Concentrations of choline-containing compounds and betaine in common foods

Dietary bioactive ingredients to modulate the gut microbiota-derived metabolite TMAO. New opportunities for functional food development

There is a growing body of clinical evidence that supports a strong association between elevated circulating trimethylamine N-oxide (TMAO) levels with increased risk of developing adverse cardiovascular outcomes such as atherosclerosis and thrombosis. TMAO is synthesized through a meta-organismal stepwise process that involves (i) the microbial production of TMA in the gut from dietary precursors and (ii) its subsequent oxidation to TMAO by flavin-containing monooxygenases in the liver. Choline, l-carnitine, betaine, and other TMA-containing compounds are the major dietary precursors of TMA. TMAO can also be absorbed directly from the gastrointestinal tract after the intake of TMAO-rich foods such as fish and shellfish. Thus, diet is an important factor as it provides the nutritional precursors to eventually produce TMAO. A number of studies have attempted to associate circulating TMAO levels with the consumption of diets rich in these foods. On the other hand, there is growing interest for the development of novel food ingredients that reduce either the TMAO-induced damage or the endogenous TMAO levels through the interference with microbiota and host metabolic processes involved in TMAO pathway. Such novel functional food ingredients would offer great opportunities to control circulating TMAO levels or its effects, and potentially contribute to decrease cardiovascular risk. In this review we summarize and discuss current data regarding the effects of TMA precursors-enriched foods or diets on circulating TMAO levels, and recent findings regarding the circulating TMAO-lowering effects of specific foods, food constituents and phytochemicals found in herbs, individually or in extracts, and their potential beneficial effect for cardiovascular health.

The Effects of Creatine and Related Compounds on Cardiovascular System: From Basic to Applied Studies

Beneficial effects of creatine were firstly shown in sport, where itself has been recognized as an ergogenic substance, increasing exercise endurancе, muscle strength and lean body mass. Creatine supplementation is very interesting, due to the fact that creatine supplementation have been reported to be beneficial for wide spectrum of diseases and conditions referring neuro-degenerative, rheumatic diseases, myopathies, cancer, type 2 diabetes. Creatine is a principle component of the creatine kinase/phosphagen system. In cardiomyocytes, it plays an important role in the buffering and transport of chemical energy to ensure that supply meets the dynamic demands of the heart. Studies in mice proved that elevated creatine protects the heart from ischemia-reperfusion injury. A natural precursor of creatine, guanidinoacetic acid (GAA), plays an important role as an energy carrier/mediator in the cell. GAA is formed in the first step of creatine synthesis. Supplementation with GAA might be of great significance in some circumstances where biosynthesis of GAA is limited like deficient diet, kidney failure, renal insufficiency, exercise-related GAA depletion. Betaine is a neutral compound in the form of zwitterion. Betaine supplementation is associated with improved cognition, neuroprotection, cardioprotection and exercise physiology. Betaine insufficiency represents increased risk for secondary heart failure and acute myocardial infarction. This mini-review outlines the evidence in support of creatine and creatine related compounds (GAA and betaine) elevation and examines the pharmacological approaches that are currently available. Since data from the available studies, regarding cardioprotection are inconsistent, this review might help clarifying the benefits of creatine, GAA and betaine supplementation on cardiovascular system.

Dietary betaine intake is associated with skeletal muscle mass change over 3 years in middle-aged adults: the Guangzhou Nutrition and Health Study

A higher dietary intake or serum concentration of betaine has been associated with greater lean body mass in middle-aged and older adults. However, it remains unknown whether betaine intake is associated with age-related loss of skeletal muscle mass (SMM). We assessed the association between dietary betaine intake and relative changes in SMM after 3 years in middle-aged adults. A total of 1242 participants aged 41-60 years from the Guangzhou Nutrition and Health Study 2011-2013 and 2014-2017 with body composition measurements by dual-energy X-ray absorptiometry were included. A face-to-face questionnaire was used to collect general baseline information. After adjustment for potential confounders, multiple linear regression found that energy-adjusted dietary betaine intake was significantly and positively associated with relative changes (i.e. percentage loss or increase) in SMM of legs, limbs and appendicular skeletal mass index (ASMI) over 3 years of follow-up (β 0·322 (se 0·157), 0·309 (se 0·142) and 0·303 (se 0·145), respectively; P < 0·05). The ANCOVA models revealed that participants in the highest betaine tertile had significantly less loss in SMM of limbs and ASMI and more increase in SMM of legs over 3 years of follow-up, compared with those in the bottom betaine tertile (all Ptrend < 0·05). In conclusion, our findings suggest that elevated higher dietary betaine intake may be associated with less loss of SMM of legs, limbs and ASMI in middle-aged adults.

Feeding Buttermilk-Derived Choline Forms During Gestation and Lactation Modulates Ex Vivo T-Cell Response in Rat Dams

BACKGROUND

Buttermilk contains a mixture of choline forms; it is high in phosphatidylcholine (PC) and sphingomyelin (SM), which could have an impact on immune system development and function.

OBJECTIVES

We aimed to determine the effect of feeding buttermilk-derived choline forms during pregnancy and lactation on maternal immune function.

METHODS

Sprague Dawley dams (n = 8 per diet) were randomly assigned midway through pregnancy (10 d of gestation) to 1 of 3 experimental diets, containing 1.7 g/kg choline: control [100% free choline (FC)]; buttermilk [37% PC, 34% SM, 17% glycerophosphocholine (GPC), 7% FC, 5% phosphocholine]; or placebo (50% PC, 25% FC, 25% GPC). Dams consumed the same diet until the end of the lactation period (21 d after parturition). Cell phenotypes and cytokine production by mitogen-stimulated splenocytes were measured and compared using 1-factor ANOVA test in order to asses the effect of diet on immune fuction of lactating dams (main outcome).

RESULTS

After ConA stimulation, splenocytes from dams in the buttermilk group produced more IL-2 (30%), TNF-α (30%), and IFN-γ (42%) compared with both the placebo and control diets. Placebo-fed dams had a higher proportion of CD8+ cells expressing CD152+ (22%) in spleen, and splenocytes from dams that were fed the buttermilk and the placebo diets produced about 50% and 53% more IL-10 after LPS and OVA stimulation, respectively, compared with the control group.

CONCLUSIONS

Feeding buttermilk-derived choline forms during pregnancy and lactation had a beneficial impact on the immune system of Sprague Dawley rat dams, especially on T-cell function.

