Plasma fatty acid responses to a calorie-restricted, DASH-style diet with lean beef.

BACKGROUND: Plasma fatty acid (FA) levels are used as biomarkers of health outcomes and nutritional intake. METHODS: This was an exploratory analysis of the plasma FA profile from a parallel-designed, controlled-feeding study in older, obese adults (females, n = 17; males, n = 11) consuming a DASH-based diet with two levels of lean beef (3oz and 6oz per day). Plasma FA levels (as percent composition) were measured by gas chromatography from five timepoints over the 12-week intervention. The primary plasma FA change patterns modeled were sustained (initial change to 'new normal') or homeostatic (initial change, then return toward original baseline). RESULTS: The study diet was low in fat (< 60 g/d), especially polyunsaturated FAs (PUFAs; < 5 g/d), compared to the average American diet of obese individuals as described by a nationally representative sample. Participants lost ∼6% of body mass and lowered plasma fasting triglyceride levels by ∼9% over the course of the study. With strong to very strong strength of evidence, the individual FAs displaying a sustained response were C16:1n7t, C18:1n9, C20:1n9, and C18:2n6, and homeostatic response, C18:0, 24:0, C24:1n9, C18:3n6, C20:4n6, and C22:6n3 (Ps < 0.0021, Bonferroni-adjusted). The data suggested that systematic changes in both the PUFA and de novo lipogenesis pathways occurred. CONCLUSIONS: Diet can affect plasma FA changes both due to nutritional composition and by affecting metabolic processes.

Harmonizing blood DHA levels in pregnancy studies: An interlaboratory investigation.

Recent trials in pregnant women on the effects of supplemental DHA on early preterm birth (ePTB) risk have shown that there is a maternal blood docosahexaenoic acid (DHA) level below which risk for ePTB was increased and supplemental DHA was effective at reducing risk. However, DHA levels were expressed in different terms across these trials making cross study comparisons impossible. The purposes of this study were 1) to report interlaboratory conversion factors from study-specific metrics to a common metric, red blood cell (RBC) DHA measured by OmegaQuant Analytics (OQA), and 2) to translate reported pre- and post-treatment DHA levels from these trials into a RBC DHA for comparison. Data from five published and one unpublished study are included. Across these studies, the effects on RBC DHA levels after supplementation with 0, 200, 600, 800 and 1000 mg of DHA were (as a% change from baseline): 0 mg, no change; 200 mg, 15-20% increase; 600 mg, 55-60% increase; 800 mg, 13-65% increase; and 1000 mg, 51% increase. Standardization of fatty acid analysis and reporting and a target omega-3 or DHA level for identifying those for which higher dose DHA supplementation is indicated to prevent ePTB are needed for clinical use.

Baseline red blood cell and breast milk DHA levels affect responses to standard dose of DHA in lactating women on a controlled feeding diet.

BACKGROUND: The importance of providing the newborn infant with docosahexaenoic acid (DHA) from breast milk is well established. However, women in the United States, on average, have breast milk DHA levels of 0.20%, which is below the worldwide average (and proposed target) of >0.32%. Additionally, the relationship between maternal red blood cell (RBC) and breast milk DHA levels may provide insight into the sufficiency of DHA recommendations during lactation. Whether the standard recommendation of at least 200 mg/day of supplemental DHA during lactation is sufficient for most women to achieve a desirable RBC and breast milk DHA status is unknown. METHODS: Lactating women (n = 27) at about 5 weeks postpartum were enrolled in a 10-12 week controlled feeding study that included randomization to 480 or 930 mg choline/d (diet plus supplementation). As part of the intervention, all participants were required to consume a 200 mg/d of microalgal DHA. RBC and breast milk DHA levels were measured by capillary gas chromatography in an exploratory analysis. RESULTS: Median RBC DHA was 5.0% (95% CI: 4.3, 5.5) at baseline and 5.1% (4.6, 5.4) after 10 weeks of supplementation (P = 0.6). DHA as a percent of breast milk fatty acids increased from 0.19% (0.18, 0.33) to 0.34% (0.27, 0.38) after supplementation (P<0.05). The proportion of women meeting the target RBC DHA level of >5% was unchanged (52% at baseline and week 10). The proportion of women achieving a breast milk DHA level of >0.32% approximately doubled from 30% to 56% (p = 0.06). Baseline RBC and breast milk DHA levels affected their responses to supplementation. Those with baseline RBC and breast milk DHA levels above the median (5% and 0.19%, respectively) experienced no change or a slight decrease in levels, while those below the median had a significant increase. Choline supplementation did not significantly influence final RBC or breast milk DHA levels. CONCLUSIONS: On average, the standard prenatal DHA dose of 200 mg/d did not increase RBC DHA but did increase breastmilk DHA over 10 weeks in a cohort of lactating women in a controlled-feeding study. Baseline DHA levels in RBC and breast milk affected the response to DHA supplementation, with lower levels being associated with a greater increase and higher levels with no change or a slight decrease. Additional larger, dose-response DHA trials accounting for usual intakes and baseline DHA status are needed to determine how to best achieve target breast milk DHA levels and to identify additional modifiers of the variable breast milk DHA response to maternal DHA supplementation.

