Erythrocyte omega-3 fatty acids increase and linoleic acid decreases with age: observations from 160,000 patients

Fatty Acid Intake and Polyunsaturated Fatty Acid Biomarkers and Risk of Total Knee or Hip Arthroplasty Among Older Women in the Women's Health Initiative

OBJECTIVE

The objective was to determine whether baseline fatty acid intake and erythrocyte omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) can predict risk of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older women.

METHODS

This was a prospective analysis of 34,990 women in the Women's Health Initiative. Dietary fatty acids were estimated from food frequency questionnaires. Imputed erythrocyte PUFAs were available in a subcohort of 3,428 women. Arthroplasty (THA and TKA), used as a surrogate of severe osteoarthritis, was identified via linked Medicare data. Cox proportional hazards models were constructed to estimate risk of arthroplasty.

RESULTS

Risk of THA was associated with higher intake of arachidonic acid, (multivariable hazard ratio [HR] quartile 4 [Q4] vs Q1: 1.16; 95% confidence interval [CI] 1.01-1.34; P = 0.03) and higher intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA; HR Q4 vs Q1: 1.20; 95% CI 1.05-1.39; P = 0.003). There was a linear trend (P = 0.04) for patients to have a higher risk of THA with higher erythrocyte EPA and DHA in body mass index-adjusted models; however, there was no significant difference in patients who had THAs by quartiles of erythrocyte EPA and DHA (P = 0.10). Dietary fatty acids and erythrocyte PUFAs were not significantly associated with risk of TKA.

CONCLUSION

Higher baseline intakes of arachidonic acid and EPA and DHA were associated with a modestly higher risk of THA. No association was found between fatty acids and patients who had TKAs. Further research in populations with direct measures of osteoarthritis severity is needed to better understand the importance of PUFAs in modulating osteoarthritis and arthroplasty risk.

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.

Serum measures of docosahexaenoic acid (DHA) synthesis underestimates whole body DHA synthesis in male and female mice

Females have higher docosahexaenoic acid (DHA) levels than males, proposed to be a result of higher DHA synthesis rates from α-linolenic acid (ALA). However, DHA synthesis rates are reported to be low, and have not been directly compared between sexes. Here, we apply a new compound specific isotope analysis model to determine n-3 PUFA synthesis rates in male and female mice and assess its potential translation to human populations. Male and female C57BL/6N mice were allocated to one of three 12-week dietary interventions with added ALA, eicosapentaenoic acid (EPA) or DHA. The diets included low carbon-13 (δ13C)-n-3 PUFA for four weeks, followed by high δ13C-n-3 PUFA for eight weeks (n=4 per diet, time point, sex). Following the diet switch, blood and tissues were collected at multiple time points, and fatty acid levels and δ13C were determined and fit to one-phase exponential decay modeling. Hepatic DHA synthesis rates were not different (P>.05) between sexes. However, n-3 docosapentaenoic acid (DPAn-3) synthesis from dietary EPA was 66% higher (P<.05) in males compared to females, suggesting higher synthesis downstream of DPAn-3 in females. Estimates of percent conversion of dietary ALA to serum DHA was 0.2%, in line with previous rodent and human estimates, but severely underestimates percent dietary ALA conversion to whole body DHA of 9.5%. Taken together, our data indicates that reports of low human DHA synthesis rates may be inaccurate, with synthesis being much higher than previously believed. Future animal studies and translation of this model to humans are needed for greater understanding of n-3 PUFA synthesis and metabolism, and whether the higher-than-expected ALA-derived DHA can offset dietary DHA recommendations set by health agencies.

Genetic association between FADS and ELOVL polymorphisms and the circulating levels of EPA/DHA in humans: a scoping review

BACKGROUND

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two omega-3 fatty acids that can be synthesized out of their precursor alpha-linolenic acid (ALA). FADS and ELOVL genes encode the desaturase and elongase enzymes required for EPA and DHA synthesis from ALA; however, single nucleotide polymorphisms (SNPs) in FADS and ELOVL genes could modify the levels of EPA and DHA synthesized from ALA although there is no consensus in this area. This review aims to investigate EPA and DHA circulating levels in human blood and their association with FADS or ELOVL.

