Red blood cell fatty acid patterns from 7 countries: Focus on the Omega-3 index

Docosahexaenoic Acid (DHA) and Eicosapentaenoic Acid (EPA)-Should They Be Mandatory Supplements in Pregnancy?

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are essential fatty acids for the human body. Seafood and microalgae are the most important sources of omega-3 fatty acids. Supplementation with 200 mg/day of DHA during pregnancy and breastfeeding has been suggested for women and infants in countries with low seafood consumption. Maternal concentration of DHA and EPA was associated with concentration in cord blood and breast milk. High concentrations of DHA and EPA were identified at the level of retinal photoreceptors and neuronal cell membranes. It was observed that supplementation with DHA and EPA during pregnancy had beneficial effects on the neurological development of the fetus and infant by improving language, memory, attention, and hand coordination, affecting sleep patterns, and improving visual acuity. Beneficial effects on the development of the infant were also associated with the maternal intake of omega-3 fatty acids during breastfeeding. Supplementation with DHA and EPA may reduce the risk of preterm birth but also of preeclampsia in low-risk pregnancies. Women of childbearing age should have an intake of 250 mg/day of DHA + EPA from their diet or supplements. To reduce the risk of premature birth, pregnant women must additionally receive at least 100-200 mg of DHA every day. It is recommended that supplementation with omega-3 fatty acids starts before 20 weeks of pregnancy. Beneficial effects on the mother have been identified, such as the reduction of postpartum depression symptoms, the decrease of cardiovascular risk, and the anti-inflammatory role.

Fatty acid composition in erythrocytes and coronary artery disease risk: a case-control study in China

Background and aims: There is limited and conflicting evidence about the association of erythrocyte fatty acids with coronary artery disease (CAD), particularly in China where the CAD rates are high. Our study aimed to explore the association between erythrocyte fatty acid composition and CAD risk in Chinese adults. Methods: Erythrocyte fatty acids of 314 CAD patients and 314 matched controls were measured by gas chromatography. Multivariable conditional logistic regression and restricted cubic spline models were used to explore the odds ratio with 95% confidence interval (OR, 95% CI) and potential association between erythrocyte fatty acids and CAD risk. Principal component analysis (PCA) was used to analyze further the potential role of various erythrocyte fatty acid patterns in relation to CAD risk. Results: Significant inverse associations were observed between high levels of erythrocyte total n-3 polyunsaturated fatty acids (n-3 PUFA) [ORT3-T1 = 0.18 (0.12, 0.28)], monounsaturated fatty acids (MUFA) [ORT3-T1 = 0.21 (0.13, 0.32)], and the risk of CAD. Conversely, levels of saturated fatty acids (SFAs) and n-6 polyunsaturated fatty acids (n-6 PUFAs) were positively associated with CAD risk [ORT3-T1 = 3.33 (2.18, 5.13), ORT3-T1 = 1.61 (1.06, 2.43)]. No significant association was observed between CAD risk and total trans fatty acids. Additionally, the PCA identifies four new fatty acid patterns (FAPs). The risk of CAD was significantly positively associated with FAP1 and FAP2, while being negatively correlated with FAP3 and FAP4. Conclusion: The different types of erythrocyte fatty acids may significantly alter susceptibility to CAD. Elevated levels of n-3-PUFAs and MUFAs are considered as protective biomarkers against CAD, while SFAs and n-6 PUFAs may be associated with higher CAD risk in Chinese adults. The risk of CAD was positively associated with FAP1 and FAP2, and negatively associated with FAP3 and FAP4. Combinations of erythrocyte fatty acids may be more important markers of CAD development than individual fatty acids or their subgroups.

Omega-3 world map: 2024 update

In 2016, the first worldwide n3 PUFA status map was published using the Omega-3 Index (O3I) as standard biomarker. The O3I is defined as the percentage of EPA + DHA in red blood cell (RBC) membrane FAs. The purpose of the present study was to update the 2016 map with new data. In order to be included, studies had to report O3I and/or blood EPA + DHA levels in metrics convertible into an estimated O3I, in samples drawn after 1999. To convert the non-RBC-based EPA + DHA metrics into RBC we used newly developed equations. Baseline data from clinical trials and observational studies were acceptable. A literature search identified 328 studies meeting inclusion criteria encompassing 342,864 subjects from 48 countries/regions. Weighted mean country O3I levels were categorized into very low ≤4%, low >4-6%, moderate >6-8%, and desirable >8%. We found that the O3I in most countries was low to very low. Notable differences between the current and 2016 map were 1) USA, Canada, Italy, Turkey, UK, Ireland and Greece (moving from the very low to low category); 2) France, Spain and New Zealand (low to moderate); and 3) Finland and Iceland (moderate to desirable). Countries such as Iran, Egypt, and India exhibited particularly poor O3I levels.

