International Psychogeriatrics

Higher fat and carbohydrate intake in dementia patients is associated with increased blood glutathione peroxidase activity

Naji Tabet a1c1, David Mantle a2, Zuzana Walker a3 and Martin Orrell a3
a1 Postgraduate Medical School, Faculty of Health, University of Brighton, U.K.
a2 Department of Agricultural and Environmental Sciences, University of Newcastle-upon-Tyne, U.K.
a3 Department of Psychiatry and Behavioral Sciences, Royal Free and University College Medical School, London, U.K.

Article author query
tabet n   [PubMed][Google Scholar] 
mantle d   [PubMed][Google Scholar] 
walker z   [PubMed][Google Scholar] 
orrell m   [PubMed][Google Scholar] 


Background: Mounting evidence implicates diets high in fats and processed sugars with increased generation of free radicals in animals. It is still not clearly established whether such a diet alters antioxidant balance in dementia patients, where an oxidative stress status may already exist. The disruption to lipid metabolism by oxidative stress has been recently linked to neurodegeneration and clinical disease. The aim of this study is to assess the relationship between fat, sugar, carbohydrate and caloric intake levels, and antioxidant status in patients with mild to moderate dementia.

Methods: The levels of 3 essential endogenous antioxidants (superoxide dismutase, catalase, glutathione peroxidase) were measured in the blood of 26 dementia subjects and 26 cognitively unimpaired controls. Concurrently, the intake levels of relevant nutrients and dietary antioxidants were assessed in all subjects.

Results: A statistically significant positive association was observed in the dementia group between glutathione peroxidase activity and the intake of fats (r=0.44; p=0.023), carbohydrates (r=0.46; p=0.018), total sugars (r=0.51; p=0.007) and calories (r=0.47; p=0.14). The only significant association in the control group was observed between glutathione peroxidase and fat (r=0.47; p=0.015).

Conclusion: The higher glutathione peroxidase activity among subjects with greater intake of fats, carbohydrates and sugars may represent a compensatory response to the additional increase in oxidative stress in dementia. Our data shed light on the influence of dietary intake on the oxidant-antioxidant system in mild to moderate dementia patients.

(Received November 27 2003)
(revision requested February 4 2004)
(revised version received March 1 2004)
(Accepted March 2 2004)

Key Words: Dementia; antioxidants; calories; diet; nutrition.

c1 Correspondence should be addressed to: Dr Naji Tabet, Postgraduate Medical School, Faculty of Health, University of Brighton, Falmer, Brighton BN1 9PH, U.K. Phone: +4401273644097. Email: