Red meat, dietary heme iron, and risk of type 2 diabetes: the involvement of advanced lipoxidation endproducts

Monounsaturated fatty acids from plant or animal sources and risk of type 2 diabetes in three large prospective cohorts of men and women

AIMS/HYPOTHESIS

Existing evidence on the relationship between intake of monounsaturated fatty acids (MUFAs) and type 2 diabetes is conflicting. Few studies have examined whether MUFAs from plant or animal sources (MUFA-Ps and MUFA-As, respectively) exhibit differential associations with type 2 diabetes. We examined associations of intakes of total MUFAs, MUFA-Ps and MUFA-As with type 2 diabetes risk.

METHODS

We used data from 51,290 women in the Nurses' Health Study (1990-2016), 61,703 women in the Nurses' Health Study II (1991-2017) and 29,497 men in the Health Professionals Follow-up Study (1990-2016). Using food frequency questionnaires and food composition tables, we calculated MUFA-P and MUFA-A intakes every 4 years and modelled their associations with type 2 diabetes using Cox regression models.

RESULTS

During 3,268,512 person-years of follow-up, we documented 13,211 incident type 2 diabetes cases. After multivariate adjustment, total MUFA intake was associated with higher type 2 diabetes risk, with HR for Q5 vs Q1 of 1.10 (95% CI 1.01, 1.22). MUFA-Ps and MUFA-As demonstrated divergent associations, with HRs of 0.87 (95% CI 0.81, 0.94) and 1.34 (1.23, 1.45), respectively. In substitution analyses, HRs were 0.92 (95% CI 0.86, 0.99) for replacing 2% of energy from trans fatty acids or 0.72 (0.66, 0.78) and 0.82 (0.77, 0.88) for replacing 5% from MUFA-As and 5% from the sum of saturated fatty acids and MUFA-As with MUFA-Ps, respectively. Substituting MUFA-As for saturated fatty acids and refined carbohydrates was associated with a 43% and 33% higher risk, respectively.

CONCLUSIONS/INTERPRETATION

Higher intake of MUFA-Ps was associated with lower type 2 diabetes risk, whereas increased intake of MUFA-As was associated with higher risk. Replacing saturated fatty acids, trans fatty acids and MUFA-As with MUFA-Ps may be beneficial for type 2 diabetes prevention.

Plant-Based Diet and Sports Performance

Recently, interest in plant-based diets has grown significantly, driven by health and environmental concerns. Plant-based diets offer potential health benefits, including decreased risk of cardiovascular disease, weight management, and blood glucose regulation. This diet profile is rich in complex carbohydrates, antioxidants, dietary fiber, and phytochemicals. However, antinutrients in some plant foods can make nutrient absorption difficult, necessitating careful dietary planning. Plant-based diets can also improve sports performance; in addition, they can positively influence the intestinal microbial community, which can promote health and performance. The present study covered a review from 1986 to 2024 and involved an experimental design with human participants. The main objective was to evaluate the impact of plant-based diets on sports performance. Recent research suggests that plant-based diets do not harm athletic performance and may positively impact sports performance by improving blood flow and reducing oxidative stress. These findings have potential clinical significance, particularly for athletes seeking to optimize their physical capabilities through dietary interventions.

PACS2/CPT1A/DHODH signaling promotes cardiomyocyte ferroptosis in diabetic cardiomyopathy

OBJECTIVES

The pathophysiology of diabetic cardiomyopathy (DCM) is a phenomenon of great interest, but its clinical problems have not yet been effectively addressed. Recently, the mechanism of ferroptosis in the pathophysiology of various diseases, including DCM, has attracted widespread attention. Here, we explored the role of PACS2 in ferroptosis in DCM through its downregulation of PACS2 expression.

METHODS AND RESULTS

Cardiomyocytes were treated with high glucose and palmitic acid (HGPA), and the detection of cardiomyocyte iron ions, lipid peroxides, and reactive oxygen species (ROS) revealed clear ferroptosis during these treatments. Silencing PACS2 downregulated CPT1A expression and upregulated DHODH expression significantly, reversing HGPA-induced ferroptosis. Further silencing of PACS2 with a CPT1A agonist exacerbated cardiomyocyte ferroptosis while promoting mitochondrial damage in cardiomyocytes. Using a mouse model of type 2 diabetes induced by streptozotocin (STZ) and a high-fat diet (HFD), we found that PACS2 deletion reversed these treatment-induced increases in cellular iron ions, impaired cardiac function, mitochondrial damage and ferroptosis in cardiac muscle tissues.

CONCLUSIONS

The PACS2/CPT1A/DHODH signalling pathway may be involved in ferroptosis in DCM by regulating cardiomyocyte mitochondrial function.

Phytochemicals targeting ferroptosis in cardiovascular diseases: Recent advances and therapeutic perspectives

Ferroptosis is a form of iron-dependent regulatory cell death that is related to the pathogenesis and progression of various cardiovascular diseases, such as arrhythmia, diabetic cardiomyopathy, myocardial infarction, myocardial ischemia/reperfusion injury, and heart failure. This makes it a promising therapeutic target for cardiovascular diseases. It is interesting that a significant number of cardiovascular disease treatment drugs derived from phytochemicals have been shown to target ferroptosis, thus producing cardioprotective effects. This study offers a concise overview of the initiation and control mechanisms of ferroptosis. It discusses the core regulatory factors of ferroptosis as potential new therapeutic targets for various cardiovascular diseases, elucidating how ferroptosis influences the progression of cardiovascular diseases. In addition, this review systematically summarizes the regulatory effects of phytochemicals on ferroptosis, emphasizing their potential mechanisms and clinical applications in treating cardiovascular diseases. This study provides a reference for further elucidating the molecular mechanisms of phytochemicals in treating cardiovascular diseases. This may accelerate their application in the treatment of cardiovascular diseases and is worth further research in this field.

Metals on the Menu-Analyzing the Presence, Importance, and Consequences

Metals are integral components of the natural environment, and their presence in the food supply is inevitable and complex. While essential metals such as sodium, potassium, magnesium, calcium, iron, zinc, and copper are crucial for various physiological functions and must be consumed through the diet, others, like lead, mercury, and cadmium, are toxic even at low concentrations and pose serious health risks. This study comprehensively analyzes the presence, importance, and consequences of metals in the food chain. We explore the pathways through which metals enter the food supply, their distribution across different food types, and the associated health implications. By examining current regulatory standards for maximum allowable levels of various metals, we highlight the importance of ensuring food safety and protecting public health. Furthermore, this research underscores the need for continuous monitoring and management of metal content in food, especially as global agricultural and food production practices evolve. Our findings aim to inform dietary recommendations, food fortification strategies, and regulatory policies, ultimately contributing to safer and more nutritionally balanced diets.

