Dietary Fat and Risk for Type 2 Diabetes: a Review of Recent Research

Quality and quantity of macronutrients, and their joint associations with the incidence of type 2 diabetes over a nine-year follow-up

BACKGROUND

The association between macronutrient consumption and the risk of type 2 diabetes (T2D) remains equivocal. Here, we investigated whether the quantity and quality of macronutrient intake are associated with T2D incidence in a West Asian population.

METHODS

T2D-free adults (n = 2457, mean age 38.5 ± 13.6 years, 54.2% women) who participated in the third examination cycle (2005-2008) of the Tehran Lipid and Glucose Study were followed for a median of 8.6 years. We estimated the macronutrient quality index (MQI), its individual sub-indices (carbohydrate quality index (CQI), fat quality index (FQI), and healthy plate protein quality index (HPPQI)), as well as the macronutrient quantity. The risk of T2D in relation to macronutrient quantity, quality, and their combined effects was examined using Cox proportional hazard models adjusted for known risk factors for T2D.

RESULTS

During the study follow-up, 257 incident cases of T2D were documented. Individuals in the highest tertiles of MQI and CQI had a 27% (HR = 0.73, 95% CI = 0.54, 0.98) and 29% (HR = 0.71, 95% CI = 0.51-0.99) lower T2D risk than those in the lowest tertiles. The T2D incidence was 35% lower in the middle HPPQI tertile than in the lowest (HR = 0.65, 95% CI = 0.47, 0.89). The multivariable adjusted model showed that individuals in the middle and highest tertiles of carbohydrate intake had 32% (HR = 0.68, 95% CI = 0.49-0.95) and 26% (HR = 0.74, 95% CI = 0.55-1.00) lower risks of T2D than individuals in the lowest tertile. A high-quantity, high-quality carbohydrate diet (≥ 58.5% of energy from carbohydrate with a CQI ≥ 13) and a low-glycemic index (GI), high-fiber diet (GI < 55 and fiber ≥ 25 g/d) were related to a reduced risk of T2D by 34% (HR = 0.66, 95% CI = 0.47, 0.93) and 42% (HR = 0.58, 95% CI = 0.38, 0.90), respectively.

CONCLUSION

A diet with a higher carbohydrate quality may be associated with a lower T2D incidence, particularly when the carbohydrate quantity is also high.

Association between circulating levels of unsaturated fatty acids and risk for prediabetes in the NHANES 2003-2004 and 2011-2012

AIMS

This study aimed to investigate the association between serum levels of common and uncommon unsaturated fatty acids and prediabetes risk.

METHODS

Data were collected from the National Health and Nutrition Examination Survey for 2003-2004 and 2011-2012. Weighted proportional and multivariate logistic regression analyses were performed to assess the association of serum PUFAs and MUFAs with prediabetes risk after adjusting for potential confounders.

RESULTS

A total of 3575 individuals were enrolled in this study. Serum levels of PUFAs EPA (20:5 n3) and GLA (18:3 n6) were associated with increased prediabetes risk (EPA (20:5 n3): OR = 1.878, 95% CI: 1.177-2.996, Ptrend = 0.002; GLA (18:3 n6): 1.702, 95% CI: 1.140-2.541, Ptrend = 0.016). The MUFAs PA (16:1 n7) and EA (20:1 n9) were associated with the risk of prediabetes (OR in quintile5: PA (16:1 n7): 1.780, 95% CI: 1.056-3.001, Ptrend = 0.003; EA (20:1 n9): 0.587, 95% CI: 0.347-0.994, Ptrend = 0.010). Moreover, nonlinear analysis revealed that serum levels of EPA (20:5 n3) and EA (20:1 n-9) were nonlinearly associated with prediabetes risk.

CONCLUSION

Some serum n-3 PUFAs are positively associated with prediabetes, several serum n-6 PUFAs are inversely associated with prediabetes. Regulating individual serum USFA levels may help prevent prediabetes, thereby providing evidence for clinical and nutritional practices.

Association of low carbohydrate diet score with the risk of type 2 diabetes in an Australian population: A longitudinal study

AIMS

We aimed to assess the association of a low carbohydrate diet score (LCD) with the incidence of type 2 diabetes (T2D) using Melbourne Collaborative Cohort Study (MCCS) data.

METHODS

Between 1990 and 1994, the MCCS recruited 41,513 people aged 40-69 years. The first and second follow-ups were conducted in 1995-1998 and 2003-2007, respectively. We analyzed data from 39,185 participants. LCD score was calculated at baseline as the percentage of energy from carbohydrate, fat, and protein. The higher the score the less percentage of carbohydrates contributed to energy intake. The association of LCD quintiles with the incidence of diabetes was assessed using modified Poisson regression, adjusted for lifestyle, obesity, socioeconomic and other confounders. Mediation of the association by adiposity (BMI) was assessed.

RESULTS

LCD was positively associated with diabetes risk. Higher LCD score (p for trend = 0.001) was associated with increased risk of T2D. Quintile 5 (38 % energy from carbohydrates) versus quintile 1 (55 % energy from carbohydrates) showed a 20 % increased diabetes risk (incidence risk ratio (IRR) = 1.20 (95 % CI: 1.05-1.37)). A further adjustment for BMI (Body Mass Index) and WHR (Waist-to-Hip-Ratio) eliminated the association. Mediation analysis demonstrated that BMI mediated 76 % of the LCD & diabetes association.

CONCLUSIONS

Consuming a low carbohydrate diet, reflected as a high LCD score, may increase the risk of T2D which is largely explained by obesity. Results highlight the need for further studies, including clinical trials investigating the effects of a low carbohydrate diet in T2D.

Litchi Pericarp Extract Treats Type 2 Diabetes Mellitus by Regulating Oxidative Stress, Inflammatory Response, and Energy Metabolism

Litchi pericarp is rich in polyphenols, and demonstrates significant biological activity. This study assessed the therapeutic effects of litchi pericarp extract (LPE) on type 2 diabetes mellitus in db/db mice. The results showed that LPE ameliorated symptoms of glucose metabolism disorder, oxidative stress, inflammatory response, and insulin resistance in db/db mice. The mechanistic studies indicated that LPE activates adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and suppresses the protein expression of phosphoenolpyruvate carboxykinase (PEPCK), thereby reducing hepatic gluconeogenesis. Additionally, LPE facilitates the translocation of nuclear factor erythroid2-related factor 2 (Nrf2) into the cell nucleus, initiating the transcription of antioxidant factors superoxide dismutase (SOD) and NAD(P)H: quinone oxidoreductase 1 (NQO1), which alleviate oxidative stress and reduce oxidative damage. Furthermore, LPE blocks nuclear factor kappa-B (NF-κB) nuclear translocation and subsequent inflammatory response initiation, thereby reducing inflammation. These findings indicate that LPE addresses type 2 diabetes mellitus by activating the AMPK energy metabolic pathway and regulating the Nrf2 oxidative stress and NF-κB inflammatory signaling pathways.

Characterizing Factors Associated with Excess Body Weight: A Descriptive Study Using Principal Component Analysis in a Population with Overweight and Obesity

Obesity is a worldwide epidemic, making it crucial to understand how it can be effectively prevented/treated. Considering that obesity is a multifactorial condition, this article carried out a baseline cross-sectional study of the variables involved in the disorder. Eighty-four subjects with overweight/obesity were recruited. Dietary baseline information was obtained by analysing three 24 h recalls. Resting metabolic rate was measured using indirect calorimetry, physical activity was measured through accelerometry, cardiometabolic parameters were determined in blood samples and body composition via anthropometry and bioimpedance. A univariant and multivariate exploratory approach was carried out using principal component analysis (PCA). Large inter-individual variability was observed in dietetic, biochemical, and physical activity measurements (coefficient of variation ≥ 30%), but body composition was more uniform. Volunteers had an unbalanced diet and low levels of physical activity. PCA reduced the 26 analysed variables to 4 factors, accounting for 65.4% of the total data variance. The main factor was the "dietetic factor", responsible for 24.0% of the total variance and mainly related to energy intake, lipids, and saturated fatty acids. The second was the "cardiometabolic factor" (explaining 16.8% of the variability), the third was the "adiposity factor" (15.2%), and the last was the "serum cholesterol factor" (9.4%).

Self-reported engagement in healthy eating behaviors is associated with favorable dietary intake among adults in Puerto Rico

A diet high in quality is essential for prevention of chronic diseases. Specific healthy eating behaviors may modulate dietary intake. However, these behaviors have been seldomly studied, particularly in Puerto Rico (PR), a population with documented poor dietary quality and high burden of chronic diseases. This study aimed to document self-reported engagement in eating behaviors and examine their associations with intake of nutrients and diet quality. We hypothesized that greater engagement in healthy eating behavior would be associated with greater diet quality. This cross-sectional analysis used data from the PRADLAD study (adults aged 30-75 years residing in the San Juan, PR, area [n = 234]). Frequency (never, sometimes, often, always) of habitual eating behaviors was measured. Dietary intake was assessed with a food frequency questionnaire. Diet quality was measured with the Alternate Healthy Eating Index-2010. Statistical analyses included adjusted linear models. The most common behavior was "controlling intake of salt" (51.7%). Engaging "always" (vs. less frequently) in making healthier meals, reading nutrition facts labels, searching media for healthy eating information, counting calories, buying organic foods, eating a vegetarian diet, and controlling intake of salt, fat, carbohydrates/sugar, and portions were associated with higher Alternate Healthy Eating Index-2010 scores (P < .05). Controlling intakes of fats, carbohydrates/sugars, and portions "always" was associated with lower intakes of trans fats, added sugars, and total food (g), respectively (P < .05). Engagement in eating a vegetarian diet "always" was associated with higher intake of plant-based protein (P < .05). In conclusion, adults following several habitual eating behaviors had greater diet quality and a lower amount of unfavorable nutrients. Encouraging adherence to these behaviors may contribute to healthier dietary intake.

Dairy foods and cardiometabolic diseases: an update and a reassessment of the impact of SFA

Type 2 diabetes (T2D) and CVD are major causes of mortality and chronic morbidity. Whilst mortality from CVD has decreased they remain the largest cause of death in Europe and the prevalence of T2D is increasing rapidly. A consistent component of public health advice is to reduce intake of SFA to reduce CVD in particular, which implies limiting dairy food consumption. The prospective studies and randomised controlled trials included in this review show that for dairy foods at least, SFA are not consistently associated with CVD or T2D risk. For CVD the association with dairy foods is generally neutral despite dairy foods being the major source of SFA in many diets. This creates considerable doubt, at least for dairy foods, concerning the validity of the traditional diet-heart hypothesis which positively relates SFA intake to increased serum LDL-cholesterol and subsequent increased CVD. There is now emerging evidence to explain this which is highly relevant to dairy foods. These include the potentially counterbalancing effect of SFA-stimulated HDL-cholesterol and specific food matrix factors. In addition, SFA are associated with the less atherogenic large buoyant LDL particles and possible counterbalancing hypotensive effects of dairy proteins. Overall, dairy foods have either a neutral or beneficial association with CVD and T2D. Beneficial associations are seen for blood pressure and the reduced T2D risk linked to yoghurt consumption, a subject that needs urgent attention given the sharp rise in T2D prevalence in many countries.

Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review

The Western diet is a modern dietary pattern characterized by high intakes of pre-packaged foods, refined grains, red meat, processed meat, high-sugar drinks, candy, sweets, fried foods, conventionally raised animal products, high-fat dairy products, and high-fructose products. The present review aims to describe the effect of the Western pattern diet on the metabolism, inflammation, and antioxidant status; the impact on gut microbiota and mitochondrial fitness; the effect of on cardiovascular health, mental health, and cancer; and the sanitary cost of the Western diet. To achieve this goal, a consensus critical review was conducted using primary sources, such as scientific articles, and secondary sources, including bibliographic indexes, databases, and web pages. Scopus, Embase, Science Direct, Sports Discuss, ResearchGate, and the Web of Science were used to complete the assignment. MeSH-compliant keywords such "Western diet", "inflammation", "metabolic health", "metabolic fitness", "heart disease", "cancer", "oxidative stress", "mental health", and "metabolism" were used. The following exclusion criteria were applied: (i) studies with inappropriate or irrelevant topics, not germane to the review's primary focus; (ii) Ph.D. dissertations, proceedings of conferences, and unpublished studies. This information will allow for a better comprehension of this nutritional behavior and its effect on an individual's metabolism and health, as well as the impact on national sanitary systems. Finally, practical applications derived from this information are made.

Novel approach to investigate the association between type 2 diabetes risk and dietary fats in a dietary pattern context: a scoping review

The effect of dietary fat on type 2 diabetes (T2D) risk is unclear. A posteriori dietary pattern methods have been increasingly used to investigate how dietary fats impact T2D risk. However, the diverse nutrients, foods and dietary patterns reported in these studies requires examination to better understand the role of dietary fats. This scoping review aimed to systematically search and synthesize the literature regarding the association between dietary patterns characterized by dietary fats and T2D risk using reduced rank regression. Medline and Embase were searched for cross-sectional, cohort or case-control studies published in English. Of the included studies (n = 8), five high-fat dietary patterns, mostly high in SFA, were associated with higher T2D risk or fasting glucose, insulin and Homeostasis Model Assessment (HOMA) levels. These were mostly low-fiber (n = 5) and high energy-density (n = 3) dietary patterns characterized by low fruit and vegetables intake, reduced fat dairy products and higher processed meats and butter intake. Findings from this review suggest that a posteriori dietary patterns high in SFA that increase T2D risk are often accompanied by lower fruits, vegetables and other fiber-rich foods intake. Therefore, healthy dietary fats consumption for T2D prevention should be encouraged as part of a healthful dietary pattern.

An Overview of the Potential Medicinal and Pharmaceutical Properties of Ru(II)/(III) Complexes

This review examines the existing knowledge about Ru(II)/(III) ion complexes with a potential application in medicine or pharmacy, which may offer greater potential in cancer chemotherapy than Pt(II) complexes, which are known to cause many side effects. Hence, much attention has been paid to research on cancer cell lines and clinical trials have been undertaken on ruthenium complexes. In addition to their antitumor activity, ruthenium complexes are under evaluation for other diseases, such as type 2 diabetes, Alzheimer's disease and HIV. Attempts are also being made to evaluate ruthenium complexes as potential photosensitizers with polypyridine ligands for use in cancer chemotherapy. The review also briefly examines theoretical approaches to studying the interactions of Ru(II)/Ru(III) complexes with biological receptors, which can facilitate the rational design of ruthenium-based drugs.

The Impact of Free Sugar on Human Health-A Narrative Review

The importance of nutrition in human health has been understood for over a century. However, debate is ongoing regarding the role of added and free sugars in physiological and neurological health. In this narrative review, we have addressed several key issues around this debate and the major health conditions previously associated with sugar. We aim to determine the current evidence regarding the role of free sugars in human health, specifically obesity, diabetes, cardiovascular diseases, cognition, and mood. We also present some predominant theories on mechanisms of action. The findings suggest a negative effect of excessive added sugar consumption on human health and wellbeing. Specific class and source of carbohydrate appears to greatly influence the impact of these macronutrients on health. Further research into individual effects of carbohydrate forms in diverse populations is needed to understand the complex relationship between sugar and health.

Is mushroom polysaccharide extract a better fat replacer than dried mushroom powder for food applications?

Introduction

β-glucans found in the cell walls of mushrooms can be a beneficial food additive in replacing fat in commercial food products.

Methods

Four commonly consumed mushroom species in Singapore, i.e., Pleurotus ostreatus spp., Lentinus edodes, Agaricus bisporus, and Flammulina velutipes were profiled for the β-glucan content in the lyophilized form and ultrasonicated assisted extracted form. Both forms were added into chicken patties, which were characterized for the moisture, cooking loss, texture, color, and chemically analyzed for the protein, crude fat, and fatty acid profiles with gas chromatography mass spectrometry (GC-MS).

Results and discussion

Pleurotus Ostreatus spp. had the highest β-glucan of 29.8 ± 0.7 g/100 g in the pure powder form and 15.9 ± 0.3 g/100 g from the extract. Crude fat in 100% fat substituted patties was lowest in Flammulina velutipes extract enriched patties and least in A. bisporus pure powder patties. Additionally, fat replacement with A. bisporus extract and powder forms resulted in the highest polyunsaturated fatty acid profile of 49.6 ± 1.9 mg/100 g patty and 79.9 ± 4.5 mg/100 g patty, respectively. Chicken patties with added mushroom extract were notable in retaining moisture, cooking yield and its structure. Fat substitution with mushroom powder was also conducted, satisfactory results indicated a possibility as a better fat replacer that is easily processed and an efficient alternative to β-glucan extract. With increasing demand for low fat foods with acceptable organoleptic properties, our study demonstrates that the inclusion of dry mushroom powder has the ability to mimic the "fattiness" of chicken patties.

The association between fatty acid quality indices and quality of life among overweight and obese women: A cross-sectional study

Background

Reduced quality of life (QOL) is a major public health challenge affecting the global population. Fatty acid quality indices (FAQIs) are novel determinants of QOL and may impact various aspects of QOL. Prior research has established a significant link between dietary habits and QOL. However, the association between FAQIs and specific dimensions of QOL has not been established. Therefore, we aimed to investigate the association between FAQIs and QOL in overweight and obese women.

