Dimethylglycine Concentrations Research Articles

Serum betaine and dimethylglycine in mid-pregnancy and the risk of gestational diabetes mellitus: a case-control study.

To investigate the associations of choline, betaine, dimethylglycine (DMG), L-carnitine, and Trimethylamine-N-oxide (TMAO) with the risk of Gestational diabetes mellitus (GDM) as well as the markers of glucose homeostasis. We performed a case-control study including 200 diagnosed GDM cases and 200 controls matched by maternal age (±2 years) and gestational age (±2 weeks). Concentrations of serum metabolites were measured by the high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). Compared to the control group, GDM group had significantly lower serum betaine concentration and betaine/choline ratio, and higher DMG concentration. Furthermore, decreased betaine concentration and betaine/choline ratio, increased DMG concentration showed significant association with the risk of GDM. In addition, serum betaine concentrations were negatively associated with blood glucose levels at 1-h post-glucose load (OGTT-1h), and both betaine and L-carnitine concentrations were positively associated with 1,5-anhydroglucitol levels. Betaine/choline ratio was negatively associated with OGTT-1h and blood glucose levels at 2-h post-glucose load (OGTT-2h) and serum choline concentrations were negatively associated with fasting blood glucose and positively associated with OGTT-2h. Decreased serum betaine concentrations and betaine/choline ratio, and elevated DMG concentrations could be significant risk factors for GDM. Furthermore, betaine may be associated with blood glucose regulation and short-term glycemic fluctuations.

Potential metabolomic biomarkers for the identification and diagnosis of type A acute aortic dissection in patients with hypertension

Most patients with acute aortic dissection (AAD) have a history of hypertension. Diagnosis of AAD in patients with hypertension at an early stage is complicated and challenging. This study aimed to explore the distinctive metabolic changes in plasma samples of AAD patients with hypertension and patients with hypertension only and provide early identification and diagnosis of AAD in patients with hypertension. We collected blood samples from 20 patients with type A AAD and hypertension admitted to the emergency department and physically examined other 20 patients with hypertension as controls. The plasma metabolomic profiles of these patients were determined using untargeted metabolomics with ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. A total of 38 metabolites that differed between the AAD and hypertension groups were screened. In the positive ion mode, 12 metabolites were different between the two groups, and in the negative ion mode, 26 metabolites were different. Among the 26 different metabolites detected by the negative ion mode, 21 were significantly upregulated and five were downregulated in patients with AAD compared to patients with hypertension. Moreover, five metabolites were upregulated and seven were significantly downregulated in patients with AAD compared to those with hypertension, as detected by the positive ion mode. The metabolites differentially expressed in AAD were mainly involved in lipid metabolism (fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, and linoleic acid metabolism), carbohydrate metabolism (galactose, fructose, and mannose metabolisms), and membrane transport (ATP-binding cassette transporters). Interestingly, plasma hydrocortisone and dimethylglycine concentrations were significantly increased in patients with type A AAD, with the highest area under the curve value (AUC = 0.9325 or 0.9200, respectively) tested by the receiver operating characteristic curve analysis. This study provides possible metabolic markers for the early clinical diagnosis of AAD in patients with hypertension.

Plasma trimethylamine-N-oxide, its precursors and risk of cardiovascular events in patients with acute coronary syndrome: Mediating effects of renal function.

AimsTo examine associations of the gut microbial metabolite trimethylamine-N-oxide (TMAO) and its precursors with risk of cardiovascular events in acute coronary syndrome (ACS), and determine whether these associations were mediated by renal function.MethodsIn this prospective cohort study, we included 309 patients with ACS. During a mean follow-up of 6.7 years, 131 patients developed major adverse cardiovascular events (MACE) (myocardial infarction, hospitalization for heart failure, and all-cause mortality). Plasma concentrations of TMAO, trimethylamine (TMA), choline, betaine, dimethylglycine and L-carnitine were profiled by liquid chromatography tandem mass spectrometry. Hazard ratios were estimated with multivariable Cox regression models. The mediating role of estimated glomerular filtration rate (eGFR) was tested under a counterfactual framework.ResultsAfter adjustment for traditional cardiovascular risk factors and medications, participants in the highest tertile vs. the lowest tertile of baseline TMAO and dimethylglycine concentrations had a higher risk of MACE [(HR: 1.83; 95% CI: 1.08, 3.09) and (HR: 2.26; 95% CI: 1.17, 3.99), respectively]. However, with regards to TMAO these associations were no longer significant, whereas for dimethylglycine, the associations were attenuated after additional adjustment for eGFR. eGFR mediated the associations of TMAO (58%) and dimethylglycine (32%) with MACE incidence. The associations between dimethylglycine and incident MACE were confirmed in an internal validation. No significant associations were found for TMA, choline, betaine and L-carnitine.ConclusionThese findings suggest that renal function may be a key mediator in the association of plasma TMAO with the development of cardiovascular events after ACS. The present findings also support a role of dimethylglycine in the pathogenesis of MACE, which may be mediated, at least partially, by renal function.