Omega-3 blood biomarkers relate to brain glucose uptake in individuals at risk of Alzheimer's disease dementia

INTRODUCTION

Brain glucose hypometabolism is a preclinical feature of Alzheimer's disease (AD). Dietary omega-3 fatty acids promote brain glucose metabolism, but clinical research is incipient. Circulating omega-3s objectively reflect their dietary intake.

METHODS

This was a cross-sectional study in 320 cognitively unimpaired participants at increased risk of AD dementia. Using lipidomics, we determined blood docosahexaenoic (DHA) and alpha-linolenic (ALA) acid levels (omega-3s from marine and plant origin, respectively). We assessed brain glucose metabolism using [18-F]-fluorodeoxyglucose (FDG) positron emission tomography (PET).

RESULTS

Blood ALA directly related to FDG uptake in brain areas known to be affected in AD. Stronger associations were observed in apolipoprotein E ε4 carriers and homozygotes. For DHA, significant direct associations were restricted to amyloid beta-positive tau-positive participants.

DISCUSSION

Blood omega-3 directly relate to preserved glucose metabolism in AD-vulnerable brain regions in individuals at increased risk of AD dementia. This adds to the benefits of omega-3 supplementation in the preclinical stage of AD dementia.

Highlights

Blood omega-3s were related to brain glucose uptake in participants at risk of Alzheimer's disease (AD) dementia.Complementary associations were observed for omega-3 from marine and plant sources.Foods rich in omega-3 might be useful in early features of AD.

ω-3 Polyunsaturated Fatty Acid Status Testing in Humans: A Narrative Review of Commercially Available Options

There is an increasing body of evidence supporting a link between low intakes of ω-3 long-chain polyunsaturated fatty acids (LCPUFA) and numerous diseases and health conditions. However, few people are achieving the levels of fish/seafood or eicosapentaenoic acid and docosahexaenoic acid intake recommended in national and international guidelines. Knowledge of a person's ω-3 LCPUFA status will benefit the interpretation of research results and could be expected to lead to an increased effort to increase intake. Dietary intake survey methods are often used as a surrogate for measuring ω-3 PUFA tissue status and its impact on health and functional outcomes. However, because individuals vary widely in their ability to digest and absorb ω-3 PUFA, analytical testing of biological samples is desirable to accurately evaluate ω-3 PUFA status. Adipose tissue is the reference biospecimen for measuring tissue fatty acids, but less-invasive methods, such as measurements in whole blood or its components (e.g., plasma, serum, red blood cell membranes) or breast milk are often used. Numerous commercial laboratories provide fatty acid testing of blood and breast milk samples by different methods and present their results in a variety of reports such as a full fatty acid profile, ω-3 and ω-6 fatty acid profiles, fatty acid ratios, as well as the Omega-3 Index, the Holman Omega-3 Test, OmegaScore, and OmegaCheck, among others. This narrative review provides information about the different ways to measure ω-3 LCPUFA status (including both dietary assessments and selected commercially available analytical tests of blood and breast milk samples) and discusses evidence linking increased ω-3 LCPUFA intake or status to improved health, focusing on cardiovascular, neurological, pregnancy, and eye health, in support of recommendations to increase ω-3 LCPUFA intake and testing.

Circulating Docosahexaenoic Acid and Risk of All-Cause and Cause-Specific Mortality

OBJECTIVE

To assess the associations of docosahexaenoic acid (DHA), a marine omega-3 fatty acid, with long-term all-cause mortality, cardiovascular (CV) mortality, and cancer mortality.

PATIENTS AND METHODS

We analyzed data from UK Biobank, which included 117,702 subjects with baseline plasma DHA levels and 12.7 years of follow-up between April 2007 and December 2021. Associations with risk for mortality endpoints were analyzed categorically by quintile of DHA plasma levels.

