Whole egg consumption increases plasma choline and betaine without affecting TMAO levels or gut microbiome in overweight postmenopausal women

Developing and evaluating the construct validity of a dietary pattern predictive of plasma TMAO and choline

BACKGROUND AND AIMS

The metabolism of choline (highly present in animal products) can produce trimethylamine N-oxide (TMAO), a metabolite with atherosclerotic effects; however, dietary fiber may suppress this metabolic pathway. This study aimed to develop a dietary pattern predictive of plasma TMAO and choline concentrations using reduced rank regression (RRR) and to evaluate its construct validity.

METHODS AND RESULTS

Diet and plasma concentrations of choline (μmol/L) and TMAO (μmol/L) were assessed in 1724 post-menopausal women who participated in an ancillary study within the Women's Health Initiative Observational Study (1993-1998). The TMAO dietary pattern was developed using RRR in half of the sample (Training Sample) and applied to the other half of the sample (Validation Sample) to evaluate its construct validity. Energy-adjusted food groups were the predictor variables and plasma choline and TMAO, the response variables. ANCOVA and linear regression models were used to assess associations between each biomarker and the dietary pattern score. Discretionary fat, potatoes, red meat, and eggs were positively associated with the dietary pattern, while yogurt, fruits, added sugar, and starchy vegetables were inversely associated. Mean TMAO and choline concentrations significantly increased across increasing quartiles of the dietary pattern in the Training and Validation samples. Positive associations between the biomarkers and the TMAO dietary pattern were also observed in linear regression models (Validation Sample: TMAO, adjusted beta-coefficient = 0.037 (p-value = 0.0088); Choline, adjusted beta-coefficient = 0.011 (p-value = 0.0224).

CONCLUSION

We established the TMAO dietary pattern, a dietary pattern reflecting the potential of the diet to contribute to plasma concentrations of TMAO and choline.

Debunking the Myth: Eggs and Heart Disease

Eggs, which are often considered a complete food, have recently been scrutinized by the media as a potential cause of cardiovascular disease. However, the media hasn't shown the same enthusiasm for processed foods high in fructose, the consumption of refined cooking oil, seed oils, and carbohydrate-rich meals, the connection between these factors and metabolic diseases, or the potential long-term impacts on population comorbidities, as they have for criticizing egg yolks as a cause for cardiovascular disease in recent times. This review investigates the relationship between eggs and lipid levels, glucose levels, atherosclerosis, and antioxidant properties, as well as comparing them to cholesterol-free egg controls. We conducted the review in response to a recent trend of discarding nutritious and energy-rich egg yolks due to the belief propagated by the media that removing egg yolks from a normal diet is cardioprotective after the media started to blame egg yolks as the cause of the recent surge in heart attacks. However, the media fails to highlight the fact that eggs have been an integral part of the human diet since the domestication of hens. On the other hand, recent additions to the human diet a few decades ago, such as fructose-rich breakfast cereals, coffee beverages with sugar levels comparable to candy bars, protein supplements for diabetics that are notorious for raising blood glucose levels, and the heightened consumption of seed oil, which causes inflammation, have been responsible for the surge in cardiovascular events in recent times. Social media platforms often showcase visually appealing junk food products and sugary beverages as a sign of wealth, promoting unhealthy processed food and ultimately causing a decline in an individual's lifespan and overall health.

Rapid and Direct Detection of Trimethylamine N-oxide Using an Off-Chip Capacitance Biosensor with Readout SoC for Early-Stage Thrombosis and Cardiovascular Disease

A demonstration of an off-chip capacitance array sensor with a limit of detection of 1 μM trimethylamine N-oxide (TMAO) to diagnose a chronic metabolism disease in urine is presented. The improved Cole-Cole model is employed to determine the parameters of R_catalyzed, C_catalyzed, and Rp_catalyzed, enabling the prediction of the catalytic resistance of enzyme, reduction effects of the analyte, and characterize the small signal alternating current properties of ionic strength caused by catalysis. Based on the standard solutions, we investigate the effects of pixel geometry parameters, driving electrode width, and sensing electrode width on the electrical field change of the off-chip capacitance sensor; the proposed off-chip sensor with readout system-on-chip exhibits a high sensitivity of 21 analog-to-digital converter counts/μM TMAO (or 2.5 mV/μM TMAO), response time of 1 s, repetition of 98.9%, and drift over time of 0.5 mV. The proposed off-chip sensor effectively discriminates TMAO in a phosphate-buffered saline solution based on minute changes in capacitance induced by the TorA enzyme, resulting in a discernible 2.15% distinction. These measurements have been successfully corroborated using the conventional cyclic voltammetry method, demonstrating a mere 0.024% variance. The off-chip sensor is crafted with a specific focus on detecting TMAO, achieved by excluding any reduction reactions between the TMAO-specific enzyme TorA and the compounds creatine and creatinine present in urine. This deliberate omission ensures that the sensor's attention remains solely on TMAO, thereby enhancing its precision in achieving accurate and reliable TMAO detection.

