Red Blood Cell Docosahexaenoic Acid Levels Research Articles

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 Data from five published and one unpublished study are included.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

BackgroundThe 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. MethodsLactating 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. ResultsMedian 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. ConclusionsOn 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.

Verbal Memory Performance in Depressed Children and Adolescents: Associations with EPA but Not DHA and Depression Severity.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been described as positively associated with cognitive functioning. Current meta-analyses have identified eicosapentaenoic acid (EPA) as potentially more effective than docosahexaenoic acid (DHA). An especially vulnerable subgroup that might benefit from these beneficial effects are depressed youths. In this study, we examined associations between red blood cell (RBC) DHA and EPA levels and depression severity and verbal memory performance in a sample of 107 moderately (n = 63) and severely (n = 44) depressed youths. The findings showed that youths with high RBC EPA levels had steeper learning curves compared to those with moderate or low RBC EPA levels (Pillai’s Trace = 0.195, p = 0.027, ηp2 = 0.097). No associations between RBC DHA levels or depression severity and verbal memory performance were observed. Our results further confirm previous findings indicating a more important role of EPA compared to DHA in relation to cognitive functioning. Future research should further investigate the differential role of EPA and DHA concerning cognitive functioning in depressed youths. Evidence supporting beneficial supplementation effects could potentially establish a recommendation for a natural and easily accessible intervention for cognitive improvement or remission.

Multiple Micronutrients and Docosahexaenoic Acid Supplementation during Pregnancy: A Randomized Controlled Study.

Maternal dietary intake during pregnancy needs to meet increased nutritional demands to maintain metabolism and to support fetal development. Docosahexaenoic acid (DHA) is essential for fetal neuro-/visual development and in immunomodulation, accumulating rapidly within the developing brain and central nervous system. Levels available to the fetus are governed by the maternal diet. In this multicenter, parallel, randomized controlled trial, we evaluated once-daily supplementation with multiple micronutrients and DHA (i.e., multiple micronutrient supplementation, MMS) on maternal biomarkers and infant anthropometric parameters during the second and third trimesters of pregnancy compared with no supplementation. Primary efficacy endpoint: change in maternal red blood cell (RBC) DHA (wt% total fatty acids) during the study. Secondary variables: other biomarkers of fatty acid and oxidative status, vitamin D, and infant anthropometric parameters at delivery. Supplementation significantly increased RBC DHA levels, the omega-3 index, and vitamin D levels. Subscapular skinfold thickness was significantly greater with MMS in infants. Safety outcomes were comparable between groups. This first randomized controlled trial of supplementation with multiple micronutrients and DHA in pregnant women indicated that MMS significantly improved maternal DHA and vitamin D status in an industrialized setting—an important finding considering the essential roles of DHA and vitamin D.

Growth and Tolerability of Healthy Term Infants Fed a New Formula Supplemented with DHA from Schizochytrium sp Microalgae

Objective: To evaluate growth and tolerability of infants fed a formula supplemented with docosahexaenoic acid (DHA) from a new strain of Schizochytrium sp (DHASCO®-B) microalgae. Methods: Healthy term infants (n=159) with weights ≥2500 gram were randomized on or before 14th day of life (DOL) to receive either DHASCO®-B or reference formula (DHASCO®) obtained from Crypthecodinium cohnii until DOL 120. Both formulas also contained arachidonic acid (ARA). Assessments included weight, length, weight/length ratio, head circumference, red blood cell (RBC) DHA and other fatty acids, metabolic panel, safety, and tolerance. Results: The rate of mean daily weight gain (±SD) at DOL 120 was not significantly different between the formulas, 29.1 ± 5.92 grams/day versus 29.9 ± 7.40 grams/day for DHASCO® and DHASCO®-B, respectively and was equivalent (90% CI: -2.94 to 1.31; p=0.553). There was no significant difference between formulas in actual weight gain over time, i.e. DOL 30, 60, 90 and 120 (p=0.252), including by gender. Other anthropometric variables were also not different between the 2 groups. RBC DHA levels at DOL 120 were bioequivalent between the formulas (ratio of geometric means was 96.85%). There was no difference between formulas in any of the tolerance variables (watery stools, hard stools, gassiness, spitting up and fussiness), and no clinically meaningful difference in adverse events or laboratory values. Conclusions: There was no significant difference in daily weight gain of healthy term infants fed a formula supplemented with DHA from Crypthecodinium cohnii versus the new strain of Schizochytrium sp microalgae. Overall weight gains were equivalent between the two formula groups. Further, RBC DHA levels were bioequivalent, and there was no difference in infant tolerability or parent satisfaction. In summary, growth, tolerability and safety profiles for the formulas were similar and typical for this age group.