Nutrition at the Intersection between Gut Microbiota Eubiosis and Effective Management of Type 2 Diabetes

Nutrition is one of the most influential environmental factors in both taxonomical shifts in gut microbiota as well as in the development of type 2 diabetes mellitus (T2DM). Emerging evidence has shown that the effects of nutrition on both these parameters is not mutually exclusive and that changes in gut microbiota and related metabolites such as short-chain fatty acids (SCFAs) and branched-chain amino acids (BCAAs) may influence systemic inflammation and signaling pathways that contribute to pathophysiological processes associated with T2DM. With this background, our review highlights the effects of macronutrients, carbohydrates, proteins, and lipids, as well as micronutrients, vitamins, and minerals, on T2DM, specifically through their alterations in gut microbiota and the metabolites they produce. Additionally, we describe the influences of common food groups, which incorporate varying combinations of these macronutrients and micronutrients, on both microbiota and metabolic parameters in the context of diabetes mellitus. Overall, nutrition is one of the first line modifiable therapies in the management of T2DM and a better understanding of the mechanisms by which gut microbiota influence its pathophysiology provides opportunities for optimizing dietary interventions.

Single-Cell Hemoprotein Diet Changes Adipose Tissue Distributions and Re-Shapes Gut Microbiota in High-Fat Diet-Induced Obese Mice

We have previously observed that feeding with single-cell hemoprotein (heme-SCP) in dogs (1 g/day for 6 days) and broiler chickens (1 ppm for 32 days) increased the proportion of lactic acid bacteria in the gut while reducing their body weights by approximately 1~2%. To define the roles of heme-SCP in modulating body weight and gut microbiota, obese C57BL/6N mice were administered varied heme-SCP concentrations (0, 0.05, and 0.5% heme-SCP in high fat diet) for 28 days. The heme-SCP diet seemed to restrain weight gain till day 14, but the mice gained weight again later, showing no significant differences in weight. However, the heme-SCP-fed mice had stiffer and oilier bodies compared with those of the control mice, which had flabby bodies and dull coats. When mice were dissected at day 10, the obese mice fed with heme-SCP exhibited a reduction in subcutaneous fat with an increase in muscle mass. The effect of heme-SCP on the obesity-associated dyslipidemia tended to be corroborated by the blood parameters (triglyceride, total cholesterol, and C-reactive protein) at day 10, though the correlation was not clear at day 28. Notably, the heme-SCP diet altered gut microbiota, leading to the proliferation of known anti-obesity biomarkers such as Akkermansia, Alistipes, Oscillibacter, Ruminococcus, Roseburia, and Faecalibacterium. This study suggests the potential of heme-SCP as an anti-obesity supplement, which modulates serum biochemistry and gut microbiota in high-fat diet-induced obese mice.

Poultry Consumption and Human Cardiometabolic Health-Related Outcomes: A Narrative Review

Poultry meats, in particular chicken, have high rates of consumption globally. Poultry is the most consumed type of meat in the United States (US), with chicken being the most common type of poultry consumed. The amounts of chicken and total poultry consumed in the US have more than tripled over the last six decades. This narrative review describes nutritional profiles of commonly consumed chicken/poultry products, consumption trends, and dietary recommendations in the US. Overviews of the scientific literature pertaining to associations between, and effects of consuming chicken/poultry on, body weight and body composition, cardiovascular disease (CVD), and type II diabetes mellitus (T2DM) are provided. Limited evidence from randomized controlled trials indicates the consumption of lean unprocessed chicken as a primary dietary protein source has either beneficial or neutral effects on body weight and body composition and risk factors for CVD and T2DM. Apparently, zero randomized controlled feeding trials have specifically assessed the effects of consuming processed chicken/poultry on these health outcomes. Evidence from observational studies is less consistent, likely due to confounding factors such as a lack of a description of and distinctions among types of chicken/poultry products, amounts consumed, and cooking and preservation methods. New experimental and observational research on the impacts of consuming chicken/poultry, especially processed versions, on cardiometabolic health is sorely needed.

Iron accumulation and lipid peroxidation: implication of ferroptosis in diabetic cardiomyopathy

Diabetic cardiomyopathy (DC) is a serious heart disease caused by diabetes. It is unrelated to hypertension and coronary artery disease and can lead to heart insufficiency, heart failure and even death. Currently, the pathogenesis of DC is unclear, and clinical intervention is mainly symptomatic therapy and lacks effective intervention objectives. Iron overdose mediated cell death, also known as ferroptosis, is widely present in the physiological and pathological processes of diabetes and DC. Iron is a key trace element in the human body, regulating the metabolism of glucose and lipids, oxidative stress and inflammation, and other biological processes. Excessive iron accumulation can lead to the imbalance of the antioxidant system in DC and activate and aggravate pathological processes such as excessive autophagy and mitochondrial dysfunction, resulting in a chain reaction and accelerating myocardial and microvascular damage. In-depth understanding of the regulating mechanisms of iron metabolism and ferroptosis in cardiovascular vessels can help improve DC management. Therefore, in this review, we summarize the relationship between ferroptosis and the pathogenesis of DC, as well as potential intervention targets, and discuss and analyze the limitations and future development prospects of these targets.

White Meat Consumption and Cardiometabolic Risk Factors: A Review of Recent Prospective Cohort Studies

Although the association between meat consumption and cardiovascular diseases (CVDs) has been extensively investigated, studies focusing specifically on the relationship between white meat consumption and CVD risk factors are fewer with controversial findings. The aim was to evaluate the relationship between white meat consumption and the incidence of cardiometabolic risk factors. A comprehensive literature search of PubMed articles was conducted from 2010 to 2022 (1 November), according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Thirteen prospective cohort studies were selected studying mainly poultry, with the exception of one study that also analyzed rabbit meat. From the seven studies on the risk of type 2 diabetes mellitus, four studies found no association, two studies found positive associations, and two studies found inverse associations when comparing poultry to other meats. Of the two studies on the risk of hypertension, one observed no association and one a positive association. Of the two studies on weight management, one observed a positive association with weight gain, the other study observed the same relationship only for chicken with skin, while for chicken without skin a positive relationship with relative weight loss was found. As for metabolic syndrome and its components, two studies revealed inverse associations with white meat intake. Only fresh lean white meat consumption seems to have potential beneficial effects on cardiometabolic risk factors. Future research should scrutinize consumption habits related to white meat intake when investigating its association with cardiometabolic risk factors.

Poultry Consumption and Human Health: How Much Is Really Known? A Systematically Searched Scoping Review and Research Perspective

This scoping review was conducted to systematically search and chronicle scientific literature pertinent to poultry intake and human health. The protocol (uploaded to Open Science Framework, https://osf.io/2k7bj/) was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews guidelines. Articles with observational and experimental research, narrative and systematic reviews, and meta-analyses were included. Among 13,141 articles identified, 525 met inclusion criteria. Among these 525 articles, 212 focused on cancer morbidity and mortality; 41 on cardiovascular disease (CVD) morbidity and mortality; 52 on CVD risk factors; 32 on type 2 diabetes mellitus (T2DM) morbidity and mortality; 33 on T2DM risk factors; and 42 on body weight and body composition. An "Other" category (181 articles) included nutrient status, psychological well-being/mental health, cognition, microbiome, chronic kidney disease, nonalcoholic fatty liver disease, skin disorders, and fertility, among others. Among the 525 included articles, 366 were observational, 64 were experimental, and 76 were reviews and meta-analyses. Eighty-three percent of articles focused on adults or older adults. A paucity of research exists to support poultry as health-promoting foods, with most research only indirectly assessing poultry intake compared with other foods of interest (e.g., red meats or plant-based protein foods). No randomized controlled trials and only 1% of OBS assessed the influence of processed poultry intake on human health. In the future, the relative health effects of consuming poultry will be compared with a widening array of traditional and new protein-rich food products, necessitating the need for research to assess poultry as foods of choice. Science and health professionals, the poultry industry, and the public will benefit from new observational and experimental research to address cutting-edge scientific, public policy, and consumer topics pertinent to poultry intake and human health.

