Circulating fatty acids as biomarkers of dairy fat intake: data from the lifelines biobank and cohort study.

Background: C14:0, C15:0, C17:0 and trans-C16:1(n-7) are often used as biomarkers for dairy fat intake. Trans-C18:1(n-7) and CLA, two fatty acids which are also present in dairy, have hardly been explored. We investigated whether trans-C18:1(n-7) and CLA can enrich the existing biomarker portfolio. Methods: Data were obtained from Lifelines (n = 769). Dairy fat intake was determined by FFQ. Fatty acids were measured in fasting plasma triglycerides (TG), phospholipids (PL) and cholesterol esters (CE). Results: Median (25th-75th percentile) intakes of dairy and dairy fat were 322(209-447) and 12.3(8.4-17.4) g/d respectively. A pilot study showed that trans-C18:1(n-7) and CLA were only detectable in TG and PL. Of the established markers, TG C15:0 was most strongly associated with dairy fat intake (standardized ß (std.ß) = 0.286, R2 = 0.111). Of the less established markers, TG trans-C18:1(n-7) was most strongly associated with dairy fat intake (Std.ß = 0.292, R2 = 0.115), followed by PL CLA (Std.ß = 0.272, R2 = 0.103) and PL trans-C18:1(n-7) (Std.ß = 0.269, R2 = 0.099). In TG, a combination of C15:0 and trans-C18:1(n-7) performed best (R2 = 0.128). In PL, a combination of C14:0, C15:0, trans-C18:1(n-7) and CLA performed best (R2 = 0.143). Conclusion: Trans-C18:1(n-7) and CLA can be used as biomarkers of dairy fat intake. Additionally, combining established with less established markers allowed even stronger predictions for dairy fat intake.

Intake of n-3 fatty acids and long-term outcome in renal transplant recipients: a post hoc analysis of a prospective cohort study.

Supplementation with n-3 fatty acids may improve long-term outcomes of renal transplant recipients (RTR). Recent evidence suggests that EPA and DHA have different outcomes compared with α-linolenic acid (ALA). We examined the prospective associations of EPA-DHA and ALA intakes with graft failure and all-cause mortality in 637 RTR. During 3·1 years (interquartile range 2·7, 3·8) of follow-up, forty-one developed graft failure and sixty-seven died. In age- and sex-adjusted analyses, EPA-DHA and ALA intakes were not associated with graft failure. EPA-DHA intake was not significantly associated with mortality (hazard ratio (HR) 0·79; 95% CI 0·54, 1·15 per 0·1 energy% difference). ALA intake was significantly associated with mortality (HR 1·17; 95% CI 1·04, 1·31 per 0·1 energy% difference). This association remained following adjustments for BMI, proteinuria and intakes of fat, carbohydrate and protein. RTR in the highest tertile of ALA intake exhibited about 2-fold higher mortality risk (HR 2·21; 95% CI 1·23, 3·97) compared with the lowest tertile. In conclusion, ALA intake may be associated with increased mortality in RTR. Future RCT are needed to confirm these results.

Circulating de novo lipogenesis fatty acids and all-cause mortality in a prospective Dutch population cohort.

BACKGROUND: Circulating fatty acids (FA) from de novo lipogenesis (DNL) are associated with all-cause mortality in individuals with elevated CVD risk. However, compared to FA early in the DNL synthetic pathway, cis-vaccenic acid, one of the FA distal in the DNL synthetic pathway, has rarely been studied in a general population cohort. We hypothesized that circulating cis-vaccenic acid is more strongly related to all-cause mortality than other circulating DNL-related FA. OBJECTIVES: The primary and secondary objectives of this study were to investigate the prospective associations of plasma levels of cis-vaccenic acid and other DNL-related FA with all-cause mortality in a general population, respectively. METHODS: We included 850 participants (mean ± SD age 53 ± 15 years) from the Dutch Lifelines cohort study. Circulating levels of palmitic (C16:0), palmitoleic (C16:1n7), cis-vaccenic (cis-C18:1n7), stearic (C18:0), oleic acid (C18:1n9) in plasma phospholipids (PL) and triglycerides (TG) were measured by gas chromatography. The associations of circulating cis-C18:1n7 and other DNL-related FA with all-cause mortality were assessed using Cox regression analyses. RESULTS: During a median follow-up of 9.3 (IQR: 5.4-10.8) years, 34 (4.0%) participants had died. In plasma PL, a 1-SD increase in cis-C18:1n7 was associated with an increased risk of all-cause mortality in univariate and multivariate models (p<0.02 for all), with a HR [95% CI] of 1.60 [1.13-2.25] after adjustment for age and sex. CONCLUSIONS: Circulating plasma PL cis-C18:1n7 was associated with a higher risk for all-cause mortality. More studies are needed in different cohorts to verify and validate our results.

Potential Biomarkers for Fat from Dairy and Fish and Their Association with Cardiovascular Risk Factors: Cross-sectional Data from the LifeLines Biobank and Cohort Study.