Methods

In total, 378 adult overweight or obese women participated in this cross-sectional study. Several anthropometric indices, systolic and diastolic blood pressure, and biochemical factors were measured using standard protocols. Dietary intake was assessed using a validated and reliable semi-quantitative food frequency questionnaire (the FFQ, 147 items). The cholesterol-saturated fat index (CSI) and the ratio of omega-6/omega-3 (N6/N3) essential fatty acids consumed were employed as FAQIs. The SF-36 questionnaire was administered to measure QOL. Linear logistic regression was used, in the form of raw and adjusted models, to evaluate the associations between FAQIs and QOL.

Results

The study sample consisted of 279 participants for whom ω-6/ω-3 ratio was measured and 378 participants for whom CSI was measured. The mean (±SD) age of participants was 36.65 ± 9.07 years. Linear logistic regression, with adjustment for potential confounders, such as age, energy intake, body mass index, employment, and thyroid status, indicated that ω-6/ω-3 intake ratio was negatively and marginally significantly associated with general health (β = -139.94, 95% CI: [-286.54, 6.66]; p = 0.061) and physical role limitations (β= -337.68, 95% CI: [-679.99, 1.61]; p = 0.051). A significant negative association was observed between ω-6/ω-3 intake ratio and social functioning (β = -247.54, 95% CI: [-458.14, -36.94]; p = 0.021), which indicates that obese and overweight women with a higher ω-6/ω-3 intake ratio obtained lower scores on social functioning.

Conclusions

It was found that FAQI scores were negatively associated with certain QOL measures among overweight and obese Iranian women, suggesting that a higher consumption of fatty acids, especially trans and saturated fatty acids, may be associated with lower QOL.

Diabetes Prevention and Measures to Ensuring a Healthy Lifestyle during COVID-19 Pandemic and after

The incidence of diabetes mellitus (DM) is increasing exponentially globally, with 90% of the confirmed cases being type 2 DM. The global incidence of DM is expected to increase by 48% during 2017-2045. The coronavirus disease 2019 (COVID-19) pandemic continues to have a massive impact on human health, causing sudden lifestyle changes through quarantine measures, such as lockdown, social distancing, various curfews, and isolation at home. This in turn might increase the risk of developing numerous chronic diseases, such as DM, obesity, and cardiovascular diseases, which increase the severity of COVID-19. To this end, we performed a comprehensive review to determine viable measures for the prevention of DM and its subsequent upsurge globally. Additionally, we have determined strategies that should be adopted globally to ensure a healthy lifestyle during the COVID-19 pandemic and later.

Is dietary intake of antioxidant vitamins associated with reduced adverse effects of air pollution on diabetes? Findings from a large cohort study

INTRODUCTION

It remains unknown whether higher dietary intake of antioxidant vitamins could reduce the harmful effects of air pollution on incident diabetes mellitus.

METHODS

A total of 156,490 participants free of diabetes mellitus in the UK Biobank data were included in this analysis. Antioxidant vitamin intake was measured using a 24-h food intake questionnaire, and results were categorized as sufficient or insufficient according to the British Recommended Nutrient Intake. Exposure to fine particles (PM_2.5), thoracic particles (PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxide (NO_x) was estimated using land use regression models at participants' residences. Incident diabetes mellitus was identified using health administrative datasets. Cox regression models were used to assess the associations.

RESULTS

A total of 4271 incident diabetes mellitus cases were identified during a median follow-up of 11.7 years. Compared with participants with insufficient intake of antioxidant vitamins, those with sufficient consumption had a weaker association between air pollution (PM_2.5, PM₁₀ and NO₂) and diabetes mellitus [sufficient vs. insufficient: HR = 1.12 (95 % CI: 0.87, 1.45) vs. 1.69 (95 % CI: 1.42, 2.02) for PM_2.5, 1.00 (95 % CI: 0.88, 1.14) vs. 1.21 (95 % CI: 1.10, 1.34) for PM₁₀, and 1.01 (95 % CI: 0.98, 1.04) vs. 1.05 (95 % CI: 1.03, 1.07) for NO₂ (all p for comparison < 0.05)]. Among different antioxidant vitamins, we observed stronger effects for vitamin C and E.

CONCLUSION

Our study suggests that ambient air pollution is one important risk factor of diabetes mellitus, and sufficient intake of antioxidant vitamins may reduce such adverse effects of air pollution on diabetes mellitus.

Dietary camellia seed oil attenuates liver injury in mice chronically exposed to alcohol

Dietary fat composition is closely associated with the pathological development of alcoholic liver disease (ALD). Fat enriched with saturated fatty acids protects whereas with polyunsaturated fatty acids aggravates alcohol-induced liver injury. However, limited study has addressed how monounsaturated fatty acids (MUFAs) determines the pathological process of ALD. Our study was conducted to evaluate the effect of MUFAs-enriched-camellia seed oil (CSO) on alcohol-induced liver injury. The ALD model was established by feeding C57BL/6 mice with Lieber-DeCarli diet, and with either CSO or polyunsaturated fatty acids (PUFAs)-enriched-corn oil (CO) as fat source. After 4-week-intervention, CSO-feed rescued alcohol-induced liver injury compared to CO-feed, evidenced by measurements of plasma ALT activity, H&E stain, and hepatic cleaved-Caspase-3 expression. Besides, CSO-feed alleviated alcohol-induced oxidative stress, associated with NRF2 and Hif-1α expressions improvement. The reduction of F4/80 immunostaining and the decreased expressions of hepatic TNF-α and IL-6 suggested CSO-feed improved alcohol-induced inflammation. The mechanistic analysis showed that the inhibition of ASK1 and MAPKs might contribute to CSO-protected liver injury. Notably, we observed CSO-feed relieved the gut microbiota disturbance with the decreased Firmicutes and Turicibater, and the increased Bacteroidota, Alloprevotella, and Bacteroides, and reduced circulatory endotoxin level and lipolysis of adipose tissue, which are the known pathogenic factors in alcohol-induced liver injury. Unexpectedly, CSO induced more hepatic steatosis than CO-feed. In conclusion, CSO attenuated chronic alcohol consumption-induced liver injury but enhanced hepatic steatosis. CSO could be a potential dietary choice for alcoholic individuals with liver injury.

Perspectives from healthcare professionals on the nutritional adequacy of plant-based dairy alternatives: results of a mixed methods inquiry

BACKGROUND

Healthcare professionals are important sources of nutrition and health information for Americans. As plant-based (PB) dairy alternative products increase in popularity, concerns have been raised about their nutritional adequacy, and whether consumers understand nutritional differences to dairy. Healthcare professionals directly advise consumers on dietary choices, therefore we sought to examine their understanding and opinions of PB dairy alternatives.

METHODS

We analyzed comments submitted to the U.S. Food and Drug Administration (FDA) by health professionals (n = 191) in 2018-2019 in response to a request for public comment on the nutrition of PB dairy alternatives and the use of dairy terms like "milk", "cheese", and "yogurt" on their labels. Survey data from healthcare professionals (n = 417) was collected in 2020-2021. Comments and survey responses to open-ended questions were coded using template analysis and thematically analyzed. Logistic regression models examined perceptions across health professional characteristics for close-ended survey responses.

RESULTS

Three-fourths of health professionals believe consumers are confused about the nutritional differences between dairy and PB dairy alternatives. Over half (53%) do not believe either product is nutritionally superior to the other. Many believe dairy products have higher nutrient value, but also believe PB dairy alternatives can be part of a healthful diet. Compared to other types of health professionals, dietetics professionals demonstrated a more accurate understanding of the nutritional value of both products and were more likely to believe nutrients like protein (OR 2.02; 95% CI 1.22-3.34, p = 0.006) and vitamin D (OR 2.46; 95% CI 1.48-4.09, p = 0.001) may be nutrients of concern for PB dairy alternative consumers. They were also more likely to believe consumers are confused about these products (OR 3.44; 95% CI 1.65-7.21; p = 0.001). Health professionals who submitted comments to the FDA showed stronger opinions in favor of PB dairy alternatives.

CONCLUSIONS

Although PB dairy alternatives have nutritional value in certain diets, responses from health professionals suggest that changing their labeling to be different than dairy may reduce confusion. Improved nutrition education among health professionals may also be necessary.

High-Fat Nutritional Challenge Reshapes Circadian Signatures in Murine Extraorbital Lacrimal Glands

Purpose

A high-fat diet (HFD) increases the risk of developing many systemic diseases; however, the effects of high fat intake on lacrimal gland functions and the molecular mechanisms underlying these effects are unknown. We explored the effects of an HFD on the circadian rhythms of the extraorbital lacrimal glands (ELGs).

Methods

Male C57BL/6J mice maintained on a 12/12-hour light/dark cycle were fed an ad libitum HFD or normal chow (NC) for 2 weeks. The ELGs were collected from euthanized animals every 3 hours throughout the circadian cycle (24 hours). Using high-throughput RNA-sequencing (RNA-Seq), we studied the circadian transcriptomic profile of the ELGs. Circadian oscillations in cell size, secretion response, lipid deposition, and immune cell trafficking of the ELGs were also analyzed.

