Effects of protein and carbohydrate content of diet on drug conjugation

Clin Pharmacol Ther. 1991 Sep;50(3):254-8. doi: 10.1038/clpt.1991.134.


Eight healthy subjects were fed a high-protein-low-carbohydrate diet and, after a 3-day washout period, an isocaloric low-protein-high-carbohydrate diet. They received acetaminophen and oxazepam, drugs metabolized primarily by conjugation, on days 11 and 13, respectively, of each diet. Changing the diets of subjects from the high-protein-low-carbohydrate diet to the low-protein-high-carbohydrate diet resulted in a 14% increase in urinary recovery of acetaminophen glucuronide and a 32% increase in urinary recovery of oxazepam glucuronide (p less than 0.05). The increases in glucuronidation were at the expense of other pathways of metabolism, and there were no significant changes in the metabolic clearance rates of acetaminophen and oxazepam. Mean renal clearances of acetaminophen glucuronide, acetaminophen sulfate, and oxazepam glucuronide decreased 45%, 32%, and 54%, respectively (p less than 0.05), when the subjects were switched to the low-protein-high-carbohydrate diet.

MeSH terms

  • Acetaminophen / pharmacokinetics
  • Adult
  • Diet
  • Dietary Carbohydrates / administration & dosage
  • Dietary Carbohydrates / pharmacology*
  • Dietary Proteins / administration & dosage
  • Dietary Proteins / pharmacology*
  • Glucuronates / metabolism
  • Glucuronates / urine
  • Half-Life
  • Humans
  • Male
  • Metabolic Clearance Rate
  • Oxazepam / pharmacokinetics
  • Sulfates / metabolism
  • Sulfates / urine


  • Dietary Carbohydrates
  • Dietary Proteins
  • Glucuronates
  • Sulfates
  • Acetaminophen
  • Oxazepam