to 14-hour fasting (14:10) or 12-hour fasting (control). The 14:10 group also consumed 200 kcal of mixed nuts as a snack at hour 12 to determine the effect on blood glucose levels. After the intervention for 8 weeks, the 14:10 group showed a significant reduction in body weight (11kg) and FBG (8mg/dl), and the 12:12 group significantly lost 9kg of body weight and showed a non-significant reduction in FBG (3mg/dl). Participants with higher baseline FBG levels showed a greater reduction in FBG, indicating potential greater improvements in people with diabetes. A comparison of the two groups did not show a statistically significant difference in intervention effects. A fasting snack at 12 hours did not affect FBG in the 14:10 group, which may help adherence. Due to the exploratory nature of this study, larger robust studies are needed to assess the effectiveness of 14:10 and 12:12 time-restricted fasting regimens with commercial weight loss programmes. However, healthcare professionals can use the results of this study to understand the beneficial effects of different time-restricted fasting regimens on cardiometabolic health.
Abstract
BACKGROUND Time restricted eating (TRE) is an emerging dietary intervention for weight loss that is hypothesized to reinforce the metabolic benefits of nightly fasting/ketosis. This pilot study investigated the effectiveness of a daily 14-h metabolic fast (14:10 TRE beginning after dinner, a "fasting snack" at hour 12, and ending with breakfast 14 h later) combined with a commercial weight management program on body weight and fasting blood glucose (FBG) in individuals with obesity. We also investigated the effect of the low-calorie, high-fat, low-carbohydrate, and low-protein "fasting snack" on blood glucose. METHODS This 8-week, randomized, controlled, clinical trial included men and women (BMI ≥ 30 kg/m2) between June and October 2020. Study procedures were conducted remotely. Participants were randomized to 14:10 or 12-h TRE (12:12, active comparator) and prescribed a diet (controlled for calories and macronutrient composition) and exercise program that included weekly customized counseling and support. The primary outcome was change from baseline in body weight in the 14:10 group. RESULTS Of the 78 randomized participants, 60 (n = 30/group) completed 8 weeks. The LS mean change from baseline in weight in the 14:10 group was -8.5% (95% CI -9.6 to -7.4; P < 0.001) and -7.1% (-8.3 to -5.8; P < 0.001) in the 12:12 group (between group difference -1.4%; -2.7 to -0.2; P < 0.05). There was a statistically significant LS mean change from baseline to week 8 in FBG in the 14:10 group of -7.6 mg/dl (95% CI -15.1 to -0.1; P < 0.05) but not in the 12:12 group (-3.1 mg/dl, -10.0 to 3.7; P = NS). Both interventions resulted in a larger reduction in FBG in participants with elevated FBG (≥100 mg/dl) at baseline (both P < 0.05). CONCLUSIONS In participants with obesity who completed 8 weeks of the 14:10 TRE schedule combined with a commercial weight loss program, there was statistically significant and clinically meaningful weight loss and improvements in FBG.
-
8.
Lipids activate skeletal muscle mitochondrial fission and quality control networks to induce insulin resistance in humans.
Axelrod, CL, Fealy, CE, Erickson, ML, Davuluri, G, Fujioka, H, Dantas, WS, Huang, E, Pergola, K, Mey, JT, King, WT, et al
Metabolism: clinical and experimental. 2021;121:154803
-
-
-
Free full text
-
Plain language summary
Insulin resistance is a key pathophysiological mechanism in the development and progression of type 2 diabetes. Abnormalities in lipid metabolism and ectopic lipid accumulation are known to directly contribute to the onset of insulin resistance. Authors hypothesised that lipid infusion would increase dynamin related protein 1 [a type of protein]-mediated mitochondrial fission in skeletal muscle independent of function and content, consequently reducing peripheral insulin sensitivity. The study included sedentary but otherwise healthy adults who were prospectively randomized to receive either lipid or saline infusion to isolate the direct contribution of fatty acids to skeletal muscle mitochondrial dynamics. Results show that mitochondrial fission and quality control networks are activated in response to lipid infusion which occurs independent of changes in mitochondrial content or capacity and contributes to the onset of insulin resistance in healthy humans. Authors conclude that treatments that limit lipid-induced activation of mitochondrial fission and/or quality control processes may have therapeutic value in the treatment of insulin resistance.
