American Journal of Clinical Nutrition, Vol 16, 123-128, Copyright © 1965 by The American Society for Clinical Nutrition, Inc.

Effect of Orally Administered Fat on the Utilization of Intravenous Fat Emulsions

¹ From the Department of Nutrition, Harvard University School of Public Health, Boston, Massachusetts

Rats given fat emulsion intravenously normally removed such lipid from the blood at a rapid rate. Fasting prior to the administration of the emulsion resulted in somewhat slower disappearance of the artificial fat particles. Oral intubation of 1 gm. of oil per 100 gm. body weight to fasted rats before the intravenous emulsion was administered delayed the rate at which the emulsion left the circulation. When oil was fed ad libitum during the period of fasting, followed by the oral intubation of oil, removal of emulsified oil given intravenously was essentially blocked. The removal was not as retarded with coconut oil as with cottonseed oil. Animals fed a diet containing 70 per cent cottonseed oil were able to remove the intravenously injected lipid normally, and after fasting were as susceptible as rats fed stock diets to the influences of orally administered oil with respect to such removal. Fasted rats given 2 gm. of fat in the form of the high-fat diet behaved much as normal rats from the standpoint of the disappearance of emulsified fat from the vascular system. Heparin was effective in accelerating the disappearance of the artificial emulsion from the blood regardless of the amount of oral fat given. No difference was observed between fasted male and female rats insofar as their ability to clear artificial emulsion from the blood was concerned. However, when oil was given by intubation, the retardation in such clearing was significantly greater in male than in female rats. The results of these studies indicate that under some conditions oil fed orally can influence the utilization of intravenously administered fat. They also demonstrate that large quantities of oil can be consumed in the form of a high-fat diet without interfering with the removal of artificial fat from the bloodstream.