Prevention of type 2 diabetes through lifestyle modification: is there a role for higher-protein diets?

Association of low-carbohydrate diet scores and type 2 diabetes in Chinese rural adults: The Henan Rural Cohort Study

PURPOSE

To investigate the association between low-carbohydrate diet scores (LCDs) and the risk of type 2 diabetes in rural China.

METHODS

A total of 38,100 adults were included in the Henan Rural Cohort Study. Macronutrient intake was assessed via a validated food-frequency questionnaire to create low-carbohydrate diet (LCD) scores. Multivariate logistic regression models and subgroup analysis were performed to estimate the odds ratio (OR) and 95% confidence interval (95% CI).

RESULTS

After multivariable adjustment, participants with a high total low-carbohydrate diet score have a high risk of T2D (extreme-quartile OR = 1.23, 95% CI: 1.04-1.41; P = 0.007), whereas plant-based LCD score is not related to T2D risk. Among individuals with a BMI < 24 (extreme-quartile OR = 1.22, 95% CI: 1.01-1.47; P < 0.001) or high levels of physical activity (extreme-quartile OR = 1.42, 95% CI: 1.17-1.72; P < 0.001), the animal-based LCD score is positively correlated with the risk of T2D.

CONCLUSION

Among Chinese rural populations, high-fat-low carbohydrate diet is associated with an increased risk of type 2 diabetes. High intake of animal protein and fat also increases T2D risk in those who are overweight or have high physical activity.

Intra-pancreatic fat is associated with high circulating glucagon and GLP-1 concentrations following whey protein ingestion in overweight women with impaired fasting glucose: A randomised controlled trial

AIM

Intra-pancreatic fat deposition (IPFD) while hypothesised to impair beta-cell function, its impact on alpha-cells remains unclear. We evaluated the association between IPFD and markers of pancreatic cells function using whey protein.

METHODS

Twenty overweight women with impaired fasting glucose (IFG) and low or high IPFD (<4.66% vs ≥4.66%) consumed 3 beverage treatments: 0 g (water control), 12.5 g (low-dose) and 50.0 g (high-dose) whey protein, after an overnight fast, in randomised order. Blood glucose, insulin, C-peptide, glucagon, gastric-inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and amylin were analysed postprandially over 4 h. Incremental area-under-the-curve (iAUC), incremental maximum concentration (iCmax), and time to maximum concentration (Tmax) for these were compared between IPFD groups using repeated measures linear mixed models, also controlled for age (pcov).

RESULTS

iAUC and iCmax glucose and insulin while similar between the two IPFD groups, high IPFD and ageing contributed to higher postprandial glucagon (iAUC: p = 0.012; pcov = 0.004; iCmax: p = 0.069; pcov = 0.021) and GLP-1 (iAUC: p = 0.006; pcov = 0.064; iCmax: p = 0.011; pcov = 0.122) concentrations.

CONCLUSION

In our cohort, there was no evidence that IPFD impaired protein-induced insulin secretion. Conversely, IPFD may be associated with increased protein-induced glucagon secretion, a novel observation which warrants further investigation into its relevance in the pathogenesis of dysglycaemia and type-2 diabetes.

Gut microbiota profiles in two New Zealand cohorts with overweight and prediabetes: a Tū Ora/PREVIEW comparative study