Dairy fat intake, reflected by the biomarkers C14:0, C15:0, C17:0, trans-C16:1 (n-7), trans-C18:1 (n-7) and CLA, may have beneficial effects on cardiovascular health. It has, however, been questioned whether this association is genuine, since C15:0 and C17:0 are also biomarkers from fish. We investigated whether the above biomarkers are reliable markers for dairy fat intake in 864 healthy subjects. Subsequently, we explored the association between these biomarkers and cardiovascular risk factors. Intakes of dairy and fish were determined by Food Frequency Questionnaires FFQs. Fatty acids were analyzed in plasma triglycerides (TG) and phospholipids (PL). Median intakes of dairy and fish fat were 12.3 (8.4-17.4) g/day and 1.14 (0.53-1.75) g/day. All fatty acids, except TG C17:0, were associated with dairy fat (std.ß range TG: 0.12 for C14:0 till 0.25 for C15:0 and Trans-C18:1 (n-7); and std.ß range PL: 0.12 for C17:0 and Trans-C16:1 (n-7) till 0.24 for Trans-C18:1 (n-7) and CLA; p < 0.001). TG C17:0 was associated with fish fat (std.ß = 0.08; p = 0.03), whereas PL C17:0 was not. Associations remained after adjustment for fish/dairy fat intake. Strongest inverse associations with biological variables were found with PL C17:0 and Trans-C18:1 (n-7) (Std.ßs: waist circumference: -0.18, p < 0.001 and -0.10, p < 0.05; BMI: -0.17, p < 0.001, -0.11, p < 0.01; glucose: -0.10, p <0.01 and -0.08, p <0.05; high sensitive C-reactive protein (hs-CRP): -0.22, p < 0.001 and -0.16, p < 0.01; uric acid: -0.27, p < 0.001 and -0.24, p < 0.001). In conclusion, fatty acid biomarkers, except plasma TG C17:0, were associated with dairy fat intake, independent of fish fat intake. PL C17:0 and trans-C18:1 (n-7) were inversely associated with adiposity, diabetes, inflammation and uric acid.

Fatty acids as biomarkers of total dairy and dairy fat intakes: a systematic review and meta-analysis.

Context: Dairy intake in humans is commonly assessed using questionnaires, but the data collected are often biased. As a result, there is increasing interest in biomarkers of dairy fat. To date, there has been no overview of the fatty acids suitable for use as biomarkers of dairy fat intake. Objective: This systematic review and meta-analysis of observational studies was performed to identify circulating fatty acids as biomarkers of total dairy and dairy fat intakes in the general population. Data Sources: MEDLINE, Embase, and Web of Knowledge databases were searched for eligible studies published until June 2017. Study Selection: Articles were included when a correlation between circulating dairy fatty acids and intakes of total dairy and dairy fat was found, as measured by dietary assessment tools. Data Extraction: Two authors extracted data independently and assessed the risk of bias. An adapted form of the Newcastle-Ottawa Scale was used for quality assessment. Results: Data were pooled using the random-effects model. Meta-analysis revealed that the fatty acids in plasma/serum were significantly correlated with intakes of total dairy (C14:0 [r = 0.15; 95%CI, 0.11 - 0.18], C15:0 [r = 0.20; 95%CI, 0.13 - 0.27], and C17:0 [r = 0.10; 95%CI, 0.03 - 0.16] and dairy fat (C14:0 [r = 0.16; 95%CI, 0.10 - 0.22], C15:0 [r = 0.33; 95%CI, 0.27 - 0.39], C17:0 [r = 0.19; 95%CI, 0.14 - 0.25], and trans-C16:1n-7 [r = 0.21; 95%CI, 0.14 - 0.29). Conclusions: C14:0, C15:0, C17:0, and trans-C16:1n-7 were identified as biomarkers of total dairy and dairy fat intakes in the general population. In light of the suboptimal measurement techniques used in some studies, correlations with trans-C18:1n-7 and conjugated linoleic acid require further investigation.

Intake of Marine-Derived Omega-3 Polyunsaturated Fatty Acids and Mortality in Renal Transplant Recipients.

The effect of marine-derived omega-3 polyunsaturated fatty acids (n-3 PUFA) on long-term outcome in renal transplant recipients (RTR) remains unclear. We investigated whether marine-derived n-3 PUFA intake is associated with all-cause and cardiovascular (CV) mortality in RTR. Intake of eicosapentaenoic acid plus docosahexaenoic acid (EPA-DHA) was assessed using a validated Food Frequency Questionnaire. Cox regression analyses were performed to evaluate the associations of EPA-DHA intake with all-cause and CV mortality. We included 627 RTR (age 53 ± 13 years). EPA-DHA intake was 102 (42-215) mg/day. During median follow-up of 5.4 years, 130 (21%) RTR died, with 52 (8.3%) due to CV causes. EPA-DHA intake was associated with lower risk of all-cause mortality (Hazard Ratio (HR) 0.85; 95% confidence interval (95% CI) 0.75-0.97). Age (p= 0.03) and smoking status (p = 0.01) significantly modified this association, with lower risk of all-cause and CV mortality particularly in older (HR 0.75, 95% CI 0.61-0.92; HR 0.68, 95% CI 0.48-0.95) and non-smoking RTR (HR 0.80, 95% CI 0.68-0.93; HR 0.74, 95% CI 0.56-0.98). In conclusion, marine-derived n-3 PUFA intake is inversely associated with risk of all-cause and CV mortality in RTR. The strongest associations were present in subgroups of patients, which adds further evidence to the plea for EPA-DHA supplementation, particularly in elderly and non-smoking RTR.