Maternal heme-enriched diet promotes a gut pro-oxidative status associated with microbiota alteration, gut leakiness and glucose intolerance in mice offspring

Maternal environment, including nutrition and microbiota, plays a critical role in determining offspring's risk of chronic diseases such as diabetes later in life. Heme iron requirement is amplified during pregnancy and lactation, while excessive dietary heme iron intake, compared to non-heme iron, has shown to trigger acute oxidative stress in the gut resulting from reactive aldehyde formation in conjunction with microbiota reshape. Given the immaturity of the antioxidant defense system in early life, we investigated the extent to which a maternal diet enriched with heme iron may have a lasting impact on gut homeostasis and glucose metabolism in 60-day-old C3H/HeN mice offspring.

As hypothesized, the form of iron added to the maternal diet differentially governed the offspring's microbiota establishment despite identical fecal iron status in the offspring. Importantly, despite female offspring was unaffected, oxidative stress markers were however higher in the gut of male offspring from heme enriched-fed mothers, and were accompanied by increases in fecal lipocalin-2, intestinal para-cellular permeability and TNF-α expression. In addition, male mice displayed blood glucose intolerance resulting from impaired insulin secretion following oral glucose challenge. Using an integrated approach including an aldehydomic analysis, this male-specific phenotype was further characterized and revealed close covariations between unidentified putative reactive aldehydes and bacterial communities belonging to Bacteroidales and Lachnospirales orders.

Our work highlights how the form of dietary iron in the maternal diet can dictate the oxidative status in gut offspring in a sex-dependent manner, and how a gut microbiota-driven oxidative challenge in early life can be associated with gut barrier defects and glucose metabolism disorders that may be predictive of diabetes development.

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Maternal heminic vs. non-heminic iron intake differentially and persistently imprints the offspring's fecal microbiota.

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Males from heme-fed dams exhibit increased gut lumen reactive aldehydes in absence of direct dietary exposure to heme iron.

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Some of the increased reactive aldehydes closely covariated with Orders belonging to Bacteroidales and Lachnospirales.

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Maternal exposure to dietary heme iron impairs gut barrier and glucose tolerance in male offspring.

Dietary iron intake and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective cohort studies

PURPOSE

We aimed to assess the long-term association of total, heme, non-heme, and supplemental iron intake and risk of type 2 diabetes (T2D).

METHODS

PubMed, Scopus, and Web of Science were searched to October 2021. Two researchers extracted data in duplicate and rated the certainty in the estimates using the GRADE approach. Random-effects models were applied to estimate the relative risks (RRs) and 95% CIs. Dose-response associations were modeled by a one-stage weighted mixed-effects meta-analysis.

RESULTS

Eleven prospective cohort studies 323,788 participants and 28,837 incident cases of T2D were included. High versus low category meta-analysis indicated that higher heme iron intake was associated with a 20% higher risk of T2D (95% CI 1.07, 1.35; I² = 77%, n = 11; GRADE = moderate). Dose-response analysis indicated a positive monotonic association, wherein each 1 mg/day increment in heme iron intake was related to a 16% higher risk (95% CI 1.03, 1.30). No significant relationship was detected between dietary intakes of total, non-heme, and supplemental iron and risk of T2D (GRADE = very low).

CONCLUSIONS

In summary, higher heme iron intake was associated with a higher risk of T2D. Our results are in line with existing evidence indicating that adopting a Western-style dietary pattern, rich in dietary sources of heme iron, was associated with a higher risk of T2D.

REGISTRY AND REGISTRY NUMBER

The protocol of this systematic review was registered at PROSPERO (registration number: CRD42021226835).

Ferroptosis is essential for diabetic cardiomyopathy and is prevented by sulforaphane via AMPK/NRF2 pathways

Herein, we define the role of ferroptosis in the pathogenesis of diabetic cardiomyopathy (DCM) by examining the expression of key regulators of ferroptosis in mice with DCM and a new ex vivo DCM model. Advanced glycation end-products (AGEs), an important pathogenic factor of DCM, were found to induce ferroptosis in engineered cardiac tissues (ECTs), as reflected through increased levels of Ptgs2 and lipid peroxides and decreased ferritin and SLC7A11 levels. Typical morphological changes of ferroptosis in cardiomyocytes were observed using transmission electron microscopy. Inhibition of ferroptosis with ferrostatin-1 and deferoxamine prevented AGE-induced ECT remodeling and dysfunction. Ferroptosis was also evidenced in the heart of type 2 diabetic mice with DCM. Inhibition of ferroptosis by liproxstatin-1 prevented the development of diastolic dysfunction at 3 months after the onset of diabetes. Nuclear factor erythroid 2-related factor 2 (NRF2) activated by sulforaphane inhibited cardiac cell ferroptosis in both AGE-treated ECTs and hearts of DCM mice by upregulating ferritin and SLC7A11 levels. The protective effect of sulforaphane on ferroptosis was AMP-activated protein kinase (AMPK)-dependent. These findings suggest that ferroptosis plays an essential role in the pathogenesis of DCM; sulforaphane prevents ferroptosis and associated pathogenesis via AMPK-mediated NRF2 activation. This suggests a feasible therapeutic approach with sulforaphane to clinically prevent ferroptosis and DCM.

The Safe and Effective Use of Plant-Based Diets with Guidelines for Health Professionals

Plant-based diets, defined here as including both vegan and lacto-ovo-vegetarian diets, are growing in popularity throughout the Western world for various reasons, including concerns for human health and the health of the planet. Plant-based diets are more environmentally sustainable than meat-based diets and have a reduced environmental impact, including producing lower levels of greenhouse gas emissions. Dietary guidelines are normally formulated to enhance the health of society, reduce the risk of chronic diseases, and prevent nutritional deficiencies. We reviewed the scientific data on plant-based diets to summarize their preventative and therapeutic role in cardiovascular disease, cancer, diabetes, obesity, and osteoporosis. Consuming plant-based diets is safe and effective for all stages of the life cycle, from pregnancy and lactation, to childhood, to old age. Plant-based diets, which are high in fiber and polyphenolics, are also associated with a diverse gut microbiota, producing metabolites that have anti-inflammatory functions that may help manage disease processes. Concerns about the adequate intake of a number of nutrients, including vitamin B12, calcium, vitamin D, iron, zinc, and omega-3 fats, are discussed. The use of fortified foods and/or supplements as well as appropriate food choices are outlined for each nutrient. Finally, guidelines are suggested for health professionals working with clients consuming plant-based diets.

