Interactions between nutritional factors and drug biotransformations in man.

This study was undertaken to examine the influence of nutritional factors on the activity of the mixed function oxidase system in man, which is cytochrome P-450 dependent. Three normal volunteers were fed a low carbohydrate-high protein diet for 2 weeks, followed by a high carbohydrate-low protein diet for the follwoing 2 weeks. At the end of each test diet period, the plasma elimination rates of antipyrine and theophylline were determined. The mean plasma half-life for antipyrine was 17.5 hr on the high carbohydrate-low protein diet and 9.2 hr on the low carbohydrate-high protein diet. The mean plasma half-life for theophylline was 8.9 hr on the high carbohydrate-low protein diet and 5.9 hr on the low carbohydrate-high protein diet. These data demonstrate marked influences of dietary carbohydrate and/or protein ingestion on oxidative biotransformation of drugs in man.