Chemico-Biological Interactions 169 (2007) 100–109
A thermolyzed diet increases oxidative stress, plasma -aldehydes
and colonic inflammation in the rat
Nandita Shangari
a
, Flore Depeint
a,b
, Rudolf Furrer
b
, W. Robert Bruce
b
,
Marija Popovic
a
, Feng Zheng
c
, Peter J. O’Brien
a,∗
a
Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ont. M5S 3M2, Canada
b
Department of Nutritional Sciences, University of Toronto, 150 College Street, Toronto, Ont. M5S 3E2, Canada
c
Experimental Diabetes & Aging, Department of Geriatrics, One Gustave L. Levy Place, Box 1640, New York, NY 10029-6574, USA
Received 26 February 2007; received in revised form 27 May 2007; accepted 28 May 2007
Available online 8 June 2007
Abstract
A thermolyzed diet has the potential of providing exogenous oxidative stress in the form of advanced glycation end-products
(AGE) and decreased thiamin. There is then a possibility that it could result in intracellular exposure to -oxoaldehydes (glyoxal
and methylglyoxal (MG)) with metabolic and genetic consequences. Two groups of Fischer 344 rats were fed the following diets:
group A was given an AIN93G diet (control diet), while group B was given a thermolyzed AIN93G diet for 77 days. At the end
of 77 days TK activity in red blood cells; glyoxal/MG levels in the plasma; glyoxal/MG HI protein adducts and dicarbonyls in the
plasma, liver and colon tissues; glutathione levels of whole blood; and oxidative stress/inflammatory markers in the colon were
measured. The thermolyzed diet resulted in: decreased thiamin status, increased plasma levels of glyoxal/MG and their adducts,
increased protein dicarbonyls in the liver and plasma, lowered blood glutathione levels, increased infiltration of macrophages and
increased colon nitrotyrosine levels. The thermolyzed diet increased the body burden of AGEs and decreased the thiamin status of
the rats. This increased endogenous -oxoaldehydes and oxidative stress has the potential to injure tissues that have low levels of
antioxidant defenses such as the colon.
© 2007 Elsevier Ireland Ltd. All rights reserved.
Keywords: Thermolyzed food; Advanced glycation end-products; Thiamin deficiency; Oxidative stress biomarkers
1. Introduction
Diet is a major risk factor for cancer, diabetes and
other chronic diseases in developed and, now more
Abbreviations: TK, transketolase; GSH, glutathione; AGE,
advanced glycation end-products; MG, methylglyoxal; TPP, thiamin
pyrophosphate
∗
Corresponding author at: University of Toronto, Department of
Pharmaceutical Sciences, 144 College Street, Rm 1004, Toronto, Ont.
M5S 3M2, Canada. Tel.: +1 416 978 2716; fax: +1 416 978 8511.
E-mail address: peter.obrien@utoronto.ca (P.J. O’Brien).
frequently, in developing countries [1–3]. Attention is
usually directed to the macro- or micro-nutrients of the
diet as the factors responsible. Less attention is given to
the effects of the ubiquitous use of heat in food prepa-
ration. Thermolysis of foods, however, can result in the
formation of new products such as advanced glycation
end-products (AGE), a heterogeneous group of com-
pounds that are formed by a complex series of parallel
and sequential reactions called the Maillard reactions
[4,5]. Thermolysis can also result in the destruction of
dietary components. For instance, vitamin coenzyme
activity can be lost resulting in reduced enzyme activity
0009-2797/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.cbi.2007.05.009