METHODS

PubMed, Cochrane, and Scopus databases were used to identify research articles. They were subsequently reviewed by two independent investigators.

RESULTS

Initially, 353 papers were identified. After removing duplicates and articles not meeting inclusion criteria, 98 full text papers were screened. Finally, this review included 40 studies investigating FADS and/or ELOVL polymorphisms. A total of 47 different SNPs in FADS genes were reported. FADS1 rs174537, rs174547, rs174556 and rs174561 were the most studied SNPs, with minor allele carriers having lower levels of EPA and DHA. SNPs in the FADS genes were in high linkage disequilibrium. SNPs in FADS were correlated with levels of EPA and DHA. No conclusion could be drawn with the ELOVL polymorphisms since the number of studies was too low.

CONCLUSION

Specific SNPs in FADS gene, such as rs174537, have strong associations with circulating levels of EPA and DHA. Continued investigation regarding the impact of genetic variants related to EPA and DHA synthesis is warranted.

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.

Long chain n-3 polyunsaturated fatty acid intake across the life span for cardiovascular disease prevention in women

Cardiovascular diseases (CVDs) are a major health concern for women. Historically there has been a misconception that men are at greater risk because CVD tends to occur earlier in life compared to women. Clinical guidelines for prevention of heart disease are currently the same for both sexes, but accumulating evidence demonstrates that risk profiles diverge. In fact, several CVD risk factors confer an even greater risk in women relative to men, including high blood pressure, obesity, diabetes and raised triglycerides. Furthermore, many female-specific CVD risk factors exist, including early menarche, pregnancy complications, polycystic ovary syndrome, reproductive hormonal treatments and menopause. Little is known about how diet interacts with CVD risk factors at various stages of a woman’s life. Long chain (LC) n-3 polyunsaturated fatty acid (PUFA) intakes are a key dietary factor that may impact risk of CVD throughout the life course differentially in men and women. Oestrogen enhances conversion of the plant n-3 PUFA, alpha-linolenic acid, to LCn-3 PUFA. Increasing the frequency of oily fish consumption or LCn-3 PUFA supplementation may be important for reducing coronary risk during the menopausal transition, during which time oestrogen levels decline and the increase in CVD risk factors is accelerated. Women are under-represented in the evidence base for CVD prevention following LC n-3 PUFA supplementation. Therefore it is not clear whether there are sex differences in response to treatment. Furthermore, there is a lack of evidence on optimal intakes of LC n-3 PUFA across the lifespan for CVD prevention in women.

Sex-dependent differences in tissue and blood n-3 PUFA levels following ALA or ALA + DHA feeding of liver-specific Elovl2-KO and control mice

Docosahexaenoic acid (DHA, 22:6n-3) must be consumed from the diet or synthesized from polyunsaturated fatty acid (PUFA) precursors, such as α-linolenic acid (ALA, 18:3n-3). Elongase 2 (encoded by Elovl2 gene) catalyzes two elongation reactions in the PUFA biosynthesis pathway and may be important in regulating the observed sex differences in n-3 PUFA levels. Our aim was to determine how targeted knockout of liver Elovl2 affects tissue and blood n-3 PUFA levels in male and female C57BL/6J mice. Twenty-eight-day old male and female liver Elovl2-KO and control mice were placed onto one of two dietary protocols for a total of 8 weeks (4-8 mice per genotype, per diet, per sex): 1) an 8-week 2 % ALA in total fat diet or 2) a 4-week 2 % ALA diet followed by a 4-week 2 % ALA + 2 % DHA diet. Following this 8-week feeding period, 12-week-old mice were sacrificed and serum, red blood cells (RBC), liver, heart and brain were collected and fatty acid levels measured. Significant interaction effects (p < 0.05, sex x genotype) for serum, RBC, liver and heart DHA levels were identified. In serum and liver, DHA levels were significantly different (p < 0.01) between all groups with male controls > female controls > female KO > male KO in serum and female controls > male controls > female KO > male KO in liver. In RBCs and the heart, female controls = male controls > female KO > male KO (p < 0.001). The addition of DHA to diet removed the interaction effects on DHA levels in the serum, liver and heart, yielding a significant sex effect in serum, liver (female > male, p < 0.01) and brain (male > female, p < 0.05) and genotype effect in serum and heart (control > KO, p < 0.05). Ablation of liver Elovl2 results in significantly lower blood and tissue DHA in a sex-dependent manner, suggesting a role for Elovl2 on sex differences in n-3 PUFA levels.