RESULTS

Comparing the lowest to highest quintiles of circulating levels of DHA, there was 21% lower risk of all-cause mortality (HR, 0.79; 95% CI, 0.74 to 0.85; P<.0001). In a secondary analysis, we merged the UK Biobank findings with those from a recent FORCE (Fatty Acid and Outcome Research Consortium) meta-analysis that included 17 prospective cohort studies and 42,702 individuals examining DHA and mortality associations. The cumulative sample population included 160,404 individuals and 24,342 deaths during a median of 14 years of follow-up. After multivariable adjustment for relevant risk factors comparing the lowest to the highest quintiles of DHA, there was 17% lower risk of all-cause mortality (95% CI, 0.79 to 0.87; P<.0001), 21% lower risk for CV disease mortality (95% CI, 0.73 to 0.87; P<.001), 17% lower risk for cancer mortality (95% CI, 0.77 to 0.89; P<.0001), and 15% lower risk for all other mortality (95% CI, 0.79 to 0.91; P<.001).

CONCLUSION

Higher DHA levels were associated with significant risk reductions in all-cause mortality, as well as reduced risks for deaths due to CV disease, cancer, and all other causes. The findings strengthen the hypothesis that DHA, a marine-sourced omega-3, may support CV health and lifespan.

Omega-3 fatty acid supplementation affects tryptophan metabolism during a 12-week endurance training in amateur runners: a randomized controlled trial

The effects of long-term omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation during endurance training on tryptophan (Trp) metabolism and mental state of healthy individuals have not been evaluated so far. Concentrations of plasma Trp, its metabolites and IL-6 were assessed in 26 male runners before and after a 12-week training program combined with supplementation of n-3 PUFAs (O-3 + TRAIN group) or medium chain triglycerides (MCTs; TRAIN group). After the 12-week program participants' mood before and after stress induction was also assessed. The effects of the same supplementation protocol were evaluated also in 14 inactive subjects (O-3 + SEDEN group). Concentrations of 3-hydroxykynurenine (3-HK) and picolinic acid (PA) significantly increased only in the O-3 + TRAIN group (p = 0.01; [Formula: see text] = 0.22 and p = 0.01; [Formula: see text]= 0.26). Favorable, but not statistically significant changes in the concentrations of kynurenic acid (KYNA) (p = 0.06; [Formula: see text]= 0.14), xanthurenic acid (XA) (p = 0.07; [Formula: see text]= 0.13) and 3-hydroxyanthranilic acid (3-HAA) (p = 0.06; [Formula: see text]= 0.15) and in the ratio of neurotoxic to neuroprotective metabolites were seen also only in the O-3 + TRAIN group. No changes in mood and IL-6 concentrations were observed in either group. Supplementation with n-3 PUFAs during endurance training has beneficial effects on Trp's neuroprotective metabolites.Trial registry: This study was registered at ClinicalTrials.gov with identifier NCT05520437 (14/07/2021 first trial registration and 2018/31/N/NZ7/02962 second trial registration).

Omega-3 fatty acids and cardiovascular prevention: is the jury still out?

The cardiovascular benefits of omega-3 polyunsaturated fatty acids (O3FA) remain a point of confusion in clinical medicine. Recently two large, randomised trials were published with discordant findings regarding the overall benefits of omega-3 supplementation, resulting in unnecessary confusion and therapeutic nihilism. Epidemiological studies clearly show high intake of fish and measured O3FA (mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) in tissues are inversely associated with cardiovascular events and total mortality. These fatty acids are 'essential' and depend almost entirely on intake with very little production from within the body. The efficacy of supplementation depends on background tissue levels, in contradistinction to drug therapy. Insufficient dosing of omega-3 supplementation using less than 1 g/day and lack of titration to target by failing to measure O3FA levels in the blood may explain these conflicting trial outcomes. We review the current evidence regarding O3FA supplementation and cardiovascular outcomes, describe possible reasons for the discrepant results in the literature including recent controversial data around the mineral oil comparator used in REDUCE-IT and discuss the potential use of the omega-3 index to guide management and optimise supplementation in those at greatest risk.