Dietary iron intake and the risk of type 2 diabetes mellitus in middle-aged and older adults in urban China: a prospective cohort study

The association between dietary Fe intake and diabetes risk remains inconsistent. We aimed to explore the association between dietary Fe intake and type 2 diabetes mellitus (T2DM) risk in middle-aged and older adults in urban China. This study used data from the Guangzhou Nutrition and Health Study, an on-going community-based prospective cohort study. Participants were recruited from 2008 to 2013 in Guangzhou community. A total of 2696 participants aged 40-75 years without T2DM at baseline were included in data analyses, with a median of 5·6 (interquartile range 4·1-5·9) years of follow-up. T2DM was identified by self-reported diagnosis, fasting glucose ≥ 7·0 mmol/l or glycosylated Hb ≥ 6·5 %. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95 % CI. We ascertained 205 incident T2DM cases during 13 476 person-years. The adjusted HR for T2DM risk in the fourth quartile of haem Fe intake was 1·92 (95 % CI 1·07, 3·46; Ptrend = 0·010), compared with the first quartile intake. These significant associations were found in haem Fe intake from total meat (HR 2·74; 95 % CI 1·22, 6·15; Ptrend = 0·011) and haem Fe intake from red meat (HR 1·86; 95 % CI 1·01, 3·44; Ptrend = 0·034), but not haem Fe intake from processed meat, poultry or fish/shellfish. The association between dietary intake of total Fe or non-haem Fe with T2DM risk had no significance. Our findings suggested that higher dietary intake of haem Fe (especially from red meat), but not total Fe or non-haem Fe, was associated with greater T2DM risk in middle-aged and older adults.

Correlation Between High Serum Ferritin Level and Gestational Diabetes: A Systematic Review

Gestational diabetes mellitus (GDM) is a growing pregnancy-related health problem all over the world. It has been noticed that women with high serum ferritin levels have a strong relationship with GDM by increased insulin resistance and increased insulin secretion from the pancreas resulting in pancreatic beta-cell exhaustion. Heme iron is also responsible for increasing the body's iron store and hence causing oxidative injury to pancreatic cells. In this systematic review, we researched the association between high serum ferritin levels and GDM. Three databases were consulted for articles related to GDM and high ferritin. These include Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed, and PubMed Central (PMC). Additional articles were retrieved from the institutional database. After filtering, 10 articles were finally selected, and quality was checked using the Joanna Briggs Institute (JBI) Critical Appraisal quality check tool. Serum iron biomarkers including ferritin, iron, and soluble transferrin receptor (sTfR) were measured. Our systematic review indicates that high maternal serum ferritin has a significant role in the development of GDM. We have also noticed the importance of sTfR and serum hepcidin as biomarkers to monitor high ferritin levels. Our study also observed a positive relationship between high heme iron intake and gestational diabetes mellitus. Therefore, more research is required to understand this relationship to identify populations at risk.

An Analysis of the Multifaceted Roles of Heme in the Pathogenesis of Cancer and Related Diseases

Heme is an essential prosthetic group in proteins and enzymes involved in oxygen utilization and metabolism. Heme also plays versatile and fascinating roles in regulating fundamental biological processes, ranging from aerobic respiration to drug metabolism. Increasing experimental and epidemiological data have shown that altered heme homeostasis accelerates the development and progression of common diseases, including various cancers, diabetes, vascular diseases, and Alzheimer's disease. The effects of heme on the pathogenesis of these diseases may be mediated via its action on various cellular signaling and regulatory proteins, as well as its function in cellular bioenergetics, specifically, oxidative phosphorylation (OXPHOS). Elevated heme levels in cancer cells intensify OXPHOS, leading to higher ATP generation and fueling tumorigenic functions. In contrast, lowered heme levels in neurons may reduce OXPHOS, leading to defects in bioenergetics and causing neurological deficits. Further, heme has been shown to modulate the activities of diverse cellular proteins influencing disease pathogenesis. These include BTB and CNC homology 1 (BACH1), tumor suppressor P53 protein, progesterone receptor membrane component 1 protein (PGRMC1), cystathionine-β-synthase (CBS), soluble guanylate cyclase (sGC), and nitric oxide synthases (NOS). This review provides an in-depth analysis of heme function in influencing diverse molecular and cellular processes germane to disease pathogenesis and the modes by which heme modulates the activities of cellular proteins involved in the development of cancer and other common diseases.

Moderate Consumption of Red Meat, Compared to Soy or Non-Soy Legume, Has No Adverse Effect on Cardio-Metabolic Factors in Patients with Type 2 Diabetes

BACKGROUND

Recently, it has been proposed that red meat consumption could enhance risk of diabetes and worsen lipid profile and glycemic status, in comparison with soy or non-soy legume, but the results of clinical trials are controversial.

OBJECTIVES

This study aimed to compare the effect of red meat, soy bean, and non-soy legume consumption on cardio-metabolic factors in patients with type 2 diabetes.

METHODS

This was a randomized controlled clinical trial which included 75 patients with diabetes, aged 40-65 years. Participants were randomly allocated to receive two servings of red meat (control group), soy bean, or non-soy legume, 3 days a week for 8 weeks. All groups also received a balanced-macronutrients weight maintenance diet. Body composition and cardio-metabolic factors including fasting blood glucose (FBG), fasting insulin, glycated hemoglobin (HbA1c), serum lipids, and blood pressure were measured at baseline and endpoint of the study. Quantitative insulin sensitivity check index (QUICKI) score and Framingham risk score (FRS) were also computed.

RESULTS

We found no significant differences in changes of FBG, fasting insulin, HbA1c, QUICKI score, serum lipids, FRS, and systolic and diastolic blood pressure among the 3 groups. Within group analysis showed that FRS reduced significantly in all groups (P<0.05). In addition, systolic (P=0.01) and diastolic (P=0.03) blood pressure reduced within red meat group.

CONCLUSIONS

Compared to soy bean or non-soy legume, moderate consumption of red meat had no adverse effect on cardio-metabolic factors including FBG, fasting insulin, HbA1C, QUICKI score, total cholesterol, low-density lipoprotein , high-density lipoprotein , and blood pressure in adults with type 2 diabetes.

Differential Effects of Dietary Patterns on Advanced Glycation end Products: A Randomized Crossover Study

Dietary advanced glycation end products (AGEs) are believed to contribute to pathogenesis of diabetes and cardiovascular disease. The objective of this study was to determine if a diet high in red and processed meat and refined grains (HMD) would elevate plasma concentrations of protein-bound AGEs compared with an energy-matched diet high in whole grain, dairy, nuts and legumes (HWD). We conducted a randomized crossover trial with two 4-week weight-stable dietary interventions in 51 participants without type 2 diabetes (15 men and 36 women aged 35.1 ± 15.6 y; body mass index (BMI), 27.7 ± 6.9 kg/m²). Plasma concentrations of protein-bound Nε-(carboxymethyl) lysine (CML), Nε-(1-carboxyethyl) lysine (CEL) and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were measured by liquid chromatography–tandem mass spectrometry (LC-MS/MS). The HMD significantly increased plasma concentrations (nmol/mL) of CEL (1.367, 0.78 vs. 1.096, 0.65; p < 0.01; n = 48) compared with the HWD. No differences in CML and MG-H1 between HMD and HWD were observed. HMD increased plasma CEL concentrations compared with HWD in individuals without type 2 diabetes.