No Association Between Riboflavin and Choline Status in a Sample of Canadian and Malaysian Women of Reproductive Age

ObjectivesRiboflavin and choline are essential nutrients that are metabolically inter-related and play major roles in one-carbon metabolism. Betaine can donate a methyl group to homocysteine, forming dimethylglycine (DMG) and methionine in the liver and kidney. Betaine is synthesized from choline in two irreversible reactions, the first of which is catalyzed by flavin adenine dinucleotide (FAD), a cofactor formed from riboflavin. In animal models, riboflavin status has been shown to influence choline and its metabolites betaine and DMG but there are no human studies. Here we examine whether riboflavin status modifies plasma choline, betaine, and DMG concentrations in healthy women (19–45 y).MethodsFasting blood was collected from 206 Canadian and 210 Malaysian women between 2015 and 2016. Riboflavin status was assessed using a functional biomarker, erythrocyte glutathione reductase activity coefficient (EGRac). Plasma choline, betaine, and DMG were determined by LCLC MS/MS. Plasma folate and vitamin B12 were determined using the microbiological method and an immune assay, respectively. General linear models were used to assess the independent relationship between EGRac and each of the choline metabolites with adjustment for potential confounders.Results71% of Malaysian women had EGRac ≥1.40 compared to 40% of Canadian women. Betaine, DMG, and vitamin B12 concentrations were significantly higher among Malaysian women compared to Canadian women (40.6 vs. 37.0 mmol/L, 2.7 vs. 2.4 mmol/L and 360 vs. 307 pmol/L, respectively). There were no significant associations between EGRac or riboflavin deficiency (defined as EGRac ≥1.40) and choline or its’ metabolites after adjustments for age, ethnicity, body mass index, plasma folate, and vitamin B12. In the adjusted models, plasma choline was positively associated with vitamin B12 concentrations (B = 0.002, 95% CI: 0.000, 0.003) and plasma betaine was positively associated with plasma folate (B = 0.18, 95%CI: 0.07, 0.29) and vitamin B12 (B = 0.011, 95%CI: 0.002, 0.020).ConclusionsOverall, riboflavin status was not associated with choline and its metabolites in Canadian and Malaysian women.Funding SourcesDairy Farmers of Canada, Saudi Arabian Cultural Bureau in Canada, and BC Children's Hospital Research Institute.

Nutritional supplementation alters associations between one-carbon metabolites and cardiometabolic risk profiles in older adults: a secondary analysis of the Vienna Active Ageing Study

PurposeCardiovascular diseases and cognitive decline, predominant in ageing populations, share common features of dysregulated one-carbon (1C) and cardiometabolic homeostasis. However, few studies have addressed the impact of multifaceted lifestyle interventions in older adults that combine both nutritional supplementation and resistance training on the co-regulation of 1C metabolites and cardiometabolic markers.Methods95 institutionalised older adults (83 ± 6 years, 88.4% female) were randomised to receive resistance training with or without nutritional supplementation (Fortifit), or cognitive training (control for socialisation) for 6 months. Fasting plasma 1C metabolite concentrations, analysed by liquid chromatography coupled with mass spectrometry, and cardiometabolic parameters were measured at baseline and the 3- and 6-month follow-ups.ResultsRegardless of the intervention group, choline was elevated after 3 months, while cysteine and methionine remained elevated after 6 months (mixed model time effects, p < 0.05). Elevated dimethylglycine and lower betaine concentrations were correlated with an unfavourable cardiometabolic profile at baseline (spearman correlations, p < 0.05). However, increasing choline and dimethylglycine concentrations were associated with improvements in lipid metabolism in those receiving supplementation (regression model interaction, p < 0.05).ConclusionCholine metabolites, including choline, betaine and dimethylglycine, were central to the co-regulation of 1C metabolism and cardiometabolic health in older adults. Metabolites that indicate upregulated betaine-dependent homocysteine remethylation were elevated in those with the greatest cardiometabolic risk at baseline, but associated with improvements in lipid parameters following resistance training with nutritional supplementation. The relevance of how 1C metabolite status might be optimised to protect against cardiometabolic dysregulation requires further attention.