Choline - a scoping review for Nordic Nutrition Recommendations 2023

Choline is an essential nutrient with metabolic roles as a methyl donor in one carbon metabolism and as a precursor for membrane phospholipids and the neurotransmitter acetylcholine. Choline content is particularly high in liver, eggs, and wheat germ, although it is present in a variety of foods. The main dietary sources of choline in the Nordic and Baltic countries are meat, dairy, eggs, and grain. A diet that is devoid of choline causes liver and muscle dysfunction within 3 weeks. Choline requirements are higher during pregnancy and lactation than in non-pregnant women. Although no randomized controlled trials are available, observational studies in human, supported by coherence from interventional studies with neurodevelopmental outcomes and experimental studies in animals, strongly suggest that sufficient intake of choline during pregnancy is necessary for normal brain development and function in the child. Observational studies suggested that adequate intake of choline could have positive effects on cognitive function in older people. However, prospective data are lacking, and no intervention studies are available in the elderly.

Precision Nutrition and Cardiovascular Disease Risk Reduction: the Promise of High-Density Lipoproteins

PURPOSE OF REVIEW

Emerging evidence supports the promise of precision nutritional approaches for cardiovascular disease (CVD) prevention. Here, we discuss current findings from precision nutrition trials and studies reporting substantial inter-individual variability in responses to diets and dietary components relevant to CVD outcomes. We highlight examples where early precision nutrition research already points to actionable intervention targets tailored to an individual's biology and lifestyle. Finally, we make the case for high-density lipoproteins (HDL) as a compelling next generation target for precision nutrition aimed at CVD prevention. HDL possesses complex structural features including diverse protein components, lipids, size distribution, extensive glycosylation, and interacts with the gut microbiome, all of which influence HDL's anti-inflammatory, antioxidant, and cholesterol efflux properties. Elucidating the nuances of HDL structure and function at an individual level may unlock personalized dietary and lifestyle strategies to optimize HDL-mediated atheroprotection and reduce CVD risk.

RECENT FINDINGS

Recent human studies have demonstrated that HDL particles are key players in the reduction of CVD risk. Our review highlights the role of HDL and the importance of personalized therapeutic approaches to improve their potential for reducing CVD risk. Factors such as diet, genetics, glycosylation, and gut microbiome interactions can modulate HDL structure and function at the individual level. We emphasize that fractionating HDL into size-based subclasses and measuring particle concentration are necessary to understand HDL biology and for developing the next generation of diagnostics and biomarkers. These discoveries underscore the need to move beyond a one-size-fits-all approach to HDL management. Precision nutrition strategies that account for personalized metabolic, genetic, and lifestyle data hold promise for optimizing HDL therapies and function to mitigate CVD risk more potently. While human studies show HDL play a key role in reducing CVD risk, recent findings indicate that factors such as diet, genetics, glycosylation, and gut microbes modulate HDL function at the individual level, underscoring the need for precision nutrition strategies that account for personalized variability to optimize HDL's potential for mitigating CVD risk.

Effect of Consumption of Animal Products on the Gut Microbiome Composition and Gut Health

The gut microbiome is critical in human health, and various dietary factors influence its composition and function. Among these factors, animal products, such as meat, dairy, and eggs, represent crucial sources of essential nutrients for the gut microbiome. However, the correlation and characteristics of livestock consumption with the gut microbiome remain poorly understood. This review aimed to delineate the distinct effects of meat, dairy, and egg products on gut microbiome composition and function. Based on the previous reports, the impact of red meat, white meat, and processed meat consumption on the gut microbiome differs from that of milk, yogurt, cheese, or egg products. In particular, we have focused on animal-originated proteins, a significant nutrient in each livestock product, and revealed that the major proteins in each food elicit diverse effects on the gut microbiome. Collectively, this review highlights the need for further insights into the interactions and mechanisms underlying the impact of animal products on the gut microbiome. A deeper understanding of these interactions would be beneficial in elucidating the development of dietary interventions to prevent and treat diseases linked to the gut microbiome.

Consumption of Different Egg-Based Diets Alters Clinical Metabolic and Hematological Parameters in Young, Healthy Men and Women

Eggs-particularly egg yolks-are a rich source of bioactive nutrients and dietary compounds that influence metabolic health, lipid metabolism, immune function, and hematopoiesis. We investigated the effects of consuming an egg-free diet, three egg whites per day, and three whole eggs per day for 4 weeks on comprehensive clinical metabolic, immune, and hematologic profiles in young, healthy adults (18-35 y, BMI < 30 kg/m2 or <30% body fat for men and <40% body fat for women, n = 26) in a 16-week randomized, crossover intervention trial. We observed that average daily macro- and micronutrient intake significantly differed across egg diet periods, including greater intake of choline during the whole egg diet period, which corresponded to increased serum choline and betaine without altering trimethylamine N-oxide. Egg white and whole egg intake increased serum isoleucine while whole egg intake reduced serum glycine-markers of increased and decreased risk of insulin resistance, respectively-without altering other markers of glucose sensitivity or inflammation. Whole egg intake increased a subset of large HDL particles (H6P, 10.8 nm) and decreased the total cholesterol:HDL-cholesterol ratio and % monocytes in female participants using combined oral contraceptive (COC) medication (n = 11) as compared to female non-users (n = 10). Whole egg intake further increased blood hematocrit whereas egg white and whole egg intake reduced blood platelet counts. Changes in clinical immune cell counts between egg white and whole egg diet periods were negatively correlated with several HDL parameters yet positively correlated with measures of triglyceride-rich lipoproteins and insulin sensitivity. Overall, the intake of whole eggs led to greater overall improvements in micronutrient diet quality, choline status, and HDL and hematologic profiles while minimally-yet potentially less adversely-affecting markers of insulin resistance as compared to egg whites.