Omega-3 Fatty Acids and Markers of Thrombosis in Patients with Atrial Fibrillation

Omega-3 fatty acids (n-3 FAs) are associated with a lower risk of ischemic stroke in patients with atrial fibrillation (AF). Antithrombotic mechanisms may in part explain this observation. Therefore, we examined the association of n-3 FAs with D-dimer and beta-thromboglobulin (BTG), markers for activated coagulation and platelets, respectively. The n-3 FAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA) and alpha-linolenic acid (ALA) were determined via gas chromatography in the whole blood of 2373 patients with AF from the Swiss Atrial Fibrillation cohort study (ClinicalTrials.gov Identifier: NCT02105844). In a cross-sectional analysis, we examined the association of total n-3 FAs (EPA + DHA + DPA + ALA) and the association of individual fatty acids with D-dimer in patients with detectable D-dimer values (n = 1096) as well as with BTG (n = 2371) using multiple linear regression models adjusted for confounders. Median D-dimer and BTG levels were 0.340 ug/mL and 448 ng/mL, respectively. Higher total n-3 FAs correlated with lower D-dimer levels (coefficient 0.94, 95% confidence interval (Cl) 0.90-0.98, p = 0.004) and lower BTG levels (coefficient 0.97, Cl 0.95-0.99, p = 0.003). Likewise, the individual n-3 FAs EPA, DHA, DPA and ALA showed an inverse association with D-dimer. Higher levels of DHA, DPA and ALA correlated with lower BTG levels, whereas EPA showed a positive association with BTG. In patients with AF, higher levels of n-3 FAs were associated with lower levels of D-dimer and BTG, markers for activated coagulation and platelets, respectively. These findings suggest that n-3 FAs may exert antithrombotic properties in patients with AF.

Associations of fatty acids composition and estimated desaturase activities in erythrocyte phospholipids with biochemical and clinical indicators of cardiometabolic risk in non-diabetic Serbian women: the role of level of adiposity

Introduction

Fatty acids (FAs) composition and desaturase activities can be altered in different metabolic conditions, but the adiposity-independent associations with clinical and biochemical indicators of cardiometabolic risk are still unclear. This study aimed to analyze the associations of FAs composition and estimated desaturase activities with anthropometric, clinical, and biochemical cardiometabolic risk indicators in non-diabetic Serbian women, and to investigate if these associations were independent of the level of adiposity and other confounders.

Methods

In 76 non-diabetic, otherwise healthy Serbian women, aged 24-68 years, with or without metabolic syndrome or obesity (BMI=23.6±5.6 kg/m2), FA composition in erythrocyte phospholipids was measured by gas-liquid chromatography. Desaturase activities were estimated from product/precursor FAs ratios (D9D:16:1n-7/16:0; D6D:20:3n-6/18:2n-6; D5D:20:4n-6/20:3n-6). Correlations were made with anthropometric, biochemical (serum glucose, triacylglycerols, LDL-C, HDL-C, ALT, AST, and their ratios) and clinical (blood pressure) indicators of cardiometabolic risk. Linear regression models were performed to test the independence of these associations.