Parallel declines in erythrocyte trans fatty acids and US fatal ischemic heart disease rates.

Ischemic heart disease (IHD) is a leading cause of mortality in the United States. There is substantial evidence that a sustained intake of industrially-produced trans fatty acids (IP-TFA) is associated with increased risk of fatal IHD. This has led many regulatory agencies to pressure dietary oil producers to remove IP-TFA from their products. That this has resulted in lower blood levels of IP-TFA in the United States is clear, but whether this has been accompanied by a reduction in the incidence of fatal IHD is unknown. To test the hypothesis that declining IP-TFA levels are associated with declining rates of fatal IHD, we compared the IP-TFA levels in red blood cells (RBC) analyzed in our laboratory between 2009 and 2016 (n = 53 194) with yearly US-specific IHD mortality rates. We found that decreasing RBC IP-TFA levels were strongly correlated with decreasing rates of fatal IHD (R2 = 0.9552, P < .0001). Recognizing the limitations of observational studies in addressing causation questions, our findings nevertheless support our hypothesis and suggest that efforts to remove IP-TFA from the food supply in the United States may be having the desired effect.

Recent Clinical Trials Shed New Light on the Cardiovascular Benefits of Omega-3 Fatty Acids.

Three recent clinical trials have demonstrated the benefits of marine omega-3 fatty acids on cardiovascular disease end points. In the Vitamin D and Omega-3 Trial (VITAL), 840 mg/d of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) resulted in a 28% reduced risk for heart attacks, 50% reduced risk for fatal heart attacks, and 17% reduced risk for total coronary heart disease events. In the ASCEND trial (A Study of Cardiovascular Events in Diabetes), cardiovascular disease death was significantly reduced by 19% with 840 mg/d of EPA and DHA. However, the primary composite end points were not significantly reduced in either study. In REDUCE-IT (the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial), there was a 25% decrease in the primary end point of major cardiovascular events with 4 g/d EPA (icosapent ethyl) in patients with elevated triglycerides (135-499 mg/dL) who also were taking a statin drug. For clinical practice, we now have compelling evidence of the cardiovascular benefits of omega-3 fatty acids. The findings of REDUCE-IT provide a strong rationale for prescribing icosapent ethyl for patients with hypertriglyceridemia who are on a statin. For primary prevention, the goal is to increase the population intake of omega-3 fatty acids to levels currently recommended, which translates to consuming at least one to two servings of fish/seafood per week. For individuals who prefer taking omega-3 fatty acid supplements, recent findings from clinical trials support the benefits for primary prevention.

Predicting the effects of supplemental EPA and DHA on the omega-3 index.

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.

Comparing the serum TAG response to high-dose supplementation of either DHA or EPA among individuals with increased cardiovascular risk: the ComparED study.