Plant-Based Nutrition: Exploring Health Benefits for Atherosclerosis, Chronic Diseases, and Metabolic Syndrome-A Comprehensive Review

Atherosclerosis, chronic non-communicable diseases, and metabolic syndrome are highly interconnected and collectively contribute to global health concerns that reduce life expectancy and quality of life. These conditions arise from multiple risk factors, including inflammation, insulin resistance, impaired blood lipid profile, endothelial dysfunction, and increased cardiovascular risk. Adopting a plant-based diet has gained popularity as a viable alternative to promote health and mitigate the incidence of, and risk factors associated with, these three health conditions. Understanding the potential benefits of a plant-based diet for human health is crucial, particularly in the face of the rising prevalence of chronic diseases like diabetes, hypertension, dyslipidemia, atherosclerosis, and cancer. Thus, this review focused on the plausible advantages of consuming a type of food pattern for the prevention and/or treatment of chronic diseases, emphasizing the dietary aspects that contribute to these conditions and the evidence supporting the benefits of a plant-based diet for human health. To facilitate a more in-depth analysis, we present separate evidence for each of these three concepts, acknowledging their intrinsic connection while providing a specific focus on each one. This review underscores the potential of a plant-based diet to target the underlying causes of these chronic diseases and enhance health outcomes for individuals and populations.

Eggs: Healthy or Risky? A Review of Evidence from High Quality Studies on Hen's Eggs

Hen's eggs (from Gallus gallus domesticus) provide choline, folate, vitamin D, iodine, B vitamins and high-quality protein and are no longer viewed by national bodies as a risk factor for hypercholesterolaemia and cardiovascular disease (CVD). Yet, questions remain about the benefits and risks of eating eggs regularly. This review evaluates recent high-quality evidence from randomised controlled trials (RCT) and meta-analyses of observational studies and considers new areas of interest, such as weight management, protein metabolism, allergy risk and sustainability. In several RCT, eggs increased muscle protein synthesis and lowered fat mass, which could support optimal body composition. Eggs within a meal improved satiety, which could translate into lower energy intakes, although more RCT are needed. In observational studies, higher egg consumption was associated with a null effect or a modest reduced risk of CVD. For type 2 diabetes (T2D) incidence and risk of CVD in people with T2D, there were inconsistencies between observational and RCT data, with the former noting positive associations and the latter seeing no effect of higher egg intake on markers of T2D and CVD. Sustainability metrics suggest that eggs have the lowest planetary impact amongst animal proteins. To lower allergy risk, earlier introduction of eggs into weaning diets is warranted. In conclusion, the balance of evidence points to eggs being a nutritious food suggesting there are broad health benefits from including eggs in the diet at intakes higher than that currently consumed by European populations.

Dietary choline increases brown adipose tissue activation markers and improves cholesterol metabolism in female APOE*3-Leiden.CETP mice

OBJECTIVES

Studies in mice have recently linked increased dietary choline consumption to increased incidence of obesity-related metabolic diseases, while several clinical trials have reported an anti-obesity effect of high dietary choline intake. Since the underlying mechanisms by which choline affects obesity are incompletely understood, the aim of the present study was to investigate the role of dietary choline supplementation in adiposity.

METHODS

Female APOE*3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism and cardiometabolic diseases, were fed a Western-type diet supplemented with or without choline (1.2%, w/w) for up to 16 weeks.

RESULTS

Dietary choline reduced body fat mass gain, prevented adipocyte enlargement, and attenuated adipose tissue inflammation. Besides, choline ameliorated liver steatosis and damage, associated with an upregulation of hepatic genes involved in fatty acid oxidation. Moreover, choline reduced plasma cholesterol, as explained by a reduction of plasma non-HDL cholesterol. Mechanistically, choline reduced hepatic VLDL-cholesterol secretion and enhanced the selective uptake of fatty acids from triglyceride-rich lipoprotein (TRL)-like particles by brown adipose tissue (BAT), consequently accelerating the clearance of the cholesterol-enriched TRL remnants by the liver.

CONCLUSIONS

In APOE*3-Leiden.CETP mice, dietary choline reduces body fat by enhancing TRL-derived fatty acids by BAT, resulting in accelerated TRL turnover to improve hypercholesterolemia. These data provide a mechanistic basis for the observation in human intervention trials that high choline intake is linked with reduced body weight.