Abstract
BACKGROUND AND AIMS A diminution in skeletal muscle mitochondrial function due to ectopic lipid accumulation and excess nutrient intake is thought to contribute to insulin resistance and the development of type 2 diabetes. However, the functional integrity of mitochondria in insulin-resistant skeletal muscle remains highly controversial. METHODS 19 healthy adults (age:28.4 ± 1.7 years; BMI:22.7 ± 0.3 kg/m2) received an overnight intravenous infusion of lipid (20% Intralipid) or saline followed by a hyperinsulinemic-euglycemic clamp to assess insulin sensitivity using a randomized crossover design. Skeletal muscle biopsies were obtained after the overnight lipid infusion to evaluate activation of mitochondrial dynamics proteins, ex-vivo mitochondrial membrane potential, ex-vivo oxidative phosphorylation and electron transfer capacity, and mitochondrial ultrastructure. RESULTS Overnight lipid infusion increased dynamin related protein 1 (DRP1) phosphorylation at serine 616 and PTEN-induced kinase 1 (PINK1) expression (P = 0.003 and P = 0.008, respectively) in skeletal muscle while reducing mitochondrial membrane potential (P = 0.042). The lipid infusion also increased mitochondrial-associated lipid droplet formation (P = 0.011), the number of dilated cristae, and the presence of autophagic vesicles without altering mitochondrial number or respiratory capacity. Additionally, lipid infusion suppressed peripheral glucose disposal (P = 0.004) and hepatic insulin sensitivity (P = 0.014). CONCLUSIONS These findings indicate that activation of mitochondrial fission and quality control occur early in the onset of insulin resistance in human skeletal muscle. Targeting mitochondrial dynamics and quality control represents a promising new pharmacological approach for treating insulin resistance and type 2 diabetes. CLINICAL TRIAL REGISTRATION NCT02697201, ClinicalTrials.gov.
-
9.
A Single Bout of Premeal Resistance Exercise Improves Postprandial Glucose Metabolism in Obese Men with Prediabetes.
Bittel, AJ, Bittel, DC, Mittendorfer, B, Patterson, BW, Okunade, AL, Abumrad, NA, Reeds, DN, Cade, WT
Medicine and science in sports and exercise. 2021;53(4):694-703
-
-
-
Free full text
-
Plain language summary
Prediabetes is a metabolic condition defined by elevated fasting (impaired fasting glucose) and/or postprandial (impaired glucose tolerance) plasma glucose. The aim of this study was to determine the effects of a single bout of resistance exercise on postprandial glucose metabolism following a mixed meal in obese, sedentary men with prediabetes. This study is a randomised, cross-over study design which enrolled ten participants. Participants were aged 39-62 years, obese, and demonstrated insulin resistance with compensatory increases in beta cell function. Results show that a single bout of resistance exercise performed 4.5 hours before a mixed meal (as opposed to an oral glucose tolerance test) reduced total postprandial glucose appearance, increased insulin sensitivity, and reduced the glycaemic response to a mixed meal. However, it did not have effect on glucose oxidation in obese men with prediabetes. Improvements in insulin sensitivity were complemented by reduced postprandial insulin concentration. Authors conclude that further investigation is needed to elucidate how resistance exercise affects exogenous (meal) vs endogenous postprandial glucose metabolism, and if additional bouts of exercise (i.e. training) produce superior outcomes for this population.
Abstract
INTRODUCTION Prediabetes is a major risk factor for type 2 diabetes and cardiovascular diseases. Although resistance exercise (RE) is recommended for individuals with prediabetes, the effects of RE on postprandial glucose metabolism in this population are poorly understood. Therefore, the purpose of this study was to elucidate how RE affects postprandial glucose kinetics, insulin sensitivity, beta cell function, and glucose oxidation during the subsequent meal in sedentary men with obesity and prediabetes. METHODS We studied 10 sedentary men with obesity (body mass index, 33 ± 3 kg·m-2) and prediabetes by using a randomized, cross-over study design. After an overnight fast, participants completed either a single bout of whole-body RE (seven exercises, 3 sets of 10-12 repetitions at 80% one-repetition maximum each) or an equivalent period of rest. Participants subsequently completed a mixed meal test in conjunction with an intravenous [6,6-2H2]glucose infusion to determine basal and postprandial glucose rate of appearance (Ra) and disappearance (Rd) from plasma, insulin sensitivity, and the insulinogenic index (a measure of beta cell function). Skeletal muscle biopsies were obtained 90 min postmeal to evaluate pyruvate-supported and maximal mitochondrial respiration. Whole-body carbohydrate oxidation was assessed using indirect calorimetry. RESULTS RE significantly reduced the postprandial rise in glucose Ra and plasma glucose concentration. Postprandial insulin sensitivity was significantly greater after RE, whereas postprandial plasma insulin concentration was significantly reduced. RE had no effect on the insulinogenic index, postprandial pyruvate respiration, or carbohydrate oxidation. CONCLUSION/INTERPRETATION A single bout of RE has beneficial effects on postprandial glucose metabolism in men with obesity and prediabetes by increasing postprandial insulin sensitivity, reducing the postprandial rise in glucose Ra, and reducing postprandial plasma insulin concentration.
-
10.
Interaction Between Type 2 Diabetes Prevention Strategies and Genetic Determinants of Coronary Artery Disease on Cardiometabolic Risk Factors.
Merino, J, Jablonski, KA, Mercader, JM, Kahn, SE, Chen, L, Harden, M, Delahanty, LM, Araneta, MRG, Walford, GA, Jacobs, SBR, et al
Diabetes. 2020;69(1):112-120
-
-
-
Free full text
-
Plain language summary
Individual risk of Coronary Artery Disease (CAD) and type 2 diabetes reflects the interplay between lifestyle behaviours acting on a backdrop of genetic predisposition. The aim of this study was to examine whether type 2 diabetes prevention strategies, either an intensive lifestyle intervention (ILS) or metformin treatment (MET), modify the association between CAD genetic risk and cardiometabolic risk factors (CRFs) in participants at high risk of type 2 diabetes. The study is a randomised controlled trial were participants were randomly allocated to one of the three groups; ILS (n = 1,079), MET (850 mg twice daily [n = 1,073]), or placebo (n = 1,082). Results indicate that there weren’t major significant differences in baseline characteristics, except for lower high-density lipoprotein and higher triglyceride in the placebo individuals compared with individuals assigned to MET or ILS. In fact, either an ILS or MET has a beneficial effect on 1-year change in different CRFs. Authors conclude that type 2 diabetes–preventive strategies for individuals at high risk of type 2 diabetes provide beneficial effects on CRFs regardless of CAD genetic risk profile.
Abstract
Coronary artery disease (CAD) is more frequent among individuals with dysglycemia. Preventive interventions for diabetes can improve cardiometabolic risk factors (CRFs), but it is unclear whether the benefits on CRFs are similar for individuals at different genetic risk for CAD. We built a 201-variant polygenic risk score (PRS) for CAD and tested for interaction with diabetes prevention strategies on 1-year changes in CRFs in 2,658 Diabetes Prevention Program (DPP) participants. We also examined whether separate lifestyle behaviors interact with PRS and affect changes in CRFs in each intervention group. Participants in both the lifestyle and metformin interventions had greater improvement in the majority of recognized CRFs compared with placebo (P < 0.001) irrespective of CAD genetic risk (P interaction > 0.05). We detected nominal significant interactions between PRS and dietary quality and physical activity on 1-year change in BMI, fasting glucose, triglycerides, and HDL cholesterol in individuals randomized to metformin or placebo, but none of them achieved the multiple-testing correction for significance. This study confirms that diabetes preventive interventions improve CRFs regardless of CAD genetic risk and delivers hypothesis-generating data on the varying benefit of increasing physical activity and improving diet on intermediate cardiovascular risk factors depending on individual CAD genetic risk profile.