Development and Validation of Novel Dietary and Lifestyle Inflammation Scores

BACKGROUND

Chronically higher inflammation, which may partly result from diet and lifestyle, is implicated in risk for multiple chronic diseases. The dietary inflammatory index (DII) and empirical dietary inflammatory pattern (EDIP), developed to characterize dietary contributions to systemic inflammation, have several limitations. There are no scores to characterize contributions of lifestyle to inflammation.

OBJECTIVES

To reflect dietary/lifestyle contributions to inflammation, we developed novel, inflammation biomarker panel-weighted, dietary (DIS) and lifestyle (LIS) inflammation scores in a subset (n = 639) of the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS) cohort.

METHODS

We selected a priori 19 food groups and 4 lifestyle characteristics to comprise the DIS and LIS, respectively. We calculated the components' weights based on their strengths of association with an inflammation biomarker score [comprising high-sensitivity C-reactive protein (hsCRP), IL-6, IL-8, and IL-10] using multivariable linear regression. The sums of the weighted components constitute the scores, such that higher scores reflect, on balance, more proinflammatory exposures. We calculated the DIS, LIS, DII, and EDIP with cross-sectional data from the remaining REGARDS cohort (  n = 14,210 with hsCRP measurements) and 2 other study populations with hsCRP and/or an 8-component inflammation biomarker panel, and investigated their associations with circulating inflammation biomarker concentrations using multivariable logistic regression.

RESULTS

In REGARDS, those in the highest relative to the lowest DIS, LIS, DII, and EDIP quintiles had statistically significant 1.66-, 4.29-, 1.56-, and 1.32-fold higher odds of a high hsCRP concentration (>3 mg/dL), respectively (all P-trend < 0.001). Those in the highest relative to the lowest joint DIS/LIS quintile had a statistically significant 7.26-fold higher odds of a high hsCRP concentration. Similar findings were noted in the other 2 validation populations.

CONCLUSION

Our results support that dietary and lifestyle exposures collectively contribute substantially to systemic inflammation, and support the use of our novel DIS and LIS.

Gut microbe-generated metabolite trimethylamine N-oxide and the risk of diabetes: A systematic review and dose-response meta-analysis

Elevated circulating concentrations of the gut bacteria choline metabolite trimethylamine N-oxide (TMAO) were found in patients with type 2 diabetes mellitus (T2DM). However, whether a high level of TMAO is related to the risk of diabetes has not been studied. We aimed to synthesize the evidence on the relation between TMAO levels and the risk of diabetes mellitus (DM) and to investigate the association further in a dose-response meta-analysis. PubMed, Web of Science, and Scopus databases were searched for studies from inception to June 2018. A total of 12 clinical studies were included in this study, and 15 314 enrolled subjects were included. A meta-analysis of two-class variables and continuous variables were used to obtain pooled effects. Dose-response meta-analysis was used to investigate the dose-response relationship between TMAO concentrations and the risk of DM. Meta-regression and subgroup analyses were applied to identify the source of heterogeneity in this study. High levels of circulating TMAO were associated with an increased risk of DM (odds ratio [OR] = 1.89) using the two-class meta-analysis. Plasma levels of TMAO in patients with diabetes were higher than in subjects without diabetes (standardized mean difference [SMD]: 0.36) using a meta-analysis of continuous variables. The OR for DM prevalence increased by 54% per 5 μmol L^-1 increment of plasma TMAO (OR = 1.54) according to the dose-response meta-analysis. This is the first systematic review and meta-analysis to demonstrate a positive dose-dependent association between circulating TMAO levels and increased diabetes risk.

Associations Between Dietary Protein Sources, Plasma BCAA and Short-Chain Acylcarnitine Levels in Adults

Elevated plasma branched-chain amino acids (BCAA) and C3 and C5 acylcarnitines (AC) levels observed in individuals with insulin resistance (IR) might be influenced by dietary protein intakes. This study explores the associations between dietary protein sources, plasma BCAA levels and C3 and C5 ACs in normal weight (NW) or overweight (OW) individuals with or without metabolic syndrome (MS). Data from 199 men and women aged 18⁻55 years with complete metabolite profile were analyzed. Associations between metabolic parameters, protein sources, plasma BCAA and AC levels were tested. OW/MS+ consumed significantly more animal protein (p = 0.0388) and had higher plasma BCAA levels (p < 0.0001) than OW/MS- or NW/MS- individuals. Plasma BCAA levels were not associated with BCAA intakes in the whole cohort, while there was a trend for an association between plasma BCAA levels and red meat or with animal protein in OW/MS+. These associations were of weak magnitude. In NW/MS- individuals, the protein sources associated with BCAA levels varied greatly with adjustment for confounders. Plasma C3 and C5 ACs were associated with plasma BCAA levels in the whole cohort (p < 0.0001) and in subgroups based on OW and MS status. These results suggest a modest association of meat or animal protein intakes and an association of C3 and C5 ACs with plasma BCAA levels, obesity and MS.

Red Meat Consumption (Heme Iron Intake) and Risk for Diabetes and Comorbidities?

PURPOSE OF REVIEW

To examine the role of red meat consumption, especially heme iron intake, and risk for diabetes and its comorbidities.

RECENT FINDINGS

Studies consistently show that consumption of red meat has been contributory to a multitude of chronic conditions such as diabetes, CVD, and malignancies. There are various emerging reasons that strengthen this link-from the basic constituents of red meat like the heme iron component, the metabolic reactions that take place after consumption, and finally to the methods used to cook it. The causative links show that even occasional use raises the risk of T2DM. Prior studies show how nitrites and nitrates in red meat can lead to increased insulin resistance, dysregulated blood glucose levels, and elevated oxidative stress all leading to chronic diseases. With the rise in these preventable chronic diseases, we examine how disease-causing links can be eliminated with appropriate lifestyle choices.

Maternal and neonatal outcomes related to iron supplementation or iron status: a summary of meta-analyses

BACKGROUND

Iron deficiency is the most abundant nutritional deficiency in the world and is discussed to be associated with adverse pregnancy outcomes. The objective of this review was to perform an umbrella summary of meta-analyses to evaluate the effects and associations of iron supplementation or iron status on maternal and birth/neonatal outcomes.

METHODS

A literature search was conducted on PubMed and Scopus by two reviewers without temporal restriction. Systematic reviews and meta-analyses of studies evaluating (1) the effects of multimicronutrient compared to iron + folic acid supplementations on maternal and birth/neonatal outcomes (2), the association of dietary iron intake or hemoglobin or ferritin status regarding the risk for maternal (gestational diabetes mellitus (GDM)) and birth/neonatal outcomes, and (3) the effects of iron supplementation on pregnancy and birth/neonatal outcomes, were included in this review.

RESULTS

Overall, 16 meta-analyses were included. Multimicronutrient supplements had significant risk reducing effects on low birth weight and small for gestational age compared to iron/folic acid supplements as controls. Furthermore, most of the meta-analyses showed that higher levels of hemoglobin or ferritin increased the risk for GDM. On the other hand, maternal anemia (low hemoglobin levels) was associated with adverse birth/neonatal outcomes. Finally, iron supplementation reduced the risk of iron deficiency and iron deficiency anemia and had some risk reducing effects on low birth weight newborns.