Contribution of Trimethylamine N-Oxide (TMAO) to Chronic Inflammatory and Degenerative Diseases

Trimethylamine N-oxide (TMAO) is a metabolite produced by the gut microbiota and has been mainly associated with an increased incidence of cardiovascular diseases (CVDs) in humans. There are factors that affect one's TMAO level, such as diet, drugs, age, and hormones, among others. Gut dysbiosis in the host has been studied recently as a new approach to understanding chronic inflammatory and degenerative diseases, including cardiovascular diseases, metabolic diseases, and Alzheimer's disease. These disease types as well as COVID-19 are known to modulate host immunity. Diabetic and obese patients have been observed to have an increase in their level of TMAO, which has a direct correlation with CVDs. This metabolite is attributed to enhancing the inflammatory pathways through cholesterol and bile acid dysregulation, promoting foam cell formation. Additionally, TMAO activates the transcription factor NF-κB, which, in turn, triggers cytokine production. The result can be an exaggerated inflammatory response capable of inducing endoplasmic reticulum stress, which is responsible for various diseases. Due to the deleterious effects that this metabolite causes in its host, it is important to search for new therapeutic agents that allow a reduction in the TMAO levels of patients and that, thus, allow patients to be able to avoid a severe cardiovascular event. The present review discussed the synthesis of TMAO and its contribution to the pathogenesis of various inflammatory diseases.

Meals and movies: making our microbiota merry

OBJECTIVE

To investigate the impact of festive cinematic diets on the gut microbiota.

DESIGN

Observational (watching films) and creative review. Sadly, we couldn't incorporate any snowball sampling.

SETTING

In front of a television, by a blazing log fire.

PARTICIPANTS

Everyone: you don't need to be on the nice list!

MAIN OUTCOME MEASURES

Microbiota INdex of Comparative Evaluation for Pictorial Infographic Evidence (MINCE PIE) scores (difference between the numbers of microbiota-enhancing and microbiota-detrimental food groups) for foods depicted in twelve festive films.

RESULTS

Most festive films featured meals or foods from a typical Western diet, with high sugar and fat content, with overall negative effects on the microbiota. However, some films promoted options containing fibre, beneficial proteins, or polyphenols. These are gifts under the Christmas tree for our microbiota.

CONCLUSION

Good balance is needed for our microbiota, and consequently our mental health. Many festive films portray a Western diet that can lead to dysbiosis. Through their action on the gut-brain axis and the influence of media on dietary choices, the festive foods consumed in these films (maybe an extra chocolate biscuit during Love Actually) can be stressful for our microbiota.

Inadequate Choline Intake in Pregnant Women in Germany

Choline is an essential nutrient that is involved in various developmental processes during pregnancy. While the general adequate choline intake (AI) for adults has been set at 400 mg/day by the European Food Safety Authority (EFSA), an AI of 480 mg/day has been derived for pregnant women. To date, the choline intake of pregnant women in Germany has not been investigated yet. Therefore, in this survey, the total choline intake from dietary and supplementary sources in pregnant women was estimated using an online questionnaire. A total of 516 pregnant women participated in the survey, of which 283 met the inclusion criteria (13 to 41 weeks of gestational age, 19−45 years). 224 (79%) of the participants followed an omnivorous diet, 59 (21%) were vegetarian or vegan. Median choline intake was 260.4 (±141.4) mg/day, and only 19 women (7%) achieved the adequate choline intake. The median choline intake of omnivores was significantly higher than that of vegetarians/vegans (269.5 ± 141.5 mg/day vs. 205.2 ± 101.2 mg/day; p < 0.0001). 5% (13/283) of pregnant women took choline-containing dietary supplements. In these women, dietary supplements provided 19% of the total choline intake. Due to the importance of choline for the developmental processes during pregnancy, the study results prove the urgent need for an improved choline supply for pregnant women.

The Role of Betaine in Patients With Chronic Kidney Disease: a Narrative Review

PURPOSE OF REVIEW

This narrative review aimed to explore the functions of betaine and discuss its role in patients with chronic kidney disease (CKD).

RECENT FINDINGS

Some studies on CKD animal models have shown the benefits of betaine supplementation, including decreased kidney damage, antioxidant recovery status, and decreased inflammation. Betaine (N-trimethylglycine) is an N-trimethylated amino acid with an essential regulatory osmotic function. Moreover, it is a methyl donor and has anti-inflammatory and antioxidant properties. Additionally, betaine has positive effects on intestinal health by regulating the osmolality and gut microbiota. Due to these crucial functions, betaine has been studied in several diseases, including CKD, in which betaine plasma levels decline with the progression of the disease. Low betaine levels are linked to increased kidney damage, inflammation, oxidative stress, and intestinal dysbiosis. Furthermore, betaine is considered an essential metabolite for identifying CKD stages.

Exploring the association between habitual food intake and the urine and blood metabolome in adolescents and young adults: a cohort study

SCOPE

Habitual diet may be reflected in metabolite profiles that can improve accurate assessment of dietary exposure and further enhance our understanding of their link to health conditions. We aimed to explore the relationship of habitual food intake with blood and urine metabolites in adolescents and young adults.

METHODS

The study population comprised 228 participants (94 male and 134 female) of the DONALD study. Dietary intake was assessed by yearly repeated 3d-food records. Habitual diet was estimated as the average consumption of 23 food groups in adolescence. Using an untargeted metabolomics approach, we quantified 2638 metabolites in plasma and 1407 metabolites in urine. In each sex, we determined unique diet-metabolite associations using orthogonal projection to latent structures (oPLS) and random forests (RF).