Obesity-related metabolic diseases such as type 2 diabetes (T2D) are major global health issues, affecting hundreds of millions of people worldwide. The underlying factors are both diverse and complex, incorporating biological as well as cultural considerations. A role for ethnicity - a measure of self-perceived cultural affiliation which encompasses diet, lifestyle and genetic components - in susceptibility to metabolic diseases such as T2D is well established. For example, Asian populations may be disproportionally affected by the adverse 'TOFI' (Thin on the Outside, Fat on the Inside) profile, whereby outwardly lean individuals have increased susceptibility due to excess visceral and ectopic organ fat deposition. A potential link between the gut microbiota and metabolic disease has more recently come under consideration, yet our understanding of the interplay between ethnicity, the microbiota and T2D remains incomplete. We present here a 16S rRNA gene-based comparison of the fecal microbiota of European-ancestry and Chinese-ancestry cohorts with overweight and prediabetes, residing in New Zealand. The cohorts were matched for mean fasting plasma glucose (FPG: mean ± SD, European-ancestry: 6.1 ± 0.4; Chinese-ancestry: 6.0 ± 0.4 mmol/L), a consequence of which was a significantly higher mean body mass index in the European group (BMI: European-ancestry: 37.4 ± 6.8; Chinese-ancestry: 27.7 ± 4.0 kg/m2; p < 0.001). Our findings reveal significant microbiota differences between the two ethnicities, though we cannot determine the underpinning factors. In both cohorts Firmicutes was by far the dominant bacterial phylum (European-ancestry: 93.4 ± 5.5%; Chinese-ancestry: 79.6 ± 10.4% of 16S rRNA gene sequences), with Bacteroidetes and Actinobacteria the next most abundant. Among the more abundant (≥1% overall relative sequence abundance) genus-level taxa, four zero-radius operational taxonomic units (zOTUs) were significantly higher in the European-ancestry cohort, namely members of the Subdoligranulum, Blautia, Ruminoclostridium, and Dorea genera. Differential abundance analysis further identified a number of additional zOTUs to be disproportionately overrepresented across the two ethnicities, with the majority of taxa exhibiting a higher abundance in the Chinese-ancestry cohort. Our findings underscore a potential influence of ethnicity on gut microbiota composition in the context of individuals with overweight and prediabetes.

Associations of percentage energy intake from total, animal and plant protein with overweight/obesity and underweight among adults in Addis Ababa, Ethiopia

OBJECTIVE

This study investigated associations between types and food sources of protein with overweight/obesity and underweight in Ethiopia.

DESIGN

We conducted a cross-sectional dietary survey using a non-quantitative FFQ. Linear regression models were used to assess associations between percentage energy intake from total, animal and plant protein and BMI. Logistic regression models were used to examine the associations of percentage energy intake from total, animal and plant protein and specific protein food sources with underweight and overweight/obesity.

SETTING

Addis Ababa, Ethiopia.

PARTICIPANTS

1624 Ethiopian adults (992 women and 632 men) aged 18-49 years in selected households sampled using multi-stage random sampling from five sub-cities of Addis Ababa.

RESULTS

Of the surveyed adults, 31 % were overweight or obese. The majority of energy intake was from carbohydrate with only 3 % from animal protein. In multivariable-adjusted linear models, BMI was not associated with percentage energy from total, plant or animal protein. Total and animal protein intake were both associated with lower odds of overweight/obesity (OR per 1 % energy increment of total protein 0·92; 95 % CI: 0·86, 0·99; P = 0·02; OR per 1 % energy increment of animal protein 0·89; 95 % CI: 0·82, 0·96; P = 0·004) when substituted for carbohydrate and adjusted for socio-demographic covariates.

CONCLUSION

Increasing proportion of energy intake from total protein or animal protein in place of carbohydrate could be a strategy to address overweight and obesity in Addis Ababa; longitudinal studies are needed to further examine this potential association.

Effects of Quality and Quantity of Protein Intake for Type 2 Diabetes Mellitus Prevention and Metabolic Control

PURPOSE OF REVIEW

The aim of this review is to evaluate the ideal protein quality and quantity and the dietary composition for the prevention and metabolic control of type 2 diabetes mellitus (T2DM).

INTRODUCTION

Although some reviews demonstrate the advantages of a diet with a higher protein intake, other reviews have observed that a diet high in carbohydrates, with low-glycaemic index carbohydrates and good fibre intake, is equally effective in improving insulin sensitivity.

METHODS

Over 2831 articles were screened, and 24 from the last 5 years were analysed and summarised for this review, using the protein, diabetes and insulin glucose metabolic keywords in Pubmed in June 2019.

RESULTS

Eleven studies demonstrate that a higher consumption of proteins has a positive effect on insulin sensitivity. A higher intake of animal protein seems to be related to an increased risk of T2DM. Four studies show that consumption of meat has a deleterious effect. Higher intake of plant protein and dairy products is associated with a modestly reduced risk.

