Fasting Whole Blood as a Biomarker of Essential Fatty Acid Intake in Epidemiologic Studies: Comparison with Adipose Tissue and Plasma

Abstract

Biomarkers could provide a more accurate measure of long-term intake than questionnaires. Adipose tissue is considered the best indicator of long-term essential fatty acid intake, but other tissues may prove equally valid. The authors evaluated the ability of fasting whole blood, relative to fasting plasma and adipose tissue, to reflect fatty acid intake. Costa Rican men (n = 99) and women (n = 101) completed a 135-item food frequency questionnaire and provided adipose tissue and blood samples from 1999 to 2001. Fatty acids were identified by using capillary gas chromatography. Correlation coefficients adjusted for age, sex, and body mass index were calculated. Diet-tissue correlation coefficients for alpha-linolenic acid and linoleic acid, respectively, were 0.38 and 0.43 in whole blood, 0.51 and 0.52 in adipose tissue, and 0.39 and 0.41 in plasma. High correlations were observed between whole-blood alpha-linolenic and linoleic acid and adipose tissue (r = 0.59 and r = 0.67) and plasma (r = 0.96 and r = 0.88), respectively. Results show that fasting whole blood is a suitable biomarker of long-term essential fatty acid intake, and its performance is comparable to that of fasting plasma. Thus, fasting whole blood could be the sample of choice in epidemiologic studies because of its ability to predict intake, its accessibility, and minimum sample processing.

Plasma n-6 and n-3 polyunsaturated fatty acids as biomarkers of their dietary intakes: a cross-sectional study within a cohort of middle-aged French men and women

“…At variance, the plasma linoleic acid levels reach values (30-35% of fatty acids) comparable to those found in United Kingdom (Rosell et al, 2005), Norway (Andersen et al, 1999), Japan (Kuriki et al, 2002(Kuriki et al, , 2003 or Costa-Rica (Kuriki et al, 2003;Baylin et al, 2005), reflecting the high intakes of linoleic acid in most world countries (4-6% of energy) (Simopoulos, 2002). Plasma levels of long-chain n-3 PUFA in our sample are much higher than in populations eating no or little fish (Baylin et al, 2005;Rosell et al, 2005), similar to those found in Norway (Andersen et al, 1999), and lower than those found in countries with a high fish consumption such as Spain (Amiano et al, 2001) or Japan (Kuriki et al, 2002(Kuriki et al, , 2003. In Europe, the French rank among the higher fish and seafood consumers, after the Spanish and the Scandinavians (Welch et al, 2002).…”

“…Thus, the plasma level of a-linolenic acid in our sample (0.5-0.6%) is lower than that found in Japan (0.8-0.9%) (Kuriki et al, 2002(Kuriki et al, , 2003 or in United Kingdom (1.3-1.4%) (Rosell et al, 2005), reflecting the low a-linolenic acid intake of the French population (Astorg et al, 2004). At variance, the plasma linoleic acid levels reach values (30-35% of fatty acids) comparable to those found in United Kingdom (Rosell et al, 2005), Norway (Andersen et al, 1999), Japan (Kuriki et al, 2002(Kuriki et al, , 2003 or Costa-Rica (Kuriki et al, 2003;Baylin et al, 2005), reflecting the high intakes of linoleic acid in most world countries (4-6% of energy) (Simopoulos, 2002). Plasma levels of long-chain n-3 PUFA in our sample are much higher than in populations eating no or little fish (Baylin et al, 2005;Rosell et al, 2005), similar to those found in Norway (Andersen et al, 1999), and lower than those found in countries with a high fish consumption such as Spain (Amiano et al, 2001) or Japan (Kuriki et al, 2002(Kuriki et al, , 2003.…”

Adipose tissue arachidonic acid and the metabolic syndrome in Costa Rican adults

“…This finding is consistent with a recent study showing no correlation between dietary arachidonic acid and that in plasma, adipose or whole blood. 32 Thus, tissue differences in arachidonic acid between subjects are most likely attributable to individual differences in metabolism.…”

Evaluation of relative intake of fatty acids according to the Northern Sweden FFQ with fatty acid levels in erythrocyte membranes as biomarkers

“…This suggests 18 : 2n-6 and 18 : 3n-3 as suitable biomarkers, but transformation to longer fatty acids in the same fatty acid series (26) , or possible demand for targeted FFQ design, may weaken the associations. Previous studies on intake and content in biological tissues are also contradictory; only studies using targeted FFQ instruments have displayed significant correlations between intake and tissue contents (1,2,23,27) , while studies failing to find such associations employed FFQ designed to measure overall intakes (24,25,28) . Thus 18 : 2n-6 and 18 : 3n-3 levels in biological tissues, such as adipose tissue, erythrocyte membranes or plasma phospholipids, may reflect intake of these fatty acids, but a very carefully designed recording instrument seems to be a prerequisite to estimate intake sufficiently well.…”