School-Aged Children in Vancouver, Canada Do Not Meet Dietary Choline Recommendations but Meet Recommendations for Folate and Vitamin B12

ObjectivesNutrients such as choline, betaine, folate, and vitamin B12 are required for proper growth and development, but little is known about these nutrients in children. Our objective was to determine intakes and biomarkers of these nutrients in school-aged children (5 to 6 years old). MethodsA cross-sectional study of healthy children (n = 285) recruited from Vancouver, Canada were assessed. Dietary information was collected using three 24-hour recalls. Nutrient intakes were estimated using the Canadian Nutrient File and USDA database for choline; supplement use was collected by questionnaire. Plasma biomarkers were quantified by mass spectrometry and immunoassay. ResultsDaily dietary intakes were (mean ± SD) choline 250 ± 96 mg, betaine 88 ± 41 mg, folate 335 ± 126 μg DFE, and vitamin B12 3.78 ± 2.71 μg. Top food sources were dairy and eggs (42–57%) for choline and vitamin B12, and cereal and grains (41–60%) for betaine and folate. Only 40% of children met the choline adequate intake (AI) recommendation for North America (≥250 mg/d); 81.5% met the European AI (≥170 mg/d). Plasma free choline, betaine, and dimethylglycine concentrations were (mean ± SD) 8.62 ± 2.13 μmol/L, 45.3 ± 13.7 μmol/L, 3.34 ± 1.03 μmol/L, respectively. Dietary choline intake and plasma free choline were not related. However, dietary choline intake was positively associated with plasma dimethylglycine. Less than 5% of children had inadequate folate and vitamin B12 intakes. More than half of the children (59.4%) were consuming a supplement containing B-vitamins, but none included choline or betaine. Some children (5.26%) had total folic acid intakes above the North American upper limit (UL; >400 μg/d); 10.90% had intakes above the European UL (>300 μg/d). Vitamin B12 intake was positively associated with plasma total vitamin B12 (mean ± SD; 594 ± 158 pmol/L) in an adjusted model (sex, age, total energy intake, and supplement use; p < 0.05). ConclusionsOur findings suggest that many school-aged children are not meeting dietary choline recommendations. Some children may have excessive folic acid intakes. The impact of imbalanced methyl nutrient intakes during this active period of growth and development needs to be determined in the future. Funding SourcesCIHR, NSERC, and BC Children’s Hospital Research Institute.

Expression Changes in Epigenetic Gene Pathways Associated With One-Carbon Nutritional Metabolites in Maternal Blood From Pregnancies Resulting in Autism and Non-Typical Neurodevelopment.

The prenatal period is a critical window for the development of autism spectrum disorder (ASD). The relationship between prenatal nutrients and gestational gene expression in mothers of children later diagnosed with ASD or non‐typical development (Non‐TD) is poorly understood. Maternal blood collected prospectively during pregnancy provides insights into the effects of nutrition, particularly one‐carbon metabolites, on gene pathways and neurodevelopment. Genome‐wide transcriptomes were measured with microarrays in 300 maternal blood samples in Markers of Autism Risk in Babies‐Learning Early Signs. Sixteen different one‐carbon metabolites, including folic acid, betaine, 5′‐methyltretrahydrofolate (5‐MeTHF), and dimethylglycine (DMG) were measured. Differential expression analysis and weighted gene correlation network analysis (WGCNA) were used to compare gene expression between children later diagnosed as typical development (TD), Non‐TD and ASD, and to one‐carbon metabolites. Using differential gene expression analysis, six transcripts (TGR‐AS1, SQSTM1, HLA‐C, and RFESD) were associated with child outcomes (ASD, Non‐TD, and TD) with genome‐wide significance. Genes nominally differentially expressed between ASD and TD significantly overlapped with seven high confidence ASD genes. WGCNA identified co‐expressed gene modules significantly correlated with 5‐MeTHF, folic acid, DMG, and betaine. A module enriched in DNA methylation functions showed a suggestive protective association with folic acid/5‐MeTHF concentrations and ASD risk. Maternal plasma betaine and DMG concentrations were associated with a block of co‐expressed genes enriched for adaptive immune, histone modification, and RNA processing functions. These results suggest that the prenatal maternal blood transcriptome is a sensitive indicator of gestational one‐carbon metabolite status and changes relevant to children's later neurodevelopmental outcomes.Lay SummaryPregnancy is a time when maternal nutrition could interact with genetic risk for autism spectrum disorder. Blood samples collected during pregnancy from mothers who had a prior child with autism were examined for gene expression and nutrient metabolites, then compared to the diagnosis of the child at age three. Expression differences in gene pathways related to the immune system and gene regulation were observed for pregnancies of children with autism and non‐typical neurodevelopment and were associated with maternal nutrients.