DISCUSSION

Based on the results obtained, for the prevention of T2DM and all disorders related to metabolic syndrome, no ideal dietary composition has yet been found. The advantage of plant protein sources may be related to the foods' low-glycaemic index due to the high fibre content. However, the right protein quality (animal and plant) and the quantity for T2DM prevention and metabolic control are unclear and need to be investigated with further long-term studies.

Evaluation of Nutrition Intervention On Snack's Eating Habits and Anthropometric Status of College Students in Malang City

Background: Problems that arise in students based on the results of the 2016 study indicate that more than 80% of students like to eat unhealthy snacks such as packaging snacks, fried foods, instant noodles, and meatballs. Where snacks contain high energy, carbohydrates, protein, saturated fat, and salt. The excess energy and nutrients intake are related to increasing the metabolic incidence of syndromes and the main risk factors for cardiovascular disease.Objectives: This study aims to determine the effectiveness of giving nutritional interventions to eating habits and anthropometric status of college students in Malang.Methods: The quasi-experimental design with 31 participants from college students in Malang. Nutrition interventions provided in the form of education related to healthy snacks and assistance in making healthy snacks. The instruments used were pretest-posttest, questionnaire, and semi FFQ. Data processing was carried out by descriptive statistical analysis and dependent t-test at a 95% confidence level.Results: There was a significant increase in knowledge related to healthy snacks for subyek penelitiants (p <0.01) indicated by the results of the pre-test and post-test. There was an increase in the influence with nutrition claims by 31% and there was a significant difference between before and after the intervention (p = 0.013). The results of a healthy semi FFQ snack for the fruit category experienced a significant increase after being given an intervention program (p <0.01), while the semi FFQ results for unhealthy snacks for the category of salted crackers, chocolate/candy, pudding, and market snacks tended to decrease in consumption although not significant. The prevalence of overweight and obese in participants before being given intervention was 29% and decreased after being given intervention to 22.6% even though there was no significant difference (p = 0.096).Conclusions: There is an increase in the influence of 'nutrition claims' and fruit consumption significantly. While the prevalence of obese tends to fall even though it is not significant between college students.

Cow's Milk and Dairy Consumption: Is There Now Consensus for Cardiometabolic Health?

Cow's milk and dairy products derived from this complex food source have long been proposed as beneficial to human health, yet underlying clinical evidence of direct benefit continues to raise controversy. Limited evidence supports positive cardiometabolic effects of a number of dairy macro- and micronutrient components including whey protein and casein, unsaturated fats, milk fat globule membrane (MFGM) and polar phospholipids, vitamin D and calcium, in addition to non-bovine components including bacterial and yeast probiotics. More controversial remain lipid components trans fats, including trans vaccenic acid, trans palmitoleic acid, and conjugated cis trans linoleic acid (CLA), plus medium-chain and odd-chain dairy fats. New evidence is rapidly identifying multiple pathways by which these dairy nutrients may effect health. Processing, including fermentation and homogenization, may also have positive effects. Conversely, the high saturated fat content of dairy has long raised concern, aligned with international guidelines to minimize dietary intake of animal-origin saturated fatty acids (SFA) to achieve better cardiometabolic health. However, led in part by observational studies and meta-analyses showing dairy to have no or even an inverse association with cardiometabolic health, evidence from randomized controlled trials (RCTs) has been scrutinized over the last 5 years, and focus on low-fat dairy has been challenged. Recent evidence supports the hypothesis that adverse effects of SFAs on metabolic health may be ameliorated when these fats are consumed within a complex matrix such as milk, cheese or yogurt, and that dairy food categories may influence outcomes as much as total fat content. For example, yogurt and high-fat, high-SFA cheese have a negative association with risk of type 2 diabetes (T2D) in many, not all, published trials. However, large sample dairy RCTs of long duration with CVD or T2D incidence as primary endpoints are lacking. This is a clear research gap, with these clinical studies required if a causative link between dairy and improved cardiometabolic health is to be confirmed and in turn promoted through dietary guidelines. Current advisories from national guidance groups such as American Heart Association (AHA) and European Society of Cardiology (ESC) continue to promote consumption of low-fat dairy products, whilst liquid milk and yogurt remain part of nutrition guidelines from joint American Diabetes Association (ADA)/European Association for Study of Diabetes (EASD) reports, and as part of a “no-one-size-fits-all” answer to diet and T2D by the ADA in their most recent 2019 Consensus Report.

Effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes: a systematic review of randomised controlled trials

The primary aim was to investigate the effects of nut and seed consumption on markers of glucose metabolism in adults with prediabetes. Studies with a randomised controlled trial (RCT) design, comparing the effects of a diet containing nuts or seeds against a diet without nuts or seeds in adults with prediabetes, were considered eligible. Primary outcome measures included fasting plasma glucose (FPG), 2-h plasma glucose during oral glucose tolerance test and glycated Hb (HbA1c) concentrations. Studies were identified by searching PubMed and Scopus electronic databases and by checking full texts and reference lists of relevant records. Risk of bias was assessed using the Cochrane Collaboration's tool. We included five RCT involving 371 adults with prediabetes or at risk of diabetes; three RCT investigated the effects of whole nut consumption and two the effects of ground flaxseed consumption. Consumption of 57 g/d pistachios or mean intake of 60 g/d almonds for 4 months improved FPG and fasting plasma insulin (FPI) concentrations, insulin resistance, cellular glucose uptake in lymphocytes and β-cell function. Consumption of 56 g/d walnuts for 6 months was not found to affect FPG or HbA1c concentrations. Consumption of 13 g/d flaxseed for 3 months improved FPG and FPI concentrations and insulin resistance. In a second study, however, flaxseed consumption was not found to affect markers of glucose metabolism. The risk of bias was generally low, thus the reported results could be reliable. Further investigation of nut and seed consumption effects in the field of prediabetes is warranted.

Development and Validation of Two Self-Reported Tools for Insulin Resistance and Hypertension Risk Assessment in A European Cohort: The Feel4Diabetes-Study

Early identification of type 2 diabetes mellitus (T2DM) and hypertension (HTN) risk may improve prevention and promote public health. Implementation of self-reported scores for risk assessment provides an alternative cost-effective tool. The study aimed to develop and validate two easy-to-apply screening tools identifying high-risk individuals for insulin resistance (IR) and HTN in a European cohort. Sociodemographic, lifestyle, anthropometric and clinical data obtained from 1581 and 1350 adults (baseline data from the Feel4Diabetes-study) were used for the European IR and the European HTN risk assessment index respectively. Body mass index, waist circumference, sex, age, breakfast consumption, alcohol, legumes and sugary drinks intake, physical activity and sedentary behavior were significantly correlated with Homeostatic Model Assessment of IR (HOMA-IR) and/or HTN and incorporated in the two models. For the IR index, the Area Under the Curve (AUC), sensitivity and specificity for identifying individuals above the 75th and 95th of HOMA-IR percentiles were 0.768 (95%CI: 0.721-0.815), 0.720 and 0.691 and 0.828 (95%CI: 0.766-0.890), 0.696 and 0.778 respectively. For the HTN index, the AUC, sensitivity and specificity were 0.778 (95%CI: 0.680-0.876), 0.667 and 0.797. The developed risk assessment tools are easy-to-apply, valid, and low-cost, identifying European adults at high risk for developing T2DM or having HTN.

Strong adherence to dietary and lifestyle recommendations is associated with decreased type 2 diabetes risk in the AusDiab cohort study

