Volume 89, Issue 1, January (2003), pp. 89-96 © The Author 2003
doi:10.1079/BJN2003749

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Carbohydrate--energy restriction may protect the rat brain against oxidative damage and improve physical performance

S. L. de Oliveira¹, D. B. Diniz² and J. Amaya-Farfan^3*
1Department of Nutrition, Federal University of Alagoas, Maceió, AL, Brazil
²Department of Nutrition, State University of Ceará, Fortaleza, CE, Brazil
³Department of Food and Nutrition, State University of Campinas, SP 13.083-970, Brazil

 (Received 28 September 2001–Revised 15 August 2002–Accepted 4 September 2002)

Chronic energy restriction, α-tocopherol supplementation and their interaction with exhaustive exercise were investigated. Eleven-week-old male Wistar rats (n 6×10) were fed either a control (C), a 30 % carbohydrate-energy-restricted control (R) or an α-tocopherol-supplemented (S) diet for 5 months. The animals in each diet were divided into exercised (E) and non-exercised (NE) groups. Before killing, the exercised rats were required to run to exhaustion (39 (SE 6), 69 (SE 11) and 18 (SE 2) min for the C, R and S groups, respectively). Lipid peroxidation (thiobarbituric acid-reactive substances; TBARS), protein damage (reactive carbonyls) and α-tocopherol were determined in gastrocnemius, liver, brain and/or plasma. There was no difference in lipid peroxidation between the R and C groups, but in liver and muscle peroxidation appeared significantly lower in the S than the other two diets. TBARS in the brain were similar in all groups. On the other hand, reactive carbonyls showed that both the R and S diets reduced protein damage in the brain, while exhaustive exercise increased it. For liver and muscle, however, reactive carbonyl levels were similar in all groups. α-Tocopherol supplementation increased the vitamin concentrations in liver, muscle and plasma, but exercise decreased them in plasma and brain. Carbohydrate-energy restriction increased (P=0·0025) resistance to exhaustive exercise considerably without depleting stores of α-tocopherol or exacerbating oxidative damage in monitored tissues. It is concluded that while exhaustive exercise promotes a tissue-specific oxidative damage detectable only in brain proteins, both experimental diets tended to ameliorate this condition.

*Corresponding author: Professor J. Amaya-Farfan, fax +55 19 3788 4060, email jaf@fea.unicamp.br

Keywords:
Energy restriction: Vitamin E: Oxidative stress: Exercise