Associations between Plasma Choline Metabolites and Genetic Polymorphisms in One-Carbon Metabolism in Postmenopausal Women: The Women's Health Initiative Observational Study

Background:Choline plays an integral role in one-carbon metabolism in the body, but it is unclear whether genetic polymorphisms are associated with variations in plasma choline and its metabolites. Objectives:This study aimed to evaluate the association of genetic variants in choline and one-carbon metabolism with plasma choline and its metabolites. Methods:We analyzed data from 1423 postmenopausal women in a case-control study nested within the Women's Health Initiative Observational Study. Plasma concentrations of choline, betaine, dimethylglycine (DMG), and trimethylamine N-oxide were determined in 12-h fasting blood samples collected at baseline (1993–1998). Candidate and tagging single-nucleotide polymorphisms (SNPs) were genotyped in betaine-homocysteine S-methyltransferase (BHMT), BHMT2, 5,10-methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (NADP+ dependent 1) (MTHFD1), 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR). Linear regression was used to derive percentage difference in plasma concentrations per variant allele, adjusting for confounders, including B-vitamin biomarkers. Potential effect modification by plasma vitamin B-12, vitamin B-6, and folate concentrations and folic-acid fortification periods was examined. ResultsThe candidate SNP BHMT R239Q (rs3733890) was associated with lower concentrations of plasma betaine and DMG concentrations (–4.00% and –6.75% per variant allele, respectively; both nominal P < 0.05). Another candidate SNP, BHMT2 rs626105 A>G, was associated with higher plasma DMG concentration (13.0%; P < 0.0001). Several tagSNPs in these 2 genes were associated with plasma concentrations after correction for multiple comparisons. Vitamin B-12 status was a significant effect modifier of the association between the genetic variant BHMT2 rs626105 A>G and plasma DMG concentration. ConclusionsGenetic variations in metabolic enzymes were associated with plasma concentrations of choline and its metabolites. Our findings contribute to the knowledge on the variation in blood nutrient concentrations in postmenopausal women.

Plasma Trimethylamine N-Oxide and Its Precursors: Population Epidemiology, Parent-Child Concordance, and Associations with Reported Dietary Intake in 11- to 12-Year-Old Children and Their Parents.

BackgroundTrimethylamine N-oxide (TMAO) is a microbiome- and diet-derived metabolite implicated in adverse cardiovascular outcomes. To date, studies of plasma TMAO concentrations have largely focused on individuals with metabolic disease. As such, data on TMAO concentrations in population settings and parent–child dyads are lacking.ObjectivesThis study aimed to investigate parent–child concordance, age, and sex effects on plasma concentrations of TMAO and its precursors [l-carnitine, choline, betaine, and dimethylglycine (DMG)]. Associations between concentrations of TMAO and its precursors and self-reported dietary intakes of animal protein (i.e., red meat, meat products, chicken, fish, milk products, and cheese) and fast-food meals were also investigated.MethodsA total of 1166 children (mean ± SD age: 11 ± 0.5 y, 51% female) and 1324 parents (mean ± SD age: 44 ± 5.1 y, 87% female) had a biomedical assessment as part of Growing Up in Australia's Child Health Checkpoint. Plasma TMAO and precursor concentrations were quantified using ultra-high-pressure LC coupled with tandem MS.ResultsFamilial dyads significantly contributed to plasma TMAO and precursor concentrations (P < 0.0001), explaining 37% of variance for TMAO concentrations. Least-square mean ± SE plasma TMAO was lower in children (0.79 ± 0.02 µM on the log-scale) than in adults (1.22 ± 0.02 µM). By contrast, children's betaine (40.30 ± 0.34 µM) and DMG concentrations (1.02 ± 0.01 µM on the log-scale) were higher than adults’ betaine (37.50 ± 0.32 µM) and DMG concentrations (0.80 ± 0.01 µM) (P < 0.0001). Mean values of all metabolites, except adult TMAO, were higher in males than in females (P < 0.001). Greater reported intake of red meat and fish was associated with higher TMAO concentrations in both children [estimates (95% CIs) for red meat: 0.06 (0.01, 0.10); fish: 0.11 (0.06, 0.17)] and adults [red meat: 0.13 (0.08, 0.17); meat products: 0.07 (0.03, 0.12); and fish: 0.09 (0.04, 0.14)].ConclusionsAge, sex, and shared family factors, including diet, contribute to variation in plasma concentrations of TMAO and its precursors.