We aimed to determine whether adherence to the Australian dietary guidelines and an index of healthy behavior was associated with a lower risk of type 2 diabetes (T2D) and to provide estimates of the proportion of preventable cases. Participants of the AusDiab cohort study were followed for 12 years (n = 6242), starting from May 1999, during which T2D cases were identified. The associations between T2D risk and a score of adherence to the dietary guidelines, its components, and a score of adherence to an index of healthy behaviors, (which included smoking, recreational physical activity, waist circumference and adherence to the dietary guidelines), were estimated using Cox proportional hazards ratios (HR) and 95% confidence intervals. The proportion of preventable cases was estimated using the population attributable fraction (PAF). Strong adherence to the dietary guidelines was not associated with T2D risk (HR = 0.64 [95% CI 0.39-1.06]), unless moderate alcohol consumption was considered as beneficial instead of no alcohol consumption (HR = 0.59 [0.36-0.96]). However, strong adherence to the guidelines regarding fruit and dairy intake were both associated with decreased risk of T2D (HR = 0.68 [0.51-0.91]; 0.56 [0.38-0.84], respectively) and could have prevented 23-37% of cases (PAF = 23.3% [7.3-38.2]; 37.1% [14.6-56.0], respectively). Strong adherence to the index of healthy behaviors was associated with decreased risk of T2D (HR = 0.30 [0.17-0.51]) and estimated to prevent almost 60% of T2D (PAF = 59.4% [34.3-76.6]). More than half of T2D cases could be preventable in Australia through modifying health behavior. These results could serve as a basis for prevention programs based on lifestyle modification.

Protein intake and the incidence of pre-diabetes and diabetes in 4 population-based studies: the PREVIEW project

BACKGROUND

Data on the relationship between protein intake and the risk of type 2 diabetes are conflicting.

OBJECTIVE

We studied prospective associations between the intake of total, plant-based, and animal protein and the risk of pre-diabetes and diabetes in 4 population-based studies included in the PREVIEW project.

METHODS

Analyses were conducted with the use of data from 3 European cohorts and 1 Canadian cohort, including 78,851 participants. Protein intake was assessed through the use of harmonized data from food-frequency questionnaires or 3-d dietary records. Cohort-specific incidence ratios (IRs) were estimated for pre-diabetes and diabetes, adjusting for general characteristics, lifestyle and dietary factors, disease history, and body mass index (BMI) and waist circumference; results were pooled based on a random-effects meta-analysis.

RESULTS

Higher total protein intake (g · kg-1 · d-1) was associated with lower incidences of pre-diabetes and diabetes (pooled IRs: 0.84; 95% CI: 0.82, 0.87 and 0.49; 95% CI: 0.28, 0.83, respectively); plant-based protein intake was the main determinant (pooled IRs: 0.83; 95% CI: 0.81, 0.86 and 0.53; 95% CI: 0.36, 0.76, respectively). Substituting 2 energy percentage (E%) protein at the expense of carbohydrates revealed increased risks of pre-diabetes and diabetes (pooled IRs: 1.04; 95% CI: 1.01, 1.07 and 1.09; 95% CI: 1.01, 1.18, respectively). Except for the associations between intakes of total protein and plant-based protein (g · kg-1 · d-1) and diabetes, all other associations became nonsignificant after adjustment for BMI and waist circumference.

CONCLUSIONS

Higher protein intake (g · kg-1 · d-1) was associated with a lower risk of pre-diabetes and diabetes. Associations were substantially attenuated after adjustments for BMI and waist circumference, which demonstrates a crucial role for adiposity and may account for previous conflicting findings. This study was registered at ISRCTN as ISRCTN31174892.

Unfolding Novel Mechanisms of Polyphenol Flavonoids for Better Glycaemic Control: Targeting Pancreatic Islet Amyloid Polypeptide (IAPP)

Type 2 diabetes (T2D) is characterised by hyperglycaemia resulting from defective insulin secretion, insulin resistance, or both. The impact of over-nutrition and reduced physical activity, evidenced by the exponential rise in obesity and the prevalence of T2D, strongly supports the implementation of lifestyle modification programs. Accordingly, an increased consumption of fruits and plant-derived foods has been advocated, as their intake is inversely correlated with T2D prevalence; this has been attributed, in part, to their contained polyphenolic compounds. Over the last decade, a body of work has focussed on establishing the mechanisms by which polyphenolic compounds exert beneficial effects to limit carbohydrate digestion, enhance insulin-mediated glucose uptake, down-regulate hepatic gluconeogenesis and decrease oxidative stress; the latter anti-oxidative property being the most documented. Novel effects on the inhibition of glucocorticoid action and the suppression of amylin misfolding and aggregation have been identified more recently. Amyloid fibrils form from spontaneously misfolded amylin, depositing in islet cells to elicit apoptosis, beta cell degeneration and decrease insulin secretion, with amyloidosis affecting up to 80% of pancreatic islet cells in T2D. Therefore, intervening with polyphenolic compounds offers a novel approach to suppressing risk or progression to T2D. This review gives an update on the emerging mechanisms related to dietary polyphenol intake for the maintenance of glycaemic control and the prevention of T2D.

