ABSTRACT: Choline is an essential nutrient for humans. It is a precursor of membrane phospholipids (e.g., phosphatidylcholine (PC)), the neurotransmitter acetylcholine, and via betaine, the methyl group donor S-adenosylmethionine. High choline intake during gestation and early postnatal development in rat and mouse models improves cognitive function in adulthood, prevents age-related memory decline, and protects the brain from the neuropathological changes associated with Alzheimer's disease (AD), and neurological damage associated with epilepsy, fetal alcohol syndrome, and inherited conditions such as Down and Rett syndromes. These effects of choline are correlated with modifications in histone and DNA methylation in brain, and with alterations in the expression of genes that encode proteins important for learning and memory processing, suggesting a possible epigenomic mechanism of action. Dietary choline intake in the adult may also influence cognitive function via an effect on PC containing eicosapentaenoic and docosahexaenoic acids; polyunsaturated species of PC whose levels are reduced in brains from AD patients, and is associated with higher memory performance, and resistance to cognitive decline.
Project description:Choline is an essential nutrient for humans. Metabolically choline is used for the synthesis of membrane phospholipids (e.g. phosphatidylcholine), as a precursor of the neurotransmitter acetylcholine, and, following oxidation to betaine, choline functions as a methyl group donor in a pathway that produces S-adenosylmethionine. As a methyl donor choline influences DNA and histone methylation--two central epigenomic processes that regulate gene expression. Because the fetus and neonate have high demands for choline, its dietary intake during pregnancy and lactation is particularly important for normal development of the offspring. Studies in rodents have shown that high choline intake during gestation improves cognitive function in adulthood and prevents memory decline associated with old age. These behavioral changes are accompanied by electrophysiological, neuroanatomical, and neurochemical changes and by altered patterns of expression of multiple cortical and hippocampal genes including those encoding key proteins that contribute to the biochemical mechanisms of learning and memory. These actions of choline are observed long after the exposure to the nutrient ended (months) and correlate with fetal hepatic and cerebral cortical choline-evoked changes in global- and gene-specific DNA cytosine methylation and with dramatic changes of the methylation pattern of lysine residues 4, 9 and 27 of histone H3. Moreover, gestational choline modulates the expression of DNA (Dnmt1, Dnmt3a) and histone (G9a/Ehmt2/Kmt1c, Suv39h1/Kmt1a) methyltransferases. In addition to the central role of DNA and histone methylation in brain development, these processes are highly dynamic in adult brain, modulate the expression of genes critical for synaptic plasticity, and are involved in mechanisms of learning and memory. A recent study documented that in a cohort of normal elderly people, verbal and visual memory function correlated positively with the amount of dietary choline consumption. It will be important to determine if these actions of choline on human cognition are mediated by epigenomic mechanisms or by its influence on acetylcholine or phospholipid synthesis.
Project description:Although single nucleotide polymorphisms (SNPs) in folate-mediated pathways predict susceptibility to choline deficiency during severe choline deprivation, it is unknown if effects persist at recommended intakes. Thus, we used stable isotope liquid chromatography-mass spectrometry (LC-MS) methodology to examine the impact of candidate SNPs on choline metabolism in a long-term, randomized, controlled feeding trial among pregnant, lactating, and nonpregnant (NP) women consuming 480 or 930 mg/d choline (22% as choline-d9, with d9 indicating a deuterated trimethyl amine group) and meeting folate-intake recommendations. Variants impairing folate metabolism, methylenetetrahydrofolate reductase (MTHFR) rs1801133, methionine synthase (MTR) rs1805087 [wild-type (WT)], MTR reductase (MTRR) rs1801394, and methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase (MTHFD1) rs2236225, influenced choline dynamics, frequently through interactions with reproductive state and choline intake, with fewer genotypic alterations observed among pregnant women. Women with these variants partitioned more dietary choline toward phosphatidylcholine (PC) biosynthesis via the cytidine diphosphate (CDP)-choline pathway at the expense of betaine synthesis even when use of betaine as a methyl donor was increased. Choline intakes of 930 mg/d restored partitioning of dietary choline between betaine and CDP-PC among NP (MTHFR rs1801133 and MTR rs1805087 WT) and lactating (MTHFD1 rs2236225) women with risk genotypes. Overall, our findings indicate that loss-of-function variants in folate-metabolizing enzymes strain cellular PC production, possibly via impaired folate-dependent phosphatidylethanolamine-N-methyltransferase (PEMT)-PC synthesis, and suggest that women with these risk genotypes may benefit from choline intakes exceeding current recommendations.-Ganz, A. B., Shields, K., Fomin, V. G., Lopez, Y. S., Mohan, S., Lovesky, J., Chuang, J. C., Ganti, A., Carrier, B., Yan, J., Taeswuan, S., Cohen, V. V., Swersky, C. C., Stover, J. A., Vitiello, G. A., Malysheva, O. V., Mudrak, E., Caudill, M. A. Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis.