RESULTS

We observed 6 metabolites in agreement between oPLS and RF in urine, 1 in females (vanillylmandelate to processed/ other meat) and 5 in males (indole-3-acetamide, and N6-methyladenosine to eggs; hippurate, citraconate/glutaconate, and X - 12111 to vegetables). We observed no association in blood in agreement.

CONCLUSION

We observed a limited reflection of habitual food group intake by single metabolites in urine and not in blood. The explored biomarkers should be confirmed in additional studies. This article is protected by copyright. All rights reserved.

Diet, Fecal Microbiome, and Trimethylamine N-Oxide in a Cohort of Metabolically Healthy United States Adults

TMAO is elevated in individuals with cardiometabolic diseases, but it is unknown whether the metabolite is a biomarker of concern in healthy individuals. We conducted a cross-sectional study in metabolically healthy adults aged 18-66 years with BMI 18-44 kg/m² and assessed the relationship between TMAO and diet, the fecal microbiome, and cardiometabolic risk factors. TMAO was measured in fasted plasma samples by liquid chromatography mass spectrometry. The fecal microbiome was assessed by 16S ribosomal RNA sequencing and recent food intake was captured by multiple ASA24 dietary recalls. Endothelial function was assessed via EndoPAT. Descriptive statistics were computed by fasting plasma TMAO tertiles and evaluated by ANOVA and Tukey's post-hoc test. Multiple linear regression was used to assess the relationship between plasma TMAO and dietary food intake and metabolic health parameters. TMAO concentrations were not associated with average intake of animal protein foods, fruits, vegetables, dairy, or grains. TMAO was related to the fecal microbiome and the genera Butyribrio, Roseburia, Coprobaciullus, and Catenibacterium were enriched in individuals in the lowest versus the highest TMAO tertile. TMAO was positively associated with α-diversity and compositional differences were identified between groups. TMAO was not associated with classic cardiovascular risk factors in the healthy cohort. Similarly, endothelial function was not related to fasting TMAO, whereas the inflammatory marker TNF-α was significantly associated. Fasting plasma TMAO may not be a metabolite of concern in generally healthy adults unmedicated for chronic disease. Prospective studies in healthy individuals are necessary.

Comparison between Egg Intake versus Choline Supplementation on Gut Microbiota and Plasma Carotenoids in Subjects with Metabolic Syndrome

We previously demonstrated that intake of three eggs/d for 4 weeks increased plasma choline and decreased inflammation in subjects with metabolic syndrome (MetS). The purpose of the current study was to further explore the effects of phosphatidylcholine (PC) provided by eggs versus a choline bitartrate (CB) supplement on the gut microbiota, trimethylamine N-oxide (TMAO) formation, and plasma carotenoids lutein and zeaxanthin in MetS. This randomized, controlled crossover clinical trial included 23 subjects with MetS. Following a washout period of 2 weeks without consuming any choline-containing foods, subjects were randomly allocated to consume either three eggs/d or a CB supplement for 4 weeks (both diets had a choline equivalent of 400 mg/day). DNA was extracted from stool samples to sequence the 16S rRNA gene region for community analysis. Operational taxonomic units (OTUs) and the α-diversity of the community were determined using QIIME software. Plasma TMAO, methionine, betaine, and dimethylglycine (DMG) were quantified by stable isotope dilution liquid chromatography with tandem mass spectrometry. Plasma carotenoids, lutein, and zeaxanthin were measured using reversed-phase high-performance liquid chromatography. There were significant increases in plasma lutein and zeaxanthin after egg intake compared to the baseline or intake of CB supplement (p < 0.01). In contrast, TMAO was not different between treatments compared to the baseline (p > 0.05). Additionally, while diet intervention had no effects on microbiota diversity measures or relative taxa abundances, a correlation between bacterial biodiversity and HDL was observed. Following egg intake, the observed increases in plasma lutein and zeaxanthin may suggest additional protection against oxidative stress, a common condition in MetS.

Plasma Choline Concentration Was Not Increased After a 6-Month Egg Intervention in 6-9-Month-Old Malawian Children: Results from a Randomized Controlled Trial

BACKGROUND

Eggs are a rich source of choline, an essential nutrient important for child growth and development. In a randomized trial of 1 egg/d in young children in Ecuador, an egg intervention led to significant improvements in growth, which were partially mediated by increased plasma choline concentration. A similar trial in Malawi (clinicaltrials.gov: NCT03385252) found little improvement in child growth or development.

OBJECTIVES

We aimed to evaluate the effect of 1 egg/d for 6 mo on plasma choline concentrations in Malawian children enrolled in a randomized trial.

METHODS

Infants aged 6-9 mo in rural Malawi were randomly assigned to receive 1 egg/d (n = 331) or serve as a nonintervention control (n = 329) for 6 mo. Anthropometric, developmental, and dietary data were collected at baseline and 6-mo follow-up, along with a blood draw. Plasma choline, betaine, dimethylglycine, trimethylamine N-oxide (TMAO), and DHA were measured at both time points using ultrahigh performance liquid chromatography-tandem MS (n = 200 per group). Linear regression analysis was used to determine the difference in plasma choline and related metabolites between groups after 6 mo of intervention.