Studies have shown that the reduction in serum TAG concentrations with long-chain n-3 fatty acid supplementation is highly variable among individuals. The objectives of the present study were to compare the proportions of individuals whose TAG concentrations lowered after high-dose DHA and EPA, and to identify the predictors of response to both modalities. In a double-blind, controlled, crossover study, 154 men and women were randomised to three supplemented phases of 10 weeks each: (1) 2·7 g/d of DHA, (2) 2·7 g/d of EPA and (3) 3 g/d of maize oil, separated by 9-week washouts. As secondary analyses, the mean intra-individual variation in TAG was calculated using the standard deviation from the mean of four off-treatment samples. The response remained within the intra-individual variation (±0·25 mmol/l) in 47 and 57 % of participants after DHA and EPA, respectively. Although there was a greater proportion of participants with a reduction >0·25 mmol/l after DHA than after EPA (45 υ. 32 %; P 0·25 mmol/l after both DHA and EPA had higher non-HDL-cholesterol, TAG and insulin concentrations compared with other responders at baseline (all P < 0·05). In conclusion, supplementation with 2·7 g/d DHA or EPA had no meaningful effect on TAG concentrations in a large proportion of individuals with normal mean TAG concentrations at baseline. Although DHA lowered TAG in a greater proportion of individuals compared with EPA, the magnitude of TAG lowering among them was similar.

Supplementation with high-dose docosahexaenoic acid increases the Omega-3 Index more than high-dose eicosapentaenoic acid.

BACKGROUND: Recent studies suggest that eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids have distinct effects on cardiometabolic risk factors. The Omega-3 Index (O3I), which is calculated as the proportion of EPA and DHA in red blood cell (RBC) membranes, has been inversely associated with the risk of coronary heart diseases and coronary mortality. The objective of this study was to compare the effects of EPA and DHA supplementation on the O3I in men and women with abdominal obesity and subclinical inflammation. METHODS: In a double-blind controlled crossover study, 48 men and 106 women with abdominal obesity and subclinical inflammation were randomized to a sequence of three treatment phases: 1-2.7g/d of EPA, 2-2.7g/d of DHA, and 3-3g/d of corn oil (0g of EPA+DHA). All supplements were provided as 3×1g capsules for a total of 3g/d. The 10-week treatment phases were separated by nine-week washouts. RBC membrane fatty acid composition and O3I were assessed at baseline and the end of each phase. Differences in O3I between treatments were assessed using mixed models for repeated measures. RESULTS: The increase in the O3I after supplementation with DHA (+5.6% compared with control, P<0.0001) was significantly greater than after EPA (+3.3% compared with control, P<0.0001; DHA vs. EPA, P<0.0001). Compared to control, DHA supplementation decreased (-0.8%, P<0.0001) while EPA increased (+2.5%, P<0.0001) proportion of docosapentaenoic acid (DPA) in RBCs (DHA vs. EPA, P<0.0001). The baseline O3I was higher in women than in men (6.3% vs. 5.8%, P=0.011). The difference between DHA and EPA in increasing the O3I tended to be higher in men than in women (+2.6% vs. +2.2% respectively, P for the treatment by sex interaction=0.0537). CONCLUSIONS: 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.

Human Milk Fatty Acid Composition: Comparison of Novel Dried Milk Spot Versus Standard Liquid Extraction Methods.

Accurate assessment of the long chain polyunsaturated fatty acid (LC-PUFA) content of human milk (HM) provides a powerful means to evaluate the FA nutrient status of breastfed infants. The conventional standard for FA composition analysis of HM is liquid extraction, trans-methylation, and analyte detection resolved by gas chromatography. This standard approach requires fresh or frozen samples, storage in deep freeze, organic solvents, and specialized equipment in processing and analysis. Further, HM collection is often impractical for many studies in the free living environment, particularly for studies in developing countries. In the present study, we compare a novel and more practical approach to sample collection and processing that involves the spotting and drying ~50 µL of HM on a specialized paper stored and transported at ambient temperatures until analysis. Deming regression indicated the two methods aligned very well for all LC-PUFA and the abundant HM FA. Additionally, strong correlations (r > 0.85) were observed for DHA, ARA, EPA, linoleic (LA), and alpha-linolenic acids (ALA), which are of particular interest to the health of the developing infant. Taken together, our data suggest this more practical and inexpensive method of collection, storage, and transport of HM milk samples could dramatically facilitate studies of HM, as well as understanding its lipid composition influences on human health and development.