CONCLUSIONS

Our summary of meta-analyses showed that multimicronutrient supplementation had beneficial effects on some neonatal outcomes. Furthermore, higher ferritin levels seem to increase the risk for GDM whereas maternal anemia was associated with adverse birth/neonatal outcomes.

Meat, Dietary Heme Iron, and Risk of Type 2 Diabetes Mellitus: The Singapore Chinese Health Study

We evaluated the relationships of red meat, poultry, fish, and shellfish intakes, as well as heme iron intake, with the risk of type 2 diabetes mellitus (T2D).The Singapore Chinese Health Study is a population-based cohort study that recruited 63,257 Chinese adults aged 45-74 years from 1993 to 1998. Usual diet was evaluated using a validated 165-item semiquantitative food frequency questionnaire at recruitment. Physician-diagnosed T2D was self-reported during 2 follow-up interviews in 1999-2004 and 2006-2010. During a mean follow-up of 10.9 years, 5,207 incident cases of T2D were reported. When comparing persons in the highest intake quartiles with those in the lowest, the multivariate-adjusted hazard ratio for T2D was 1.23 (95% confidence interval (CI): 1.14, 1.33) for red meat intake (P for trend < 0.001), 1.15 (95% CI: 1.06, 1.24) for poultry intake (P for trend = 0.004), and 1.07 (95% CI: 0.99, 1.16) for fish/shellfish intake (P for trend = 0.12). After additional adjustment for heme iron, only red meat intake remained significantly associated with T2D risk (multivariate-adjusted hazard ratio = 1.13, 95% CI: 1.01, 1.25; P for trend = 0.02). Heme iron was associated with a higher risk of T2D even after additional adjustment for red meat intake (multivariate-adjusted hazard ratio = 1.14, 95% CI: 1.02, 1.28; P for trend = 0.03). In conclusion, red meat and poultry intakes were associated with a higher risk of T2D. These associations were mediated completely for poultry and partially for red meat by heme iron intake.

Association between microbiota-dependent metabolite trimethylamine-N-oxide and type 2 diabetes

Background: The association of trimethylamine-N-oxide (TMAO), a microbiota-dependent metabolite from dietary choline and carnitine, with type 2 diabetes was inconsistent.Objective: We evaluated the association of plasma TMAO with newly diagnosed type 2 diabetes and the potential modification of TMAO-generating enzyme flavin monooxygenase 3 (FMO3) polymorphisms.Design: This was an age- and sex-matched case-control study of 2694 participants: 1346 newly diagnosed cases of type 2 diabetes and 1348 controls. Concentrations of plasma TMAO were measured, and FMO3 E158K polymorphisms (rs2266782) were genotyped.Results: Medians (IQRs) of plasma TMAO concentration were 1.47 μmol/L (0.81-2.20 μmol/L) for controls and 1.77 μmol/L (1.09-2.80 μmol/L) for type 2 diabetes cases. From the lowest to the highest quartiles of plasma TMAO, the multivariable adjusted ORs of type 2 diabetes were 1.00 (reference), 1.38 (95% CI: 1.08, 1.77), 1.64 (95% CI: 1.28, 2.09), and 2.55 (95% CI: 1.99, 3.28) (P-trend < 0.001); each SD of ln-transformed plasma TMAO was associated with a 38% (95% CI: 26%, 51%) increment in ORs of type 2 diabetes. The FMO3 rs2266782 polymorphism was not associated with type 2 diabetes. The positive association between plasma TMAO and type 2 diabetes was consistent in each rs2266782 genotype group, and no significant interaction was observed (P = 0.093).Conclusions: Our results suggested that higher plasma TMAO was associated with increased odds of newly diagnosed type 2 diabetes and that this association was not modified by the FMO3 rs2266782 polymorphism. This study was registered at clinicaltrials.gov as NCT03130894.

Red meat, diseases, and healthy alternatives: A critical review

Meat is an important food for human nutrition, by especially providing high-quality protein and also some essential micronutrients, in front iron, zinc, and vitamin B₁₂. However, a high intake of red and processed meat is associated with an increased risk for diseases, especially type 2 diabetes and colorectal cancer, as several epidemiological studies and meta-analyses have shown. This review summarizes meta-analyses of publications studying the association between red and processed meat intake and type 2 diabetes, cardiovascular diseases, colorectal and other cancers, and all-cause mortality. Various potential mechanisms involved in the increased disease risk are discussed. Furthermore, the beneficial effects of healthy alternatives for meat, like fish, nuts, vegetables and fruits, pulses and legumes, whole grains, and dairy products are reviewed by including selected papers and recent meta-analyses.

Vegetarian Diets in the Prevention and Management of Diabetes and Its Complications

IN BRIEF Epidemiological studies have found a lower prevalence of type 2 diabetes among vegetarians compared to nonvegetarians. This reduced risk is likely a function of improved weight status, higher intake of dietary fiber, and the absence of animal protein and heme iron in the diet. Interventional studies have shown that vegetarian diets, especially a vegan diet, are effective tools in glycemic control and that these diets control plasma glucose to a greater level than do control diets, including diets traditionally recommended for patients with diabetes (e.g., diets based on carbohydrate counting). Vegetarian diets are associated with improvement in secondary outcomes such as weight reduction, serum lipid profile, and blood pressure. Studies indicate that vegetarian diets can be universally used in type 2 diabetes prevention and as tools to improve blood glucose management.

Association of serum ferritin levels with metabolic syndrome and insulin resistance in a Chinese population

AIMS

Increased iron is associated with type 2 diabetes, dyslipidemia, and high blood pressure. Therefore, serum ferritin may be a suitable biomarker to detect metabolic syndrome (MetS). We investigated the relationship between serum ferritin, and the prevalence of MetS and insulin resistance (IR).

METHODS

This cross-sectional study assessed 2,786 Chinese participants, aged 25-75 years. MetS was defined using the 2006 International Diabetes Federation guidelines. IR was assessed with homeostasis model assessment estimated IR (HOMA-IR). Regression analysis was used to estimate the association between serum ferritin and the prevalence of MetS and IR.

RESULTS

MetS prevalence within each serum ferritin quartile (Q1-4) was 31.7%, 37.1%, 43.6%, and 55.4%, respectively in men (P<0.001), and 30.1%, 34.8%, 48.2%, and 66.9%, respectively in women (P<0.001). Increased serum ferritin correlated with the number of MetS components (P<0.001). The odds ratio for MetS in the ferritin Q4 group was 1.95 (1.39-2.73) for men and 1.66(1.12-2.47) for women, compared with Q1. Serum ferritin correlated positively with HOMA-IR in men (regression coefficient: 0.058, P=0.009) and women (regression coefficient: 0.082, P=0.001).

CONCLUSION

MetS prevalence increased with elevated serum ferritin levels, and serum ferritin levels were independently associated with MetS and IR.

Red Meat and Health

Despite its nutritional benefits, there is an increasing body of evidence to suggest that regular consumption of red meat may negatively impact health and disease risk, including the risk of most common chronic diseases. This chapter reviews the current evidence linking red and processed meat intakes with chronic disease, obesity and mortality risks and discusses possible mechanisms to explain these associations. Research on the health benefits of diets low in red meat, including vegetarian, vegan, Mediterranean and other plant-based diets, is also reviewed.