RESULTS

Plasma choline, betaine, dimethylglycine, and DHA concentrations did not differ between groups at 6-mo follow-up. Plasma TMAO was significantly (26%; 95% CI: 7%, 48%) higher in the egg intervention group in a fully adjusted model.

CONCLUSIONS

Provision of 1 egg/d for 6 mo did not result in increases in plasma choline or related metabolites, except TMAO. This could partially explain the lack of effect on growth and development. Additional interventions are needed to improve choline status, growth, and development in this population.

Egg consumption improves vascular and gut microbiota function without increasing inflammatory, metabolic, and oxidative stress markers

Egg consumption is one of the many inconsistencies in evidence linking dietary cholesterol to cardiovascular disease (CVD). In addition, the gut microbiota and its metabolite, trimethylamine-N-oxide (TMAO), have been shown to play a crucial role in the development of CVD. The fact that egg is rich in choline suggests that excessive egg consumption may increase TMAO production by altering the gut microbiota. However, the effects of egg consumption on vascular function and gut microbiota remain unclear. Here, the diet of nine young male subjects was supplemented with two boiled eggs daily for 2 weeks. Changes in vascular function, inflammation, metabolism, oxidative stress, and gut microbiota were examined. We found that egg consumption increased flow-mediated dilation and decreased brachial-ankle pulse wave velocity. Furthermore, egg consumption positively modulated the gut microbiota function but had no effects on the levels of C-reactive protein, glucose, lipid profile, malondialdehyde, superoxide dismutase, or TMAO. The current study provides evidence that egg consumption improves vascular function, which may be related to the alterations seen in the gut microbiota. Therefore, moderate egg consumption may help to improve vascular and intestinal function in individuals at low risk of developing CVD and other metabolic disorders.

Adopting a Mediterranean-style eating pattern with low, but not moderate, unprocessed, lean red meat intake reduces fasting serum trimethylamine N-oxide (TMAO) in adults who are overweight or obese

A Mediterranean-style eating pattern (MED-EP) may include moderate red meat intake. However, it is unknown if the pro-atherogenic metabolite trimethylamine N-oxide (TMAO) is affected by the amount of red meat consumed with a MED-EP. The results presented are from a secondary, retrospective objective of an investigator-blinded, randomized, crossover, controlled feeding trial (two 5-wk interventions separated by a 4-wk washout) to determine if a MED-EP with 200g unprocessed lean red meat/wk (MED-CONTROL) reduces circulating TMAO concentrations compared to a MED-EP with 500g unprocessed lean red meat/wk (MED-RED). Participants were 27 women and 12 men (n=39 total) who were either overweight or obese (BMI: 30.5 ± 0.3 kg/m2 mean ± SEM). Serum samples were obtained following an overnight fast both before (pre) and after (post) each intervention. Fasting serum TMAO, choline, carnitine, and betaine concentrations were measured using a targeted Liquid chromatography-mass spectrometry. Data were analyzed to assess if (a) TMAO and related metabolites differed by intervention, and (b) if changes in TMAO were associated with changes in Framingham 10-year risk score. Serum TMAO was lower post-intervention following MED-CONTROL compared to MED-RED intervention (post-MED-CONTROL 3.1 ± 0.2 µM vs. post-MED-RED 5.0 ± 0.5 µM, p<0.001), and decreased following MED-CONTROL (pre- vs post-MED-CONTROL, p = 0.025). Exploratory analysis using mixed model analysis of covariance identified a positive association between changes in TMAO and changes in HOMA-IR (p = 0.036). These results suggest that lower amounts of red meat intake leads to lower TMAO concentrations in the context of a MED-EP.

Are eggs good again? A precision nutrition perspective on the effects of eggs on cardiovascular risk, taking into account plasma lipid profiles and TMAO

Although eggs are a nutrient dense food delivering high quality protein and micronutrients, given that eggs are also rich in cholesterol and choline, whether egg intake is contraindicated for individuals at risk for cardiovascular disease (CVD) remains controversial. In this mini review, we provide a Precision Nutrition perspective, highlighting the importance of two factors: the effect of egg cholesterol on plasma cholesterol concentrations in most people and in cholesterol hyper-absorbers, and the effect of egg choline on plasma concentrations of trimethylamine-N-oxide (TMAO), a microbe-host co-metabolite independently associated with increased CVD risk. We discuss recent evidence from intervention studies showing that in most individuals egg intake does not have a deleterious effect on plasma lipid profiles, but also highlight that some individuals are cholesterol hyper-absorbers or individuals who are not able to maintain cholesterol homeostasis by suppressing endogenous cholesterol synthesis, and that for these individuals the intake of eggs and other dietary sources of cholesterol would be contraindicated. We also discuss the complex relationship between dietary sources of choline vs. phosphatidylcholine, the gut microbiome, and plasma TMAO concentrations, highlighting the high inter-individual variability in TMAO production and gut microbiome profiles among healthy individuals and those with metabolic conditions. Precision Nutrition approaches that allow the clinician to stratify risk and improve dietary recommendations for individual patients are desirable for improving patient compliance and health outcomes. More clinical studies are needed to determine how to identify individuals at risk for CVD for whom egg intake is contraindicated vs. those for whom egg intake is not associated with negative effects on plasma lipid profiles nor plasma TMAO concentrations.

