title: Energy restriction dilutes the changes related to dietary fat type in membrane phospholipid fatty acid composition in rats.
abstract: To investigate liver cell membrane phospholipid (PL) fatty acid (FA) composition in response to the consumption of different types of dietary fat and graded levels of energy intake, rats were fed for 10 weeks on a diet containing either fish oil, safflower oil, or beef tallow. Within each dietary fat group, subgroups were either provided free access to food or energy-restricted to 85% or 70% of the ad libitum intake by reducing the dietary carbohydrate content while keeping other macronutrient intakes constant. Higher (P < .05) proportions of docosahexaenoic acid, linoleic acid, and monounsaturated FA were observed in the membrane PL of the fish oil, safflower oil, and beef tallow groups, respectively, resembling the FA composition in the diets. However, such modifications of dietary FA composition in, membrane PL FA were influenced by body energy status. The higher docosahexaenoic acid and total n-3 FA content in phosphatidylcholine (PC), sphingomyelin (SPH), and phosphatidylserine (PS) of the ad libitum fish oil group compared with the other dietary groups no longer existed when energy supply was restricted. Therefore, reducing energy intake tended to dilute the changes of membrane PL FA composition occurring as a function of dietary FA composition. These data suggest that the influence of dietary fat type on cellular structure and perhaps function becomes increasingly important with progressively positive energy balance.
authors.affiliation: School of Dietetics and Human Nutrition, McGill University, Ste Anne de Bellevue, Quebec, Canada.
authors.forename: M C
authors.initials: MC
authors.lastname: Cha
authors.forename: P J
authors.initials: PJ
authors.lastname: Jones
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology*; D005223:Fats / Q000378:metabolism / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism*; D005395:Fish Oils / Q000378:metabolism / Q000494:pharmacology; D008099:Liver / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009929:Organ Size / Q000502:physiology; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012450:Safflower Oil / Q000378:metabolism / Q000494:pharmacology
chemical_list: D004041:Dietary Fats; D005223:Fats; D005227:Fatty Acids; D005395:Fish Oils; D010743:Phospholipids; D012450:Safflower Oil; C013698:tallow