Serum Betaine and Dimethylglycine Are Higher in South Asian Compared with European Pregnant Women in Canada, with Betaine and Total Homocysteine Inversely Associated in Early and Midpregnancy, Independent of Ethnicity

As a methyl donor required in the folate-vitamin B-12 independent remethylation of total homocysteine (tHcy) to methionine, betaine is critical for fetal development. Pregnant South Asian women living in Canada had a higher reported prevalence of low vitamin B-12 status compared with Europeans; betaine concentrations in this population are unknown. We aimed to compare serum betaine concentrations between South Asian and European pregnant women, and to determine the relation between betaine and tHcy concentrations in early pregnancy. A retrospective cohort study was conducted using biobanked serum samples of 723 apparently healthy pregnant women of South Asian (50%) and European ethnicity residing in British Columbia, Canada. Betaine, dimethylglycine (DMG), tHcy, and related metabolites were quantified in samples collected in the first (8-13 weeks of gestation) and second (14-20 weeks of gestation) trimesters. The relation between betaine and tHcy concentrations was assessed using a generalized regression model adjusted for weeks of gestation, ethnicity, prepregnancy BMI, maternal age, neonatal sex, parity, total vitamin B-12, folate, pyridoxal 5'-phosphate, and methionine concentrations. Median serum concentrations of betaine and its metabolite DMG were higher in South Asian women in the first (19.8 [IQR: 16.3-25.0] and 1.55 [IQR: 1.30-1.96] $\mu {\rm mol/L} $, respectively) and second trimesters (16.1 [IQR: 12.9-19.8] and 1.42 [IQR: 1.14-1.81] $\mu {\rm mol/L} $, respectively) compared with European women (17.6 [IQR: 13.7-22.6] and 1.38 [IQR: 1.12-1.77] $\mu {\rm mol/L} $, respectively) and (12.9 [IQR: 10.6-16.7] and 1.19 [IQR: 0.97-1.52] $\mu {\rm mol/L} $, respectively; all P values <0.0001). Betaine was inversely associated with tHcy concentration (β=-0.0208; 95% CI: -0.0341, -0.00742; P=0.002). Additionally, total vitamin B-12 was associated with tHcy concentration (β=-0.0312; 95% CI: -0.0401, -0.0224), after adjusting for confounding factors. Pregnant South Asian women residing in Canada had higher betaine and DMG concentrations, compared with women of European ethnicity, while betaine and total vitamin B-12 predicted tHcy independent of ethnicity. Our results emphasize the role of betaine, as methyl donor, in the remethylation of tHcy in a folate-replete population.

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.

Plasma Betaine Is Positively Associated with Developmental Outcomes in Healthy Toddlers at Age 2 Years Who Are Not Meeting the Recommended Adequate Intake for Dietary Choline

Choline is an important nutrient during development. However, there are limited data on dietary choline intake and status in toddlers and the relation to neurodevelopmental outcomes. This study assessed dietary choline intake and status in healthy toddlers at ages 1 and 2 y and determined the relation to neurodevelopmental outcomes. This is a secondary analysis of data from healthy toddlers enrolled in a double-blind, randomized controlled trial of long-chain polyunsaturated fatty acid supplementation between ages 1 and 2 y. Dietary intakes of betaine and choline were estimated by 3-d food records; plasma free choline, betaine, and dimethylglycine were quantified by liquid chromatography-tandem mass spectrometry. Developmental outcomes were assessed at age 2 y with the use of the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III), Cognitive and Language composites, and the Beery-Buktenica Developmental Test of Visual-Motor Integration (Beery-VMI). The mean±SD daily intake for total choline at age 1 y was 174±56.2 mg/d and increased (P<0.001) to 205±67.5 mg/d at age 2 y. At ages 1 and 2 y, 71.8% and 55.8%, respectively, of toddlers did not meet the recommended 200-mg/d Adequate Intake (AI) for dietary choline. At age 1 y, mean±SD plasma free choline, betaine, and dimethylglycine concentrations were 10.4±3.3, 41.1±15.4, and 4.1±1.9 µmol/L, respectively. Plasma free choline (8.5±2.3 µmol/L) and dimethylglycine (3.2±1.3 µmol/L) concentrations were lower (P<0.001) at age 2 y. Plasma betaine concentrations were positively associated with the Beery-VMI (β=0.270; 95% CI: 0.026, 0.513; P=0.03) at age 2 y. These findings suggest that most toddlers are not meeting the recommended AI for dietary choline and that higher plasma betaine concentrations are associated with better visual-motor development at age 2 y. Further work is required to investigate choline metabolism and its role in neurodevelopment in toddlers. The trial is registered at clinicaltrials.gov as NCT01263912.

