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Dietary (n-3) fatty acids reduce plasma F2-isoprostanes but not prostaglandin F2alpha in healthy humans
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Clinical Nutrition Research.
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Clinical Nutrition Research.
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2006 (English)In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 136, no 5, 1222-1228 p.Article in journal (Refereed) Published
Abstract [en]

(n-3) Fatty acids are unsaturated and are therefore easily subject to oxidization; however, they have several beneficial health effects, which include protection against cardiovascular diseases. The aim of this study was to investigate whether (n-3) fatty acids, with a controlled fat quality in the background diet, affect nonenzymatic and enzymatic lipid peroxidation and antioxidant status in humans. A total of 162 men and women in a multicenter study (The KANWU study) were randomly assigned to a diet containing a high proportion of saturated fatty acids or monounsaturated fatty acids (MUFA) for 3 mo. Within each diet group, there was a second random assignment to supplementation with fish-oil capsules [3.6 g (n-3) fatty acids/d] or placebo. Biomarkers of nonenzymatic and enzymatic lipid peroxidation in vivo were determined by measuring 8-iso-prostaglandin F (8-iso-PGF) and prostaglandin F (PGF) concentrations in plasma at baseline and after 3 mo. Antioxidant status was determined by measuring plasma antioxidant capacity with an enhanced chemiluminescence assay. The plasma 8-iso-PGF concentration was significantly decreased after 3 mo of supplementation with (n-3) fatty acids (P = 0.015), whereas the PGF concentration was not affected. The antioxidant status was not affected by supplementation of (n-3) fatty acids, but was improved by the background diet with a high proportion of MUFA. We conclude that supplementation with (n-3) fatty acids decreases nonenzymatic free radical–catalyzed isoprostane formation, but does not affect cyclooxygenase-mediated prostaglandin formation.

Place, publisher, year, edition, pages
2006. Vol. 136, no 5, 1222-1228 p.
Keyword [en]
Administration; Oral, Comparative Study, Diet, Dinoprost/*blood, Energy Intake, F2-Isoprostanes/*blood, Fatty Acids/administration & dosage/pharmacology, Fatty Acids; Omega-3/administration & dosage/*pharmacology, Female, Humans, Male, Reference Values, Research Support; Non-U.S. Gov't
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-94252PubMedID: 16614408OAI: oai:DiVA.org:uu-94252DiVA: diva2:168039
Available from: 2006-04-05 Created: 2006-04-05 Last updated: 2013-03-21Bibliographically approved
In thesis
1. Measurement and Evaluation of Antioxidant Status and Relation to Oxidative Stress in Humans
Open this publication in new window or tab >>Measurement and Evaluation of Antioxidant Status and Relation to Oxidative Stress in Humans
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Numerous diseases are associated with reduced antioxidant defence and oxidative stress. The antioxidant defence includes dietary and endogenous antioxidants and involves complex interactions between them. The effects of dietary factors on antioxidant status and oxidative stress of healthy humans were investigated in the studies described in this thesis. Assays of plasma antioxidant capacity encompass interactions between various antioxidants. Although uric acid has an unclear function as an antioxidant, it is a major determinant of antioxidant capacity. We measured antioxidant capacity in the presence and absence of uric acid to provide more information on the application of measures of antioxidant capacity. Individuals with high dietary intakes of various antioxidants and antioxidant rich foods, especially when combined, had higher plasma antioxidant capacities than those with lower antioxidant intakes. However, there were no associations between dietary intake of antioxidants or antioxidant rich foods and the plasma concentration of F2-isoprostanes, which is considered a reliable biomarker for oxidative stress. Intakes of various doses of a mixture of bilberry juice and black tea, rich in flavonoids for four weeks, increased antioxidant capacity in some groups, but urine levels of F2-isoprostanes were not affected. There were substantial individual variations in responses to the drinks related to baseline antioxidant capacity. Supplementation with eicosapentaenoic acid and docosahexaenoic acid decreased the plasma levels of F2-isoprostanes, but not prostaglandin F formation or antioxidant capacity.

It was concluded that a high intake of foods rich in antioxidants is related to improved antioxidant status. After intake of foods rich in antioxidants, the antioxidant status may increase, but with considerable individual variation in the responses, which warrants further investigation. Lipid peroxidation in vivo is not easily affected by dietary antioxidants in healthy humans. Although n-3 fatty acids are highly unsaturated, they reduce nonenzymatic free radical-catalyzed lipid peroxidation, but not enzymatic lipid peroxidation.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 71 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 131
Nutrition, antioxidant, antioxidant status, antioxidant capacity, oxidative stress, lipid peroxidation, F2-isoprostanes, dietary factors, vitamin E, n-3 fatty acids, human, Näringslära
urn:nbn:se:uu:diva-6742 (URN)91-554-6519-6 (ISBN)
Public defence
2006-04-26, Sal IX, Universitetshuset, Uppsala, 13:15
Available from: 2006-04-05 Created: 2006-04-05Bibliographically approved

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