Results

An HFD modulated the circadian transcriptomic profile of the ELGs, including the composition, phase, and amplitude of cyclical transcript oscillations, and affected the associated signaling pathways at spatiotemporal levels. HFD feeding significantly altered the normal rhythmic oscillations of ELG cell size, immune cell trafficking, secretion response, and lipid deposition. After dietary reversal in HFD-fed animals, the activity, core temperature, and lipid accumulation in lacrimal glands recovered partially to the level of NC-fed animals. However, the average cell size of the ELGs, the recruitment of immune cells, and the rhythm of lacrimal secretion did not return to the levels of the NC-fed group.

Conclusions

HFD perturbation interferes with the cyclical transcriptomic profile, cell size, immune cell trafficking, and secretion function of the ELGs with a strikingly high sensitivity.

Association between Adherence to the Mediterranean Diet and Risk of Type 2 Diabetes: An Updated Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Despite earlier meta-analyses on the association between adherence to a Mediterranean diet (MD) and risk of diabetes, there is no comprehensive and updated study assessing this issue. Furthermore, no earlier study has examined the nonlinear dose-response relation between consumption of an MD and risk of diabetes. The current systematic review and meta-analysis was conducted to investigate the linear and nonlinear dose-response relation between MD and incidence of diabetes. Using relevant keywords, electronic searches for prospective studies were conducted in ISI Web of Science, PubMed, and Scopus until January 2022. The reported HRs or ORs in the primary studies were regarded as RRs. The overall effect was calculated using a random-effects model that accounts for between-study variability. The potential nonlinear dose-response associations were tested using a 2-stage hierarchical regression model. Based on 16 prospective studies (with 17 effect sizes), we found that the greatest adherence to the MD was significantly associated with a reduced risk of diabetes (pooled RR: 0.83; 95% CI: 0.77, 0.90; I2 = 79%, P ≤ 0.001). Based on linear dose-response analysis, each 1-score increase in the Mediterranean diet score was associated with a 3% decreased risk of diabetes (HR = 0.97; 95% CI: 0.96, 0.98; P < 0.001). A nonlinear relation (P-nonlinearity = 0.001) was also observed between MD score and risk of type 2 diabetes. Even modest adherence to the MD was linked to a decreased incidence of type 2 diabetes. The protocol is also registered in the International Prospective Register Of Systematic Reviews (PROSPERO) database (https://www.crd.york.ac.uk/PROSPERO/; registration ID: CRD 42021265332).

Heart-Healthy Diets and the Cardiometabolic Jackpot

This review highlights the key components of a heart-healthy diet and presents an evidence-based overview of recent research. Diets that increase plant-based food sources and healthy unsaturated fats consumption and limit foods that are processed and/or high in sodium, refined sugar, and saturated fat are recommended. Dietary modification can be supplemented with lifestyle-based therapies (eg, exercise, time-restricted eating) to maximize clinical benefit and achieve the "cardiometabolic jackpot." Physicians should take into account cultural preferences, affordability and accessibility of foods, and their patients' cultural values or expectations when recommending dietary interventions.

Clinical Characteristics of Patients With HNF1-alpha MODY: A Literature Review and Retrospective Chart Review

The clinical manifestation of hepatocyte nuclear factor-1-alpha (HNF1-alpha) maturity-onset diabetes of the young (MODY) is highly variable. This study aims to investigate the clinical characteristics of patients with HNF1-alpha MODY in general, by geographical regions (Asian or non-Asian), HNF1-alpha mutations, and islet autoantibody status. A literature review and a chart review of patients with HNF1-alpha MODY were performed. The means and proportions from studies were pooled using the inverse variance method for pooling, and subgroup analyses were performed. A total of 109 studies involving 1,325 patients [41.5%, 95% confidence interval (CI): 35.2, 48.1; male] were identified. The mean age of diagnosis was 20.3 years (95% CI: 18.3-22.2), and the mean glycated hemoglobin was 7.3% (95% CI: 7.2-7.5). In comparison, Asian patients exhibited significantly higher HbA1c (p = 0.007) and 2-h post-load C-peptide (p = 0.012) levels and lower levels of triglyceride (TG) (p < 0.001), total cholesterol (TC) (p < 0.001), and high-density lipoprotein cholesterol (HDL-c) (p < 0.001) and less often had macrovascular complications (p = 0.014). The age of diagnosis was oldest in patients with mutations in the transactivation domain (p < 0.001). The levels of 2-h post-load C-peptide (p < 0.001), TG (p = 0.007), TC (p = 0.017), and HDL-c (p = 0.001) were highest and the prevalence of diabetic neuropathy was lowest (p = 0.024) in patients with DNA-binding domain mutations. The fasting (p = 0.004) and 2-h post-load glucose (p = 0.003) levels and the prevalence of diabetic neuropathy (p = 0.010) were higher among patients with positive islet autoantibodies. The study demonstrated that the clinical manifestations of HNF1-alpha MODY differed by geographical regions, HNF1-alpha mutations, and islet autoantibody status.

Assessment of Polyunsaturated Fatty Acids on COVID-19-Associated Risk Reduction

Pooled evidence conveys the association between polyunsaturated fatty acids and infectious disease. SARS-CoV-2, an enveloped mRNA virus, was also reported to interact with polyunsaturated fatty acids. The present review explores the possible mode of action, immunology, and consequences of these polyunsaturated fatty acids during the viral infection. Polyunsaturated fatty acids control protein complex formation in lipid rafts associated with the function of two SARS-CoV-2 entry gateways: angiotensin-converting enzyme-2 and cellular protease transmembrane protease serine-2. Therefore, the viral entry can be mitigated by modulating polyunsaturated fatty acids contents in the body. α-Linolenic acid is the precursor of two clinically important eicosanoids eicosapentaenoic acid and docosahexaenoic acid, the members of ω-3 fats. Resolvins, protectins, and maresins derived from docosahexaenoic acid suppress inflammation and augment phagocytosis that lessens microbial loads. Prostaglandins of 3 series, leukotrienes of 5 series, and thromboxane A₃ from eicosapentaenoic acid exhibit anti-inflammatory, vasodilatory, and platelet anti-aggregatory effects that may also contribute to the control of pre-existing pulmonary and cardiac diseases. In contrast, ω-6 linoleic acid-derived arachidonic acid increases the prostaglandin G₂, lipoxins A₄ and B₄, and thromboxane A₂. These cytokines are pro-inflammatory and enhance the immune response but aggravate the COVID-19 severity. Therefore, the rational intake of ω-3-enriched foods or supplements might lessen the complications in COVID-19 and might be a preventive measure.

Graphic Abstract

The association of dietary macronutrients composition with the incidence of type 2 diabetes, using iso-energetic substitution models: Tehran Lipid and Glucose Study

AIMS

There is still controversy on optimal percentage of macronutrient intakes especially carbohydrate on prevention of type 2 diabetes (T2D). The aim of the current study was to evaluate the iso-energetic substitution of dietary macronutrients in relation to incidence of T2D.

METHODS

This prospective study was conducted on 6547 subjects who were followed for 3.0 ± 1.6 years. Dietary intakes were evaluated using a valid and reliable semi-quantitative food frequency questionnaire. Biochemical variables and anthropometrics were evaluated at baseline and follow-up examinations. Multivariate Cox proportional hazard regression models were used to estimate the hazards ratio (HR) of T2D.

RESULTS

A one unit higher proportion of carbohydrate from whole grain at the expense of carbohydrate from non-whole grain (HR = 0.82, 95% CI = 0.71-0.95), protein (HR = 0.75, 95% CI = 0.60-0.94), total fat (HR = 0.79, 95% CI = 0.67-0.93), saturated fatty acid (HR = 0.79, 95% CI = 0.65-0.96), poly-unsaturated fatty acid (HR = 0.81, 95% CI = 0.68-0.96) and mono-unsaturated fatty acid (HR = 0.75, 95% CI = 0.60-0.94) was associated with decreased risk of T2D. The substitution of protein and fats was not associated with diabetes. Risk of T2D increased from quartiles 1-4 for trans-fatty acid (HR: 1.00, 1.27, 0.95, 1.97, P_trend = 0.01).

CONCLUSIONS

A higher proportion of carbohydrate from whole grain in replacement of refined grain, and other macronutrients was associated with decreased risk of T2D. Also our study suggests a positive association between trans-fatty acid intake and risk of T2D.

Effect of dietary fat intake and genetic risk on glucose and insulin-related traits in Brazilian young adults

PURPOSE

The development of metabolic diseases such as type 2 diabetes (T2D) is closely linked to a complex interplay between genetic and dietary factors. The prevalence of abdominal obesity, hyperinsulinemia, dyslipidaemia, and high blood pressure among Brazilian adolescents is increasing and hence, early lifestyle interventions targeting these factors might be an effective strategy to prevent or slow the progression of T2D.