Gut microbiota, dysbiosis and atrial fibrillation. Arrhythmogenic mechanisms and potential clinical implications

Recent preclinical and observational cohort studies have implicated imbalances in gut microbiota composition as a contributor to atrial fibrillation (AF). The gut microbiota is a complex and dynamic ecosystem containing trillions of microorganisms, which produces bioactive metabolites influencing host health and disease development. In addition to host-specific determinants, lifestyle-related factors such as diet and drugs are important determinants of the gut microbiota composition. In this review, we discuss the evidence suggesting a potential bidirectional association between AF and gut microbiota, identifying gut microbiota-derived metabolites as possible regulators of the AF substrate. We summarize the effect of gut microbiota on the development and progression of AF risk-factors, including heart failure, hypertension, obesity and coronary artery disease. We also discuss the potential antiarrhythmic effects of pharmacological and diet-induced modifications of gut microbiota composition, which may modulate and prevent the progression to AF. Finally, we highlight important gaps in knowledge and areas requiring future investigation. Although data supporting a direct relationship between gut microbiota and AF are very limited at the present time, emerging preclinical and clinical research dealing with mechanistic interactions between gut microbiota and AF is important as it may lead to new insights into AF pathophysiology and the discovery of novel therapeutic targets for AF.

Lifelong dietary omega-3 fatty acid suppresses thrombotic potential through gut microbiota alteration in aged mice

Aging is a major risk factor for cardiovascular diseases, including thrombotic events. The gut microbiota has been implicated in the development of thrombotic risk. Plant-derived omega-3 fatty acid ɑ-linolenic acid (ALA) confers beneficial anti-platelet and anti-inflammatory effects. Hence, antithrombotic activity elicited by ALA may be partly dependent on its interaction with gut microbiota during aging. Here, we demonstrate that lifelong dietary ALA decreases platelet hyperresponsiveness and thrombus formation in aged mice. These phenotypic changes can be partly attributed to alteration of microbial composition and reduction of its metabolite trimethylamine N-oxide and inflammatory mediators including TNF-α, as well as the upregulated production of short-chain fatty acid acetate. ALA-rich diet also dampens secretion of increased procoagulant factors, tissue factor and plasminogen activator inhibitor-1, in aged mice. Our results suggest long-term ALA supplementation as an attractive, accessible, and well-tolerated nutritional strategy against age-associated platelet hyperreactivity and thrombotic potential.

Association of Urinary and Plasma Levels of Trimethylamine N-Oxide (TMAO) with Foods

Introduction: Trimethylamine N-oxide (TMAO) may play a key mediator role in the relationship between the diet, gut microbiota and cardiovascular diseases, particularly in people with kidney failure. The aim of this review is to evaluate which foods have a greater influence on blood or urinary trimethylamine N-oxide (TMAO) levels. Methods: 391 language articles were screened, and 27 were analysed and summarized for this review, using the keywords “TMAO” AND “egg” OR “meat” OR “fish” OR “dairy” OR “vegetables” OR “fruit” OR “food” in December 2020. Results: A strong correlation between TMAO and fish consumption, mainly saltwater fish and shellfish, but not freshwater fish, has been demonstrated. Associations of the consumption of eggs, dairy and meat with TMAO are less clear and may depend on other factors such as microbiota or cooking methods. Plant-based foods do not seem to influence TMAO but have been less investigated. Discussion: Consumption of saltwater fish, dark meat fish and shellfish seems to be associated with an increase in urine or plasma TMAO values. Further studies are needed to understand the relationship between increased risk of cardiovascular disease and plasma levels of TMAO due to fish consumption. Interventions coupled with long-term dietary patterns targeting the gut microbiota seem promising.

Neighborhood Environment Associates with Trimethylamine-N-Oxide (TMAO) as a Cardiovascular Risk Marker

Background: Neighborhoods and the microbiome are linked to cardiovascular disease (CVD), yet investigations to identify microbiome-related factors at neighborhood levels have not been widely investigated. We sought to explore relationships between neighborhood deprivation index (NDI) and the microbial metabolite, trimethylamine-N-oxide. We hypothesized that inflammatory markers and dietary intake would be mediators of the relationship. Methods: African-American adults at risk for CVD living in the Washington, DC area were recruited to participate in a cross-sectional community-based study. US census-based neighborhood deprivation index (NDI) measures (at the census-tract level) were determined. Serum samples were analyzed for CVD risk factors, cytokines, and the microbial metabolite, trimethylamine-N-oxide (TMAO). Self-reported dietary intake based on food groups was collected. Results: Study participants (n = 60) were predominantly female (93.3%), with a mean (SD) age of 60.83 (+/−10.52) years. Mean (SD) NDI was −1.54 (2.94), and mean (SD) TMAO level was 4.99 (9.65) µmol/L. Adjusting for CVD risk factors and BMI, NDI was positively associated with TMAO (β = 0.31, p = 0.02). Using mediation analysis, the relationship between NDI and TMAO was significantly mediated by TNF-α (60.15%) and interleukin)-1 β (IL; 49.96%). When controlling for clustering within neighborhoods, the NDI-TMAO association was no longer significant (β = 5.11, p = 0.11). However, the association between NDI and IL-1 β (β = 0.04, p = 0.004) and TNF-α (β = 0.17, p = 0.003) remained. Neither NDI nor TMAO was significantly associated with daily dietary intake. Conclusion and Relevance: Among a small sample of African-American adults at risk for CVD, there was a significant positive relationship with NDI and TMAO mediated by inflammation. These hypothesis-generating results are initial and need to be confirmed in larger studies.

