Validation of the omega-3 fatty acid intake measured by a web-based food frequency questionnaire against omega-3 fatty acids in red blood cells in men with prostate cancer.

BACKGROUND/OBJECTIVES: The objective of this study was to evaluate the ability of a web-based self-administered food frequency questionnaire (web-FFQ) to assess the omega-3 (ω-3) fatty acids (FAs) intake of men affected with prostate cancer (PCa) against a biomarker. SUBJECTS/METHODS: The study presented herein is a sub-study from a phase II clinical trial. Enrolled patients afflicted with PCa were included in the sub-study analysis if the FA profiles from the red blood cell (RBC) membranes and FA intakes at baseline were both determined at the time of the data analysis (n=60). Spearman's correlation coefficients were calculated to estimate the correlations between FA intakes and their proportions in the RBC membranes. RESULTS: Intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were highly correlated with their respective proportions in the RBC membranes (both rs=0.593, P<0.0001). Correlation between alpha-linolenic acid (ALA) intake and its proportion in RBC was not significant (rs=0.130, P=0.332). Correlations were observed between fatty fish intake and total ω-3 FAs (rs=0.304, P=0.02), total long-chain ω-3 FAs (rs=0.290, P=0.03) and DHA (rs=0.328, P=0.01) in RBC membranes. CONCLUSIONS: This study has shown that the web-FFQ is an accurate tool to assess total long-chain ω-3 FAs, EPA and DHA but not ALA intake in clinical trials and epidemiological studies carried out in men with PCa.

Docosahexaenoic acid-enriched canola oil increases adiponectin concentrations: a randomized crossover controlled intervention trial.

BACKGROUND AND AIMS: Little is known about the effect of various dietary fatty acids on pro- and anti-inflammatory processes. We investigated the effect of 5 oils containing various amounts of alpha-linolenic acid (ALA), linoleic acid (LA), oleic acid (OA) and docosahexaenoic acid (DHA) on plasma inflammatory biomarkers and expression levels of key inflammatory genes and transcription factors in whole blood cells. METHODS AND RESULTS: In a randomized, crossover controlled nutrition intervention, 114 adult men and women with abdominal obesity and at least one other criterion for the metabolic syndrome consumed 5 experimental isoenergetic diets for 4 weeks each, separated by 4-week washout periods. Each diet provided 60 g/3000 kcal of different oils: 1) control corn/safflower oil blend (CornSaff; LA-rich), 2) flax/safflower oil blend (FlaxSaff; ALA-rich), 3) conventional canola oil (Canola; OA-rich), 4) high oleic canola oil (CanolaOleic; highest OA content), 5) DHA-enriched high oleic canola oil (CanolaDHA; OA- and DHA-rich). Gene expression in whole blood cells was assessed in a subset of 62 subjects. CanolaDHA increased plasma adiponectin concentrations compared with the control CornSaff oil treatment (+4.5%, P = 0.04) and FlaxSaff (+6.9%, P = 0.0008). CanolaDHA also reduced relative expression levels of interleukin (IL)1B compared with CornSaff and Canola (-11% and -13%, respectively, both P = 0.03). High-sensitivity C-reactive protein concentrations were lower after Canola than after FlaxSaff (-17.8%, P = 0.047). CONCLUSION: DHA-enriched canola oil exerts anti-inflammatory effects compared with polyunsaturated fatty acids from plant sources.

Association of red blood cell n-3 polyunsaturated fatty acids with plasma inflammatory biomarkers among the Quebec Cree population.

BACKGROUND/OBJECTIVES: We examined the prevalence of elevated plasma high-sensitivity C-reactive protein (hs-CRP) concentrations and associations with red blood cell (RBC) long-chain n-3 polyunsaturated fatty acids (LCn-3PUFA) in the James Bay Cree population from the province of Quebec (Canada). SUBJECTS/METHODS: A total of 744 Cree adults (18-91 years) from seven communities of Eastern James Bay were included in these cross-sectional analyses. Associations between RBC LCn-3PUFA and proinflammatory markers (hs-CRP, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α)) were assessed by using multivariate general linear models with adjustment for sex, age and waist circumference. An arbitrary inflammation score was defined based on the sum of the quartiles of hs-CRP, IL-6 and TNF-α concentrations (range=3-12). RESULTS: Elevated hs-CRP concentrations (>3 mg/l) were present in 46.9% (95% confidence interval (CI) 43.3-50.5) of the James Bay Cree population. RBC docosapentaenoic acid (DPAn-3; C22:5n-3) was inversely associated with hs-CRP, TNF-α and the inflammation score (all P trend<0.02), whereas eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) in RBC were not associated with inflammation (all P trend>0.18). Among participants with RBC DPAn-3 levels above the median of the population, odds ratio of having an elevated inflammation score (≥9) was 0.67 (95% CI, 0.48-0.93) compared with participants below the median. CONCLUSIONS: RESULTS indicate that low-grade systemic inflammation is highly prevalent and that higher RBC DPAn-3 levels are associated with a lower risk of systemic inflammation in the James Bay Cree population.

Impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol homeostasis in men and women.

BACKGROUND AND AIMS: Sphingolipids (SL) are important components of the milk fat globule membrane (MFGM) found in buttermilk. While studies in animal models suggest that dietary SL may have cholesterol-lowering properties, data in human are lacking. The aim of this study was to investigate the impact of buttermilk consumption on plasma lipids and surrogate markers of cholesterol (C) homeostasis in humans. METHODS AND RESULTS: Men and women (n = 34) with serum LDL-C <5.0 mmol/L at screening (mean LDL-C = 3.8 mmol/L) were recruited in this double-blinded randomized crossover placebo controlled study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro/micronutrient matched placebo (4 weeks each in random order). Serum lipid concentrations and surrogate markers of cholesterol homeostasis were measured post diet and compared using mixed models for repeated measures. Consumption of buttermilk led to reduction in serum cholesterol (-3.1%, P = 0.019), LDL-C (-3.1%, P = 0.057) and triacylglycerol (-10.7%, P = 0.007). Buttermilk consumption increased plasma lathosterol concentrations (+12.1%, P = 0.001), but multiple regression analysis indicated that variations in ß-sitosterol concentrations (P = 0.002) were the only significant predictor of the LDL-C response to buttermilk consumption. CONCLUSION: Buttermilk consumption may be associated with reduced cholesterol concentrations in men and women, primarily through inhibition of intestinal absorption of cholesterol. REGISTRATION NUMBER: This trial is registered at clinicaltrials.gov as NCT01248026.