Association between serum choline and betaine concentrations and longitudinal changes of body composition in community-dwelling middle-aged and older Chinese adults

Previous studies suggest that betaine and choline may be beneficial for body composition. However, no longitudinal study has been conducted to illustrate if choline and betaine have long-term effects on changes in body composition. This study aimed to prospectively investigate the association between serum choline and betaine concentrations and 3-year changes in body composition in community-dwelling Chinese adults. This present analysis used data from 1384 women and 554 men aged 40–75 years. Serum concentrations of betaine and choline at baseline were assessed using high-performance liquid chromatography-tandem mass spectrometry. Body composition parameters, i.e., muscle mass (MM), fat mass (FM), and body fat percentage (FM%) were measured using dual-energy X-ray absorptiometry at the first and the second follow-ups. After adjustment for potential cofounders, higher serum choline concentrations were associated with a lower decrease in MM in men (β = 0.022, P = 0.025) and a lower increase in FM and FM% in women with baseline choline concentrations below 21.5 μmol/L (all P for nonlinearity = 0.007); higher serum betaine concentrations were associated with a lower decline in MM and a lower increase in FM and FM% among men whose betaine concentrations were lower than 55 μmol/L (all P for nonlinearity < 0.05). These findings suggest that higher concentrations of serum choline and betaine may be associated with favorable changes in body composition profiles among men and women who have relatively low concentrations, especially in men.

Novelty Higher concentrations of serum choline and betaine were associated with favorable changes in body composition. Such favorable associations were more pronounced in men.

Choline, Neurological Development and Brain Function: A Systematic Review Focusing on the First 1000 Days

The foundations of neurodevelopment across an individual's lifespan are established in the first 1000 days of life (2 years). During this period an adequate supply of nutrients are essential for proper neurodevelopment and lifelong brain function. Of these, evidence for choline has been building but has not been widely collated using systematic approaches. Therefore, a systematic review was performed to identify the animal and human studies looking at inter-relationships between choline, neurological development, and brain function during the first 1000 days of life. The database PubMed was used, and reference lists were searched. In total, 813 publications were subject to the title/abstract review, and 38 animal and 16 human studies were included after evaluation. Findings suggest that supplementing the maternal or child's diet with choline over the first 1000 days of life could subsequently: (1) support normal brain development (animal and human evidence), (2) protect against neural and metabolic insults, particularly when the fetus is exposed to alcohol (animal and human evidence), and (3) improve neural and cognitive functioning (animal evidence). Overall, most offspring would benefit from increased choline supply during the first 1000 days of life, particularly in relation to helping facilitate normal brain development. Health policies and guidelines should consider re-evaluation to help communicate and impart potential choline benefits through diet and/or supplementation approaches across this critical life stage.

Associations of plasma trimethylamine N-oxide, choline, carnitine, and betaine with inflammatory and cardiometabolic risk biomarkers and the fecal microbiome in the Multiethnic Cohort Adiposity Phenotype Study

BACKGROUND

Trimethylamine N-oxide (TMAO), a compound derived from diet and metabolism by the gut microbiome, has been associated with several chronic diseases, although the mechanisms of action are not well understood and few human studies have investigated microbes involved in its production.

OBJECTIVES

Our study aims were 1) to investigate associations of TMAO and its precursors (choline, carnitine, and betaine) with inflammatory and cardiometabolic risk biomarkers; and 2) to identify fecal microbiome profiles associated with TMAO.

METHODS

We conducted a cross-sectional analysis using data collected from 1653 participants (826 men and 827 women, aged 60-77 y) in the Multiethnic Cohort Study. Plasma concentrations of TMAO and its precursors were measured by LC-tandem MS. We also analyzed fasting blood for markers of inflammation, glucose and insulin, cholesterol, and triglycerides (TGs), and further measured blood pressure. Fecal microbiome composition was evaluated by sequencing the 16S ribosomal RNA gene V1-V3 region. Associations of TMAO and its precursors with disease risk biomarkers were assessed by multivariable linear regression, whereas associations between TMAO and the fecal microbiome were assessed by permutational multivariate ANOVA and hurdle regression models using the negative binomial distribution.

RESULTS

Median (IQR) concentration of plasma TMAO was 3.05 μmol/L (2.10-4.60 μmol/L). Higher concentrations of TMAO and carnitine, and lower concentrations of betaine, were associated with greater insulin resistance (all P < 0.02). Choline was associated with higher systolic blood pressure, TGs, lipopolysaccharide-binding protein, and lower HDL cholesterol (P ranging from <0.001 to 0.03), reflecting an adverse cardiometabolic risk profile. TMAO was associated with abundance of 13 genera (false discovery rate < 0.05), including Prevotella, Mitsuokella, Fusobacterium, Desulfovibrio, and bacteria belonging to the families Ruminococcaceae and Lachnospiraceae, as well as the methanogen Methanobrevibacter smithii.

CONCLUSIONS

Plasma TMAO concentrations were associated with a number of trimethylamine-producing bacterial taxa, and, along with its precursors, may contribute to inflammatory and cardiometabolic risk pathways.

Trimethylamine N-Oxide in Relation to Cardiometabolic Health-Cause or Effect?

Trimethylamine-N-oxide (TMAO) is generated in a microbial-mammalian co-metabolic pathway mainly from the digestion of meat-containing food and dietary quaternary amines such as phosphatidylcholine, choline, betaine, or L-carnitine. Fish intake provides a direct significant source of TMAO. Human observational studies previously reported a positive relationship between plasma TMAO concentrations and cardiometabolic diseases. Discrepancies and inconsistencies of recent investigations and previous studies questioned the role of TMAO in these diseases. Several animal studies reported neutral or even beneficial effects of TMAO or its precursors in cardiovascular disease model systems, supporting the clinically proven beneficial effects of its precursor, L-carnitine, or a sea-food rich diet (naturally containing TMAO) on cardiometabolic health. In this review, we summarize recent preclinical and epidemiological evidence on the effects of TMAO, in order to shed some light on the role of TMAO in cardiometabolic diseases, particularly as related to the microbiome.