Effect of docosahexaenoic acid supplementation on inflammatory cytokine levels in infants at high genetic risk for type 1 diabetes.

Type 1 diabetes (T1D) results from the inflammatory destruction of pancreatic β-cells. In this study, we investigated the effect of docosahexaenoic acid (DHA) supplementation on stimulated inflammatory cytokine production in white blood cells (WBC) from infants with a high genetic risk for T1D. This was a multicenter, two-arm, randomized, double-blind pilot trial of DHA supplementation, beginning either in the last trimester of pregnancy (41 infants) or in the first 5 months after birth (57 infants). Levels of DHA in infant and maternal red blood cell (RBC) membranes and in breast milk were analyzed by gas chromatography/mass spectrometry. Inflammatory cytokines were assayed from whole blood culture supernatants using the Luminex multiplex assay after stimulation with high dose lipopolysaccharide (LPS), 1 µg/mL. The levels of RBC DHA were increased by 61-100% in treated compared to control infants at ages 6-36 months. There were no statistically significant reductions in production of the inflammatory cytokines, IL-1β, TNFα, or IL-12p40 at any of the six timepoints measured. The inflammatory marker, high-sensitivity C-reactive protein (hsCRP), was significantly lower in breast-fed DHA-treated infants compared to all formula-fed infants at the age of 12 months. Three infants (two received DHA) were removed from the study as a result of developing ≥two persistently positive biochemical islet autoantibodies. This pilot trial showed that supplementation of infant diets with DHA is safe and fulfilled the pre-study goal of increasing infant RBC DHA levels by at least 20%. Inflammatory cytokine production was not consistently reduced.

Four-Year Placebo-Controlled Trial of Docosahexaenoic Acid in X-Linked Retinitis Pigmentosa (DHAX Trial)

X-linked retinitis pigmentosa is a severe inherited retinal degenerative disease with a frequency of 1 in 100,000 persons. Because no cure is available for this orphan disease and treatment options are limited, slowing of disease progression would be a meaningful outcome. To determine whether high-dose docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid, slows progression of X-linked retinitis pigmentosa measured by cone electroretinography (ERG). A 4-year, single-site, randomized, placebo-controlled, double-masked phase 2 clinical trial at a research center specializing in medical retina. Seventy-eight male patients diagnosed as having X-linked retinitis pigmentosa were randomized to DHA or placebo. Data were omitted for 2 patients with non-X-linked retinitis pigmentosa and 16 patients who were unable to follow protocol during the first year. The remaining participants were tested annually and composed a modified intent-to-treat cohort (DHA group, n = 33; placebo group, n = 27). All participants received a multivitamin and were randomly assigned to oral DHA (30 mg/kg/d) or placebo. The primary outcome was the rate of loss of cone ERG function. Secondary outcomes were rod and maximal ERG amplitudes and cone ERG implicit times. Capsule counts and red blood cell DHA levels were assessed to monitor adherence. Average (6-month to 4-year) red blood cell DHA levels were 4-fold higher in the DHA group than in the placebo group (P < .001). There was no difference between the DHA and placebo groups in the rate of cone ERG functional loss (0.028 vs 0.022 log µV/y, respectively; P = .30). No group differences were evident for change in rod ERG (P = .27), maximal ERG (P = .65), or cone implicit time (no change over 4 years). The rate of cone loss (ie, event rate) was markedly reduced compared with rates in previous studies. No severe treatment-emergent adverse events were found. Long-term DHA supplementation was not effective in slowing the loss of cone or rod ERG function associated with X-linked retinitis pigmentosa. Participant dropout and lower-than-expected disease event rate limited power to detect statistical significance. A larger sample size, longer trial, and attainment of a target blood DHA level (13%) would be desirable. While DHA supplementation at 30 mg/kg/d does not present serious adverse effects, routine monitoring of gastrointestinal tolerance is prudent. clinicaltrials.gov Identifier: NCT00100230.