Perinatal Dietary Choline Deficiency in Sows Influences Concentrations of Choline Metabolites, Fatty Acids, and Amino Acids in Milk throughout Lactation

Background: Choline is essential for synthesis of phospholipids, neurodevelopment, and DNA methylation. It is unknown whether dietary perinatal choline deficiency affects maternal milk composition.Objective: We examined whether perinatal maternal dietary choline deficiency influences porcine-milk composition.Methods: Yorkshire sows were fed choline-deficient (CD) or choline-sufficient (CS) gestation diets [544 or 1887 mg choline/kg dry matter (DM), respectively] from 65 d before to 48 h after parturition and then fed lactation diets (517 or 1591 mg choline/kg DM, respectively) through day 19 of lactation. Milk was collected from 7 sows fed each diet at days 0 (colostrum), 7–9 (mature milk), and 17–19 (preweaning) of lactation. Sow plasma was collected 65 d before and 19 d after parturition. Milk was analyzed for choline metabolite, fatty acid (FA), and amino acid composition. All outcomes were analyzed to assess main and interactive effects of choline intake and time.Results: Plasma choline metabolites did not differ before treatment, but free choline, betaine, and dimethylglycine concentrations were lower in CD-fed than in CS-fed sows at day 19 of lactation (interaction; P < 0.05). Milk betaine concentrations responded similarly, with no differences due to choline intake at day 0 of lactation, but lower concentrations in CD-fed than in CS-fed sows at day 18 of lactation (interaction; P < 0.001). Certain milk long-chain FAs also exhibited no differences at day 0 of lactation but higher concentrations in CD-fed than in CS-fed sows at day 18 of lactation (P < 0.05).Conclusions: These data indicate that, in pigs, dietary choline deficiency induces alterations in plasma choline metabolites that are evident at the end of lactation. Betaine and select FAs in milk are sensitive to maternal dietary choline deficiency and day of lactation. Alterations in concentrations of these nutrients may affect early-life neonatal development.

Structure and biochemical properties of recombinant human dimethylglycine dehydrogenase and comparison to the disease‐related H109R variant

The human dimethylglycine dehydrogenase (hDMGDH) is a flavin adenine dinucleotide (FAD)‐ and tetrahydrofolate (THF)‐dependent, mitochondrial matrix enzyme taking part in choline degradation, one‐carbon metabolism and electron transfer to the respiratory chain. The rare natural variant H109R causes dimethylglycine dehydrogenase deficiency leading to increased blood and urinary dimethylglycine concentrations. A detailed biochemical and structural characterization of hDMGDH was thus far hampered by insufficient heterologous expression of the protein. In the present study, we report the development of an intracellular, heterologous expression system in Komagataella phaffii (formerly known as Pichia pastoris) providing the opportunity to determine kinetic parameters, spectroscopic properties, thermostability, and the redox potential of hDMGDH. Moreover, we have successfully crystallized the wild‐type enzyme and determined the structure to 3.1‐Å resolution. The structure‐based analysis of our biochemical data provided new insights into the kinetic properties of the enzyme in particular with respect to oxygen reactivity. A comparative study with the H109R variant demonstrated that the variant suffers from decreased protein stability, cofactor saturation, and substrate affinity.DatabaseStructural data are available in the PDB database under the accession number 5L46.

Low folate status enhances pregnancy changes in plasma betaine and dimethylglycine concentrations and the association between betaine and homocysteine