Egg consumption and risk of type 2 diabetes mellitus in middle and elderly Chinese population: An observational study

Data on the association between egg consumption and the risk of type 2 diabetes mellitus (T2DM) in the Chinese population are scarce. In the present study, we aimed to examine the association between egg consumption and the risk of T2DM in a middle and elderly Chinese population. A total of 3298 subjects (1645 men and 1653 women) from the Nutrition and Health Survey (2015-2017) in Hangzhou city were selected for the final analysis. Egg consumption was assessed using a validated food frequency questionnaire. All biochemical data and anthropometric measurements were collected following standardized procedures. Multivariable logistic regression analyses were used to assess the association between egg consumption and the risk of T2DM and the results were presented as odds ratios and 95% confidence interval (CI). Restricted cubic spline combined with logistic regression was used to explore the dose-response relationship between egg consumption and T2DM. Among 3298 subjects, 693 (21.0%) people had T2DM. Compared with participants who did not consume egg per week, the multivariable-adjusted odds ratios were 0.97 (95%CI : 0.78-1.21), 1.08 (95%CI : 0.91-1.06), 1.20 (95%CI : 0.94-1.55), 1.27 (95%CI : 0.99-1.68) in men (P > .05); 1.06 (95%CI : 0.81-1.37), 0.97 (95%CI : 0.78-1.21), 1.26 (95%CI : 0.99-1.59), 1.19 (0.92-1.54) in women (P > .05); 0.89 (95%CI : 0.79-1.04), 0.98 (95%CI : 0.91-1.06), 1.06 (95%CI : 0.87-1.30), 1.09 (95%CI : 0.88-1.34) in both men and women for egg consumption 0∼7, 7, 7∼14, and ≥14 eggs/week, respectively (P > .05). The dose-response curve showed that, with the increase of egg consumption, the risk of T2DM first increased and then decreased (P = .027).We found that the association between egg consumption and T2DM was nonlinear, and higher egg consumption was not associated with an elevated risk for T2DM in middle-aged and elderly Chinese. However, future prospective studies are needed to confirm these findings.

Gut microbiota in atherosclerosis: focus on trimethylamine N-oxide

The increasing prevalence of cardiovascular diseases cannot adequately be explained by traditional risk factors. Recently, accumulating evidence has suggested that gut microbiota‐derived numerous metabolites are contributors to atherosclerotic events. Among them, the role of trimethylamine N‐oxide (TMAO) in promoting atherosclerosis has gained attention. TMAO is reported to exert the proatherogenic effects by impacting on the traditional risk factors of atherosclerosis and is associated with high risk of cardiovascular events. Besides that, TMAO is involved in the complex pathological processes of atherosclerotic lesion formation, such as endothelial dysfunction, platelet activation and thrombus generation. In light of these promising findings, TMAO may serve as a potential target for atherosclerosis prevention and treatment, which is conceptually novel, when compared with existing traditional treatments. It is likely that regulating TMAO production and associated gut microbiota may become a promising strategy for the anti‐atherosclerosis therapy.

Circulating Pro- and Anti-Inflammatory Metabolites and Its Potential Role in Rheumatoid Arthritis Pathogenesis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that affects synovial joints, leading to inflammation, joint destruction, loss of function, and disability. Although recent pharmaceutical advances have improved the treatment of RA, patients often inquire about dietary interventions to improve RA symptoms, as they perceive pain and/or swelling after the consumption or avoidance of certain foods. There is evidence that some foods have pro- or anti-inflammatory effects mediated by diet-related metabolites. In addition, recent literature has shown a link between diet-related metabolites and microbiome changes, since the gut microbiome is involved in the metabolism of some dietary ingredients. But diet and the gut microbiome are not the only factors linked to circulating pro- and anti-inflammatory metabolites. Other factors including smoking, associated comorbidities, and therapeutic drugs might also modify the circulating metabolomic profile and play a role in RA pathogenesis. This article summarizes what is known about circulating pro- and anti-inflammatory metabolites in RA. It also emphasizes factors that might be involved in their circulating concentrations and diet-related metabolites with a beneficial effect in RA.

Precision (Personalized) Nutrition: Understanding Metabolic Heterogeneity

People differ in their requirements for and responses to nutrients and bioactive molecules in the diet. Many inputs contribute to metabolic heterogeneity (including variations in genetics, epigenetics, microbiome, lifestyle, diet intake, and environmental exposure). Precision nutrition is not about developing unique prescriptions for individual people but rather about stratifying people into different subgroups of the population on the basis of biomarkers of the above-listed sources of metabolic variation and then using this stratification to better estimate the different subgroups’ dietary requirements, thereby enabling better dietary recommendations and interventions. The hope is that we will be able to subcategorize people into ever-smaller groups that can be targeted in terms of recommendations, but we will never achieve this at the individual level, thus, the choice of precision nutrition rather than personalized nutrition to designate this new field. This review focuses mainly on genetically related sources of metabolic heterogeneity and identifies challenges that need to be overcome to achieve a full understanding of the complex interactions between the many sources of metabolic heterogeneity that make people differ from one another in their requirements for and responses to foods. It also discusses the commercial applications of precision nutrition.

Association between Dietary Intake of One-Carbon Metabolism Nutrients in the Year before Pregnancy and Birth Anthropometry

Few studies have evaluated the role of methylation-pathway nutrients involved in fetal growth (B vitamins, choline, betaine, and methionine). These one-carbon metabolism (OCM) nutrients are essential for DNA methylation in the periconception period. We aimed to characterize dietary patterns of 1638 women from the EDEN mother-child cohort in the year before pregnancy according to the contribution of OCM nutrients and to study the association of such patterns with anthropometric measurements at birth. Dietary intake before pregnancy was assessed by using a semi-quantitative food frequency questionnaire. We used the reduced-rank regression (RRR) method to identify dietary patterns using OCM nutrients as intermediate variables. We ran linear regressions models to study the association between dietary patterns scores and birth weight, length, head circumference, gestational age, and sex-specific z-scores, adjusting for maternal characteristics and vitamin supplementation before and during pregnancy. Three patterns, “varied and balanced”, “vegetarian tendency”, and “bread and starchy food” were identified, explaining 58% of the variability in OCM nutrient intake. Higher scores on the “varied and balanced” pattern tended to be associated with higher birth length and weight. In mainly well-nourished young French women, we did not find evidence that variability in OCM nutrient intake has major effects on fetal growth.

Non-polyphenolic natural inhibitors of amyloid aggregation

Protein misfolding diseases (PMDs) are chronic and progressive, with no effective therapy so far. Aggregation and misfolding of amyloidogenic proteins are closely associated with the onset and progression of PMDs, such as amyloid-β (Aβ) in Alzheimer's disease, α-Synuclein (α-Syn) in Parkinson's disease and human islet amyloid polypeptide (hIAPP) in type 2 diabetes. Inhibiting toxic aggregation of amyloidogenic proteins is regarded as a promising therapeutic approach in PMDs. The past decade has witnessed the rapid progresses of this field, dozens of inhibitors have been screened and verified in vitro and in vivo, demonstrating inhibitory effects against the aggregation and misfolding of amyloidogenic proteins, together with beneficial effects. Natural products are major sources of small molecule amyloid inhibitors, a number of natural derived compounds have been identified with great bioactivities and translational prospects. Here, we review the non-polyphenolic natural inhibitors that potentially applicable for PMDs treatment, along with their working mechanisms. Future directions are proposed for the development and clinical applications of these inhibitors.