Analysis of breast milk fatty acid composition using dried milk samples.

BACKGROUND: The 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). RESULTS: Both % DHA and % iTFA levels in liquid and DMS samples were strongly correlated (R(2) = 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. CONCLUSIONS: Valid 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.

Should there be a target level of docosahexaenoic acid in breast milk?

PURPOSE OF REVIEW: This article examines the evidence for and against establishing a target level of docosahexaenoic acid (DHA) in breast milk. RECENT FINDINGS: Two target levels for milk DHA have been recently proposed. One (∼0.3% of milk fatty acids) was based on milk DHA levels achieved in women consuming the amount of DHA recommended by the American Academy of Pediatrics for pregnant and lactating women (at least 200 mg DHA/day). Another (∼1.0%) was based on biomarker studies of populations with differing lifelong intakes of fish. Populations or research cohorts with milk DHA levels of 1.0% are associated with intakes that allow both the mother and infant to maintain relatively high DHA levels throughout lactation. Lower milk DHA levels may signal suboptimal maternal stores and possibly suboptimal infant intakes. SUMMARY: Based on the current data, a reasonable milk DHA target appears to be approximately 0.3%, which is about the worldwide average. Although this may not be the 'optimal' level (which remains to be defined), it is clearly an improvement over the currently low milk DHA levels (∼0.2%) seen in many Western populations.

Breast milk DHA levels may increase after informing women: a community-based cohort study from South Dakota USA.

BACKGROUND: Docosahexaenoic 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. METHODS: New 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. RESULTS: At 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). CONCLUSIONS: Findings suggest that providing nursing mothers with their breast milk DHA level and education about DHA intake while breastfeeding motivates change to increase DHA levels.

Higher Intake of PUFAs Is Associated with Lower Total and Visceral Adiposity and Higher Lean Mass in a Racially Diverse Sample of Children.

BACKGROUND: Polyunsaturated fatty acids (PUFAs) are associated with protection from obesity-related phenotypes in adults; however, the relation between reported intake of PUFAs with body-composition outcomes in children remains unknown. OBJECTIVE: Our objective was to examine how self-reported intakes of PUFAs, including total, n-6 (ω-6), and n-3 (ω-3) PUFAs and ratios of n-6 to n-3 PUFAs and PUFAs to saturated fatty acids (SFAs), are associated with measures of adiposity and lean mass (LM) in children. We hypothesized that higher self-reported intakes of PUFAs and the ratio of PUFAs to SFAs would be positively associated with LM and negatively associated with total adiposity. METHODS: Body composition and dietary intake were measured in a racially diverse sample of 311 children (39% European American, 34% African American, and 27% Hispanic American) aged 7-12 y. Body composition and abdominal fat distribution were measured by dual-energy X-ray absorptiometry and computed tomography scans, respectively. Self-reported dietary intakes (including total PUFAs, n-3 PUFAs, n-6 PUFAs, and SFAs) were assessed by using two 24-h recalls. Independent-sample t tests and multiple linear regression analyses were conducted. RESULTS: Total PUFA intake was positively associated with LM (P = 0.049) and negatively associated with percentage of body fat (%BF; P = 0.033) and intra-abdominal adipose tissue (IAAT; P = 0.022). A higher ratio of PUFAs to SFAs was associated with higher LM (P = 0.030) and lower %BF (P = 0.028) and IAAT (P = 0.048). Intakes of n-3 and n-6 PUFAs were positively associated with LM (P = 0.017 and P = 0.021, respectively), and the ratio of n-6 to n-3 PUFAs was negatively associated with IAAT (P = 0.014). All results were independent of biological, environmental, and genetic covariates. CONCLUSIONS: Our results show that a higher self-reported intake of PUFAs and a higher ratio of PUFAs to SFAs are positively associated with LM and negatively associated with visceral adiposity and %BF in a healthy cohort of racially diverse children aged 7-12 y. This trial was registered at clinicaltrials.gov as NCT00726778.