title: Prolonged fasting in humans results in diminished plasma choline concentrations but does not cause liver dysfunction.
abstract: Choline is a major donor of methyl groups, a precursor for membrane synthesis, and a component of the neurotransmitter acetylcholine. Choline-deficient diets deplete humans of choline and cause hepatic dysfunction and steatosis. In this study we determined whether acute starvation also depletes choline, as indicated by changes in plasma choline or phosphatidylcholine. Healthy humans (n = 10) fasted for 7 d, ingesting only water and mineral-vitamin supplements. Their mean (+/- SEM) plasma choline concentration was 9.5 +/- 0.5 micromol/L at the start of the study and dropped to 7.8 +/- 0.3 micromol/L after 1 wk of fasting (P < 0.01). The plasma phosphatidylcholine concentration did not change significantly (2.2 +/- 0.1 mmol/L at the start of the study and 2.4 +/- 0.2 mmol/L after 1 wk of fasting). Capacity of the liver to secrete lipoproteins was not affected by prolonged fasting. The mean plasma concentration of low-density-lipoprotein cholesterol was 3.3 +/- 0.2 mmol/L (126 +/- 8 mg/dL) at the start of the study and 4.9 +/- 0.5 mmol/L (188 +/- 19 mg/dL) after 1 wk of fasting. Liver damage assessed by serum alanine aminotransferase activity occurred in only 1 of 10 subjects. We conclude that prolonged fasting in humans modestly diminished plasma choline but was not associated with signs of choline deficiency, such as perturbed lipoprotein secretion and liver damage.
authors.affiliation: Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, USA.
authors.forename: L
authors.initials: L
authors.lastname: Savendahl
authors.forename: M H
authors.initials: MH
authors.lastname: Mar
authors.forename: L E
authors.initials: LE
authors.lastname: Underwood
authors.forename: S H
authors.initials: SH
authors.lastname: Zeisel
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001663:Bilirubin / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D002794:Choline / Q000097:blood*; D005215:Fasting; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008099:Liver / Q000502:physiology*; D008111:Liver Function Tests; D008297:Male
chemical_list: D008078:Cholesterol, LDL; D007770:L-Lactate Dehydrogenase; D000410:Alanine Transaminase; D002794:Choline; D001663:Bilirubin