Omega-3 Polyunsaturated Fatty Acid Levels in Maternal and Cord Plasma Are Associated with Maternal Socioeconomic Status

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) play a crucial role in fetal growth and neurodevelopment, while omega-6 (n-6) PUFAs have been associated with adverse pregnancy outcomes. Previous studies have demonstrated that socioeconomic status (SES) influences dietary intake of n-3 and n-6 PUFAs, but few studies have evaluated the association between maternal and cord plasma biomarkers of PUFAs and socioeconomic markers. An IRB-approved study enrolled mother-infant pairs (n = 55) at the time of delivery. Maternal and cord plasma PUFA concentrations were analyzed using gas chromatography. Markers of SES were obtained from validated surveys and maternal medical records. Mann-Whitney U tests and linear regression models were utilized for statistical analysis. Maternal eicosapentaenoic acid (EPA) (p = 0.02), cord EPA (p = 0.04), and total cord n-3 PUFA concentrations (p = 0.04) were significantly higher in college-educated mothers vs. mothers with less than a college education after adjustment for relevant confounders. Insurance type and household income were not significantly associated with n-3 or n-6 PUFA plasma concentrations after adjustment. Our findings suggest that mothers with lower educational status may be at risk of lower plasma concentrations of n-3 PUFAs at delivery, which could confer increased susceptibility to adverse pregnancy and birth outcomes.

Effects of Varied Omega-3 Fatty Acid Supplementation on Postpartum Mental Health and the Association between Prenatal Erythrocyte Omega-3 Fatty Acid Levels and Postpartum Mental Health

We investigated the postpartum mental health of women who had consumed perilla oil or fish oil containing various omega-3 fatty acids for 12 weeks starting in mid-pregnancy. The association between fatty acids in maternal erythrocytes and mental health risk factors was also examined. Healthy Japanese primiparas in mid-pregnancy (gestational weeks 18-25) were randomly divided into two groups and consumed approximately 2.0 g/day of omega-3 fatty acids in either perilla oil (the ALA dose was 2.4 g/day) or fish oil (the EPA + DHA dose was 1.7 g/day) for 12 weeks. Maternal mental health was assessed using the Edinburgh Postnatal Depression Scale (EPDS) as the primary measure and the Mother-to-Infant Bonding Scale (MIBS) as the secondary measure. Data from an observational study were used as a historical control. Maternal blood, cord blood, and colostrum samples were collected for fatty acid composition analysis. In addition, completers of the observational studies were enrolled in a case-control study, wherein logistic regression analysis was performed to examine the association between maternal fatty acids and EPDS score. The proportion of participants with a high EPDS score (≥9) was significantly lower in the perilla oil group (12.0%, p = 0.044) but not in the fish oil group (22.3%, p = 0.882) compared with the historical control (21.6%), while the proportions between the former groups also tended to be lower (p = 0.059). No marked effect of omega-3 fatty acid intake was observed from the MIBS results. In the case-control study of the historical control, high levels of α-linolenic acid in maternal erythrocytes were associated with an EPDS score of <9 (odds ratio of 0.23, 95% confidence interval: 0.06, 0.84, p = 0.018 for trend). The results of this study suggest that consumption of α-linolenic acid during pregnancy may stabilize postpartum mental health.

Very low Omega-3 Index in young healthy students from Palestine

Oily fish is rich in long-chain omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have been associated with several health benefits. However, fish consumption is generally low in many countries, including the Middle East, resulting in low omega-3 blood levels. In Palestine, no data on the omega-3 blood status is available. The aim of this cross-sectional study was to assess the omega-3 status and related factors in young healthy subjects from Palestine. Omega-3 status was assessed using the Omega-3 Index-defined as the sum of EPA + DHA in relation to the total fatty acid content of erythrocytes. A total of 149 subjects, 50 males and 99 females (age range: 18-24 years), were included in the study. In addition to the Omega-3 Index, data on anthropometrics, physical activity, smoking status, fish intake, dietary supplement intake, blood lipid profile, and whole erythrocyte fatty acid pattern were collected. The mean (SD) Omega-3 Index was 2.56 (0.57)%, with 97.9% of subjects having an index below 4%. The majority of participants (91.8%) consumed less than two portions of fish per week, and only 4% reported taking omega-3 supplements, mostly irregularly. Our findings show that young Palestinian students have an alarmingly low omega-3 status. Further studies are needed to investigate whether the omega-3 status is also low in the general Palestinian population.