Project description:BACKGROUND:Although biomarkers of choline metabolism are altered by pregnancy, little is known about the influence of human pregnancy on the dynamics of choline-related metabolic processes. OBJECTIVE:This study used stable isotope methodology to examine the effects of pregnancy on choline partitioning and the metabolic activity of choline-related pathways. DESIGN:Healthy third-trimester pregnant (n = 26; initially week 27 of gestation) and nonpregnant (n = 21) women consumed 22% of their total choline intake (480 or 930 mg/d) as methyl-d9-choline for the final 6 wk of a 12-wk feeding study. RESULTS:Plasma d9-betaine:d9-phosphatidylcholine (PC) was lower (P ≤ 0.04) in pregnant than in nonpregnant women, suggesting greater partitioning of choline into the cytidine diphosphate-choline (CDP-choline) PC biosynthetic pathway relative to betaine synthesis during pregnancy. Pregnant women also used more choline-derived methyl groups for PC synthesis via phosphatidylethanolamine N-methyltransferase (PEMT) as indicated by comparable increases in PEMT-PC enrichment in pregnant and nonpregnant women despite unequal (pregnant > nonpregnant; P < 0.001) PC pool sizes. Pregnancy enhanced the hydrolysis of PEMT-PC to free choline as shown by greater (P < 0.001) plasma d3-choline:d3-PC. Notably, d3-PC enrichment increased (P ≤ 0.011) incrementally from maternal to placental to fetal compartments, signifying the selective transfer of PEMT-PC to the fetus. CONCLUSIONS:The enhanced use of choline for PC production via both the CDP-choline and PEMT pathways shows the substantial demand for choline during late pregnancy. Selective partitioning of PEMT-PC to the fetal compartment may imply a unique requirement of PEMT-PC by the developing fetus.
Project description:Fetal nutrition sets the stage for organ function in later life. In this review we discuss the fetal and neonatal origins of brain function. Numerous research observations point to the importance of choline for the developing fetus and neonate. This essential nutrient is involved in 1-carbon metabolism and is the precursor for many important compounds, including phospholipids, acetylcholine, and the methyl donor betaine. Dietary intake of choline by the pregnant mother and later by the infant directly affects brain development and results in permanent changes in brain function. In rodents, perinatal supplementation of choline enhances memory and learning functions, changes that endure across the lifespan. Conversely, choline deficiency during these sensitive periods results in memory and cognitive deficits that also persist. Furthermore, recent studies suggest that perinatal choline supplementation can reduce the behavioral effects of prenatal stress and the cognitive effects of prenatal alcohol exposure in offspring. The likely mechanism for these effects of choline involves DNA methylation, altered gene expression, and associated changes in stem cell proliferation and differentiation. The currently available animal data on choline and hippocampal development are compelling, but studies are needed to determine whether the same is true in humans.