Unexpected similarity in RBC DHA and AA levels between bottlenose dolphins and humans

BackgroundThe Omega-3 Index [red blood cell (RBC) content of eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA)] is inversely related to risk of cardiovascular disease in humans. In the U.S., the average Omega-3 Index is about 4–6% of RBC fatty acids, whereas in Japan it is 9–10%. The range of physiologically-possible levels for the Omega-3 Index in other mammals is unknown. ObjectiveTo compare the RBC fatty acid composition of a common piscivorous mammal, the bottlenose dolphin (Tursiops truncatus), with that of (U.S.) humans, and to examine the extent to which dietary fatty acid patterns were reflected in RBCs. MethodsRBCs were isolated from routine blood samples collected from 35 healthy dolphins at two display facilities and were analyzed by gas chromatography. For humans, historic, deidentified RBC fatty acid data from our laboratory were used (n=11,329; mean age 58). ResultsThe mean Omega-3 Index of the dolphins was 19.9% compared with 6.0% for humans. EPA levels were 15.3% vs 1.2%, respectively, but DHA levels were virtually identical (4.6% vs 4.8%). Linoleic acid (LNA) levels were much lower in dolphins vs humans (0.5% vs 12.5%) whereas arachidonic acid (ARA) levels were similar (12.3% vs 14.5%). In a subgroup of humans with an Omega-3 Index in the >99.2 percentile, the mean index was similar to that of the dolphins. Based on an analysis of their food, the dolphins consumed about 60g of EPA+DHA per day as compared to about 0.1g in humans. ConclusionDolphins have an Omega-3 Index that is (only) 3–4× higher than that of U.S. adults despite their intake of EPA+DHA being about 165× higher (as a percent of kcal). RBC, EPA and LNA levels are relatively more reflective of dietary intakes than are DHA and ARA levels. The mechanisms by which certain fatty acid levels appear to be fixed and others may vary in RBC membranes are unknown.

U-shaped relationship between tissue docosahexaenoic acid and atrial fibrillation following cardiac surgery

Randomised controlled trials (RCTs) evaluating the effect of fish oil supplementation on postoperative atrial fibrillation (POAF) following cardiac surgery have produced mixed results. In this study, we examined relationships between levels of red blood cell (RBC) n-3 long-chain polyunsaturated fatty acids (LC-PUFAs) and the incidence of POAF. We used combined data (n=355) from RCTs conducted in Australia and Iceland. The primary end point was defined as POAF lasting >10 min in the first 6 days following surgery. The odds ratios (ORs) for POAF were compared between quintiles of preoperative RBC n-3 LC-PUFA levels by multivariable logistic regression. Subjects with RBC docosahexaenoic acid (DHA) in the fourth quintile, comprising a RBC DHA range of 7.0-7.9%, had the lowest incidence of POAF. Subjects in the lowest and highest quintiles had significantly higher risk of developing POAF compared with those in the fourth quintile (OR=2.36: 95% CI; 1.07-5.24 and OR=2.45: 95% CI; 1.16-5.17, respectively). There was no association between RBC eicosapentaenoic acid levels and POAF incidence. The results suggest a 'U-shaped' relationship between RBC DHA levels and POAF incidence. The possibility of increased risk of POAF at high levels of DHA suggests an upper limit for n-3 LC-PUFAs in certain conditions.

