Serum and adipose tissue fatty acid composition as biomarkers of habitual dietary fat intake in elderly men with chronic kidney disease.

BACKGROUND Fatty acid (FA) composition in serum cholesterol esters (CE) and adipose tissue (AT) reflect the long-term FA intake in the general population. Because both dietary intake and FA biomarkers associate with renal function, our aim was to identify which CE and AT FAs are useful biomarkers of habitual FA intake in individuals with chronic kidney disease (CKD). METHODS Cross-sectional analysis was performed in 506 men (aged 70 years) with a glomerular filtration rate (GFR) of <60 mL/min per 1.73 m(2) from the Uppsala Longitudinal Study of Adult Men cohort. Dietary habits were evaluated with a 7-day dietary record. FA compositions in CE and AT were analyzed by gas-liquid chromatography in two random subsamples of 248 and 318 individuals, respectively. RESULTS Both CE and AT linoleic acid and docosahexaenoic acid (DHA) were strongly associated with their corresponding intake, after adjustments for non-dietary factors. The proportions of eicosapentaenoic acid (EPA) and palmitic acid in CE and AT moderately correlated with dietary intake, whereas correlations of other FAs were weaker or absent. Proportions of EPA and DHA in CE and AT were positively associated with the total energy-adjusted fish intake. Results were confirmed in adequate reporters as identified by the Goldberg cutoff method. These relationships held constant, regardless of a GFR above or below 45 mL/min per 1.73 m(2) or the prevalence of microalbuminuria. CONCLUSIONS Proportions of EPA, DHA, palmitic and linoleic acid in serum CE and AT are good indicators of their dietary intake in men with CKD. They can be considered valid biomarkers for epidemiological studies and assessment of compliance.