Project description:Choline is an essential nutrient for humans that is used to synthesize membrane phospholipids and the neurotransmitter acetylcholine. Betaine, a metabolite of choline, functions as a methyl-group donor in the conversion of homocysteine to methionine, and is important for renal function. Accurate analysis of choline intake was previously not possible because the choline content of most foods was not known. Using new and recently published data on the concentrations of choline in common foods, we measured the choline content of diets consumed ad libitum by healthy adult volunteers housed in a clinical research center and compared these with estimates of choline intake derived from 3-d food records kept by subjects immediately before study enrollment. Mean choline intake in this subject population met or slightly exceeded the current Adequate Intake (AI) of 7 mg/(kg . d) set by the Institute of Medicine. Men and women consumed similar amounts of choline per day (8.4 and. 6.7 mg/kg, respectively; P = 0.11). Choline intakes estimated from the 3-d food records were significantly lower than this (when expressed as mg/kg, or as total mg, but not when normalized to energy intake), suggesting underreporting of food intake. Intake of betaine, which may spare choline utilization as a methyl-group donor, was 5.3 mg/(kg . d) in men and 4.7 mg/(kg . d) in women. Intake of folate, vitamin B-12, and methionine + cysteine, were similar and sufficient in all subjects. The current recommended AI for choline seems to be a good approximation of the actual intake of this nutrient.
Project description:Choline and betaine are important nutrients for human health, but reference food composition databases for these nutrients became available only recently. We tested the feasibility of using these databases to estimate dietary choline and betaine intakes among ethnically diverse adults who participated in the Multiethnic Cohort (MEC) Study. Of the food items (n = 965) used to quantify intakes for the MEC FFQ, 189 items were exactly matched with items in the USDA Database for the Choline Content of Common Foods for total choline, choline-containing compounds, and betaine, and 547 items were matched to the USDA National Nutrient Database for Standard Reference for total choline (n = 547) and 148 for betaine. When a match was not found, choline and betaine values were imputed based on the same food with a different form (124 food items for choline, 300 for choline compounds, 236 for betaine), a similar food (n = 98, 284, and 227, respectively) or the closest item in the same food category (n = 6, 191, and 157, respectively), or the values were assumed to be zero (n = 1, 1, and 8, respectively). The resulting mean intake estimates for choline and betaine among 188,147 MEC participants (aged 45-75) varied by sex (372 and 154 mg/d in men, 304 and 128 mg/d in women, respectively; P-heterogeneity < 0.0001) and by race/ethnicity among Caucasians, African Americans, Japanese Americans, Latinos, and Native Hawaiians (P-heterogeneity < 0.0001), largely due to the variation in energy intake. Our findings demonstrate the feasibility of assessing choline and betaine intake and characterize the variation in intake that exists in a multiethnic population.
Project description:Choline is essential for infant nutrition, and breast milk is a rich source of this nutrient. Common single nucleotide polymorphisms (SNPs) change dietary requirements for choline intake.The aim of this study was to determine whether total choline intake and/or SNPs influence concentrations of choline and its metabolites in human breast milk and plasma.We gave a total of 103 pregnant women supplemental choline or a placebo from 18 wk gestation to 45 d postpartum and genotyped the women for 370 common SNPs. At 45 d postpartum, we measured choline metabolite concentrations in breast milk and plasma and assessed the dietary intake of choline by using a 3-d food record.On average, lactating women in our study ate two-thirds of the recommended intake for choline (Adequate Intake = 550 mg choline/d). Dietary choline intake (no supplement) correlated with breast-milk phosphatidylcholine and plasma choline concentrations. A supplement further increased breast-milk choline, betaine, and phosphocholine concentrations and increased plasma choline and betaine concentrations. We identified 5 SNPs in MTHFR that altered the slope of the intake-metabolite concentration relations, and we identified 2 SNPs in PEMT that shifted these curves upward. Individuals who shared sets of common SNPs were outliers in plots of intake-metabolite concentration curves; we suggest that these SNPs should be further investigated to determine how they alter choline metabolism.Total intake of choline and genotype can influence the concentrations of choline and its metabolites in the breast milk and blood of lactating women and thereby affect the amount of choline available to the developing infant. This study was registered at clinicaltrials.gov as NCT00678925.
