Background Supplemental long-chain omega-3 (n–3) fatty acids (EPA and DHA) raise erythrocyte EPA + DHA [omega-3 index (O3I)] concentrations, but the magnitude or variability of this effect is unclear. Objective The purpose of this study was to model the effects of supplemental EPA + DHA on the O3I. Methods Deidentified data from 1422 individuals from 14 published n–3 intervention trials were included. Variables considered included dose, baseline O3I, sex, age, weight, height, chemical form [ethyl ester (EE) compared with triglyceride (TG)], and duration of treatment. The O3I was measured by the same method in all included studies. Variables were selected by stepwise regression using the Bayesian information criterion. Results Individuals supplemented with EPA + DHA (n = 846) took a mean ± SD of 1983 ± 1297 mg/d, and the placebo controls (n = 576) took none. The mean duration of supplementation was 13.6 ± 6.0 wk. The O3I increased from 4.9% ± 1.7% to 8.1% ± 2.7% in the supplemented individuals ( P < 0.0001). The final model included dose, baseline O3I, and chemical formulation type (EE or TG), and these explained 62% of the variance in response (P < 0.0001). The model predicted that the final O3I (and 95% CI) for a population like this, with a baseline concentration of 4.9%, given 850 mg/d of EPA + DHA EE would be ∼6.5% (95% CI: 6.3%, 6.7%). Gram for gram, TG-based supplements increased the O3I by about 1 percentage point more than EE products. Conclusions Of the factors tested, only baseline O3I, dose, and chemical formulation were significant predictors of O3I response to supplementation. The model developed here can be used by researchers to help estimate the O3I response to a given EPA + DHA dose and chemical form.

BackgroundThe effect of breast milk fatty acid (FA) composition, particularly levels of docosahexaenoic acid (DHA), on infant health outcomes is unclear. Part of the reason for this is difficulties in collecting, storing and shipping milk samples to the laboratory. Here we report the validation of a dried milk spot (DMS) system to measure FA composition to help overcome these obstacles.Milk FA were measured by gas chromatography and reported as percent of total FA; the FA of primary interest in this study were DHA and industrially produced trans FA (iTFA). Experiments were carried out using pooled milk samples from US (n = 5) and Malawian women (n = 50). Experiments compared liquid vs. DMS samples (n = 55), assessed stability of FA composition under different storage conditions (n = 5), and compared the results from two different labs using the same methods (n = 5).ResultsBoth % DHA and % iTFA levels in liquid and DMS samples were strongly correlated (R2 = 0.99 and 0.99, respectively, P < 0.0001). The % DHA in DMS samples was stable for up to four weeks at room temperature and up to three years at -80 °C; only slight deviations from the acceptable range of variability (±15 %) occurred in the 4 °C and -20 °C conditions for % DHA. The % iTFA was stable under all conditions. All % DHA and % iTFA were within 15 % of the referent when analyzed in two laboratories.ConclusionsValid FA composition values can be obtained from DMS samples using this robust collection and transport system which should facilitate studies of the role of milk FA composition in infant development.Electronic supplementary materialThe online version of this article (doi:10.1186/s13006-016-0060-2) contains supplementary material, which is available to authorized users.

The increase in the O3I is greater with high dose DHA supplementation than with high dose EPA, which is consistent with the greater potency of DHA to modulate cardiometabolic risk factors. The extent to which such differences between EPA and DHA in increasing the O3I relates to long-term cardiovascular risk needs to be investigated in the future.

BackgroundDocosahexaenoic acid (DHA), an omega-3 fatty acid found in breast milk, has many health benefits for both mother and baby. A 2007 meta-analysis found U.S. women had breast milk DHA levels (0.20% of total fatty acids) below the worldwide mean (0.32%). In 2008, international dietary recommendations were made for pregnant and lactating women to consume 200 mg of DHA per day. This community-based study aimed to define current milk DHA levels from upper Midwest USA lactating mothers and to determine if providing information about their own level along with dietary recommendations would incite changes to increase breast milk DHA content.MethodsNew mothers attending lactation classes or using hospital pumping rooms in Sioux Falls, South Dakota, USA participated by providing one drop of breast milk on a card for fatty acid analysis at baseline and 1 month after initial reporting. DHA levels were analyzed by gas chromatography. Mothers received a report of their own breast milk level along with dietary recommendations on DHA intake for lactating women. Median baseline and follow-up DHA levels were determined and differences were compared by Wilcoxon signed-rank test.ResultsAt baseline, breast milk DHA content (n = 84) was highly variable (range 0.05 to 0.73%) with a median of 0.18% (IQR, 0.13, 0.28; mean ± SD, 0.22 ± 0.13%), well below the worldwide average (0.32%). Women who reported taking DHA supplements (n = 43) had higher levels than those who did not (0.23% vs. 0.15%, P < 0.0001). In a subset of 60 mothers who submitted a second sample, median breast milk DHA content increased from 0.19 to 0.22% (P < 0.01).ConclusionsFindings suggest that providing nursing mothers with their breast milk DHA level and education about DHA intake while breastfeeding motivates change to increase DHA levels.Electronic supplementary materialThe online version of this article (doi:10.1186/s13006-016-0099-0) contains supplementary material, which is available to authorized users.

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