Association between fish intake and prevalence of frailty in community-dwelling older adults after 4-year follow-up: the Korean frailty and aging cohort study

Cross-sectional epidemiological studies suggested the intake of fish and seafood was negatively associated with the prevalence of frailty. This study aimed to investigate the hypothesis that the prevalence of frailty is negatively associated with the consumption of total seafood and fish at baseline and 4-year follow-up. Using a multicenter longitudinal study of community-dwelling Korean adults aged 70-84 years old, 953 participants at baseline and 623 participants at 4-year follow-up were included after excluding participants without data on frailty or dietary intake in the Korean Frailty and Aging Cohort Study. Frailty was defined using the Cardiovascular Health Study index, and participants with scores ≥3 were considered frail. The trained dietitians obtained two non-consecutive 24-h dietary recalls during spring and fall at baseline. The prevalence of frailty was 13.5%. The intake of fish (OR 0.47; 95% CI 0.24-0.91; p for trend = 0.028) and total seafood (OR 0.34; 95% CI 0.18-0.68; p for trend = 0.002) at baseline was associated with frailty at 4-year follow-up after adjusting for the confounding factors. The intake of fish and total seafood at the baseline was negatively associated with the prevalence of exhaustion, low handgrip strength, and slow gait speed at 4-year follow-up. However, shellfish intake was not associated with frailty. In addition, the intake of fish, shellfish, and total seafood did not differ among the frailty transition groups in terms of deterioration, persistence, and reversal. The total consumption of seafood, particularly fish, could be beneficial for preventing frailty in Korean community-dwelling older adults. In particular, the consumption of fish (total seafood) at baseline could be beneficial for preventing exhaustion, low handgrip strength, and slow gait speed at 4-year follow-up.

De Novo Lipogenesis-Related Monounsaturated Fatty Acids in the Blood Are Associated with Cardiovascular Risk Factors in HFpEF Patients

De novo lipogenesis (DNL)-related monounsaturated fatty acids (MUFAs) in the blood are associated with incident heart failure (HF). This observation's biological plausibility may be due to the potential of these MUFAs to induce proinflammatory pathways, endoplasmic reticulum stress, and insulin resistance, which are pathophysiologically relevant in HF. The associations of circulating MUFAs with cardiometabolic phenotypes in patients with heart failure with a preserved ejection fraction (HFpEF) are unknown. In this secondary analysis of the Aldosterone in Diastolic Heart Failure trial, circulating MUFAs were analysed in 404 patients using the HS-Omega-3-Index® methodology. Patients were 67 ± 8 years old, 53% female, NYHA II/III (87/13%). The ejection fraction was ≥50%, E/e' 7.1 ± 1.5, and the median NT-proBNP 158 ng/L (IQR 82-298). Associations of MUFAs with metabolic, functional, and echocardiographic patient characteristics at baseline/12 months follow-up (12 mFU) were analysed using Spearman's correlation coefficients and linear regression analyses, using sex/age as covariates. Circulating levels of C16:1n7 and C18:1n9 were positively associated with BMI/truncal adiposity and associated traits (dysglycemia, atherogenic dyslipidemia, and biomarkers suggestive of non-alcoholic-fatty liver disease). They were furthermore inversely associated with functional capacity at baseline/12 mFU. In contrast, higher levels of C20:1n9 and C24:1n9 were associated with lower cardiometabolic risk and higher exercise capacity at baseline/12 mFU. In patients with HFpEF, circulating levels of individual MUFAs were differentially associated with cardiovascular risk factors. Our findings speak against categorizing FA based on physicochemical properties. Circulating MUFAs may warrant further investigation as prognostic markers in HFpEF.

Oleic Acid Status Positively Correlates with the Soluble Receptor for Advanced Glycation End-Products (sRAGE) in Healthy Adults Who Are Homozygous for G Allele of RAGE G82S Polymorphism

BACKGROUND

The soluble form of receptor for advanced glycation end products (sRAGE) have been implicated in the prevention of numerous pathologic states, and highlights as an attractive therapeutic target. Because diets rich in monounsaturated fatty acids (MUFA) reduce postprandial oxidative stress and inflammation that is related to better health during aging, we investigated the association between red blood cell (RBC) fatty acids with circulatory AGE biomarkers and further stratified this correlation based on GG and GA + AA genotype.

