Depletion of linoleate induced by weight-cycling is independent of
extent of calorie restriction.
Chen, Zhen-Yu, Man-Mei Sea, Kwok-Yiu Kwan, Yan-Ho Leung, and Pik-Fung
Leung.
Department of Biochemistry, The Chinese University of Hong Kong,
Shatin, New Territories, Hong Kong
APStracts 3:0274R, 1996.
Recent epidemiological studies have suggested that weight cycling
induced by repeated dieting over time may increase the risk of
cardiovascular disease. It is speculated that the increased mortality
from coronary heart disease for people with a history of excessive
weight cycling could be attributed to change in lipid metabolism.
Previous studies have demonstrated that repeated cycling of 100% food
restriction followed by ad libitum refeeding caused a depletion of
linoleate and [alpha]-linolenate in rats. The objective of the
present study was to test the hypothesis that the weight cycling
-induced reduction in linoleate and [alpha]-linolenate is independent
of extent of calorie restriction. Two consecutive weight cycles in
three experiments were induced by 100% calorie restriction, 60%
calorie restriction, and 36% calorie restriction, respectively,
followed by ad libitum refeeding. As the consequence of the two
weight cycles, linoleate and linolenate were decreased whereas
myristate, palmitate and palmitoleate were proportionally increased
in carcass and adipose tissue lipids. The results of all three
experiments showed a preferential depletion of linoleate and [alpha]
-linolenate without changing the final body weight, total body fat and
adipose tissue pads in the weight-cycled rats. In addition, the
triacylglycerol species profile in the adipose tissue of weight
-cycled rats was significantly remodelled with a proportional
depletion of linoleate-enriched triacylglycerol species (LLL, LLO and
LLP) and a proportional accumulation of palmitate-enriched
triacylglycerol species (OPPo, PPPo and PPP). We conclude that weight
cycling changes the ratio of polyunsaturated fatty acids to saturated
fatty acids and remodels the adipose tissue triacylglycerol species
profile in rats.
Received 27 November 1995; accepted in final form 26 June 1996.
APS Manuscript Number R746-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996