British Journal of Nutrition

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British Journal of Nutrition (2010), 103:1331-1339 Cambridge University Press
Copyright © The Authors 2009

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Metabolism and Metabolic Studies

Peanut protein reduces body protein mass and alters skeletal muscle contractile properties and lipid metabolism in rats

Hélène Jacquesa1 c1, Nadine Leblanca1, Roxanne Papineaua1, Denis Richarda2 and Claude H. Côtéa3

a1 Department of Food Science and Nutrition, Institute of Nutraceuticals and Functional Foods, Laval University, Paul-Comtois Building, 2425 Agriculture Street, Québec, Canada G1V 0A6
a2 Research Center, Laval Hospital, Ste-Foy, Québec, Canada G1V 4G5
a3 Lipid Research Center, CHUL Research Center, Québec, Canada G1V 4G2
Article author query
jacques h [PubMed]  [Google Scholar]
leblanc n [PubMed]  [Google Scholar]
papineau r [PubMed]  [Google Scholar]
richard d [PubMed]  [Google Scholar]
côté ch [PubMed]  [Google Scholar]


It is well known that diets high in nuts or peanuts favourably affect plasma lipid concentrations. However, few studies have examined the effects of nut and peanut protein (PP) on body composition and skeletal muscle properties. The present study was aimed at evaluating the effect of dietary PP compared with two animal proteins, casein (C) and cod protein (CP) on body composition, skeletal muscle contractile properties and lipid metabolism in rats. Thirty-two male rats were assigned to one of the following four diets containing either C, CP, PP or C+peanut protein (CPP, 50:50) mixture. After 28 d of ad libitum feeding and after 12-h fast, blood, liver and muscle were collected for measurements of plasma and hepatic cholesterol and TAG, plasma glucose and insulin and contractile properties. Rats fed with the low-quality protein, PP, had lower body weight gain, body protein mass, soleus mass and liver weight than those fed with the high-quality dietary proteins, C and CP. PP also caused a deficit in contractile properties in soleus. Likewise, PP increased plasma cholesterol and body fat mass compared with CP. However, these elevations were accompanied with increased hepatic TAG concentrations and lowered intestinal fat excretion. These results show that PP intake alters body composition by reducing skeletal muscle mass and liver weight as well as muscle contractility and lipid metabolism. Adding a complete protein such as C might partially counteract these adverse effects.

(Received June 01 2009)

(Revised September 03 2009)

(Accepted October 12 2009)

(Online publication December 23 2009)

Key Words:Peanut protein; Skeletal muscle; Lipid metabolism


c1 Corresponding author: Hélène Jacques, fax +1 418 656 3353, email


Abbreviations: ED, experimental diet; EDL, extensor digitorum longus; Lf, fibre length; NPD, non-purified diet; Po, tetanic tension; Pt, twitch tension