Effects of betaine on non-alcoholic liver disease

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) poses a growing challenge in terms of its prevention and treatment. The 'multiple hits' hypothesis of multiple insults, such as dietary fat intake, de novo lipogenesis, insulin resistance, oxidative stress, mitochondrial dysfunction, gut dysbiosis and hepatic inflammation, can provide a more accurate explanation of the pathogenesis of NAFLD. Betaine plays important roles in regulating the genes associated with NAFLD through anti-inflammatory effects, increased free fatty oxidation, anti-lipogenic effects and improved insulin resistance and mitochondrial function; however, the mechanism of betaine remains elusive.

Nutritional Viewpoints on Eggs and Cholesterol

Although most current epidemiologic studies indicate no significant association between consuming one egg daily and blood cholesterol levels and cardiovascular risk, arguments still persist with a positive association. Since the diet is one of the most influential factors for this association, we illustrate characteristic features in Japanese people whose dietary pattern is distinct from that, for example, the US (United States) population. Available epidemiologic studies in healthy Japanese people show no association between consumption of one egg daily and blood cholesterol level, consistent with those observed in the US population. However, when consumption of major nutrients and food sources of cholesterol are compared to the US population, Japanese people may have an extra-reserve against the influence of eggs on cardiovascular risk markers, despite consuming relatively more eggs. Further discussion on the influence of nutrients contained in the egg and dietary pattern, including interaction with gut microbes, is necessary. In addition, special consideration at the personalized level is needed for judgment regarding dietary cholesterol not only for hypercholesterolemic patients but for hyper-responsive healthy persons. Although randomized controlled trials with long-term follow-up are required to evaluate the association between consumption of eggs and human health, available information, at least from the nutritional viewpoint, suggests that egg is a healthy and cost-efficient food worldwide.

Trimethylamine N-Oxide (TMAO), Diet and Cardiovascular Disease

PURPOSE OF REVIEW

The association between plasma Trimethylamine N-Oxide (TMAO), diet and risk for cardiovascular disease (CVD) is still not fully understood. While epidemiologic research shows a causal relationship between plasma TMAO concentrations and CVD risk, the role of dietary precursors in determining plasma concentrations of TMAO and biomarkers for CVD is inconclusive.

RECENT FINDINGS

Studies in diverse populations show that plasma TMAO concentrations are positively associated with inflammation, endothelial dysfunction, type-2 diabetes, central adiposity and hypertension. Most recent studies utilizing challenges of dietary choline have not shown increases in plasma chronic TMAO concentrations while studies with carnitine have shown increases in plasma TMAO but in some cases, no alterations in plasma lipids or biomarkers of oxidative stress were observed. TMAO is an important plasma metabolite that through several mechanisms can increase the risk of CVD. The correlations between dietary choline and carnitine on chronic plasma TMAO levels and risk for CVD requires further investigation.

Whole egg consumption increases gene expression within the glutathione pathway in the liver of Zucker Diabetic Fatty rats

Nutrigenomic evidence supports the idea that Type 2 Diabetes Mellitus (T2DM) arises due to the interactions between the transcriptome, individual genetic profiles, lifestyle, and diet. Since eggs are a nutrient dense food containing bioactive ingredients that modify gene expression, our goal was to examine the role of whole egg consumption on the transcriptome during T2DM. We analyzed whether whole egg consumption in Zucker Diabetic Fatty (ZDF) rats alters microRNA and mRNA expression across the adipose, liver, kidney, and prefrontal cortex tissue. Male ZDF (fa/fa) rats (n = 12) and their lean controls (fa/+) (n = 12) were obtained at 6 wk of age. Rats had ad libitum access to water and were randomly assigned to a modified semi-purified AIN93G casein-based diet or a whole egg-based diet, both providing 20% protein (w/w). TotalRNA libraries were prepared using QuantSeq 3' mRNA-Seq and Lexogen smallRNA library prep kits and were further sequenced on an Illumina HighSeq3000. Differential gene expression was conducted using DESeq2 in R and Benjamini-Hochberg adjusted P-values controlling for false discovery rate at 5%. We identified 9 microRNAs and 583 genes that were differentially expressed in response to 8 wk of consuming whole egg-based diets. Kyto Encyclopedia of Genes and Genomes/Gene ontology pathway analyses demonstrated that 12 genes in the glutathione metabolism pathway were upregulated in the liver and kidney of ZDF rats fed whole egg. Whole egg consumption primarily altered glutathione pathways such as conjugation, methylation, glucuronidation, and detoxification of reactive oxygen species. These pathways are often negatively affected during T2DM, therefore this data provides unique insight into the nutrigenomic response of dietary whole egg consumption during the progression of T2DM.