High maternal iron status, dietary iron intake and iron supplement use in pregnancy and risk of gestational diabetes mellitus: a prospective study and systematic review

AIM

High iron measured using dietary intake and biomarkers is associated with Type 2 diabetes. It is uncertain whether a similar association exists for gestational diabetes mellitus. The aim of this systematic review was to conduct a cohort study examining first trimester body iron stores and subsequent risk of gestational diabetes, and to include these findings in a systematic review of all studies examining the association between maternal iron status, iron intake (dietary and supplemental) and the risk of gestational diabetes.

METHODS

Serum samples from women with first trimester screening were linked to birth and hospital records for data on maternal characteristics and gestational diabetes diagnosis. Blood was analysed for ferritin, soluble transferrin receptor and C-reactive protein. Associations between iron biomarkers and gestational diabetes were assessed using multivariate logistic regression. A systematic review and meta-analysis, registered with PROSPERO (CRD42014013663) included studies of all designs published in English from January 1995 to July 2015 that examined the association between iron and gestational diabetes and included an appropriate comparison group.

RESULTS

Of 3776 women, 3.4% subsequently developed gestational diabetes. Adjusted analyses found increased odds of gestational diabetes for ferritin (OR 1.41; 95% CI 1.11, 1.78), but not for soluble transferrin receptor (OR 1.00; 95% CI 0.97, 1.03) per unit increase of the biomarker. Two trials of iron supplementation found no association with gestational diabetes. Increased risk of gestational diabetes was associated with higher levels of ferritin and serum iron and dietary haem iron intakes.

CONCLUSIONS

Increased risk of gestational diabetes among women with high serum ferritin and iron levels and dietary haem iron intakes warrants further investigation.

Red Meat and Health

Despite its nutritional benefits, there is an increasing body of evidence to suggest that regular consumption of red meat may negatively impact health and disease risk, including the risk of most common chronic diseases. This chapter reviews the current evidence linking red and processed meat intakes with chronic disease, obesity and mortality risks and discusses possible mechanisms to explain these associations. Research on the health benefits of diets low in red meat, including vegetarian, vegan, Mediterranean and other plant-based diets, is also reviewed.

Qualidade da dieta entre consumidores e não consumidores de carnes vermelhas e processadas: estudo ISA-Capital

OBJETIVO: Avaliar a qualidade da dieta entre consumidores e não consumidores de carnes vermelhas e processadas em residentes do município de São Paulo. MÉTODOS: Foram utilizados dados do estudo transversal do Inquérito de Saúde de São Paulo - 2008, com informações de 726 indivíduos que possuíam todas as informações dos inquéritos dietéticos, sendo 195 adolescentes, 272 adultos e 259 idosos. Os dados de consumo alimentar foram obtidos por dois recordatórios alimentares de 24 horas, aplicados em dias não consecutivos, incluindo final de semana e todas as estações do ano, e um questionário de frequência alimentar para estimar a frequência do consumo de carnes vermelhas e processadas. A ingestão alimentar habitual foi estimada pelo Multiple Source Method. O Índice de Qualidade da Dieta - Revisado foi calculado a partir da ingestão habitual dos participantes. As recomendações da Organização Mundial de Saúde foram utilizadas para estimar a participação percentual dos macronutrientes no valor energético total. RESULTADOS: O grupo de não consumidores apresentou maior pontuação média do índice (p=0,006), do grupo das frutas integrais (p=0,022), dos leites e derivados (p<0,001) e menor pontuação média de gordura sólida, álcool e açúcar de adição (p=0,039) e carnes, ovos e leguminosas (p<0,001). Também se mostrou maior percentual de adequação de gordura no grupo de não consumidores de carnes vermelhas e processadas. CONCLUSÃO: Sugere-se que não consumidores de carne vermelha e processada tenha melhor qualidade da dieta e maior adequação da contribuição energética dos lipídeos em comparação com consumidores desse alimento.

Non-transferrin-bound iron is associated with biomarkers of oxidative stress, inflammation and endothelial dysfunction in type 2 diabetes

AIMS

To investigate the association between circulating non-transferrin-bound iron [NTBI], and markers of oxidative stress, endothelial function and inflammation in subjects with type 2 diabetes and non-diabetic subjects with varying degrees of obesity.

METHODS

Plasma NTBI was measured by HPLC, together with total iron, iron-binding capacity, transferrin saturation and soluble transferrin receptor, together with total and reduced ascorbate, malondialdehyde [MDA], E-selectin and high-sensitivity c-reactive protein [hs-CRP] in groups of 28 subjects with type 2 diabetes, 28 non-obese controls and 17 obese non-diabetic subjects.

RESULTS

Levels of NTBI were higher than controls in the diabetes group, but the total serum iron levels were lower. MDA levels were higher than controls in both the diabetes and obese groups, and this was associated with higher levels of oxidised ascorbate. hs-CRP levels were higher in both the diabetes and obese groups, and E-selectin was significantly higher in the diabetes group. There were strong positive correlations between HbA1c levels and NTBI [P<0.01], HbA1c and E-selectin [P<0.001] and NTBI and E-selectin [P<0.02] in the diabetes group.

CONCLUSION

These results support the hypothesis that iron-mediated oxidative stress may be a mechanism linking poor glycaemic control with vascular dysfunction in type 2 diabetes.

Lipid Peroxidation in a Stomach Medium Is Affected by Dietary Oils (Olive/Fish) and Antioxidants: The Mediterranean versus Western Diet

Red meat is an integral part of the Western diet, and high consumption is associated with an increased risk of chronic diseases. Using a system that simulated the human stomach, red meat was interacted with different oils (olive/fish) and lipid peroxidation was determined by measuring accumulation of malondialdehyde (MDA) and lipid peroxides (LOOH). Olive oil decreased meat lipid peroxidation from 121.7 ± 3.1 to 48.2 ± 1.3 μM and from 327.1 ± 9.5 to 77.3 ± 6.0 μM as assessed by MDA and ROOH, respectively. The inhibitory effect of olive oil was attributed to oleic acid rather than its polyphenol content. In contrast, fish oils from tuna or an ω-3 supplement dramatically increased meat lipid peroxidation from 96.2 ± 3.6 to 514.2 ± 6.7 μM MDA. Vitamin E inhibited meat lipid peroxidation in the presence of olive oil but paradoxically increased peroxidation in the presence of fish oil. The inhibitory properties of oleic acid may play a key role in the health benefits of the Mediterranean diet.

