Two methods for assessment of choline status in a randomized crossover study with varying dietary choline intake in people: isotope dilution MS of plasma and in vivo single-voxel magnetic resonance spectroscopy of liver

Abstract

Background Choline deficiency has numerous negative health consequences; although the preponderance of the US population consumes less than the recommended Adequate Intake (AI), clinical assessment of choline status is difficult. Further, several pathways involved in primary metabolism of choline are estrogen-sensitive and the AI for premenopausal women is lower than that for men. Objectives We sought to determine whether in vivo magnetic resonance spectroscopy (MRS) of liver and/or isotope-dilution MS of plasma could identify biomarkers reflective of choline intake (preregistered primary outcomes 1 and 2, secondary outcome 1). Determination of whether biomarker concentrations showed sex dependence was a post hoc outcome. This substudy is a component of a larger project to identify a clinically useful biomarker panel for assessment of choline status. Methods In a double-blind, randomized, crossover trial, people consumed 3 diets, representative of ∼100%, ∼50%, and ∼25% of the choline AI, for 2-wk periods. We measured the concentrations of choline and several metabolites using 1H single-voxel MRS of liver in vivo and using 2H-labeled isotope dilution MS of several choline metabolites in extracted plasma. Results Plasma concentrations of 2H9-choline, unlabeled betaine, and 2H9-betaine, and the isotopic enrichment ratio (IER) of betaine showed highly significant between-diet effects (q < 0.0001), with unlabeled betaine concentration decreasing 32% from highest to lowest choline intake. Phosphatidylcholine IER was marginally significant (q = 0.03). Unlabeled phosphatidylcholine plasma concentrations did not show between-diet effects (q = 0.34). 2H9 (trimethyl)-phosphatidylcholine plasma concentrations (q = 0.07) and MRS-measured total soluble choline species liver concentrations (q = 0.07) showed evidence of between-diet effects but this was not statistically significant. Conclusions Although MRS is a more direct measure of choline status, variable spectral quality limited interpretation. MS analysis of plasma showed clear correlation of plasma betaine concentration, but not plasma phosphatidylcholine concentration, with dietary choline intake. Plasma betaine concentrations also correlate with sex status (premenopausal women, postmenopausal women, men). This trial was registered at clinicaltrials.gov as NCT03726671.

Characterization of Choline Nutriture among Adults and Children with Phenylketonuria

“…A limitation of this study is that dietary intakes were not determined in tandem with biochemical measures. The utility of this, however, remains unclear as there are important limitations associated with choline biomarkers [ 48 ]. For example, plasma choline has not been found to reflect the diet at very low intake levels [ 47 , 49 ] and plasma betaine concentrations, which may be a better marker of dietary intake, does not accurately represent tissue concentrations [ 50 ].…”

“…For example, plasma choline has not been found to reflect the diet at very low intake levels [ 47 , 49 ] and plasma betaine concentrations, which may be a better marker of dietary intake, does not accurately represent tissue concentrations [ 50 ]. Through the use of metabolomics and isotope dilution, emerging studies can better estimate the relationship between choline intake and choline status to provide new clinically useful biomarkers [ 48 ]. Other shortcomings of the present study were potential confounding and measurement error.…”

Deuterium Metabolic Imaging—Rediscovery of a Spectroscopic Tool

“…Recently, [ 2 H 9 ] choline was used in single voxel MRS of the liver to measure the choline concentration in healthy volunteers following randomly assigned diets of variable choline levels as well as a choline bolus 72 h prior to scanning. However, no significant correlation between the choline intake and the choline liver concentration was noted [ 122 ].…”

Optimal Dietary Intake Composition of Choline and Betaine Is Associated with Minimized Visceral Obesity-Related Hepatic Steatosis in a Case-Control Study

“…However, choline supplementation alone did not reduce liver steatosis of PEMT -/mice fed a high-fat diet [52]. In choline-feeding studies involving Mexican-American men [53] and healthy men [54,55], total choline intake exceeding AI levels was reported to optimize PC and free choline levels in blood and the liver, thus reducing liver dysfunction markers. High betaine supplementation could substitute for choline and folate to normalize Hcy levels under methyl donor methionine-restriction conditions [56].…”