Results

Estimated desaturase activities and certain FAs were associated with anthropometric, clinical and biochemical indicators of cardiometabolic risk: D9D, D6D, 16:1n-7 and 20:3n-6 were directly associated, while D5D and 18:0 were inversely associated. However, the associations with clinical and biochemical indicators were not independent of the associations with the level of adiposity, since they were lost after controlling for anthropometric indices. After controlling for multiple confounders (age, postmenopausal status, education, smoking, physical activity, dietary macronutrient intakes, use of supplements, alcohol consumption), the level of adiposity was the most significant predictor of desaturase activities and aforementioned FAs levels, and mediated their association with biochemical/clinical indicators. Vice versa, desaturase activities predicted the level of adiposity, but not other components of cardiometabolic risk (if the level of adiposity was accounted). While the associations of anthropometric indices with 16:1n-7, 20:3n-6, 18:0 and D9D and D6D activities were linear, the associations with D5D activity were the inverse U-shaped. The only adiposity-independent association of FAs profiles with the indicators of cardiometabolic risk was a positive association of 20:5n-3 with ALT/AST ratio, which requires further exploration.

Discussion

Additional studies are needed to explore the mechanisms of the observed associations.

Age-associated changes in circulatory fatty acids: new insights on adults and long-lived individuals

Long-lived individuals (LLIs) are considered an ideal model to study healthy human aging. Blood fatty acid (FA) profile of a cohort of LLIs (90-111 years old, n = 49) from Sicily was compared to adults (18-64 years old, n = 69) and older adults (65-89 years old, n = 54) from the same area. Genetic variants in key enzymes related to FA biosynthesis and metabolism were also genotyped to investigate a potential genetic predisposition in determining the FA profile. Gas chromatography was employed to determine the FA profile, and genotyping was performed using high-resolution melt (HRM) analysis. Blood levels of total polyunsaturated FA (PUFA) and total trans-FA decreased with age, while the levels of saturated FA (SFA) remained unchanged. Interestingly, distinctively higher circulatory levels of monounsaturated FA (MUFA) in LLIs compared to adults and older adults were observed. In addition, among LLIs, rs174537 in the FA desaturase 1/2 (FADS1/2) gene was associated with linoleic acid (LA, 18:2n-6) and docosatetraenoic acid (DTA, 22:4n-6) levels, and the rs953413 in the elongase of very long FA 2 (ELOVL2) was associated with DTA levels. We further observed that rs174579 and rs174626 genotypes in FADS1/2 significantly affect delta-6 desaturase (D6D) activity. In conclusion, our results suggest that the LLIs have a different FA profile characterized by high MUFA content, which indicates reduced peroxidation while maintaining membrane fluidity.

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.

Familial risk for bipolar I disorder is associated with erythrocyte omega-3 polyunsaturated fatty acid deficits in youth with attention-deficit hyperactivity disorder

Although attention-deficit/hyperactivity disorder (ADHD) and a family history of bipolar I disorder (BD) increase the risk for developing BD, associated pathoetiological mechanisms remain poorly understood. One candidate risk factor is a neurodevelopmental deficiency in omega-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This study investigated erythrocyte EPA+DHA biostatus in psychostimulant-free ADHD youth with ('high-risk', HR) and without ('low-risk', LR) a first-degree relative with BD, and healthy controls (HC). Erythrocyte EPA+DHA composition was determined by gas chromatography, and symptom ratings were performed. A total of n = 123 (HR, n = 41; LR, n = 42; HC, n = 40) youth (mean age: 14.4 ± 2.5 years) were included in the analysis. Compared with HC, erythrocyte EPA+DHA composition was significantly lower in HR (-13%) but not LR (-3%), and there was a trend for HR to be lower than LR (-11%). Both HR and LR differed significantly from HC on all symptom ratings. HR had greater ADHD hyperactivity/impulsive symptom severity, manic symptom severity, and higher parent-reported ratings of internalization, externalization, and dysregulation, compared with LR. ADHD youth with a BD family history exhibit erythrocyte EPA+DHA deficits and a more severe clinical profile, including greater manic and dysregulation symptoms, compared with ADHD youth without a BD family history.

Disrupted leptin-fatty acid biosynthesis is an early manifestation of metabolic abnormalities in schizophrenia

BACKGROUND

Insulin resistance (IR) and impaired energy expenditure (IEE) are irreparable metabolic comorbidities in schizophrenia. Although mechanism(s) underlying IR and IEE remains unclear, leptin and fatty acid signaling, which has profound influence on insulin secretion/sensitivity, glucose metabolism and energy expenditure, could be disrupted. However, no association of plasma leptin with erythrocyte membrane fatty acids, body mass index (BMI), and psychotic symptoms in the same cohort of untreated patients with first-episode psychosis (FEP) or medicated patients with chronic schizophrenia (CSZ) is presented before. These studies are crucial for deciphering the role of leptin and fatty acids in the development of IR and IEE in schizophrenia.