A High-Protein Diet Reduces Weight Gain, Decreases Food Intake, Decreases Liver Fat Deposition, and Improves Markers of Muscle Metabolism in Obese Zucker Rats

A primary factor in controlling and preventing obesity is through dietary manipulation. Diets higher in protein have been shown to improve body composition and metabolic health during weight loss. The objective of this study was to examine the effects of a high-protein diet versus a moderate-protein diet on muscle, liver and fat metabolism and glucose regulation using the obese Zucker rat. Twelve-week old, male, Zucker (fa/fa) and lean control (Fa/fa) rats were randomly assigned to either a high-protein (40% energy) or moderate-protein (20% energy) diet for 12 weeks, with a total of four groups: lean 20% protein (L20; n = 8), lean 40% protein (L40; n = 10), obese 20% protein (O20; n = 8), and obese 40% protein (O40; n = 10). At the end of 12 weeks, animals were fasted and euthanized. There was no difference in food intake between L20 and L40. O40 rats gained less weight and had lower food intake (p < 0.05) compared to O20. O40 rats had lower liver weight (p < 0.05) compared to O20. However, O40 rats had higher orexin (p < 0.05) levels compared to L20, L40 and O20. Rats in the L40 and O40 groups had less liver and muscle lipid deposition compared to L20 and L40 diet rats, respectively. O40 had decreased skeletal muscle mechanistic target of rapamycin complex 1 (mTORC1) phosphorylation and peroxisome proliferator-activated receptor gamma (PPARγ) mRNA expression compared to O20 (p < 0.05), with no difference in 5' AMP-activated protein kinase (AMPK), eukaryotic translation initiation factor 4E binding protein 1 (4EBP1), protein kinase B (Akt) or p70 ribosomal S6 kinase (p70S6K) phosphorylation. The data suggest that high-protein diets have the potential to reduce weight gain and alter metabolism, possibly through regulation of an mTORC1-dependent pathway in skeletal muscle.

Intake of different dietary proteins and risk of type 2 diabetes in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

The roles of different dietary proteins in the aetiology of type 2 diabetes (T2D) remain unclear. We investigated the associations of dietary proteins with the risk of incident T2D in Finnish men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study. The study included 2332 men aged 42–60 years at the baseline examinations in 1984–1989. Protein intakes were calculated from 4-d dietary records. Incident T2D was determined by self-administered questionnaires, fasting blood glucose measurements, 2-h oral glucose tolerance tests, and with national registers. The multivariable-adjusted risk of T2D on the basis of protein intakes was compared by the Cox proportional hazard ratios (HR). During the mean follow-up of 19·3 years, 432 incident T2D cases were identified. Total, animal, meat or dairy product protein intakes were not associated with risk of T2D when the potential confounders were accounted for. Plant (multivariable-adjusted extreme-quartile HR 0·65; 95 % CI 0·42, 1·00; Ptrend 0·04) and egg (HR 0·67; 95 % CI 0·44, 1·00; Ptrend 0·03) protein intakes were associated with a decreased risk of T2D. Adjustments for BMI, plasma glucose and serum insulin slightly attenuated associations. Replacing 1 % energy from carbohydrates with energy from protein was associated with a 5 % (95 % CI 0, 11) increased risk of T2D, but adjustment for fibre intake attenuated the association. Replacing 1 % of energy from animal protein with energy from plant protein was associated with 18 % (95 % CI 0, 32) decreased risk of T2D. This association remained after adjusting for BMI. In conclusion, favouring plant and egg proteins appeared to be beneficial in preventing T2D.