A faster and simpler UPLC-MS/MS method for the simultaneous determination of trimethylamine N-oxide, trimethylamine and dimethylamine in different types of biological samples

Gut microbiota-dependent metabolites trimethylamine N-oxide (TMAO), trimethylamine (TMA) and dimethylamine (DMA) from dietary methylamines have recently gained much attention due to their high association with chronic kidney disease risk. Hence a simpler and faster performance liquid chromatography-tandem mass spectrometry method was developed and validated. The quantitative analysis was achieved within 6 min by using Agilent 6460C UPLC-MS/MS with 10% methyl alcohol isocratic elution and was more simple, convenient and rapid than that of previously reported methods. Furthermore, method verification results showed that the method correlation coefficient was 0.99978293, 0.99997514 and 0.98784721, and the detection limit was 0.121, 8.063 and 0.797 μg L-1, and the precision of the retention time and peak area of analytes was less than 0.331 and 3.280, respectively. The method was applied to simultaneously determine TMAO, TMA and DMA in the urine and serum from mice treated with normal, high l-carnitine, or high choline diet. Quantitative recoveries of TMAO, TMA and DMA were in the range of 94.2%-101.0%, and the RSD values were lower than 5.17%. The proposed UPLC-MS/MS-based assay should be of value for further evaluating TMAO as a risk marker and for examining the effect of dietary factors on TMAO metabolism.

Comparative Proteomics of Meat Spoilage Bacteria Predicts Drivers for Their Coexistence on Modified Atmosphere Packaged Meat

Besides intrinsic and extrinsic factors such as antagonism for organic substrates or temperature, the storage atmosphere of meat has a high influence on the development of its initial microbiota. Specific modified atmospheres (MAs) selectively suppress growth of aerobic and anaerobic bacteria, thus reshaping the initial microbiota. As some microorganisms are more tolerant to MA, they overgrow competitors and produce metabolites that cause rejection of the product. In order to elucidate responses to different MA by means of metabolic adaptation and competition for organic substrates on meat, the typical representative meat spoilage bacteria Brochothrix (B.) thermosphacta TMW2.2101 and four lactic acid bacteria Carnobacterium (C.) divergens TMW2.1577, C. maltaromaticum TMW2.1581, Leuconostoc (L.) gelidum subsp. gelidum TMW2.1618 and L. gelidum subsp. gasicomitatum TMW2.1619 were chosen. Bacteria were grown in sterile glass bottles filled with a meat simulation medium, which was aerated constantly with either air, 100%_N₂, 30%_CO₂/70%_O₂ or 30%_CO₂/70%_N₂. Growth of bacteria during incubation at 25°C and stirring at 120 rpm was monitored over 48 h and a label-free quantitative mass spectrometric approach was employed to determine changes within the bacterial proteomes in response to oxygen and carbon dioxide. Both Leuconostoc subsp. were intrinsically tolerant to MA, exhibiting no proteomic regulation of enzymes, whereas the other species provide a set of metabolic adaptation mechanism, enabling higher resistance to the detrimental effects of MA. Those mechanisms comprise: enhanced oxidative stress reduction, adjustment of the pyruvate metabolism and catabolic oxygen consumption in response to oxygen and intracellular pH homeostasis, maintenance of osmotic balance and alteration of the fatty acid composition in response to carbon dioxide. We further evaluated the potential of industrial used MA to inhibit specific bacterial spoilage. No bacterial inhibition is predicted for 30%_CO₂/70%_O₂ for the analyzed species, whereas 30%_CO₂/70%_N₂ predictively inhibits C. divergens TMW21577 and B. thermosphacta TMW2.2101. Furthermore, species-specific metabolic pathways enabling different and preferential carbon source utilization were identified, which enable non-competitive coexistence of respective bacteria on meat, resulting in synergistic spoilage. In conclusion, this study gives mechanistically explanations of their acknowledged status as typical spoilage organisms on MAP meats.

Dietary Choline or Trimethylamine N-oxide Supplementation Does Not Influence Atherosclerosis Development in Ldlr-/- and Apoe-/- Male Mice

BACKGROUND

Choline, an essential nutrient, is required for cell membranes, lipoprotein secretion, and methyl-group metabolism. Recently, it has been proposed that excess dietary choline consumption is metabolized to trimethylamine (TMA) by the gut microbiota; TMA is then oxidized to trimethylamine N-oxide (TMAO) in the liver. Epidemiological studies have clearly shown a positive correlation between plasma TMAO concentrations and cardiovascular events. Furthermore, some studies have shown an association between excess dietary choline, plasma TMAO concentrations, and atherosclerotic lesion size in apoE knockout (Apoe-/-) mice.

OBJECTIVE

The aim of this study was to further investigate the relation between dietary choline and atherosclerosis in 2 atherogenic mouse models, the LDL receptor knockout (Ldlr-/-) and Apoe-/- mice.

METHODS

Six feeding trials were performed in Ldlr-/- (40% high-fat diet) and Apoe-/- (unpurified diet) male mice, aged 8-10 wk. Mice randomly received control diet (0.1% choline), or choline- (1% choline), betaine- (0.1% choline and 0.9% betaine), or TMAO- (0.1% choline and 0.12% or 0.2% TMAO) supplemented diet for ≤28 wk. After the dietary intervention, the animals were killed and tissues and blood collected. Aortic atherosclerotic plaque area, plasma lipids, and choline metabolites were quantified.

RESULTS

In Ldlr-/- mice, dietary supplementation for 8 wk with choline or TMAO increased plasma TMAO concentrations by 1.6- and 4-fold, respectively. After 16 wk, there was a 2-fold increase in plasma TMAO after dietary TMAO supplementation. In Apoe-/- mice, dietary supplementation with choline, betaine, or TMAO for 12 wk did not increase plasma TMAO concentrations. However, choline and TMAO supplementation for 28 wk significantly increased plasma TMAO concentrations by 1.8- and 1.5-fold, respectively. Contrary to predictions, atherosclerotic lesion size was not altered by any of the dietary interventions, irrespective of mouse model.

CONCLUSIONS

In our study, high intakes of dietary choline or TMAO supplementation did not influence atherosclerosis development in Ldlr-/- or Apoe-/- male mice.

Urinary TMAO Levels Are Associated with the Taxonomic Composition of the Gut Microbiota and with the Choline TMA-Lyase Gene (cutC) Harbored by Enterobacteriaceae

Gut microbiota metabolization of dietary choline may promote atherosclerosis through trimethylamine (TMA), which is rapidly absorbed and converted in the liver to proatherogenic trimethylamine-N-oxide (TMAO). The aim of this study was to verify whether TMAO urinary levels may be associated with the fecal relative abundance of specific bacterial taxa and the bacterial choline TMA-lyase gene cutC. The analysis of sequences available in GenBank grouped the cutC gene into two main clusters, cut-Dd and cut-Kp. A quantitative real-time polymerase chain reaction (qPCR) protocol was developed to quantify cutC and was used with DNA isolated from three fecal samples collected weekly over the course of three consecutive weeks from 16 healthy adults. The same DNA was used for 16S rRNA gene profiling. Concomitantly, urine was used to quantify TMAO by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). All samples were positive for cutC and TMAO. Correlation analysis showed that the cut-Kp gene cluster was significantly associated with Enterobacteriaceae. Linear mixed models revealed that urinary TMAO levels may be predicted by fecal cut-Kp and by 23 operational taxonomic units (OTUs). Most of the OTUs significantly associated with TMAO were also significantly associated with cut-Kp, confirming the possible relationship between these two factors. In conclusion, this preliminary method-development study suggests the existence of a relationship between TMAO excreted in urine, specific fecal bacterial OTUs, and a cutC subgroup ascribable to the choline-TMA conversion enzymes of Enterobacteriaceae.

Glycine-betaine-derived ionic liquids: Synthesis, characterization and ecotoxicological evaluation

Ionic Liquids (ILs) are generically regarded as environmentally "harmless" and thus, assumed as "non-toxic". However, due to the endless design possibilities, their ecotoxicological profile is still poorly known. An accurate knowledge on the toxicity of a substance is required, under the scope of environmental regulation worldwide, before their application and commercialization. Knowledge on the relationship between the chemical structure and toxic effects is essential for the future design of more biocompatible solvents. Focusing on the use of ILs as base lubricants, lubricant additives, or even as potential working fluids for absorption heat pumps, the knowledge on its environmental impact is of great importance, due to the possibility of spills. In this specific context, four analogues of glycine-betaine-based ILs (AGB-ILs) and four glycine-betaine based ILs (GB-ILs) were synthesized and characterized. Their ecotoxicity was assessed using representatives of two trophic levels in aquatic ecosystems, the bacteria Allivibrio fischeri (commonly used as a screening test organism) and the microalgae Raphidocelis subcapitata (as an alternative test organism that has been proven very sensitive to several IL families). The microalgae were more sensitive than the bacteria, hence, following a precautionary principle, we recommend considering the toxicity towards microalgae as an indicator in future studies regarding the focused ILs. Although four of the studied ILs were derived from a natural amino acid, all were considered hazardous for the aquatic environment, disproving the primary theory that all ILs derived from natural compounds are benign. Furthermore, the modification in the structure of anion and the cation can lead to the increase of toxicity.

Natural Choline from Egg Yolk Phospholipids Is More Efficiently Absorbed Compared with Choline Bitartrate; Outcomes of A Randomized Trial in Healthy Adults

Choline is a vitamin-like essential nutrient, important throughout one’s lifespan. Therefore, choline salts are added to infant formula, supplements and functional foods. However, if choline is present in a natural form, e.g. bound to phospholipids, it may be more efficiently absorbed. The study’s aim was to evaluate if choline uptake is improved after consumption of an egg yolk phospholipid drink, containing 3 g of phospholipid bound choline, compared to a control drink with 3 g of choline bitartrate. We performed a randomized, double blind, cross-over trial with 18 participants. Plasma choline, betaine and dimethylglycine concentrations were determined before and up to six hours after consumption of the drinks. The plasma choline response, as determined by the incremental area under the curve, was four times higher after consumption of the egg yolk phospholipid drink compared with the control drink (p < 0.01). Similar outcomes were also observed for choline’s main metabolites, betaine (p < 0.01) and dimethylglycine (p = 0.01). Consumption of natural choline from egg yolk phospholipids improved choline absorption compared to consumption of chemically produced choline bitartrate. This information is of relevance for the food industry, instead of adding choline-salts, adding choline from egg yolk phospholipids can improve choline uptake and positively impact health.

A New Perspective on the Health Benefits of Moderate Beer Consumption: Involvement of the Gut Microbiota

Beer is the most widely consumed fermented beverage in the world. A moderate consumption of beer has been related to important healthy outcomes, although the mechanisms have not been fully understood. Beer contains only a few raw ingredients but transformations that occur during the brewing process turn beer into a beverage that is enriched in micronutrients. Beer also contains an important number of phenolic compounds and it could be considered to be a source of dietary polyphenols. On the other hand, gut microbiota is now attracting special attention due to its metabolic effects and as because polyphenols are known to interact with gut microbiota. Among others, ferulic acid, xanthohumol, catechins, epicatechins, proanthocyanidins, quercetin, and rutin are some of the beer polyphenols that have been related to microbiota. However, scarce literature exists about the effects of moderate beer consumption on gut microbiota. In this review, we focus on the relationship between beer polyphenols and gut microbiota, with special emphasis on the health outcomes.

Plasma Kinetics of Choline and Choline Metabolites After A Single Dose of SuperbaBoostTM Krill Oil or Choline Bitartrate in Healthy Volunteers

As an essential nutrient, the organic water-soluble compound choline is important for human health. Choline is required for numerous biological processes, including the synthesis of neurotransmitters, and it is an important prerequisite for structural integrity and the functioning of cells. A choline-rich diet provides crucial choline sources, yet additional choline dietary supplements might be needed to fully meet the body’s requirements. Dependent on the structure of choline in different sources, absorption and metabolism may differ and strongly impact the bioavailability of circulating choline. This study in healthy volunteers aimed to compare the pharmacokinetics of free choline and of selected choline metabolites between the single dose intake of phosphatidylcholine, present in SuperbaBoost^TM krill oil, and choline bitartrate salt. Results demonstrate that albeit free choline levels in plasma were comparable between both choline sources, peak choline concentration was reached significantly later upon intake of SuperbaBoost^TM. Moreover, the occurrence of choline metabolites differed between the study products. Levels of the biologically important metabolites betaine and dimethylglycine (DMG) were higher, while levels of trimethylamine N-oxide (TMAO) were substantially lower upon intake of SuperbaBoost^TM compared to choline bitartrate.

