Open this publication in new window or tab >>2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]
Dietary fat quality influences the risk of type 2 diabetes and cardiovascular disease. A low-grade inflammation is suggested to contribute to the disease development, often accompanied by obesity. Whereas n-3 polyunsaturated fatty acids (PUFA) have been considered anti-inflammatory, n-6 PUFA have been proposed to act pro-inflammatory. Saturated fatty acids (SFA) act pro-inflammatory in vitro.
This thesis aimed to investigate effects of different fatty acids on low-grade inflammation in observational and interventional studies. In Paper I and II, fatty acid composition in serum cholesterol esters was used as objective marker of dietary fat quality and related to serum C-reactive protein (CRP) and other circulating inflammatory markers in two population-based cohorts, conducted in middle-aged men and elderly men and women, respectively. In Paper III and IV, the impact of diets differing in fat quality on inflammation and oxidative stress was investigated in randomised controlled studies, in subjects with metabolic syndrome and abdominal obesity.
In Paper I and II, a low proportion of linoleic acid (18:2 n-6) in serum was associated with higher CRP concentrations, indicating that a low intake of vegetable fats may be related to low-grade inflammation. High CRP concentrations were also associated with high proportions of palmitoleic (16:1) and oleic (18:1) acids and high stearoyl coenzymeA desaturase index, possibly reflecting altered fat metabolism and/or high SFA intake in this population. When comparing two high-fat diets rich in either saturated or monounsaturated fat, and two low-fat diets with or without long-chain n-3 PUFA supplementation during 12 weeks (Paper III), no differences in inflammation or oxidative stress markers were observed. Moreover, a 10-week intervention (Paper IV) with high linoleic acid intake showed no adverse effects on inflammation or oxidative stress. Instead, interleukin-1 receptor antagonist and tumor necrosis factor receptor-2 decreased after linoleic acid intake compared with a diet high in SFA.
The results in this thesis indicate that dietary n-6 PUFA found in vegetable fats is associated with lower inflammation marker levels, and to some extent reduces systemic inflammation when compared with SFA. Supplementation of n-3 PUFA did not exert any systemic anti-inflammatory effects, maybe due to a relatively low dose.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. p. 75
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 683
Keywords
Dietary fat, Fatty acids, Serum fatty acid composition, Linoleic acid, Stearoyl coenzymeA desaturase, SCD-1, Inflammation, C-reactive protein, Oxidative stress, Lipid peroxidation, Isoprostanes, Prostaglandins, Obesity, Epidemiology, Dietary intervention, Metabolic syndrome
National Category
Nutrition and Dietetics Public Health, Global Health, Social Medicine and Epidemiology Public Health, Global Health, Social Medicine and Epidemiology Immunology in the medical area Endocrinology and Diabetes Cardiac and Cardiovascular Systems
Research subject
Medical Science
Identifiers
urn:nbn:se:uu:diva-156074 (URN)978-91-554-8112-4 (ISBN)
Public defence
2011-09-14, Sal IV, Universitetshuset, Biskopsgatan 3, Uppsala, 09:15 (English)
Opponent
Supervisors
2011-08-242011-07-112018-01-12