A two-sample Mendelian randomization study explores metabolic profiling of different glycemic traits.

We assessed the causal relation of four glycemic traits and type 2 diabetes liability with 167 metabolites using Mendelian randomization with various sensitivity analyses and a reverse Mendelian randomization analysis. We extracted instruments for fasting glucose, 2-h glucose, fasting insulin, and glycated hemoglobin from the Meta-Analyses of Glucose and Insulin-related traits Consortium (n = 200,622), and those for type 2 diabetes liability from a meta-analysis of multiple cohorts (148,726 cases, 965,732 controls) in Europeans. Outcome data were from summary statistics of 167 metabolites from the UK Biobank (n = 115,078). Fasting glucose and 2-h glucose were not associated with any metabolite. Higher glycated hemoglobin was associated with higher free cholesterol in small low-density lipoprotein. Type 2 diabetes liability and fasting insulin were inversely associated with apolipoprotein A1, total cholines, lipoprotein subfractions in high-density-lipoprotein and intermediate-density lipoproteins, and positively associated with aromatic amino acids. These findings indicate hyperglycemia-independent patterns and highlight the role of insulin in type 2 diabetes development. Further studies should evaluate these glycemic traits in type 2 diabetes diagnosis and clinical management.

Nut and seed consumption is inversely associated with metabolic syndrome in females but not males: findings from the 2005-2018 NHANES data.

PURPOSE: To assess the association between nut and seed consumption, both combined and separately, and metabolic syndrome and its components, including fasting glucose, triglycerides, high-density lipoprotein (HDL) cholesterol, central obesity, and blood pressure. METHODS: This cross-sectional analysis used data from 22,687 adults (aged ≥ 18 years) involved in seven cycles (2005-2018) of the National Health and Nutrition Examination Survey (NHANES). Habitual nut and seed intakes were estimated by the Multiple Source Method using data from two 24-h dietary recalls. Metabolic syndrome was ascertained using biochemical data and self-reported medication use. Sex-specific effect estimates were obtained using logistic and linear regressions adjusting for lifestyle and socioeconomic confounders. RESULTS: Compared to non-consumers, female, but not male, habitual consumers of either nuts or seeds had lower odds of having metabolic syndrome (OR: 0.83, 95% CI 0.71, 0.97). Both nut intake alone and seed intake alone were inversely associated with high fasting glucose and low HDL-cholesterol in females compared to non-consumers. When restricted to habitual consumers only, the combined intake of nuts and seeds at 6 g/day was associated with the lowest triglycerides and highest HDL-cholesterol in females. Combined consumption of nuts and seeds up to one ounce-equivalent (15 g) per day, but not in higher intake levels, was inversely associated with metabolic syndrome, high fasting glucose, central obesity, and low HDL-cholesterol in females. CONCLUSIONS: Nut and seed consumption, both separately or combined, below 15 g/day was inversely associated with metabolic syndrome and its component conditions in females but not males.

Flash Glucose Monitoring Can Accurately Reflect Postprandial Glucose Changes in Healthy Adults in Nutrition Studies.

OBJECTIVE: This study investigated the accuracy of a flash glucose monitoring system (FGMS) in a postprandial setting. METHODS: Ten fasted adults without diabetes wore the FGMS sensors then consumed a standard breakfast. Their glucose levels were subsequently recorded for 2 hours, both by the FGMS and by measuring capillary glucose levels using the glucose oxidase method. The accuracy of the FGMS data was assessed using the accuracy limits stated in ISO 15197:2013. RESULTS: FGMS measurements were mostly lower than glucose oxidase measurements (mean absolute relative difference ± SD: 25.4 ± 17.0%, p < 0.001). However, the maximum difference from baseline captured by the two methods was not significantly different (mean ± SD, glucose oxidase: 58.5 ± 18.9 mg/dl; FGMS, 54.4 ± 28.9 mg/dl, p = 0.366). CONCLUSIONS: FGMS could track the incremental glycaemic excursions after meals in adults without diabetes, yet further studies with greater sample sizes are needed to confirm this finding.

The Association Between Coffee Consumption and Metabolic Syndrome in Adults: A Systematic Review and Meta-Analysis.