Red blood cell omega-3 fatty acid levels and markers of accelerated brain aging

Higher dietary intake and circulating levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been related to a reduced risk for dementia, but the pathways underlying this association remain unclear. We examined the cross-sectional relation of red blood cell (RBC) fatty acid levels to subclinical imaging and cognitive markers of dementia risk in a middle-aged to elderly community-based cohort. We related RBC DHA and EPA levels in dementia-free Framingham Study participants (n = 1575; 854 women, age 67 ± 9 years) to performance on cognitive tests and to volumetric brain MRI, with serial adjustments for age, sex, and education (model A, primary model), additionally for APOE ε4 and plasma homocysteine (model B), and also for physical activity and body mass index (model C), or for traditional vascular risk factors (model D). Participants with RBC DHA levels in the lowest quartile (Q1) when compared to others (Q2-4) had lower total brain and greater white matter hyperintensity volumes (for model A: β ± SE = -0.49 ± 0.19; p = 0.009, and 0.12 ± 0.06; p = 0.049, respectively) with persistence of the association with total brain volume in multivariable analyses. Participants with lower DHA and ω-3 index (RBC DHA+EPA) levels (Q1 vs. Q2-4) also had lower scores on tests of visual memory (β ± SE = -0.47 ± 0.18; p = 0.008), executive function (β ± SE = -0.07 ± 0.03; p = 0.004), and abstract thinking (β ± SE = -0.52 ± 0.18; p = 0.004) in model A, the results remaining significant in all models. Lower RBC DHA levels are associated with smaller brain volumes and a "vascular" pattern of cognitive impairment even in persons free of clinical dementia.

Membrane Level of Omega-3 Docosahexaenoic Acid Is Associated with Severity of Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) are at increased risk of cardiovascular disease (CVD). The omega-3 fatty acid docosahexaenoic acid (DHA) is a major component of neural tissues, and supplementation with fish oils improves autonomic tone and reduces risk for CVD. A link between low DHA status and less mature sleep patterns was observed in newborns. We investigated the relations between red blood cell (RBC) levels of DHA and OSA severity in 350 sequential patients undergoing sleep studies. Severity categories were defined as none/mild, moderate, and severe, based on apnea hypopnea index (AHI) scores of 0 to 14, 15 to 34, and > 34, respectively. After controlling for age, sex, race, smoking, BMI, alcohol intake, fish intake, and omega-3 supplementation, RBC DHA was inversely related with OSA severity. For each 1-SD increase in DHA levels, a patient was about 50% less likely to be classified with severe OSA. The odds ratios (95% CI) were 0.47 (0.28 to 0.80) and 0.55 (0.31 to 0.99) for being in the severe group versus the none/mild or moderate groups, respectively. These findings suggest that disordered membrane fatty acid patterns may play a causal role in OSA and that the assessment of RBC DHA levels might help in the diagnosis of OSA. The effects of DHA supplementation on OSA should be explored.

Nutritional Biomarkers in Alzheimer's Disease: The Association between Carotenoids, n-3 Fatty Acids, and Dementia Severity

Carotenoids are fat-soluble antioxidants that may protect polyunsaturated fatty acids, such as n-3 fatty acids from oxidation, and are potentially important for Alzheimer's disease (AD) prevention and treatment. Fasting plasma carotenoids were measured in 36 AD subjects and 10 control subjects by HPLC. Correlations between plasma carotenoid levels, red blood cell (RBC) n-3 fatty acids, and dementia severity were examined in AD patients. Moderately severe AD patients (MMSE=16-19) had much lower plasma levels of two major carotenoids: lutein and beta-carotene, compared to mild AD patients (MMSE=24-27) or controls. Among AD patients, variables (lutein, beta-carotene, RBC docosahexaenoic acid (DHA) and LDL-cholesterol) were significantly correlated with MMSE. A lower MMSE score was associated with lower lutein, beta-carotene and RBC DHA levels, and a higher LDL-cholesterol level. These variables explained the majority of variation in dementia severity (55% of variance in MMSE). Lutein, beta-carotene and beta-cryptoxanthin were positively correlated with RBC DHA in AD patients. The association between higher carotenoids levels and DHA and higher MMSE scores, supports a protective role of both types of nutrients in AD. These findings suggest targeting multiple specific nutrients, lutein, beta-carotene, and DHA in strategies to slow the rate of cognitive decline.

