Adipose tissue biomarkers of fatty acid intake.
BACKGROUND
Biomarkers can provide a more accurate measure of long-term intake than can dietary questionnaires.


OBJECTIVE
The objective was to identify which adipose tissue fatty acids are suitable biomarkers of intake as assessed with a validated food-frequency questionnaire.


METHODS
Costa Rican men with a mean (+/- SD) age of 56 +/- 11 y (n = 367) and women aged 60 +/- 10 y (n = 136) completed a 135-item food-frequency questionnaire and provided an adipose tissue sample. Fifty fatty acids were identified by capillary gas chromatography. Correlation coefficients were calculated after adjustment for age, sex, body mass index, and smoking status.


RESULTS
The best adipose tissue marker for total intake of saturated fatty acids was 15:0 + 17:0 (r = 0.18). Both 15:0 and 17:0 were also the best correlates of dairy product intake (r = 0.31 for each). The diet-adipose tissue correlations for n-3 fatty acids were r = 0.34 for 18:3, r = 0.15 for 20:5, and r = 0.18 for 22:6. Fish intake correlated significantly with these adipose tissue n-3 fatty acids. Dietary and adipose tissue n-6 fatty acids were highly correlated: 18:2 (r = 0.58) and 18:3 (r = 0.24). The best indicators of total trans fatty acid intake were ct18:2n-6 and tc18:2n-6 (r = 0.58 for each); total 18:1 trans fatty acid (r = 0.45) and 16:1 trans fatty acid (r = 0.16) were the next best indicators.


CONCLUSIONS
Adipose tissue is a suitable biomarker of dietary fatty acid intake, particularly for n-3 and n-6 cis polyunsaturated fatty acids and trans fatty acids. Ideally, adipose tissue and dietary questionnaires should complement, rather than substitute for, each other in epidemiologic studies.
D000273:Adipose Tissue / Q000737:chemistry*; D000368:Aged; D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D003364:Costa Rica; D003611:Dairy Products; D004032:Diet; D015930:Diet Records; D004041:Dietary Fats / Q000008:administration & dosage*; D002149:Energy Intake; D005227:Fatty Acids / Q000008:administration & dosage*; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000032:analysis; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000032:analysis; D005260:Female; D005399:Fishes; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000032:analysis
D015415:Biomarkers; D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid