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- Bjermo, Helena, et al.
(författare)
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Effects of n-6 PUFAs compared with SFAs on liver fat, lipoproteins, and inflammation in abdominal obesity : a randomized controlled trial
- 2012
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 95:5, s. 1003-1012
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Replacing SFAs with vegetable PUFAs has cardiometabolic benefits, but the effects on liver fat are unknown. Increased dietary n-6 PUFAs have, however, also been proposed to promote inflammation-a yet unproven theory. OBJECTIVE: We investigated the effects of PUFAs on liver fat, systemic inflammation, and metabolic disorders. DESIGN: We randomly assigned 67 abdominally obese subjects (15% had type 2 diabetes) to a 10-wk isocaloric diet high in vegetable n-6 PUFA (PUFA diet) or SFA mainly from butter (SFA diet), without altering the macronutrient intake. Liver fat was assessed by MRI and magnetic resonance proton (1H) spectroscopy (MRS). Proprotein convertase subtilisin/kexin type-9 (PCSK9, a hepatic LDL-receptor regulator), inflammation, and adipose tissue expression of inflammatory and lipogenic genes were determined. RESULTS: A total of 61 subjects completed the study. Body weight modestly increased but was not different between groups. Liver fat was lower during the PUFA diet than during the SFA diet [between-group difference in relative change from baseline; 16% (MRI; P < 0.001), 34% (MRS; P = 0.02)]. PCSK9 (P = 0.001), TNF receptor-2 (P < 0.01), and IL-1 receptor antagonist (P = 0.02) concentrations were lower during the PUFA diet, whereas insulin (P = 0.06) tended to be higher during the SFA diet. In compliant subjects (defined as change in serum linoleic acid), insulin, total/HDL-cholesterol ratio, LDL cholesterol, and triglycerides were lower during the PUFA diet than during the SFA diet (P < 0.05). Adipose tissue gene expression was unchanged. CONCLUSIONS: Compared with SFA intake, n-6 PUFAs reduce liver fat and modestly improve metabolic status, without weight loss. A high n-6 PUFA intake does not cause any signs of inflammation or oxidative stress. Downregulation of PCSK9 could be a novel mechanism behind the cholesterol-lowering effects of PUFAs.
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- Iggman, David, 1981-, et al.
(författare)
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Adipose tissue fatty acids and cardiovascular and all-cause mortality in elderly men : a prospective cohort study
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: For several fatty acids, adipose tissue reflects long-term dietary intake and may provide more objective information than self-reported intake. No prospective studies have examined whether adipose tissue fatty acids predict cardiovascular and all-cause mortality.Objective: To investigate associations between adipose tissue fatty acids and cardiovascular and overall mortality in a cohort of elderly men. We hypothesized that polyunsaturated fatty acids (PUFA) could be inversely associated with cardiovascular and all-cause mortality.Methods: In the Swedish community-based cohort study ULSAM, adipose tissue biopsies were taken from the buttocks of 853 men at age 71. Cox regression analyses were performed primarily for four PUFA that were considered to reflect dietary intake (linoleic acid, 18:2n-6, alpha-linolenic acid, 18:3n-3, eicosapentaenoic acid, 20:5n-3, and docosahexaenoic acid, 22:6n-3), and for all other available fatty acids (secondary analyses) analyzed by gas-liquid chromatography.Results: During 20-year follow-up, 605 individuals died of which 251 were cardiovascular deaths. After adjusting for risk factors, none of the four primary fatty acids were associated with cardiovascular mortality (hazard ratios (HR)=0.92-1.05 for each SD increase, P≥0.27). Linoleic acid was inversely associated with mortality (HR=0.90, 95% confidence interval (CI) 0.82-0.99, P=0.03). In secondary analyses, palmitoleic acid, 16:1n-7, (HR=1.11, 95% CI 1.02-1.21, P=0.01), and arachidonic acid, 20:4n-6, (HR=1.09, 95% CI 1.00-1.19, P=0.05) were associated with increased mortality, whereas heptadecanoic acid, 17:0, was inversely associated with mortality (HR=0.89, 95% CI 0.79-1.00, P=0.05).Conclusions: Adipose tissue PUFA was inversely associated with total mortality, but not cardiovascular mortality in elderly men. The mechanisms behind adipose tissue PUFA and longevity warrant further investigation.