Application of 1H-NMR Metabolomics for the Discovery of Blood Plasma Biomarkers of a Mediterranean Diet

The Mediterranean diet (MD) is a dietary pattern well-known for its benefits in disease prevention. Monitoring adherence to the MD could be improved by discovery of novel dietary biomarkers. The MEDiterranean Diet in Northern Ireland (MEDDINI) intervention study monitored the adherence of participants to the MD for up to 12 months. This investigation aimed to profile plasma metabolites, correlating each against the MD score of participants (n = 58). Based on an established 14-point scale MD score, subjects were classified into two groups (“low” and “high”). ¹H-Nuclear Magnetic Resonance (¹H-NMR) metabolomic analysis found that citric acid was the most significant metabolite (p = 5.99 × 10⁻⁴*; q = 0.03), differing between ‘low’ and ‘high’. Furthermore, five additional metabolites significantly differed (p < 0.05; q < 0.35) between the two groups. Discriminatory metabolites included: citric acid, pyruvic acid, betaine, mannose, acetic acid and myo-inositol. Additionally, the top five most influential metabolites in multivariate models were also citric acid, pyruvic acid, betaine, mannose and myo-inositol. Metabolites significantly correlated with the consumption of certain food types. For example, citric acid positively correlated fruit, fruit juice and vegetable constituents of the diet, and negatively correlated with sweet foods alone or when combined with carbonated drinks. Citric acid was the best performing biomarker and this was enhanced by paired ratio with pyruvic acid. The present study demonstrates the utility of metabolomic profiling for effectively assessing adherence to MD and the discovery of novel dietary biomarkers.

Consuming egg yolk decreases body weight and increases serum HDL and brain expression of TrkB in male SD rats

BACKGROUND

Egg yolks contain large amounts of cholesterol and are suspected to be harmful after long-term consumption. In this experiment, 63 rats were used to evaluate the effect of egg white (EW) and egg yolk (EY) supplementation on serum lipids and brain cognition. The feeding time lasted 4 weeks after a 1-week acclimation.

RESULTS

Body weight was significantly higher in rats fed 132.0 g kg^-1 EW and significantly lower when fed 40 g kg^-1 EY (P < 0.05). Total cholesterol and low-density lipoprotein increased in rats fed 72.0 g kg^-1 EW compared with rats from NC and EY groups (P < 0.05). High-density lipoprotein (HDL) was higher in rats fed 40 g kg^-1 EY and decreased when fed 72.0 g kg^-1 EW (P < 0.05). Rats fed a diet with EY exhibited abundant neurons in the CA1 hippocampus and complete subcellular structures. Rats fed 132 g kg^-1 EW exhibited shrunken cells and swollen mitochondria. Brain-derived neurotrophic factor had constitutively low expression among groups, while tyrosine kinase B (TrkB) exhibited higher expression levels in rats fed a diet containing EY compared with other groups (P < 0.05).

CONCLUSION

EY consumption reduced body weight and increased HDL levels. Diet containing EY could improve cognition through enhanced trkB expression. © 2019 Society of Chemical Industry.

Development of a Choline Database to Estimate Australian Population Intakes

The AUSNUT 2011-13 food composition database was expanded to include Australian choline values. The development began with a systematic literature review of published studies. Analytical data from the food studies were extracted and aligned with their equivalent AUSNUT food identification code. Global food composition databases containing choline values were matched to the remaining AUSNUT food codes, following the FAO INFOODS food matching guidelines, including adjustments for moisture and protein composition. Composite foods, and not further-specified foods, were developed using the Food Standards Australia New Zealand (FSANZ) recipe files. The completed choline database was then employed to analyse the Australian National Nutrition and Physical Activity Survey 2011-12, with population and sampling weightings applied. Survey respondents were classified into categories based on their level of choline intake and compared with the Australian Adequate Intake levels. Food sources of intake were also explored. Multiple linear regression models were developed for food group contributors to choline intake. Mean choline intakes varied from 151.50 mg for pregnant 14-18 years old, to 310.54 mg for 19-64 year old males. Less than 10% of the population by age and gender were achieving the Adequate Intake for choline. Eggs and their contributing food groups were the top ranked food sources of choline for the population.

Prospective associations of maternal choline status with offspring body composition in the first 5 years of life in two large mother-offspring cohorts: the Southampton Women's Survey cohort and the Growing Up in Singapore Towards healthy Outcomes cohort

BACKGROUND

Choline status has been positively associated with weight and fat mass in animal and human studies. As evidence examining maternal circulating choline concentrations and offspring body composition in human infants/children is lacking, we investigated this in two cohorts.

METHODS

Maternal choline concentrations were measured in the UK Southampton Women's Survey (SWS; serum, n = 985, 11 weeks' gestation) and Singapore Growing Up Towards healthy Outcomes (GUSTO); n = 955, 26-28 weeks' gestation) mother-offspring cohorts. Offspring anthropometry was measured at birth and up to age 5 years. Body fat mass was determined using dual-energy x-ray absorptiometry at birth and age 4 years for SWS; and using air-displacement plethysmography at birth and age 5 years for GUSTO. Linear-regression analyses were performed, adjusting for confounders.

RESULTS

In SWS, higher maternal choline concentrations were associated with higher neonatal total body fat mass {β = 0.60 standard deviation [SD]/5 µmol/L maternal choline [95% confidence interval (CI) 0.04-1.16]} and higher subscapular skinfold thickness [β = 0.55 mm/5 µmol/L (95% CI, 0.12-1.00)] at birth. In GUSTO, higher maternal choline concentrations were associated with higher neonatal body mass index-for-age z-score [β = 0.31 SD/5 µmol/L (0.10-0.51)] and higher triceps [β = 0.38 mm/5 µmol/L (95% CI, 0.11-0.65)] and subscapular skinfold thicknesses [β = 0.26 mm/5 µmol/L (95% CI, 0.01-0.50)] at birth. No consistent trends were observed between maternal choline and offspring gain in body mass index, skinfold thicknesses, abdominal circumference, weight, length/height and adiposity measures in later infancy and early childhood.

CONCLUSION

Our study provides evidence that maternal circulating choline concentrations during pregnancy are positively associated with offspring BMI, skinfold thicknesses and adiposity at birth, but not with growth and adiposity through infancy and early childhood to the age of 5 years.

A Conceptual Framework for Studying and Investing in Precision Nutrition

Nutrients and food-derived bioactive molecules must transit complex metabolic pathways, and these pathways vary between people. Metabolic heterogeneity is caused by genetic variation, epigenetic variation, differences in microbiome composition and function, lifestyle differences and by variation in environmental exposures. This review discusses a number of these sources of metabolic heterogeneity and presents some of the research investments that will be needed to make applications of precision nutrition practical.

Modulation of the Gut Microbiota by Resistant Starch as a Treatment of Chronic Kidney Diseases: Evidence of Efficacy and Mechanistic Insights

Chronic kidney disease (CKD) has been associated with changes in gut microbial ecology, or "dysbiosis," which may contribute to disease progression. Recent studies have focused on dietary approaches to favorably alter the composition of the gut microbial communities as a treatment method in CKD. Resistant starch (RS), a prebiotic that promotes proliferation of gut bacteria such as Bifidobacteria and Lactobacilli, increases the production of metabolites including short-chain fatty acids, which confer a number of health-promoting benefits. However, there is a lack of mechanistic insight into how these metabolites can positively influence renal health. Emerging evidence shows that microbiota-derived metabolites can regulate the incretin axis and mitigate inflammation via expansion of regulatory T cells. Studies from animal models and patients with CKD show that RS supplementation attenuates the concentrations of uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate. Here, we present the current state of knowledge linking the microbiome to CKD, we explore the efficacy of RS in animal models of CKD and in humans with the condition, and we discuss how RS supplementation could be a promising dietary approach for slowing CKD progression.

Retail liver juices enhance the survivability of Campylobacter jejuni and Campylobacter coli at low temperatures

The high prevalence of Campylobacter spp. in retail liver products was previously reported and has been linked to several outbreaks of campylobacteriosis. The main objective of this study was to investigate the influence of retail liver juices on the survivability of several strains of C. jejuni and C. coli, which were previously isolated from various retail meats at 4 °C. All tested Campylobacter strains showed higher survival in beef liver juice (BLJ) and chicken liver juice (CLJ) as compared to beef and chicken juices (BJ and CJ) or Mueller Hinton broth (MHB) at 4 °C. Overall, C. jejuni strains showed greater survival in retail liver and meat juices as compared to C. coli. CLJ enhanced biofilm formation of most C. coli strains and supported growth in favorable conditions. When diluted, retail liver and meat juices enhanced survival of Campylobacter strains at low temperatures and increased aerotolerance. In conclusion, beef and chicken liver juices enhanced the survival of C. jejuni and C. coli strains at low temperatures, which helps explain the high prevalence of Campylobacter spp. in retail liver products.

Detection of toxic choline based on Mn2O3/NiO nanomaterials by an electrochemical method

In this study, a novel in situ choline sensor was assembled by attaching the binary Mn₂O₃/NiO nanoparticles (NPs) onto a glassy carbon electrode (GCE). Initially, Mn₂O₃/NiO NPs were synthesized via a wet-chemical process and fully characterized via XRD, XPS, FESEM, EDS, FTIR and UV-Vis methods. The analytical performances of the choline sensor were evaluated by an electrochemical method in the phosphate buffer phase. The estimated linear dynamic range (LDR) was found to be 0.1 nM to 0.1 mM. The other analytical performances of the choline sensor, such as sensitivity (16.4557 μA μM⁻¹ cm⁻²) and detection limit (5.77 ± 0.29 pM), were also calculated very carefully from the calibration plot. Overall, the choline sensor exhibited a reliable reproducibility, in situ validity, selectivity, interference effect, stability, and intra-day and inter-day performances with high accuracy in a short response time. Moreover, the probe was successfully applied to detect choline in real human, mouse and rabbit serum. This fabrication route would be a novel approach for the detection of selective biochemical sensor in the healthcare and biomedical fields.

In this study, a novel in situ choline sensor was assembled by attached the binary Mn₂O₃/NiO nanoparticles onto glassy carbon electrode, which might be a reliable way to develop of future sensor in the field of biomedical and healthcare fields.

Detection of Secondary Metabolites as Biomarkers for the Early Diagnosis and Prevention of Type 2 Diabetes

BACKGROUND

Type 2 diabetes, or T2D, is a metabolic disease that results in insulin resistance. In the present study, we hypothesize that metabolomic analysis in blood samples of T2D patients sharing the same ethnic background can recover new metabolic biomarkers and pathways that elucidate early diagnosis and predict the incidence of T2D.

METHODS

The study included 34 T2D patients and 33 healthy volunteers recruited between the years 2012 and 2013; the secondary metabolites were extracted from blood samples and analyzed using HPLC.

RESULTS

Principal coordinate analysis and hierarchical clustering patterns for the uncharacterized negatively and positively charged metabolites indicated that samples from healthy individuals and T2D patients were largely separated with only a few exceptions. The inspection of the top 10% secondary metabolites indicated an increase in fucose, tryptophan and choline levels in the T2D patients, while there was a reduction in carnitine, homoserine, allothreonine, serine and betaine as compared to healthy individuals. These metabolites participate mainly in three cross-talking pathways, namely "glucagon signaling", "glycine, serine and threonine" and "bile secretion". Reduced level of carnitine in T2D patients is known to participate in the impaired insulin-stimulated glucose utilization, while reduced betaine level in T2D patients is known as a common feature of this metabolic syndrome and can result in the reduced glycine production and the occurrence of insulin resistance. However, reduced levels of serine, homoserine and allothrionine, substrates for glycine production, indicate the depletion of glycine, thus possibly impair insulin sensitivity in T2D patients of the present study.

CONCLUSION

We introduce serine, homoserine and allothrionine as new potential biomarkers of T2D.