METHODS

We aimed to assess the interaction between dietary and genetic factors on metabolic disease-related traits in 200 healthy Brazilian young adults. Dietary intake was assessed using 3-day food records. Ten metabolic disease-related single nucleotide polymorphisms (SNPs) were used to construct a metabolic-genetic risk score (metabolic-GRS).

RESULTS

We found significant interactions between the metabolic-GRS and total fat intake on fasting insulin level (Pinteraction = 0.017), insulin-glucose ratio (Pinteraction = 0.010) and HOMA-B (Pinteraction = 0.002), respectively, in addition to a borderline GRS-fat intake interaction on HOMA-IR (Pinteraction = 0.051). Within the high-fat intake category [37.98 ± 3.39% of total energy intake (TEI)], individuals with ≥ 5 risk alleles had increased fasting insulin level (P = 0.021), insulin-glucose ratio (P = 0.010), HOMA-B (P = 0.001) and HOMA-IR (P = 0.053) than those with < 5 risk alleles.

CONCLUSION

Our study has demonstrated a novel GRS-fat intake interaction in young Brazilian adults, where individuals with higher genetic risk and fat intake had increased glucose and insulin-related traits than those with lower genetic risk. Large intervention and follow-up studies with an objective assessment of dietary factors are needed to confirm our findings.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40200-021-00863-7.

Revisiting the contribution of mitochondrial biology to the pathophysiology of skeletal muscle insulin resistance

While the etiology of type 2 diabetes is multifaceted, the induction of insulin resistance in skeletal muscle is a key phenomenon, and impairments in insulin signaling in this tissue directly contribute to hyperglycemia. Despite the lack of clarity regarding the specific mechanisms whereby insulin signaling is impaired, the key role of a high lipid environment within skeletal muscle has been recognized for decades. Many of the proposed mechanisms leading to the attenuation of insulin signaling - namely the accumulation of reactive lipids and the pathological production of reactive oxygen species (ROS), appear to rely on this high lipid environment. Mitochondrial biology is a central component to these processes, as these organelles are almost exclusively responsible for the oxidation and metabolism of lipids within skeletal muscle and are a primary source of ROS production. Classic studies have suggested that reductions in skeletal muscle mitochondrial content and/or function contribute to lipid-induced insulin resistance; however, in recent years the role of mitochondria in the pathophysiology of insulin resistance has been gradually re-evaluated to consider the biological effects of alterations in mitochondrial content. In this respect, while reductions in mitochondrial content are not required for the induction of insulin resistance, mechanisms that increase mitochondrial content are thought to enhance mitochondrial substrate sensitivity and submaximal adenosine diphosphate (ADP) kinetics. Thus, this review will describe the central role of a high lipid environment in the pathophysiology of insulin resistance, and present both classic and contemporary views of how mitochondrial biology contributes to insulin resistance in skeletal muscle.

Dietary Patterns Characterized by Fat Type in Association with Obesity and Type 2 Diabetes: A Longitudinal Study of UK Biobank Participants

BACKGROUND

The fat type consumed is considered a risk factor for developing obesity and type 2 diabetes (T2D). However, these associations have not been investigated using a dietary patterns approach, which can capture combinations of foods and fat type consumed.

OBJECTIVES

This study aimed to investigate associations between dietary patterns with varying proportions of SFAs, MUFAs, or PUFAs and obesity, abdominal obesity, and self-reported T2D incidence.

METHODS

This study included UK Biobank participants with 2 or more 24-h dietary assessments, free from the outcome of interest at recruitment, and with outcome data at follow-up (n = 16,523; mean follow-up: 6.3 y). Reduced rank regression was used to derive dietary patterns with SFAs, MUFAs, and PUFAs (% of energy intake) as response variables. Logistic regression, adjusted for sociodemographic and health characteristics, was used to investigate the associations between dietary patterns and obesity [BMI (kg/m2) ≥30], abdominal obesity (waist circumference; men: ≥102 cm; women: ≥88 cm) and T2D incidence.

RESULTS

Two dietary patterns, DP1 and DP2, were identified: DP1 positively correlated with SFAs (r = 0.48), MUFAs (r = 0.67), and PUFAs (r = 0.56), characterized by higher intake of nuts, seeds, and butter and lower intake of fruit and low-fat yogurt; DP2 positively correlated with SFAs (r = 0.76) and negatively with PUFAs (r = -0.64) and MUFAs (r = -0.01), characterized by higher intake of butter and high-fat cheese and lower intake of nuts and seeds. Only DP2 was associated with higher obesity and abdominal obesity incidence (OR: 1.24; 95% CI: 1.02, 1.45; and OR: 1.19; 95% CI: 1.02, 1.38, respectively). Neither of the dietary patterns was associated with T2D incidence.

CONCLUSIONS

These findings provide evidence that a dietary pattern characterized by higher SFA and lower PUFA foods is associated with obesity and abdominal obesity incidence, but not T2D.

The relationship between lifestyle and metabolic evaluation in women with a history of gestational diabetes

BACKGROUND

Gestational diabetes is one of the most common metabolic diseases during pregnancy. The risk of a lifestyle role in the prevention of metabolic syndrome in women with a history of gestational diabetes has now been identified. The present study was performed to investigate the relationship between lifestyle and metabolic syndrome in women with a history of gestational diabetes.

MATERIALS AND METHODS

The present study was a retrospective case-control study that was performed on 90 women (45 women with a history of gestational diabetes and 45 women without a history of gestational diabetes) in Kerman health centers 5 years after delivery in 2020. Data were collected using a demographic questionnaire and a standardized Walker lifestyle Health promoting Lifestyle profile II questionnaire. The reference laboratory was also used to perform the experiments. SPSS21 software and Spearman's and Chi-square tests were used to analyze the data.

RESULTS

The mean age was 35.67 in the case group and 34.27 in the control group (P = 0.230). Lifestyle did not show any difference between the two groups (P = 0.058). However, metabolic evaluation was different in the two groups (P = 0.030). Furthermore, the results of Spearman's test to examine the relationship between lifestyle and other variables studied showed that in the case group (P = 0.075) and in the control group (P = 0.819) there was no relationship between lifestyle and metabolic assessments 5 years after delivery.

CONCLUSIONS

In case group women, it is possible to prevent the progression to type 2 diabetes and disturb the metabolic assessment by teaching a healthy lifestyle and timely follow-up after delivery. A history of gestational diabetes can be one of the causes of type 2 diabetes and metabolic syndrome. Getting training to change your lifestyle during pregnancy and postpartum can reduce the incidence of gestational diabetes and type 2 diabetes. Screening pregnant women during childbirth is a good opportunity to diagnose diabetes early and predict it in the coming years.

Nutritional management of type 2 diabetes in subjects with obesity: an international guideline for clinical practice

Type 2 diabetes mellitus (T2DM) and obesity represent a global public health problem. Current nutritional recommendations focused on weight loss and overall dietary quality. However, there is no consensus on the optimal macronutrient composition of the diet, particularly for the long-term management of T2DM in subjects with obesity. An international panel of experts reviewed and critically appraised the updated literature published on the topic. This review primarily examines the evidence for areas of consensus and uncertainty about nutritional therapy in patients with T2DM and obesity. The aim of this article is to provide nutritional advice to manage these patients in clinical practice.

Metabolite patterns link diet, obesity, and type 2 diabetes in a Hispanic population

INTRODUCTION

Obesity is a precursor of type 2 diabetes (T2D).

OBJECTIVES

Our aim was to identify metabolic signatures of T2D and dietary factors unique to obesity.

METHODS

We examined a subsample of the Boston Puerto Rican Health Study (BPRHS) population with a high prevalence of obesity and T2D at baseline (n = 806) and participants (without T2D at baseline) at 5-year follow-up (n = 412). We determined differences in metabolite profiles between T2D and non-T2D participants of the whole sample and according to abdominal obesity status. Enrichment analysis was performed to identify metabolic pathways that were over-represented by metabolites that differed between T2D and non-T2D participants. T2D-associated metabolites unique to obesity were examined for correlation with dietary food groups to understand metabolic links between dietary intake and T2D risk. False Discovery Rate method was used to correct for multiple testing.

RESULTS

Of 526 targeted metabolites, 179 differed between T2D and non-T2D in the whole sample, 64 in non-obese participants and 120 unique to participants with abdominal obesity. Twenty-four of 120 metabolites were replicated and were associated with T2D incidence at 5-year follow-up. Enrichment analysis pointed to three metabolic pathways that were overrepresented in obesity-associated T2D: phosphatidylethanolamine (PE), long-chain fatty acids, and glutamate metabolism. Elevated intakes of three food groups, energy-dense takeout food, dairy intake and sugar-sweetened beverages, associated with 13 metabolites represented by the three pathways.