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- Iggman, David, et al.
(författare)
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Adipose tissue fatty acids and insulin sensitivity in elderly men.
- 2010
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 53:5, s. 850-857
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS Dietary fatty acids may affect insulin sensitivity. Adipose tissue fatty acid composition partly reflects long-term dietary intake, but data from large studies regarding relationships with insulin sensitivity are lacking. We aimed to determine the association between adipose tissue fatty acids and insulin sensitivity in elderly Swedish men. METHODS In a cross-sectional analysis of the community-based Uppsala Longitudinal Study of Adult Men (n = 795, mean age 71 years), adipose tissue biopsies were obtained and fatty acid composition was determined by gas-liquid chromatography. Insulin sensitivity was measured directly by a euglycaemic clamp. RESULTS Palmitic acid (16:0), the major saturated fatty acid (SFA) in the diet and in adipose tissue, was negatively correlated with insulin sensitivity (r = -0.14), as were 16:1 n-7 (r = -0.15), 20:3 n-6 (r = -0.31), 20:4 n-6 (r = -0.38), 22:4 n-6 (r = -0.37) and 22:5 n-3 (r = -0.24; p < 0.001 for all). Some minor SFAs were positively correlated; 12:0 (r = 0.46), 14:0 (r = 0.32), 17:0 (r = 0.21) and 18:0 (r = 0.41; p < 0.001 for all), as were essential polyunsaturated fatty acids (PUFAs) 18:2 n-6 (r = 0.10, p < 0.01) and 18:3 n-3 (r = 0.16, p < 0.001). Docosahexaenoic acid (22:6 n-3) was negatively correlated (r = -0.11, p < 0.01), whereas eicosapentaenoic acid (20:5 n-3) was not (r = -0.02, NS). Most associations diminished or disappeared in lean individuals, indicating an effect of obesity. CONCLUSIONS/INTERPRETATION Adipose tissue enriched with palmitic acid and depleted of essential PUFAs is associated with insulin resistance. The positive association between minor SFAs and insulin sensitivity merits further investigation.
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| 6. |
- Iggman, David, et al.
(författare)
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Association of adipose tissue fatty acids with cardiovascular and all-cause mortality in elderly men
- 2016
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Ingår i: JAMA cardiology. - : American Medical Association (AMA). - 2380-6583 .- 2380-6591. ; 1:7, s. 745-753
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Tidskriftsartikel (refereegranskat)abstract
- Importance: The major polyunsaturated fatty acids in adipose tissue objectively reflect long-term dietary intake, and may provide more reliable information than would self-reported intake. Whether adipose tissue fatty acids predict cardiovascular and all-cause mortality needs investigation.Objective: To investigate associations between adipose tissue fatty acids and cardiovascular and overall mortality in a cohort of elderly men.Design, Setting, and Participants: We hypothesized that polyunsaturated fatty acids reflecting dietary intake, are inversely associated with cardiovascular and all-cause mortality. In the Swedish cohort study Uppsala Longitudinal Cohort of Adult Men, buttock fatty acid composition was analyzed by gas-liquid chromatography in 1992 to 1993 and 2008. The study participants were followed during 11 311 person-years, between 1991 and 2011 (median follow-up, 14.8 years). In this community-based study that took place from 1970 to 1973, all men born in 1920 to 1924 in Uppsala, Sweden, were invited and 2322 (82%) were included (at age 50 years). At the reinvestigation at age 71 years, 1221 (73%) of the 1681 invited men participated. Adipose tissue biopsy specimens were taken in a subsample of 853 men. There was no loss to follow-up.Exposures: Adipose tissue proportions of 4 polyunsaturated fatty acids that were considered to mainly reflect dietary intake (linoleic acid, 18:2n-6; α-linolenic acid, 18:3n-3; eicosapentaenoic acid, 20:5n-3; and docosahexaenoic acid, 22:6n-3) comprised primary