Phospholipase D and Choline Metabolism

Phospholipases D (PLDs) catalyze hydrolysis of the diester bond of phospholipids to generate phosphatidic acid and the free lipid headgroup. In mammals, PLD enzymes comprise the intracellular enzymes PLD1 and PLD2 and possibly the proteins encoded by related genes, as well as a class of cell surface and secreted enzymes with structural homology to ectonucleotide phosphatases/phosphodiesterases as typified by autotaxin (ENPP2) that have lysoPLD activities. Genetic and pharmacological loss-of-function approaches implicate these enzymes in intra- and intercellular signaling mediated by the lipid products phosphatidic acid, lysophosphatidic acid, and their metabolites, while the possibility that the water-soluble product of their reactions is biologically relevant has received far less attention. PLD1 and PLD2 are highly selective for phosphatidylcholine (PC), whereas autotaxin has broader substrate specificity for lysophospholipids but by virtue of the high abundance of lysophosphatidylcholine (LPC) in extracellular fluids predominantly hydrolyses this substrate. In all cases, the water-soluble product of these PLD activities is choline. Although choline can be formed de novo by methylation of phosphatidylethanolamine, this activity is absent in most tissues, so mammals are effectively auxotrophic for choline. Dietary consumption of choline in both free and esterified forms is substantial. Choline is necessary for synthesis of the neurotransmitter acetylcholine and of the choline-containing phospholipids PC and sphingomyelin (SM) and also plays a recently appreciated important role as a methyl donor in the pathways of "one-carbon (1C)" metabolism. This review discusses emerging evidence that some of the biological functions of these intra- and extracellular PLD enzymes involve generation of choline with a particular focus on the possibility that these choline and PLD dependent processes are dysregulated in cancer.

Dietary Choline Intake: Current State of Knowledge Across the Life Cycle

Choline, an essential dietary nutrient for humans, is required for the synthesis of the neurotransmitter, acetylcholine, the methyl group donor, betaine, and phospholipids; and therefore, choline is involved in a broad range of critical physiological functions across all stages of the life cycle. The current dietary recommendations for choline have been established as Adequate Intakes (AIs) for total choline; however, dietary choline is present in multiple different forms that are both water-soluble (e.g., free choline, phosphocholine, and glycerophosphocholine) and lipid-soluble (e.g., phosphatidylcholine and sphingomyelin). Interestingly, the different dietary choline forms consumed during infancy differ from those in adulthood. This can be explained by the primary food source, where the majority of choline present in human milk is in the water-soluble form, versus lipid-soluble forms for foods consumed later on. This review summarizes the current knowledge on dietary recommendations and assessment methods, and dietary choline intake from food sources across the life cycle.

Preliminary study of urinary arsenic concentration and arsenic methylation capacity effects on neurodevelopment in very low birth weight preterm children under 24 months of corrected age

The neurological prognoses of very low birth weight preterm (VLBWP) children during the first 2 years of life will influence their neurodevelopment during subsequent childhood years and adolescence. The objective of this study was to systemic investigate relationships of urinary arsenic (As) concentrations, the As methylation capability, and toenail As concentrations on cognitive, language, and motor development in VLBWP children under 24 months of corrected age.Participants (n = 60) in our study were recruited from October 2010 to April 2013. Urine and toenail samples were collected for evaluation to assess As exposure. The Bayley scales of infant development III were used to evaluate neurodevelopment at 2 years of corrected age. Concentrations of As species in urine and the As concentration in toenails were, respectively, analyzed using HPLC-HG-AAS and ICP-MS.The mean concentration of total As was 28.6 μg/g creatinine, and inorganic As was 1.01 μg/L in urine. The urine contained an average of 3% inorganic As, 2% monomethylarsonic acid, and 95% dimethylarsinic acid (DMA). The mean concentration of As in toenails was 225 ng/g. Children with a longer gestational age (≥28 weeks) and higher DMA % levels appeared to have the highest unadjusted cognitive and fine motor scores.Our study results suggest that gestational age is associated with neurodevelopment in VLBWP children. We recommend that further study simultaneously analyze multiple environmental contaminants that may have adverse effects on neurodevelopment, use biomarkers for the mother-child pair, and determine whether prenatal or postnatal As exposure has a greater influence on the neurological development of VLBWP children.

Dietary intake of one-carbon metabolism nutrients and DNA methylation in peripheral blood

Background

Folate and other one-carbon metabolism nutrients are essential to enable DNA methylation to occur, but the extent to which their dietary intake influences methylation in adulthood is unclear.

Objective

We assessed associations between dietary intake of these nutrients and DNA methylation in peripheral blood, overall and at specific genomic locations.

Design

We conducted a cross-sectional study using baseline data and samples from 5186 adult participants in the Melbourne Collaborative Cohort Study (MCCS). Nutrient intake was estimated from a food-frequency questionnaire. DNA methylation was measured by using the Illumina Infinium HumanMethylation450 BeadChip array (HM450K). We assessed associations of intakes of folate, riboflavin, vitamins B-6 and B-12, methionine, choline, and betaine with methylation at individual cytosine-guanine dinucleotides (CpGs), and with median (genome-wide) methylation across all CpGs, CpGs in gene bodies, and CpGs in gene promoters. We also assessed associations with methylation at long interspersed nuclear element 1 (LINE-1), satellite 2 (Sat2), and Arthrobacter luteus restriction endonuclease (Alu) repetitive elements for a subset of participants. We used linear mixed regression, adjusting for age, sex, country of birth, smoking, energy intake from food, alcohol intake, Mediterranean diet score, and batch effects to assess log-linear associations with dietary intake of each nutrient. In secondary analyses, we assessed associations with low or high intakes defined by extreme quintiles.

Results

No evidence of log-linear association was observed at P < 10-7 between the intake of one-carbon metabolism nutrients and methylation at individual CpGs. Low intake of riboflavin was associated with higher methylation at CpG cg21230392 in the first exon of PROM1 (P = 5.0 × 10-8). No consistent evidence of association was observed with genome-wide or repetitive element measures of methylation.

Conclusion

Our findings suggest that dietary intake of one-carbon metabolism nutrients in adulthood, as measured by a food-frequency questionnaire, has little association with blood DNA methylation. An association with low intake of riboflavin requires replication in independent cohorts. This study was registered at http://www.clinicaltrials.gov as NCT03227003.

Dietary protein source and butyrylated high-amylose maize starch included in a high-protein diet determines the urinary metabolome of rats

Intake of red and processed meat increases the risk of colorectal cancer (CRC), whereas dairy product consumption and the intake of dietary fibre are negatively associated with this risk. We investigated the effect of (i) low-protein diets with either whey or cooked meat (beef) as the protein source and (ii) high-protein diets with cooked meat (beef) either without or with the inclusion of 10% butyrylated high-amylose maize starch (HAMSB), on the urinary metabolome of rats. Urine samples from rats were analysed using untargeted LC-MS metabolomics. The level and source of the dietary protein affected the urinary excretion of numerous metabolites indicating that several metabolic pathways were changed. The inclusion of HAMSB in a high-protein diet caused significant alterations in the excretion of several metabolites. HAMSB reduced urinary excretion of potentially harmful metabolites resulting from a high level of meat consumption.