CONCLUSION

Metabolic signatures of lipid and glutamate metabolism link obesity to T2D, in parallel with increased intake of dairy and sugar-sweetened beverages, thereby providing insight into the relationship between dietary habits and T2D risk.

Dose-Responses Relationship in Glucose Lowering and Gut Dysbiosis to Saskatoon Berry Powder Supplementation in High Fat-High Sucrose Diet-Induced Insulin Resistant Mice

Administration of freeze-dried powder of Saskatoon berry (SB), a popular fruit enriched with antioxidants, reduced glucose level, inflammatory markers and gut microbiota disorder in high fat-high sucrose (HFHS) diet-induced insulin resistant mice. The present study examined the dose-response relationship in metabolic, inflammatory and gut microbiotic variables to SB power (SBp) supplementation in HFHS diet-fed mice. Male C57 BL/6J mice were fed with HFHS diet supplemented with 0, 1%, 2.5% or 5% SBp for 11 weeks. HFHS diet significantly increased the levels of fast plasma glucose (FPG), cholesterol, triglycerides, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), tumor necrosis factor-α, monocyte chemotactic protein-1 and plasminogen activator inhibitor-1, but decreased fecal Bacteroidetes phylum bacteria and Muribaculaceae family bacteria compared to low fat diet. SBp dose-dependently reduced metabolic and inflammatory variables and gut dysbiosis in mice compared with mice receiving HFHS diet alone. Significant attenuation of HFHS diet-induced biochemical disorders were detected in mice receiving ≥1% SBp. The abundances of Muribaculaceae family bacteria negatively correlated with body weights, FPG, lipids, insulin, HOMA-IR and inflammatory markers in the mice. The results suggest that SBp supplementation dose-dependently attenuated HFHS diet-induced metabolic and inflammatory disorders, which was associated with the amelioration of gut dysbiosis in the mice.

Extent reflecting overall dietary amino acids composition adherence to the human requirement amino acids pattern is associated with the development of type 2 diabetes

This study aimed to elucidate whether dietary amino acids (AAs) composition is associated with type 2 diabetes mellitus (T2DM) and to investigate how serum AAs profiles mediated this association. Two prospective cohorts of 1750 and 4024 adults were enrolled. Dietary AAs compositions index (AACI) was developed to reflect the overall quality of dietary AAs composition. Multivariate linear regression and logistic regression models were used to examine associations of AACI and T2DM. The AACI was associated with the incidence of T2DM with the relative risk and 95%CI from the bottom to the top tertiles being 1.00, 1.49 (0.88-2.51) and 2.27 (1.20-4.28), and 1.00, 1.58 (1.13-2.19) and 2.33 (1.56-3.47) in the two cohorts, respectively. The AACI was positively associated with serum valine, isoleucine, glutamic acid and phenylalanine, and it was negatively associated with serum glycine and histidine in both cohorts (P<0.01). Valine, glutamic acid and histidine consistently and partially mediated the association between the AACI and T2DM in the two cohorts, with total mediation effects of 33.4% and 54.6%, respectively. Dietary AAs composition was associated with the incidence of T2DM, meanwhile, the relationship was mediated by some degree of serum AAs. Future dietary strategies should focus on the improvement of the overall quality of dietary AAs compositions.

Molecular mechanisms of lipotoxicity-induced pancreatic β-cell dysfunction

Type 2 diabetes (T2D), a heterogeneous disorder derived from metabolic dysfunctions, leads to a glucose overflow in the circulation due to both defective insulin secretion and peripheral insulin resistance. One of the critical risk factor for T2D is obesity, which represents a global epidemic that has nearly tripled since 1975. Obesity is characterized by chronically elevated free fatty acid (FFA) levels, which cause deleterious effects on glucose homeostasis referred to as lipotoxicity. Here, we review the physiological FFA roles onto glucose-stimulated insulin secretion (GSIS) and the pathological ones affecting many steps of the mechanisms and modulation of GSIS. We also describe in vitro and in vivo experimental evidences addressing lipotoxicity in β-cells and the role of saturation and chain length of FFA on the potency of GSIS stimulation. The molecular mechanisms underpinning lipotoxic-β-cell dysfunction are also reviewed. Among them, endoplasmic reticulum stress, oxidative stress and mitochondrial dysfunction, inflammation, impaired autophagy and β-cell dedifferentiation. Finally therapeutic strategies for the β-cells dysfunctions such as the use of metformin, glucagon-like peptide 1, thiazolidinediones, anti-inflammatory drugs, chemical chaperones and weight are discussed.

Transient NADPH oxidase 2-dependent H2O2 production drives early palmitate-induced lipotoxicity in pancreatic islets

Modern lifestyles, including lack of physical activity and poor nutritional habits, are driving the rapidly increasing prevalence of obesity and type 2 diabetes. Increased levels of free fatty acids (FFAs), particularly saturated FFAs, in obese individuals have been linked to pancreatic β-cell failure. This process, termed lipotoxicity, involves activation of several stress responses, including ER stress and oxidative stress. However, the molecular underpinnings and causal relationships between the disparate stress responses remain unclear. Here we employed transgenic mice, expressing a genetically-encoded cytosolic H₂O₂ sensor, roGFP2-Orp1, to monitor dynamic changes in H₂O₂ levels in pancreatic islets in response to chronic palmitate exposure. We identified a transient increase in H₂O₂ levels from 4 to 8 h after palmitate addition, which was mirrored by a concomitant decrease in cellular NAD(P)H levels. Intriguingly, islets isolated from NOX2 knock-out mice displayed no H₂O₂ transient upon chronic palmitate treatment. Furthermore, NOX2 knockout rescued palmitate-dependent impairment of insulin secretion, calcium homeostasis and viability. Chemical inhibition of NOX activity protected islets from palmitate-induced impairment in insulin secretion, however had no detectable impact upon the induction of ER stress. In summary, our results reveal that transient NOX2-dependent H₂O₂ production is a likely cause of early palmitate-dependent lipotoxic effects.

Ruthenium compounds as potential therapeutic agents for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder which is globally responsible for millions of fatalities per year. Management of T2DM typically involves orally administered anti-hyperglycaemic drugs in conjunction with dietary interventions. However, the current conventional therapy seems to be largely ineffective as patients continue to develop complications such as cardiovascular diseases, blindness and kidney failure. Existing alternative treatment entails the administration of organic therapeutic pharmaceuticals, but these drugs have various side effects such as nausea, headaches, weight gain, respiratory and liver damage. Transition metal complexes have shown promise as anti-diabetic agents owing to their diverse mechanisms of activity. In particular, selected ruthenium compounds have exhibited intriguing biological behaviours as Protein Tyrosine Phosphatase (PTP) 1B and Glycogen Synthase Kinase 3 (GSK-3) inhibitors, as well as aggregation suppressants for the human islet amyloid polypeptide (hIAPP). This focussed review serves as a survey on studies pertaining to ruthenium compounds as metallo-drugs for T2DM. Herein, we also provide perspectives on directions to fully elucidate in vivo functions of this class of potential metallopharmaceuticals. More specifically, there is still a need to investigate the pharmacokinetics of ruthenium drugs in order to establish their biodistribution patterns which will affirm whether these metal complexes are substitutionally inert or serve as pro-drugs. In addition, embedding oral-administered ruthenium complexes into bio-compatible polymers can be a prospective means of enhancing stability during drug delivery.

Diet-induced rodent models of obesity-related metabolic disorders-A guide to a translational perspective

Diet is a critical element determining human health and diseases, and unbalanced food habits are major risk factors for the development of obesity and related metabolic disorders. Despite technological and pharmacological advances, as well as intensification of awareness campaigns, the prevalence of metabolic disorders worldwide is still increasing. Thus, novel therapeutic approaches with increased efficacy are urgently required, which often depends on cellular and molecular investigations using robust animal models. In the absence of perfect rodent models, those induced by excessive consumption of fat and sugars better replicate the key aspects that are the root causes of human metabolic diseases. However, the results obtained using these models cannot be directly compared, particularly because of the use of different dietary protocols, and animal species and strains, among other confounding factors. This review article revisits diet-induced models of obesity and related metabolic disorders, namely, metabolic syndrome, prediabetes, diabetes and nonalcoholic fatty liver disease. A critical analysis focused on the main pathophysiological features of rodent models, as opposed to the criteria defined for humans, is provided as a practical guide with a translational perspective for the establishment of animal models of obesity-related metabolic diseases.