analyses, and all other available fatty acids were secondary analyses.Main Outcomes and Measures: Hazard ratios (HRs) for cardiovascular and all-cause mortality using Cox proportional hazards regression analyses, performed in 2015.Results: Among the 853 Swedish men, there were 605 deaths, of which 251 were cardiovascular deaths. After adjusting for risk factors, none of the 4 primary fatty acids were associated with cardiovascular mortality (HR, 0.92-1.05 for each standard deviation increase; P ≥ .27). Linoleic acid was inversely associated with all-cause mortality (HR, 0.90; 95% CI, 0.82-0.98; P = .02) and directly associated with intake (P < .001). In secondary analyses, palmitoleic acid, 16:1n-7 (HR, 1.11; 95% CI, 1.02-1.21; P = .02) was associated with higher all-cause mortality, whereas heptadecanoic acid, 17:0, tended to be associated with lower all-cause mortality (HR, 0.89; 95% CI, 0.79-1.00; P = .05). Arachidonic:linoleic acid ratio was associated with both cardiovascular (HR, 1.15; 95% CI, 1.05-1.31; P = .04) and all-cause (HR, 1.13; 95% CI, 1.04-1.23; P = .005) mortality.Conclusions and Relevance: Adipose tissue linoleic acid was inversely associated with all-cause mortality in elderly men, although not significantly with cardiovascular mortality.
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| 7. |
- Iggman, David
(författare)
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Dietary Fatty Acids and Cardiometabolic Risk : Influence on Lipoproteins, Insulin Resistance and Liver Fat
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to investigate how dietary fatty acids affect the risk for cardiometabolic disease, i.e. cardiovascular disease (CVD), type 2 diabetes and obesity. The overall hypothesis was that unsaturated fatty acids and especially the predominant polyunsaturated fatty acid (PUFA) linoleic acid (LA), 18:2n-6, would decrease cardiometabolic risk compared with saturated fatty acids (SFAs), in line with current recommendations to partly replace dietary SFA with PUFA.Papers I and V were observational studies based on the community-based cohort Uppsala Longitudinal Study of Adult Men (ULSAM). Adipose tissue fatty acid composition was determined as biomarker for dietary fat intake. Studies II, III and IV were randomised short-term interventions on human volunteers, in which different dietary fats were provided to the participants.In 71-year-old men, adipose tissue LA and α-linolenic acid (18:3n-3) were associated with insulin sensitivity (euglycaemic clamp), although this association was diminished for LA after adjusting for lifestyle variables. Different SFA displayed divergent associations; only palmitic acid (16:0) was inversely associated with insulin sensitivity (Paper I). In Cox regression analyses, LA was modestly associated with decreased all-cause mortality, but not CVD mortality during 15 years follow-up (Paper V).In a 3+3-week cross-over study on 20 weight-stable volunteers with dyslipidaemia, all foods were provided. A rapeseed oil-based diet distinctly lowered low-density lipoprotein cholesterol and triglycerides compared with a dairy-fat based diet (butter, cream and fatty cheese). Insulin sensitivity or coagulation factors were not affected (Paper II).In a 10-week randomised trial on 67 abdominally obese participants, PUFA (mostly sunflower oil) decreased liver fat compared with SFA (mostly butter) under isocaloric conditions. In individuals considered highly compliant to study diets, lipoproteins were also decreased during the PUFA diet (Paper III).In a 7-week double-blind randomised trial on 41 healthy volunteers, PUFA (sunflower oil) decreased the total:HDL cholesterol ratio compared with SFA (palm oil) during moderate weight gain (1.5 kg) (Paper IV).In conclusion, LA (PUFA) intake is associated with decreased cardiometabolic risk compared with higher SFA intake, overall supporting a beneficial role of non-tropical vegetable oils in place of solid fats in preventing fatty liver and cardiometabolic disorders.
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