1. ¹Division of Nutrition, Department of Applied Chemistry and Microbiology, University of Helsinki, Helsinki, Finland
2. ²Institute of Human Nutrition, University of Copenhagen, Copenhagen, Denmark
3. ³Institute of Public Health, Department of Occupational and Environmental Health, University of Copenhagen, Copenhagen, Denmark

Correspondence: Dr R Freese, Department of Applied Chemistry and Microbiology, Division of Nutrition, University of Helsinki, PO Box 66 (Viikki, Agnes Sjöbergin katu 2), FIN-00014, Finland. E-mail: riitta.freese@helsinki.fi

Received 21 April 2006; Revised 21 May 2007; Accepted 22 May 2007; Published online 1 August 2007.

Abstract

Diet may both increase and decrease oxidative stress in the body. We compared the effects of four strictly controlled isocaloric diets with different intakes of polyunsaturated fatty acids (PUFA, 11 or 3% of energy) and vegetables and fruit (total amount of vegetables and fruit 516 or 1059 g/10 MJ) on markers associated with oxidative stress in 77 healthy volunteers (19–52 years). Plasma protein carbonyls (2-aminoadipic semialdehyde residues) and whole-body DNA and nucleotide oxidation (urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine excretion) tended to decrease in all treatment groups with no differences between the diets. The diets did not differ in their effects on red blood cell antioxidative enzyme activities, either. The results suggest that in healthy volunteers with adequate nutrient intakes, 6-week diets differing markedly in the amount of PUFA or vegetables and fruit do not differ in their effects on markers associated with oxidative stress.