Consumption of fish yielded substantially greater increases in circulating TMAO than eggs or beef. The higher Firmicutes to Bacteroidetes enrichment among men exhibiting a greater response to dietary TMAO precursor intake indicates that TMAO production is a function of individual differences in the gut microbiome.

These data suggest that an increment of 25 mg choline/d to meet the demands of pregnancy is insufficient and show that a higher maternal choline intake increases the use of choline as a methyl donor in both maternal and fetal compartments. This trial was registered at clinicaltrials.gov as NCT01127022.

The in utero availability of methyl donors, such as choline, may modify fetal epigenetic marks and lead to sustainable functional alterations throughout the life course. The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol production and is sensitive to perinatal epigenetic programming. As an extension of a 12-wk dose-response choline feeding study conducted in third-trimester pregnant women, we investigated the effect of maternal choline intake (930 vs. 480 mg/d) on the epigenetic state of cortisol-regulating genes, and their expression, in placenta and cord venous blood. The higher maternal choline intake yielded higher placental promoter methylation of the cortisol-regulating genes, corticotropin releasing hormone (CRH; P=0.05) and glucocorticoid receptor (NR3C1; P=0.002); lower placental CRH transcript abundance (P=0.04); lower cord blood leukocyte promoter methylation of CRH (P=0.05) and NR3C1 (P=0.04); and 33% lower (P=0.07) cord plasma cortisol. In addition, placental global DNA methylation and dimethylated histone H3 at lysine 9 (H3K9me2) were higher (P=0.02) in the 930 mg choline/d group, as was the expression of select placental methyltransferases. These data collectively suggest that maternal choline intake in humans modulates the epigenetic state of genes that regulate fetal HPA axis reactivity as well as the epigenomic status of fetal derived tissues.

Few studies have examined associations between plasma choline metabolites and risk of colorectal cancer (CRC). Therefore, we investigated associations between plasma biomarkers of choline metabolism [choline, betaine, dimethylglycine and trimethylamine N-oxide (TMAO)] and CRC risk among postmenopausal women in a case-control study nested within the Women’s Health Initiative Observational Study. We selected 835 matched case-control pairs, and cases were further stratified by tumor site (proximal, distal, or rectal) and stage (local/regional or metastatic). CRC was assessed by self-report and confirmed by medical records over the mean 5.2y of follow-up. Baseline plasma choline metabolites were measured by liquid chromatography-tandem mass spectrometry. In multivariable-adjusted conditional logistic regression models, plasma choline tended to be positively associated with rectal cancer risk [OR (95% CI)highest vs. lowest quartile=2.44 (0.93–6.40);P-trend=0.08], while plasma betaine was inversely associated with CRC overall [0.68 (0.47–0.99);P-trend=0.01] and with local/regional tumors [0.64 (0.42–0.99);P-trend=0.009]. Notably, the plasma betaine:choline ratio was inversely associated with CRC overall [0.56 (0.39–0.82);P-trend=0.004] as well as with proximal [0.66 (0.41–1.06);P-trend=0.049], rectal [0.27 (0.10–0.78);P-trend=0.02] and local/regional [0.50 (0.33–0.76);P-trend=0.001] tumors. Finally, plasma TMAO, an oxidative derivative of choline produced by intestinal bacteria, was positively associated with rectal cancer [3.38 (1.25–9.16);P-trend=0.02] and with overall CRC risk among women with lower (vs. higher) plasma vitamin B12 levels (P-interaction=0.003). Collectively, these data suggest that alterations in choline metabolism, which may arise early in disease development, may be associated with higher risk of CRC. The positive association between plasma TMAO and CRC risk is consistent with an involvement of the gut microbiome in CRC pathogenesis.

Background: Increased consumption of folic acid is prevalent, leading to concerns about negative consequences. The effects of folic acid on the liver, the primary organ for folate metabolism, are largely unknown. Methylenetetrahydrofolate reductase (MTHFR) provides methyl donors for S-adenosylmethionine (SAM) synthesis and methylation reactions.Objective: Our goal was to investigate the impact of high folic acid intake on liver disease and methyl metabolism.Design: Folic acid–supplemented diet (FASD, 10-fold higher than recommended) and control diet were fed to male Mthfr+/+ and Mthfr+/− mice for 6 mo to assess gene-nutrient interactions. Liver pathology, folate and choline metabolites, and gene expression in folate and lipid pathways were examined.Results: Liver and spleen weights were higher and hematologic profiles were altered in FASD-fed mice. Liver histology revealed unusually large, degenerating cells in FASD Mthfr+/− mice, consistent with nonalcoholic fatty liver disease. High folic acid inhibited MTHFR activity in vitro, and MTHFR protein was reduced in FASD-fed mice. 5-Methyltetrahydrofolate, SAM, and SAM/S-adenosylhomocysteine ratios were lower in FASD and Mthfr+/− livers. Choline metabolites, including phosphatidylcholine, were reduced due to genotype and/or diet in an attempt to restore methylation capacity through choline/betaine-dependent SAM synthesis. Expression changes in genes of one-carbon and lipid metabolism were particularly significant in FASD Mthfr+/− mice. The latter changes, which included higher nuclear sterol regulatory element-binding protein 1, higher Srepb2 messenger RNA (mRNA), lower farnesoid X receptor (Nr1h4) mRNA, and lower Cyp7a1 mRNA, would lead to greater lipogenesis and reduced cholesterol catabolism into bile.Conclusions: We suggest that high folic acid consumption reduces MTHFR protein and activity levels, creating a pseudo-MTHFR deficiency. This deficiency results in hepatocyte degeneration, suggesting a 2-hit mechanism whereby mutant hepatocytes cannot accommodate the lipid disturbances and altered membrane integrity arising from changes in phospholipid/lipid metabolism. These preliminary findings may have clinical implications for individuals consuming high-dose folic acid supplements, particularly those who are MTHFR deficient.