METHODS

A total of 172 healthy participants (median age = 53.74 ± 0.61 years) were recruited for the study. RBC fatty acid was analysed using gas chromatography and sRAGE was measured using a commercial ELISA kit.

RESULTS

The result showed a non-significant correlation between total MUFA with sRAGE however oleic acid (C18:1) exhibited a positive correlation (r = 0.178, p = 0.01) that remained statistically significant (β = 0.178, p = 0.02) after a stepwise multivariate regression analysis after adjusting for age, BMI and gender. In a univariate analysis, a positive significant correlation between C18:1 and sRAGE in GG genotype (r = 0.169, p = 0.02) and a non-significant correlation with GA + AA genotype (r = 0.192, p = 0.21) was evident. When C18:1 was stratified, a significant difference was observed for oleic acid and G82S polymorphism: low C18:1/GA + AA versus high C18:1/GG (p = 0.015) and high C18:1/GA + AA versus high C18:1/GG (p = 0.02).

CONCLUSION

Our study suggests that increased levels of C18:1 may be a potential therapeutic approach in increasing sRAGE in those with GG genotype and play a role in modulating AGE metabolism.

Occupational life-style programme over 12 months and changes of metabolic risk profile, vascular function, and physical fitness in blue-collar workers

PURPOSE

Occupational health programmes have been successfully implemented to improve body composition, physical fitness and cardiovascular risk. However, most programmes have been small and have not included long-term evaluation. Therefore, we evaluated a twelve-month life-style change programme in a German refinery.

METHODS

We offered a supervised six-week endurance exercise programme (2 × 90 min/week), starting after a two-day life-style seminar. After the active intervention and a half-day refresher seminar, employees were encouraged to continue exercising over one year on their own, with monthly supervised sessions to maintain adherence. Anthropometry, bicycle ergometry, cardio-metabolic risk profile, inflammatory parameters, and vascular function e.g. endothelial function was studied at baseline, after three and after twelve months.

RESULTS

Of 550 employees, n = 327 (age 40.8 ± 9.7 years, 88% males) participated in the study. Twelve-month intervention was associated with a reduced waist circumference (92.6 ± 12.2 to 90.8 ± 11.7 cm, 95% confidence interval for the mean change (CI): -2.5 to -1.1 cm) and a gain in maximal exercise capacity (202 ± 39.6 to 210 ± 38.9 Watt; 95% CI: + 5.1 to + 10.9 Watt). Metabolic and inflammatory parameters likewise HbA_1c and C-reactive protein improved in central tendency at a local 95% level of confidence. Vascular function e.g. Reactive-Hyperaemia-Index revealed a slight reduction, whereas no statistically robust changes in mean Cardio-Ankle-Vascular-Index and mean Ankle-Brachial-Index were observed.

CONCLUSION

Health education added by a six-week supervised exercise programme was associated with minor long-term twelve-month improvements of body composition as well as physical fitness and a concomitant improvement of inflammatory state. These changes were, however, not clinically relevant and not accompanied by statistically robust improvements of vascular function.

TRIAL REGISTRATION

ClinTrialsGov: NCT01919632; date of registration: August 9, 2013; retrospectively registered.

Lower omega-3 status associated with higher erythrocyte distribution width and neutrophil-lymphocyte ratio in UK Biobank cohort

High red blood distribution width (RDW) is associated with decreased red blood cell deformability, and high neutrophil-lymphocyte ratio (NLR) is a biomarker of systemic inflammation and innate-adaptive immune system imbalance. Both RDW and NLR are predictors of chronic disease risk and mortality. Omega-3 index (O3I) values have previously been shown to be inversely associated with RDW and NLR levels. Our objective was to determine if total plasma long chain omega-3 fatty acids (Omega3%) measured in the UK Biobank cohort were associated with RDW and NLR values. RDW- and NLR- relationships with Omega3% were characterized in 109,191 adults (58.4% female). RDW- and NLR-Omega3% relationships were inversely associated with Omega3% (both p < 0.0001). These cross-sectional associations confirm previous findings that increasing RDW and NLR values are associated with low O3I. The hypothesis that RDW and/or NLR values can be reduced in individuals with less-than optimal long chain omega 3 values need to be tested in randomized controlled intervention trials using EPA and/or DHA.