A review of potential metabolic etiologies of the observed association between red meat consumption and development of type 2 diabetes mellitus

Epidemiological studies suggest that red and processed meat consumption is related to an increased risk of type 2 diabetes. However, it is not clearly understood which components of red and processed meat contribute to this increased risk. This review examines potential mechanisms addressing the role of saturated fatty acid, sodium, advanced glycation end products (AGEs), nitrates/nitrites, heme iron, trimethylamine N-oxide (TMAO), branched amino acids (BCAAs) and endocrine disruptor chemicals (EDCs) in the development of type 2 diabetes based on data from published clinical trials and animal models. TMAO which is derived from dietary carnitine and choline by the action of bacterial enzymes followed by oxidation in the liver may be a strong candidate molecule mediating the risk of type 2 diabetes. BCAAs may induce insulin resistance via the mammalian target of rapamycin complex 1 (mTORC1) and ribosomal protein S6 kinase β 1 (S6k1)-associated pathways. The increased risk associated with processed meat compared with red meat suggests that there are interactions between the saturated fat, salt, and nitrates in processed meat and iron, AGEs and TMAO. Intervention studies are required to clarify potential mechanisms and explore interactions among components, in order to make firm recommendations on red and processed meat consumption.

Role of poultry meat in a balanced diet aimed at maintaining health and wellbeing: an Italian consensus document

The relationship between the consumption of meat and health is multifaceted, and it needs to be analyzed in detail, with specific attention to the relevant differences that characterize the effects of the different meat types, as yet considered by only a limited literature. A variable but moderate energy content, highly digestible proteins (with low levels of collagen) of good nutritional quality, unsaturated lipids (mainly found in the skin and easily removed), B-group vitamins (mainly thiamin, vitamin B6, and pantothenic acid), and minerals (like iron, zinc, and copper) make poultry meat a valuable food. Epidemiological studies performed across the world, in highly diverse populations with different food preferences and nutritional habits, provide solid information on the association between poultry consumption, within a balanced diet, and good health. Consumption of poultry meat, as part of a vegetable-rich diet, is associated with a risk reduction of developing overweight and obesity, cardiovascular diseases, and type 2 diabetes mellitus. Also, white meat (and poultry in particular) is considered moderately protective or neutral on cancer risk. The relevance of poultry meat for humans also has been recognized by the UN Food and Agricultural Organization (FAO), who considers this widely available, relatively inexpensive food to be particularly useful in developing countries, where it can help to meet shortfalls in essential nutrients. Moreover, poultry meat consumption also contributes to the overall quality of the diet in specific ages and conditions (prior to conception, during pregnancy up to the end of breastfeeding, during growth, and in the geriatric age) and is suitable for those who have an increased need for calorie and protein compared to the general population.

Poorly controlled type 2 diabetes is accompanied by significant morphological and ultrastructural changes in both erythrocytes and in thrombin-generated fibrin: implications for diagnostics

We have noted in previous work, in a variety of inflammatory diseases, where iron dysregulation occurs, a strong tendency for erythrocytes to lose their normal discoid shape and to adopt a skewed morphology (as judged by their axial ratios in the light microscope and by their ultrastructure in the SEM). Similarly, the polymerization of fibrinogen, as induced in vitro by added thrombin, leads not to the common ‘spaghetti-like’ structures but to dense matted deposits. Type 2 diabetes is a known inflammatory disease. In the present work, we found that the axial ratio of the erythrocytes of poorly controlled (as suggested by increased HbA1c levels) type 2 diabetics was significantly increased, and that their fibrin morphologies were again highly aberrant. As judged by scanning electron microscopy and in the atomic force microscope, these could be reversed, to some degree, by the addition of the iron chelators deferoxamine (DFO) or deferasirox (DFX). As well as their demonstrated diagnostic significance, these morphological indicators may have prognostic value.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

Substitution of red meat with legumes in the therapeutic lifestyle change diet based on dietary advice improves cardiometabolic risk factors in overweight type 2 diabetes patients: a cross-over randomized clinical trial

BACKGROUND/OBJECTIVE

The objective of this study was to determine the effects of substitution of red meat with legumes in the Therapeutic Lifestyle Change (TLC) diet on cardiometabolic risk factors in type 2 diabetes patients based on dietary education.

SUBJECTS/METHODS

This study was a randomized, controlled, cross-over trial. Thirty-one participants (24 women and 7 men; age: 58.1 ± 6.0 years) with type 2 diabetes were randomly assigned to consume a control diet (legume-free TLC diet) and legume-based TLC diet for 8 weeks. Legume-based TLC diet was the same as the control diet, but the legume-based TLC group was advised to replace two servings of red meat with legumes, 3 days per week. After the interventional period, a washout period was conducted for 4 weeks. The groups were then advised to follow the alternate treatment for 8 weeks. Cardiometabolic risk factors were measured.

RESULTS

Compared with the legume-free TLC diet, the legume-based TLC diet significantly decreased fasting blood glucose (P=0.04), fasting insulin (P=0.04), triglyceride concentrations (P=0.04) and low-density lipoprotein cholesterol (P=0.02). Total cholesterol concentrations decreased after consumption of both TLC diet and legume TLC diet; however, the data did not differ significantly between the two diets. body mass index (BMI), waist circumference, systolic and diastolic blood pressures did not change significantly after consumption of either the legume-free TLC diet or the legume-based TLC diet.

CONCLUSIONS

Dietary advice given for substitution of red meat with legume intakes within a TLC diet-improved lipid profiles and glycemic control among diabetes patients, which were independent from BMI change. This trial was registered in the Iranian Registry of Clinical Trials (http://www.irct.ir) as IRCT201202251640N7.

Evidence that multiple defects in lipid regulation occur before hyperglycemia during the prodrome of type-2 diabetes

BACKGROUND

Blood-vessel dysfunction arises before overt hyperglycemia in type-2 diabetes (T2DM). We hypothesised that a metabolomic approach might identify metabolites/pathways perturbed in this pre-hyperglycemic phase. To test this hypothesis and for specific metabolite hypothesis generation, serum metabolic profiling was performed in young women at increased, intermediate and low risk of subsequent T2DM.

METHODS

Participants were stratified by glucose tolerance during a previous index pregnancy into three risk-groups: overt gestational diabetes (GDM; n = 18); those with glucose values in the upper quartile but below GDM levels (UQ group; n = 45); and controls (n = 43, below the median glucose values). Follow-up serum samples were collected at a mean 22 months postnatally. Samples were analysed in a random order using Ultra Performance Liquid Chromatography coupled to an electrospray hybrid LTQ-Orbitrap mass spectrometer. Statistical analysis included principal component (PCA) and multivariate methods.

FINDINGS

Significant between-group differences were observed at follow-up in waist circumference (86, 95%CI (79-91) vs 80 (76-84) cm for GDM vs controls, p<0.05), adiponectin (about 33% lower in GDM group, p = 0.004), fasting glucose, post-prandial glucose and HbA1c, but the latter 3 all remained within the 'normal' range. Substantial differences in metabolite profiles were apparent between the 2 'at-risk' groups and controls, particularly in concentrations of phospholipids (4 metabolites with p ≤ 0.01), acylcarnitines (3 with p ≤ 0.02), short- and long-chain fatty acids (3 with p<  = 0.03), and diglycerides (4 with p ≤ 0.05).

INTERPRETATION

Defects in adipocyte function from excess energy storage as relatively hypoxic visceral and hepatic fat, and impaired mitochondrial fatty acid oxidation may initiate the observed perturbations in lipid metabolism. Together with evidence from the failure of glucose-directed treatments to improve cardiovascular outcomes, these data and those of others indicate that a new, quite different definition of type-2 diabetes is required. This definition would incorporate disturbed lipid metabolism prior to hyperglycemia.