Impact of Cyanidin-3-Glucoside on Gut Microbiota and Relationship with Metabolism and Inflammation in High Fat-High Sucrose Diet-Induced Insulin Resistant Mice

The present study assessed the effects of freeze-dried cyanidin-3-glucoside (C3G), an anthocyanin enriched in dark-red berries, compared to Saskatoon berry powder (SBp) on metabolism, inflammatory markers and gut microbiota in high fat-high sucrose (HFHS) diet-induced insulin-resistant mice. Male C57 BL/6J mice received control, HFHS, HFHS + SBp (8.0 g/kg/day) or HFHS + C3G (7.2 mg/kg/day, equivalent C3G in SBp) diet for 11 weeks. The HFHS diet significantly increased plasma levels of glucose, cholesterol, triglycerides, insulin resistance and inflammatory markers. The HFHS + SBp diet increased the Bacteroidetes/Firmicutes (B/F) ratio and relative abundance of Muriculaceae family bacteria in mouse feces detected using 16S rRNA gene sequencing. The HFHS + SBp or HFHS + C3G diet attenuated glucose, lipids, insulin resistance and inflammatory markers, and increased the B/F ratio and Muriculaceae relative abundance compared to the HFHS diet alone. The relative abundances of Muriculaceae negatively correlated with body weight, glucose, lipids, insulin resistance and inflammatory mediators. Functional predication analysis suggested that the HFHS diet upregulated gut bacteria genes involved in inflammation, and downregulated bacteria involved in metabolism. C3G and SBp partially neutralized HFHS diet-induced alterations of gut bacteria. The results suggest that C3G is a potential prebiotic, mitigating HFHS diet-induced disorders in metabolism, inflammation and gut dysbiosis, and that C3G contributes to the metabolic beneficial effects of SBp.

A Translational In Vivo and In Vitro Metabolomic Study Reveals Altered Metabolic Pathways in Red Blood Cells of Type 2 Diabetes

Clinical parameters used in type 2 diabetes mellitus (T2D) diagnosis and monitoring such as glycosylated haemoglobin (HbA1c) are often unable to capture important information related to diabetic control and chronic complications. In order to search for additional biomarkers, we performed a pilot study comparing T2D patients with healthy controls matched by age, gender, and weight. By using ¹H-nuclear magnetic resonance (NMR) based metabolomics profiling of red blood cells (RBCs), we found that the metabolic signature of RBCs in T2D subjects differed significantly from non-diabetic controls. Affected metabolites included glutathione, 2,3-bisphophoglycerate, inosinic acid, lactate, 6-phosphogluconate, creatine and adenosine triphosphate (ATP) and several amino acids such as leucine, glycine, alanine, lysine, aspartate, phenylalanine and tyrosine. These results were validated by an independent cohort of T2D and control patients. An analysis of the pathways in which these metabolites were involved showed that energetic and redox metabolism in RBCs were altered in T2D, as well as metabolites transported by RBCs. Taken together, our results revealed that the metabolic profile of RBCs can discriminate healthy controls from T2D patients. Further research is needed to determine whether metabolic fingerprint in RBC could be useful to complement the information obtained from HbA1c and glycemic variability as well as its potential role in the diabetes management.

Adherence to a Mediterranean-style eating pattern and risk of diabetes in a U.S. prospective cohort study

BACKGROUND

A Mediterranean-style eating pattern is consistently associated with a decreased diabetes risk in Mediterranean and European populations. However, results in U.S. populations are inconsistent. The objective of this study was to assess whether a Mediterranean-style eating pattern would be associated with diabetes risk in a large, nationally representative U.S. cohort of black and white men and women.

METHODS

Participants from the Atherosclerosis Risk in Communities study prospective cohort without diabetes, cardiovascular disease, or cancer at baseline (visit 1, 1987-1989; n = 11,991) were included (mean age 54 years, 56% female, 75% white). Alternate Mediterranean Diet scores (aMed) were calculated using the mean dietary intake self-reported at visit 1 and visit 3 (1993-1995) or visit 1 only for participants censored before visit 3. Participants were followed from visit 1 through 31 December 2016 for incident diabetes. We used Cox regression models to characterize associations of aMed (quintiles as well as per 1-point higher) with incident diabetes adjusted for energy intake, age, sex, race and study center, and education (Model 1) for all participants then stratified by race and body mass index (BMI). Model 2 included potential mediating behavioral and clinical measures associated with diabetes. Results are presented as hazard ratios and 95% confidence intervals.

RESULTS

Over a median follow-up of 22 years, there were 4024 incident cases of diabetes. Higher aMed scores were associated with lower diabetes risk [Model 1: 0.83 (0.73-0.94) for Q5 vs Q1 (p-trend < 0.001) and 0.96 (0.95-0.98) for 1-point higher]. Associations were stronger for black vs white participants (interaction p < 0.001) and weaker for obese vs normal BMI (interaction p < 0.01). Associations were attenuated but statistically significant in Model 2.

CONCLUSIONS

An eating pattern high in fruits, vegetables, whole grains, legumes, nuts, and fish, and moderate in alcohol was associated with a lower risk of diabetes in a community-based U.S.

POPULATION

Are marine n-3 fatty acids protective towards insulin resistance? From cell to human

Marine n-3 fatty acids improve most of the biochemical alterations associated with insulin resistance (IR). Experimental models of dietary-induced IR in rodents have shown their ability (often at a very high dose) to prevent IR, but with sometimes a tissue specific effect. However, in a high sucrose diet-induced IR rat model, they are unable to reverse IR once installed; in other rodent models (dexamethasone, Zucker rats), they are inefficacious perhaps because of the severity of IR. The very low incidence of type-2 diabetes (T2D) in Inuits in the 1960s, which largely increased over the following decades in parallel to the replacement of their traditional marine food for a western diet strongly suggests a protective effect of marine n-3 towards the risk of T2D; this was confirmed by reversal of its incidence in intervention studies reintroducing their traditional food. In healthy subjects and insulin-resistant non-diabetic patients, most trials and meta-analyses conclude to an insulin-sensitising effect and to a very probable preventive or alleviating effect towards IR. Concerning the risk of T2D, concordant data allow us to conclude the protective effect of marine n-3 in Asians while suspicion exists of an aggravation of risk in Westerners, but with the possibility that it could be explained by a high heterogeneity of studies performed in this population. Some longitudinal cohorts in US/European people showed no association or a decreased risk. Further studies using more homogeneous doses, sources of n-3 and assessment of insulin sensitivity methods are required to better delineate their effects in Westerners.

Dairy foods and health: an umbrella review of observational studies

Evidence on consumption of dairy foods and human health is contradictory. This study aimed to summarize the level of evidence of dairy consumption on various health outcomes. A systematic search for meta-analyses was performed: study design, dose-response relationship, heterogeneity and agreement of results over time, and identification of potential confounding factors were considered to assess the level of evidence. Convincing and probable evidence of decreased risk of colorectal cancer, hypertension and cardiovascular disease, elevated blood pressure and fatal stroke, respectively, was found for total dairy consumption; possible decreased risk of breast cancer, metabolic syndrome, stroke and type-2 diabetes, and increased risk of prostate cancer and Parkinson's disease was also found. Similar, yet not entirely consistent evidence for individual dairy products was reported. Among potential confounding factors, geographical localisation and fat content of dairy have been detected. In conclusions, dairy may be part of a healthy diet; however, additional studies exploring confounding factors are needed to ascertain the potential detrimental effects.

The Effects of Low-Energy Moderate-Carbohydrate (MCD) and Mixed (MixD) Diets on Serum Lipid Profiles and Body Composition in Middle-Aged Men: A Randomized Controlled Parallel-Group Clinical Trial

Carbohydrate-restricted diets have become very popular due to their numerous health benefits. The aim of this study was to determine the influence of 4 weeks of a well-planned, low-energy moderate-carbohydrate diet (MCD) and a low-energy mixed diet (MixD) on the lipoprotein profile, glucose and C-reactive protein concentrations, body mass, and body composition in middle-aged males. Sixty middle-aged males were randomly assigned to the following groups: hypocaloric MCD (32% carbohydrates, 28% proteins, and 40% fat), hypocaloric MixD (50% carbohydrates, 20% proteins, and 30% fat), and a conventional (control) diet (CD; 48% carbohydrates, 15% proteins, and 37% fat). The participants who were classified into the MCD and MixD groups consumed 20% fewer calories daily than the total daily energy expenditure (TDEE). Baseline and postintervention fasting triacylglycerol (TG), LDL (low-density lipoprotein) cholesterol (LDL-C), HDL (high-density lipoprotein) cholesterol (HDL-C), total cholesterol (tCh), glucose (Gl), and C-reactive protein were evaluated. Body mass (BM) and body composition changes, including body fat (BF), % body fat (PBF), and muscle mass (MM), were monitored. Compared with MixD and CD, MCD significantly changed the fasting serum concentrations of TG (p < 0.05), HDL-C (p < 0.05), LDL-C (p < 0.05), tCh (p < 0.05), and glucose (p < 0.01). Additionally, body fat content (kg and %) was significantly reduced (p < 0.05) after MCD compared with MixD and CD. After the MixD intervention, BM and MM decreased (p < 0.05) compared with baseline values. Compared with baseline, after the MixD, BM, MM, tCh, LDL-C, and TG changed significantly. The 4 week low-energy MCD intervention changed lipoproteins, glucose, and body fat to a greater extent than the low-energy MixD. A hypocaloric MCD may be suggested for middle-aged male subjects who want to lose weight by reducing body fat content without compromising muscle mass.