Higher stress response and altered quality of life in schizophrenia patients with low membrane levels of docosahexaenoic acid

Schizophrenia is a severe, chronic, and heterogeneous mental disorder that affects approximately 1% of the world population. Ongoing research aims at clustering schizophrenia heterogeneity into various "biotypes" to identify subgroups of individuals displaying homogeneous symptoms, etiopathogenesis, prognosis, and treatment response. The present study is in line with this approach and focuses on a biotype partly characterized by a specific membrane lipid composition. We have examined clinical and biological data of patients with stabilized schizophrenia, including the fatty acid content of their erythrocyte membranes, in particular the omega-3 docosahexaenoic acid (DHA). Two groups of patients of similar size were identified: the DHA- group (N = 19) with a lower proportion of membrane DHA as compared to the norm in the general population, and the DHAn group (N = 18) with a normal proportion of DHA. Compared to DHAn, DHA- patients had a higher number of hospitalizations and a lower quality of life in terms of perceived health and physical health. They also exhibited significant higher interleukin-6 and cortisol blood levels. These results emphasize the importance of measuring membrane lipid and immunoinflammatory biomarkers in stabilized patients to identify a specific subgroup and optimize non-pharmacological interventions. It could also guide future research aimed at proposing specific pharmacological treatments.

Association between Omega-3 Index and Hyperglycemia Depending on Body Mass Index among Adults in the United States

There is inconsistency regarding the association between long-chain n-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA; 20:5n3) and docosahexaenoic acid (DHA; 22:6n3) and the risk of type 2 diabetes. The present study aimed to investigate the association between the Omega-3 Index (erythrocyte EPA + DHA) and glycemic status as a function of body mass index (BMI). Cross-sectional data from routine clinical laboratory testing with a total of 100,572 people aged over 18 years and BMI ≥ 18.5 kg/m² were included. Of the patients, 10% were hyperglycemic (fasting plasma glucose levels ≥ 126 mg/dL) and 24.7% were of normal weight, 35.0% were overweight, and 40.3% were obese. Odds ratios (ORs) of being hyperglycemic were inversely associated with the Omega-3 Index, but weakened as BMI increased. Thus, ORs (95% CI) comparing quintile 5 with quintile 1 were 0.54 (0.44-0.66) in the normal weight group, 0.70 (0.61-0.79) in the overweight group, and 0.74 (0.67-0.81) in the obese group. Similar patterns were seen for EPA and DHA separately. The present study suggested that a low Omega-3 Index is associated with a greater risk of disordered glucose metabolism and this is independent of BMI.

Estimation and predictors of the Omega-3 Index in the UK Biobank

Information on the Omega-3 Index (O3I) in the United Kingdom (UK) are scarce. The UK-Biobank (UKBB) contains data on total plasma omega-3 polyunsaturated fatty acids (n3-PUFA%) and DHA% measured by NMR. The aim of our study was to create an equation to estimate the O3I (eO3I) from these data. We first performed an interlaboratory experiment with 250 random blood samples in which the O3I was measured in erythrocytes by gas chromatography, and total n3% and DHA% were measured in plasma by NMR. The best predictor of eO3I included both DHA% and a derived metric, the total n3%-DHA%. Together these explained 65% of the variability (r=0.832, p<0.0001). We then estimated the O3I in 117,108 UKBB subjects and correlated it with demographic and lifestyle variables in multivariable adjusted models. The mean (SD) eO3I was 5.58% (2.35%) this UKBB cohort. Several predictors were significantly correlated with eO3I (all p<0.0001). In general order of impact and with directionality (- = inverse, + = direct): oily-fish consumption (+), fish oil supplement use (+), female sex (+), older age (+), alcohol use (+), smoking (-), higher waist circumference and BMI (-), lower socioeconomic status and less education (-). Only 20.5% of eO3I variability could be explained by predictors investigated, and oily-fish consumption accounted for 7.0% of that. With the availability of the eO3I in the UKBB cohort we will be in a position to link risk for a variety of diseases with this commonly-used and well-documented marker of n3-PUFA biostatus.