Previous meta-analyses that found an inverse association between coffee consumption and metabolic syndrome pooled data from cross-sectional and longitudinal studies, which could lead to potentially misleading conclusions. Hence, this work aimed to reassess this association by analyzing data from the 2 types of studies separately and including recent studies. Online databases including PubMed, Scopus, Embase, The Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus, and Science Direct were searched for relevant studies published up to July 2020. Both cross-sectional and longitudinal studies were included if published after 1999, reported both effect estimates and CIs, and presented results adjusted for confounding variables. Data of the highest coffee consumption level in each study, as well as those of medium consumption levels in studies with ≥3 consumption categories, were pooled using random-effect models, with sex-stratified and sex-adjusted results being analyzed separately. Results were obtained based on data from 13 cross-sectional studies involving 280,803 participants and 2 longitudinal studies involving 17,014 participants. The overall sex-adjusted association of the highest consumption level was not significant (n = 9 studies; OR: 0.88; 95% CI: 0.70, 1.10; I2: 91.5%) and the 2 longitudinal studies both yielded no association. Subgroup analysis revealed inverse associations in both males and females, as well as in Caucasians with medium coffee consumption (n = 4 studies, OR: 0.88; 95% CI: 0.84, 0.93; I2: 0%). Although residual confounding could affect the results of this meta-analysis, our findings suggested with a low certainty that coffee consumption may not be associated with metabolic syndrome, a finding that is different from those of previous meta-analyses and could be due to variation in characteristics of study participants. More longitudinal studies are also needed to further assess the temporal association between coffee consumption and metabolic syndrome. This meta-analysis was registered at https://www.crd.york.ac.uk/prospero as CRD42018110650.

Consuming decaffeinated coffee with milk and sugar added before a high-glycaemic index meal improves postprandial glycaemic and insulinaemic responses in healthy adults.

The present study aimed to compare the effects of drinking different types of coffee before a high-glycaemic index (GI) meal on postprandial glucose metabolism and to assess the effects of adding milk and sugar into coffee. In this randomised, crossover, acute feeding study, apparently healthy adults (n 21) consumed the test drink followed by a high-GI meal in each session. Different types of coffee (espresso, instant, boiled and decaffeinated, all with milk and sugar) and plain water were tested in separate sessions, while a subset of the participants (n 10) completed extra sessions using black coffees. Postprandial levels of glucose, insulin, active glucagon-like peptide 1 (GLP-1) and nitrotyrosine between different test drinks were compared using linear mixed models. Results showed that only preloading decaffeinated coffee with milk and sugar led to significantly lower glucose incremental AUC (iAUC; 14 % lower, P = 0·001) than water. Preloading black coffees led to greater postprandial glucose iAUC than preloading coffees with milk and sugar added (12-35 % smaller, P < 0·05 for all coffee types). Active GLP-1 and nitrotyrosine levels were not significantly different between test drinks. To conclude, preloading decaffeinated coffee with milk and sugar led to a blunted postprandial glycaemic response after a subsequent high-GI meal, while adding milk and sugar into coffee could mitigate the impairment effect of black coffee towards postprandial glucose responses. These findings may partly explain the positive effects of coffee consumption on glucose metabolism.

Is there a soft drink vs. alcohol seesaw? A cross-sectional analysis of dietary data in the Australian Health Survey 2011-12.

PURPOSE: Previous studies in older Australians have reported higher alcohol intake in those with low added sugar intake, yet the relationship between energy in liquid form [alcoholic beverages vs. sugar-sweetened beverages (SSB)] and measures of obesity has not been evaluated. We aimed to assess the association between the energy derived from SSB and alcoholic beverages, and to model the association between the substitution of SSB with alcoholic beverages and waist circumference. METHODS: In this cross-sectional analysis, dietary data from the Australian Health Survey 2011-12 were analyzed. Participants with implausible dietary intake were excluded by applying the Goldberg cut-off. Usual SSB intake of adults ≥ 19 years old was estimated using the Multiple Source Method and participants were classified into zero-, low- or high-SSB consumers according to their usual SSB intake. Energy from alcoholic beverages in the three SSB consumption groups was compared using multivariable general linear models. A substitution model was used to assess the association between the replacement of SSB with alcoholic beverages and waist circumference. RESULTS: Zero-SSB consumers made up 33% of the included participants. In all age groups, zero-SSB consumers had significantly higher energy intakes from alcoholic beverages than low- and high-SSB consumers. Low- and high-SSB consumers had similar consumption of alcoholic beverages. Substituting SSB intake with alcoholic beverage intake was not associated with significant differences in waist circumference in most age groups. CONCLUSIONS: Australian adults who avoid SSB are common but consume substantially more energy in the form of alcoholic beverages. An increase in alcoholic beverage intake could be an 'unintended consequence' of strictly discouraging SSB consumption.