Project description:BACKGROUND:Choline is an essential nutrient and betaine is an osmolyte and methyl donor. Both are important to maintain health including adequate lipid metabolism. Supplementation of dietary choline and betaine increase muscle mass and reduce body fat in animals. However, little data is available regarding the role of dietary choline and betaine on body composition in humans. OBJECTIVE:To investigate the association between dietary choline and betaine intakes with body composition in a large population based cross-sectional study. DESIGN:A total of 3214 subjects from the CODING (Complex Disease in Newfoundland population: Environment and Genetics) study were assessed. Dietary choline and betaine intakes were computed from the Willett Food Frequency questionnaire. Body composition was measured using dual-energy X-ray absorptiometry following a 12-hour fast. Major confounding factors including age, sex, total calorie intake and physical activity level were controlled in all analyses. RESULT:Significantly inverse correlations were found between dietary choline and betaine intakes, with all obesity measurements: total percent body fat (%BF), percent trunk fat (%TF), percent android fat (%AF), percent gynoid fat (%GF) and anthropometrics: weight, body mass index, waist circumference, waist-to-hip ratio in both women and men (r range from -0.13 to -0.47 for choline and -0.09 to -0.26 for betaine, p<0.001 for all). Dietary choline intake had stronger association than betaine. Moreover, obese subjects had the lowest dietary choline and betaine intakes, with overweight subjects in the middle, and normal weight subjects consumed the highest dietary choline and betaine (p<0.001). Vice versa, when subjects were ranked according to dietary choline and betaine intakes, subjects with the highest intake of both had the lowest %TF, %AF, %GF, %BF and highest %LM among the groups in both sexes. CONCLUSION:Our findings indicate that high dietary choline and betaine intakes are significantly associated with favorable body composition in humans.
Project description:1. Serum choline concentration in the newborn rat is extremely high and declines as the rat matures until adult values are attained at 20 days of age. 2. Rat milk is a rich source of choline, and rat pups denied access to milk had significantly lower serum choline concentrations than did fed littermates. We conclude that dietary intake of choline contributes to the maintenance of high serum choline concentrations in the neonatal rat. 3. In vivo, choline disappears with a half-life of 70 min. It is converted into betaine, phosphocholine and phosphatidylcholine. The rate of phosphocholine formation is identical in 3- and 10-day-old rats (3.3 mumol/h), whereas the rate of betaine formation is slower in younger animals (0.15 mumol/h at 3 days versus 0.69 mumol/h at 10 days). In vitro, choline oxidase activity [choline dehydrogenase (EC 188.8.131.52) and betaine aldehyde dehydrogenase (EC 184.108.40.206)] increased between birth and 40 days of age. The age-related acceleration in choline's conversion into betaine probably tends to diminish unesterified choline concentration in the rat.
Project description:Choline and betaine provide methyl groups for one-carbon metabolism. Humans obtain these nutrients from a wide range of foods. Betaine can also be synthesized endogenously from its precursor, choline. Although animal studies have implied a causal relationship between choline deficiency and carcinogenesis, the role of these two nutrients in human carcinogenesis and tumor progression is not well understood. We investigated the associations of dietary intakes of choline and betaine and breast cancer risk and mortality in the population-based Long Island Breast Cancer Study Project. Among the 1508 case-group women, 308 (20.2%) deaths occurred, among whom 164 (53.2%) died of breast cancer by December 31, 2005. There was an indication that a higher intake of free choline was associated with reduced risk of breast cancer (P(trend)=0.04). Higher intakes of betaine, phosphocholine, and free choline were associated with reduced all-cause as well as breast cancer-specific mortality in a dose-dependent fashion. We also explored associations of polymorphisms of three key choline- and betaine-metabolizing genes and breast cancer mortality. The betaine-homocysteine methyltransferase gene (BHMT) rs3733890 polymorphism was associated with reduced breast cancer-specific mortality (hazard ratio, 0.64; 95% confidence interval, 0.42-0.97). Our study supports the important roles of choline and betaine in breast carcinogenesis. It suggests that high intake of these nutrients may be a promising strategy to prevent the development of breast cancer and to reduce its mortality.