Diet-Induced Rodent Models of Diabetic Peripheral Neuropathy, Retinopathy and Nephropathy

Unhealthy dietary habits are major modifiable risk factors for the development of type 2 diabetes mellitus, a metabolic disease with increasing prevalence and serious consequences. Microvascular complications of diabetes, namely diabetic peripheral neuropathy (DPN), retinopathy (DR), and nephropathy (DN), are associated with high morbidity rates and a heavy social and economic burden. Currently, available therapeutic options to counter the evolution of diabetic microvascular complications are clearly insufficient, which strongly recommends further research. Animal models are essential tools to dissect the molecular mechanisms underlying disease progression, to unravel new therapeutic targets, as well as to evaluate the efficacy of new drugs and/or novel therapeutic approaches. However, choosing the best animal model is challenging due to the large number of factors that need to be considered. This is particularly relevant for models induced by dietary modifications, which vary markedly in terms of macronutrient composition. In this article, we revisit the rodent models of diet-induced DPN, DR, and DN, critically comparing the main features of these microvascular complications in humans and the criteria for their diagnosis with the parameters that have been used in preclinical research using rodent models, considering the possible need for factors which can accelerate or aggravate these conditions.

Melatonin Alleviates Glucose and Lipid Metabolism Disorders in Guinea Pigs Caused by Different Artificial Light Rhythms

Modern lifestyle-associated factors, such as high-calorie intake, high-fat diet (HFD), and excessive artificial light, are risk factors for glucose and lipid metabolism disturbances. Melatonin may be beneficial for managing obesity and diabetes; however, the underlying molecular mechanisms are not well elucidated. We aimed to assess whether melatonin has beneficial effects on constant artificial light-induced fat deposition, lipid metabolism, and insulin resistance. Guinea pigs were randomly divided into five experimental groups: control (C), HFD (H), 12 h light (12HL), 24 h light (24HL), and melatonin (M). The majority of indexes, including insulin resistance and obesity, were measured after 10 weeks. AMP-activated protein kinase α (AMPKα)/peroxisome proliferator-activated receptor-α (PPARα) pathway expression was analyzed by quantitative reverse transcription PCR and western blotting. Although insulin resistance and obesity indexes were higher in the 24HL group than in the 12HL group, they were significantly lower in the M group than in the 24HL group. Melatonin treatment markedly upregulated AMPKα, phosphorylated AMPKα (p-AMPKα), PPARα, and carnitine palmitoyl-CoA transferase 1 A (CPT1A) gene and protein expression. Melatonin may alleviate insulin resistance and obesity caused by persistent artificial light exposure in guinea pigs, likely via activation of the AMPKα/PPARα signaling pathway.

Association Between Plant-Based Dietary Patterns and Risk of Type 2 Diabetes: A Systematic Review and Meta-analysis

IMPORTANCE

Accumulating epidemiologic evidence has suggested favorable associations between plant-based dietary patterns and risk of type 2 diabetes, although there is a lack of a quantitative summary of evidence substantiating this important association.

OBJECTIVE

To quantitatively synthesize available prospective observational evidence on the association between plant-based dietary patterns and risk of type 2 diabetes.

DATA SOURCES

A systematic search of PubMed and MEDLINE, Embase, Web of Science, and reference lists through February 15, 2019, was conducted. Data analysis was conducted between December 2018 and February 2019.

STUDY SELECTION

All prospective observational studies that examined the association between adherence to plant-based dietary patterns and incidence of type 2 diabetes among adults 18 years or older were identified.

DATA EXTRACTION AND SYNTHESIS

Meta-analysis of Observational Studies in Epidemiology guidelines for data abstraction and reporting were followed, and a National Heart, Lung, and Blood Institute assessment tool was used to evaluate study quality. Two authors independently conducted full-text assessments and data abstraction. Meta-analysis was conducted using the random-effects method to calculate the overall relative risk (RR) and 95% CI.

MAIN OUTCOMES AND MEASURES

Level of adherence to a plant-based diet and incidence of type 2 diabetes.

RESULTS

A total of 9 studies were identified, totaling 307 099 participants with 23 544 cases of incident type 2 diabetes. A significant inverse association was observed between higher adherence to a plant-based dietary pattern and risk of type 2 diabetes (RR, 0.77; 95% CI, 0.71-0.84) in comparison with poorer adherence, with modest heterogeneity across studies (I2 = 44.5%; P = .07 for heterogeneity). Similar findings were obtained when using the fixed-effects model (RR, 0.80; 95% CI, 0.75-0.84). Consistent associations were observed across predefined subgroups. This association was strengthened when healthy plant-based foods, such as fruits, vegetables, whole grains, legumes, and nuts, were included in the definition of plant-based patterns (RR, 0.70; 95% CI, 0.62-0.79). Most studies were deemed to have good quality in terms of dietary assessment, disease outcomes, and statistical adjustment for confounding factors. Using restricted cubic splines, a significant inverse linear dose-response association was identified between plant-based dietary indices and risk of type 2 diabetes.

CONCLUSIONS AND RELEVANCE

Plant-based dietary patterns, especially when they are enriched with healthful plant-based foods, may be beneficial for the primary prevention of type 2 diabetes.

Changes in Plasma Free Fatty Acids Associated with Type-2 Diabetes

Type 2 diabetes mellitus (T2DM) is associated with increased total plasma free fatty acid (FFA) concentrations and an elevated risk of cardiovascular disease. The exact mechanisms by which the plasma FFA profile of subjects with T2DM changes is unclear, but it is thought that dietary fats and changes to lipid metabolism are likely to contribute. Therefore, establishing the changes in concentrations of specific FFAs in an individual’s plasma is important. Each type of FFA has different effects on physiological processes, including the regulation of lipolysis and lipogenesis in adipose tissue, inflammation, endocrine signalling and the composition and properties of cellular membranes. Alterations in such processes due to altered plasma FFA concentrations/profiles can potentially result in the development of insulin resistance and coagulatory defects. Finally, fibrates and statins, lipid-regulating drugs prescribed to subjects with T2DM, are also thought to exert part of their beneficial effects by impacting on plasma FFA concentrations. Thus, it is also interesting to consider their effects on the concentration of FFAs in plasma. Collectively, we review how FFAs are altered in T2DM and explore the likely downstream physiological and pathological implications of such changes.

The Influence of Different Fat Sources on Steatohepatitis and Fibrosis Development in the Western Diet Mouse Model of Non-alcoholic Steatohepatitis (NASH)

Non-alcoholic steatohepatitis (NASH) is the leading cause of chronic liver injury and the third most common reason for liver transplantations in Western countries. It is unclear so far how different fat sources in Western diets (WD) influence the development of NASH. Our study investigates the impact of non-trans fat (NTF) and corn oil (Corn) as fat source in a WD mouse model of steatohepatitis on disease development and progression. C57BL/6J wildtype (WT) mice were fed “standard” WD (WD-Std), WD-NTF or WD-Corn for 24 weeks. WT animals treated with WD-NTF exhibit distinct features of the metabolic syndrome compared to WD-Std and WD-Corn. This becomes evident by a worsened insulin resistance and elevated serum ALT, cholesterol and triglyceride (TG) levels compared to WD-Corn. Animals fed WD-Corn on the contrary tend to a weakened disease progression in the described parameters. After 24 weeks feeding with WD-NTF and WD-Std, WD-Corn lead to a comparable steatohepatitis initiation by histomorphological changes and immune cell infiltration compared to WD-Std. Immune cell infiltration results in a significant increase in mRNA expression of the pro-inflammatory cytokines IL-6 and TNF-α, which is more pronounced in WD-NTF compared to WD-Std and WD-Corn. Interestingly the fat source has no impact on the composition of accumulating fat within liver tissue as determined by matrix-assisted laser desorption/ionization mass spectrometry imaging of multiple lipid classes. The described effects of different fat sources on the development of steatohepatitis finally resulted in variations in fibrosis development. Animals treated with WD-NTF displayed massive collagen accumulation, whereas WD-Corn even seems to protect from extracellular matrix deposition. Noteworthy, WD-Corn provokes massive histomorphological modifications in epididymal white adipose tissue (eWAT) and severe accumulation of extracellular matrix which are not apparent in WD-Std and WD-NTF treatment. Different fat sources in WD-Std contribute to strong steatohepatitis development in WT mice after 24 weeks treatment. Surprisingly, corn oil provokes histomorphological changes in eWAT tissue. Accordingly, both WD-NTF and WD-Corn appear suitable as alternative dietary treatment to replace “standard” WD-Std as a diet mouse model of steatohepatitis whereas WD-Corn leads to strong changes in eWAT morphology.