Growth, tolerance, and DHA and ARA status of healthy term infants receiving formula with two different ARA concentrations: Double-blind, randomized, controlled trial.

Circulating docosahexaenoic acid (DHA) and arachidonic acid (ARA) in total red blood cells (RBC) are considered indicators of fatty acid status. In this study, healthy term infants received study formula through 120 days of age. All study formulas had 17 mg DHA/100 kcal. Investigational formulas had 1) 25 g ARA/100 kcal and no added prebiotic blend (ARA-25; n = 29) or 2) 34 mg ARA/100 kcal and a prebiotic blend (1:1 ratio; 4 g/L) of polydextrose and galactooligosaccharides (PDX/GOS; n = 20). The control formula had 34 mg ARA/100 kcal and no added prebiotic blend (Control: n = 31). Fatty acids in total RBCs and plasma phospholipids (PPLs) at 120 days and buccal epithelial PLs at 14 and 120 days of age were assessed by capillary column gas chromatography. The calculated 90% confidence interval (CI) of each investigational formula relative to the Control for total RBC ARA (ARA-25: 93-105%; PDX/GOS: 96-110%) and total RBC DHA (ARA-25: 95-113%; PDX/GOS: 94-113%) fell within the pre-specified equivalence limit (85-118%), establishing study formula equivalence with respect to ARA and DHA. At day 120, total RBC and buccal epithelia PL ARA (µg/ml) were not significantly correlated (r = 0.041; p = 0.732); correlation in total RBC and buccal epithelia PL DHA was low, albeit significant (r = 0.324; p = 0.006). Consequently, buccal epithelial may not provide a suitable substitute for RBC when assessing fatty acid status and availability. The present RBC data suggest availability of DHA for central nervous system development and function is equivalent among infants receiving formulas that had 34 or 25 mg/100 kcal ARA and 17 mg/100 kcal DHA.

Assessment of blood measures of n-3 polyunsaturated fatty acids with acute fish oil supplementation and washout in men and women.

Changes in n-3 highly unsaturated fatty acids (HUFA, > or =20 carbons and > or =3 carbon-carbon double bonds) at baseline, during fish oil supplementation (4 weeks) and during washout (8 weeks) were compared in venous plasma, erythrocytes, whole blood and fingertip prick blood (weeks 0, 4, 8 and 12) with additional weekly fingertip prick samples. Correlations between the various blood fractions were slightly stronger when n-3 HUFA status was expressed as the percentage of n-3 HUFA in total HUFA as compared with the sum of EPA and DHA. Increases and decreases in n-3 HUFA were more dramatic in plasma, and EPA responded rapidly (within 1 week) with fish oil supplementation and cessation. Sex differences in the proportions of n-3 HUFA in blood were also apparent at baseline with females (n=7) having a tendency for higher docosahexaenoic acid (DHA, 22:6n-3) relative to eicosapentaenoic acid (EPA, 20:5n-3) and n-3 docosapentaenoic acid (DPAn-3, 22:5n-3) as compared with males (n=9). Further n-3 biomarker research in larger populations is required.