Folate, choline, and betaine participate in homocysteine metabolism. It is not known whether they interact during pregnancy. The objective was to investigate how folate status affects choline, betaine, and dimethylglycine during pregnancy. Fasting plasma folate, cobalamin, free choline, betaine, dimethylglycine, and total homocysteine (tHcy) were measured longitudinally at <12, 15, 24-27, and 34 gestational weeks (GW); at labor (nonfasting); and in the cord in participants (n = 522) from the Reus-Tarragona Birth Cohort (NUTrició i Creixement Intrauterí Retardat phase). Timing, dose, and duration of folic acid supplement use were recorded. Folate status was classified as below (low) or above (high) median plasma folate at baseline (27.6 nmol/L) and at 24-27 GW (11.4 nmol/L). Associations between folate or betaine with tHcy were investigated by using multiple linear regression analysis. Plasma betaine decreased by 34.8% (1.0%) throughout pregnancy, and dimethylglycine increased by 39.7% (2.7%) between 24-27 GW and labor (all P < 0.001). Compared with high folate status, low status was associated with a higher dimethylglycine/betaine ratio from 15 GW and with lower plasma betaine and higher dimethylglycine from 24 to 27 GW, for the rest of pregnancy. Regression analysis showed that by 24-27 GW, both plasma folate and betaine were inversely associated with tHcy when folate status was low and that the association between betaine and tHcy depended on folate status at 24-27 and 34 GW (interaction terms: P < 0.001 and P < 0.01). Betaine was inversely associated with tHcy at labor regardless of folate status. Low folate status enhances the reduction in betaine and the increase in dimethylglycine during pregnancy and strengthens the association between betaine and tHcy. This trial was registered at clinicaltrials.gov as NCT01778205.

Choline status and neurodevelopmental outcomes at 5 years of age in the Seychelles Child Development Nutrition Study

Choline is an essential nutrient that is found in many food sources and plays a critical role in the development of the central nervous system. Animal studies have shown that choline status pre- and postnatally can have long-lasting effects on attention and memory; however, effects in human subjects have not been well studied. The aim of the present study was to examine the association between plasma concentrations of free choline and its related metabolites in children and their neurodevelopment in the Seychelles Child Development Nutrition Study, an ongoing longitudinal study assessing the development of children born to mothers with high fish consumption during pregnancy. Plasma concentrations of free choline, betaine, dimethylglycine (DMG), methionine and homocysteine and specific measures of neurodevelopment were measured in 210 children aged 5 years. The children's plasma free choline concentration (9·17 (sd 2·09) μmol/l) was moderately, but significantly, correlated with betaine (r 0·24; P= 0·0006), DMG (r 0·15; P= 0·03), methionine (r 0·24; P= 0·0005) and homocysteine (r 0·19; P= 0·006) concentrations. Adjusted multiple linear regression revealed that betaine concentrations were positively associated with Preschool Language Scale – total language scores (β = 0·066; P= 0·04), but no other associations were evident. We found no indication that free choline concentration or its metabolites, within the normal physiological range, are associated with neurodevelopmental outcomes in children at 5 years of age. As there is considerable animal evidence suggesting that choline status during development is associated with cognitive outcome, the issue deserves further study in other cohorts.

Variability of plasma and urine betaine in diabetes mellitus and its relationship to methionine load test responses: an observational study

BackgroundSince betaine is an osmolyte and methyl donor, and abnormal betaine loss is common in diabetes mellitus (>20% patients), we investigated the relationship between betaine and the post-methionine load rise in homocysteine, in diabetes and control subjects. The post-methionine load test is reported to be both an independent vascular risk factor and a measure of betaine sufficiency.MethodsPatients with type 2 diabetes (n = 34) and control subjects (n = 17) were recruited. We measured baseline fasting plasma and 4-hour post-methionine load (L-methionine, 0.1 mg/kg body weight) concentrations of homocysteine, betaine, and the betaine metabolite N,N-dimethylglycine. Baseline urine excretions of betaine, dimethylglycine and glucose were measured on morning urine samples as the ratio to urine creatinine. Statistical determinants of the post-methionine load increase in homocysteine were identified in multiple linear regression models.ResultsPlasma betaine concentrations and urinary betaine excretions were significantly (p < 0.001) more variable in the subjects with diabetes compared with the controls. Dimethylglycine excretion (p = 0.00014) and plasma dimethylglycine concentrations (p = 0.039) were also more variable. In diabetes, plasma betaine was a significant negative determinant (p < 0.001) of the post-methionine load increase in homocysteine. However, it was not conclusive that this was different from the relationship in the controls. In the patients with diabetes, a strong relationship was found between urinary betaine excretion and urinary glucose excretion (but not with plasma glucose).ConclusionsBoth high and low plasma betaine concentrations, and high and low urinary betaine excretions, are more prevalent in diabetes. The availability of betaine affects the response in the methionine load test. The benefits of increasing betaine intake should be investigated.

Plasma lipids and betaine are related in an acute coronary syndrome cohort.

BackgroundLow plasma betaine has been associated with unfavorable plasma lipid profiles and cardiovascular risk. In some studies raised plasma betaine after supplementation is associated with elevations in plasma lipids. We aimed to measure the relationships between plasma and urine betaine and plasma lipids, and the effects of lipid-lowering drugs on these.MethodologyFasting plasma samples were collected from 531 subjects (and urine samples from 415) 4 months after hospitalization for an acute coronary syndrome episode. In this cross-sectional study, plasma betaine and dimethylglycine concentrations and urine excretions were compared with plasma lipid concentrations. Subgroup comparisons were made for gender, with and without diabetes mellitus, and for drug treatment.Principal FindingsPlasma betaine negatively correlated with triglyceride (Spearman's rs = −0.22, p<0.0001) and non-high-density lipoprotein cholesterol (rs = −0.27, p<0.0001). Plasma betaine was a predictor of BMI (p<0.05) and plasma non-high-density lipoprotein cholesterol and triglyceride (p<0.001) independently of gender, age and the presence of diabetes. Using data grouped by plasma betaine decile, increasing plasma betaine was linearly related to decreases in BMI (p = 0.008) and plasma non-HDL cholesterol (p = 0.002). In a non-linear relationship betaine was negatively associated with elevated plasma triglycerides (p = 0.004) only for plasma betaine >45 µmol/L. Subjects taking statins had higher plasma betaine concentrations (p<0.001). Subjects treated with a fibrate had lower plasma betaine (p = 0.003) possibly caused by elevated urine betaine loss (p<0.001). The ratio of coenzyme Q to non-high-density lipoprotein cholesterol was higher in subjects with higher plasma betaine, and in subjects taking a statin.ConclusionLow plasma betaine concentrations correlated with an unfavourable lipid profile. Betaine deficiency may be common in the study population. Controlled clinical trials of betaine supplementation should be conducted in appropriate populations to determine whether correction affects cardiovascular risk.

Plasma and urine betaine and dimethylglycine variation in healthy young male subjects

Objectives We aimed to compare the individuality (within subject consistency) of plasma and urine betaine and N, N-dimethylglycine. Design and methods In two separate groups of 8 males (ages 19 to 40), plasma (10) and urine (6) samples were collected either over a single day or over an 8 week period. The individuality of the betaine and N, N-dimethylglycine plasma concentrations and excretions were estimated by one-way repeated measures analysis of variance. The reliability coefficients and indices of individuality were calculated. The between-subject variation in the study population was compared with that in a normal population ( n = 192 for plasma, 205 for urine). Results Plasma betaine concentrations were significantly different between subjects over 24 h and 8 weeks ( p < 0.00001). Plasma dimethylglycine concentrations were different over 24 h. Urine betaine and dimethylglycine excretions were different in both ( p < 0.0001). Betaine was more individual than dimethylglycine in both plasma and urine. Compared with a normal healthy population, the between-subject variation in plasma betaine was less ( p < 0.001) in the study group, but similar for dimethylglycine and for urine betaine. Conclusions Plasma betaine and urinary betaine excretions are more individual than dimethylglycine. Plasma and urine betaine are highly individual in the general population.

Choline and homocysteine interrelations in umbilical cord and maternal plasma at delivery

Little is known about the interactions between choline and folate and homocysteine metabolism during pregnancy despite the facts that pregnancy places considerable stress on maternal folate and choline stores and that choline is a critical nutrient for the fetus. Choline, via betaine, is an important folate-independent source of methyl groups for remethylating homocysteine in liver. Our aims were to examine the intermediates of choline oxidation in maternal and umbilical cord plasma and to determine the relations between this pathway and folate-dependent homocysteine remethylation. Blood samples were taken from 201 pregnant women and, at delivery, from the umbilical cord veins of their healthy, full-term infants. The blood samples were analyzed for plasma free choline, betaine, dimethylglycine, folate, vitamin B-12, total homocysteine (tHcy), and creatinine concentrations. Choline concentrations in umbilical cord plasma were approximately 3 times those in maternal plasma (geometric x: 36.6 and 12.3 micromol/L, respectively; P < 0.0001). Betaine and dimethylglycine concentrations were also significantly higher in umbilical cord than in maternal plasma. Choline was positively associated with tHcy (r = 0.34, P < 0.0001), betaine (r = 0.58, P < 0.0001), and dimethylglycine (r = 0.30, P < 0.0001) in maternal blood. Much weaker relations were seen in the fetal circulation. In a multiple regression model, choline was a positive predictor of maternal tHcy, whereas vitamin B-12 and betaine were negative predictors. The positive association between maternal choline and tHcy during pregnancy suggests that the high fetal demand for choline stimulates de novo synthesis of choline in maternal liver, with a resultant increase in tHcy concentrations. If this is confirmed, it may be appropriate to provide choline supplements during pregnancy to prevent elevated tHcy concentrations.