Omega‐3 PUFA plasma and red blood cell status in chronic hemodialysis patients

Omega-3 (n-3) polyunsaturated fatty acid (PUFA) levels have been inversely associated with cardiovascular (CVD) mortality. Chronic hemodialysis patients (HP), who suffer from extremely high rates of CVD, may be at risk for inadequate n-3 consumption. This study was designed to determine n-3 status in a hemodialysis population by comparing their PUFA levels to those of a healthy control group. Fasting plasma and red blood cell (RBC) fatty acid levels were measured in 75 HP and 25 control subjects (CS). The HP were more likely to have diabetes mellitus (43% vs. 20%), hypertension (91% vs. 36%), and less formal education. CS had significantly higher levels of plasma eicosapentaenoic acid (EPA) (mean wt % ± SD) (0.42 ± 0.13 vs. 0.35 ± 0.32, p<0.001), docosahexaenoic acid (DHA) (1.51 ± 0.36 vs. 1.33 ± 0.38, p=0.03), long chain (LC) (2.44 ± 0.50 vs. 2.11 ± 0.56, p=0.005) and total (3.12 ± 0.49 vs. 2.76 ± 0.58, p=0.007)) n-3 levels. Though RBC EPA levels were not significantly different, HP had higher DHA levels (4.65 ± 0.92 vs. 3.16 ± 1.15, p<0.0001), LC (7.32 ± 1.05 vs. 5.07 ± 1.73, p<0.0001) and total n-3 (7.61 ± 1.21 vs. 5.20 ± 1.75, p<0.001). Plasma findings suggest that short-term fish consumption was greater in CS. The fact that RBC DHA levels and LC n-3 PUFA were higher in HP (while EPA levels were not different) raises the possibility that the uremic milieu upregulates the Sprecher pathway or reduces DHA retroconversion to EPA. The relatively modest amount of fish oil-associated n-3 PUFA (i.e. EPA + DHA) in HP suggest they may benefit from fish oil supplementation. This research was supported by the National Kidney Foundation of Indiana, Inc.

Different Levels of Docosahexaenoic Acid (DHA) in Formula Affect Red Blood Cell Dha Levels in Term Infants.

DHA is an important component of the brain. Red blood cell (RBC) DHA levels are thought to be related to brain DHA content and to visual acuity in infancy. The DHA content of the RBC of infants is determined by the DHA content of the feeding. To assess the effects of different levels of formula DHA on RBC DHA levels of infants, we conducted a multi-center, double-blind, prospective study. Infants were randomized to one of two infant formulas: Formula Higher DHA with DHA at 0.32% of total fatty acids, similar to worldwide mean levels found in breast milk, and Formula Lower DHA with DHA at 0.15% of total fatty acids, similar to lower levels typically found in breast milk in the USA. Infants were fed study formula from 14 through 120 days of age. Fatty acids in blood lipid fractions were analyzed by capillary gas chromatography at 120 days of age. The table summarizes DHA levels in total-RBC lipids, RBC-phosphatidylcholine (RBC-PC), RBC-phosphatidylethanolamine (RBC-PE), and plasma phospholipids (Plasma-PL) at 120 days (% of total fatty acids, Mean ± SE). Both formulas were well tolerated, and infants in both groups had similar growth. We conclude that infants fed formula containing higher levels of DHA have significantly higher circulating levels of DHA. We speculate that greater incorporation of DHA into brain and retinal tissues may result from higher circulating levels of RBC DHA. Fig. 1