AIM

To determine the association between plasma leptin, erythrocyte membrane fatty acids, particularly, saturated fatty acids (SFAs), BMI and psychotic symptoms in patients with FEP and CSZ.

METHODS

In this study, twenty-two drug naive patients with FEP, twenty-one CSZ patients treated with atypical antipsychotic drugs, and fourteen healthy control (CNT) subjects were analyzed. Plasma leptin was measured using sandwich mode enzyme-linked immunosorbent assay. Erythrocyte membrane SFAs were measured using ultrathin capillary gas chromatography. BMI was calculated by using the formula: weight (kg)/height (m²). Psychiatric symptoms were evaluated at baseline using brief psychiatric rating scale (BPRS), and positive and negative syndrome scale (PANSS). The total BPRS scores, positive and negative symptom scores (PANSS-PSS and PANSS-NSS, respectively) were recorded. Pearson correlation coefficient (r) analyses were performed to find the nature and strength of association between plasma leptin, PANSS scores, BMI and SFAs, particularly, palmitic acid (PA).

RESULTS

In patients with FEP, plasma leptin not BMI was significantly lower (P = 0.034), whereas, erythrocyte membrane SFAs were significantly higher (P < 0.005) compared to the CNT subjects. Further, plasma leptin showed negative correlation with erythrocyte membrane SFAs-PA (r = −0.4972, P = 0.001), PANSS-PSS (r = −0.4034, P = 0.028), and PANSS-NSS (r = −0.3487, P = 0.048). However, erythrocyte membrane SFAs-PA showed positive correlation with PANSS-PSS (r = 0.5844, P = 0.0034) and PANSS-NSS (r = 0.5380, P = 0.008). In CSZ patients, plasma leptin, BMI, and erythrocyte membrane SFAs, all were significantly higher (P < 0.05) compared to the CNT subjects. Plasma leptin showed positive correlation with BMI (r = 0.312, P = 0.032) but not with PANSS scores or erythrocyte membrane SFAs-PA. However, erythrocyte membrane SFAs-PA showed positive correlation with PANSS-NSS only (r = 0.4729, P = 0.031). Similar changes in the plasma leptin and erythrocyte membrane SFAs have also been reported in individuals at ultra-high risk of developing psychosis; therefore, the above findings suggest that leptin-fatty acid biosynthesis could be disrupted before the onset of psychosis in schizophrenia.

CONCLUSION

Disrupted leptin-fatty acid biosynthesis/signaling could be an early manifestation of metabolic comorbidities in schizophrenia. Large-scale studies are warranted to validate the above findings.

Linoleic Acid Intake and Physical Function: Pilot Results from the Health ABC Energy Expenditure Sub-Study

Background:

Dietary fat quality is important for health and physical functioning in older adults. Linoleic acid is a dietary polyunsaturated fatty acid that is necessary for optimal inner-mitochondrial membrane function. However, limited evidence exists for examining the role of linoleic acid intake on indices of mobility and physical function. In this pilot study, we sought to examine the associations between linoleic acid intake and physical functioning in older adults.

Methods:

This secondary analysis of data from the Health, Aging, and Body Composition energy expenditure sub-study was conducted for our investigation. Ability to complete physical tasks such as climbing a flight of stairs, walking a quarter mile, and lifting 10 lbs. was self-reported. Daily linoleic acid intake was estimated from a food frequency questionnaire. Persons with daily linoleic acid intake below approximately 85% of Adequate Intake were considered as having low linoleic acid intake. Covariate-adjusted logistic models were used for the analyses.

Results:

The final analytical sample included 317 participants aged 74.4 ± 2.8 years who consumed 18.9 ± 11.4 g/day of linoleic acid, with 78 (24.6%) participants having low daily linoleic acid intake. Persons with low daily linoleic acid intake had 2.58 (95% confidence interval: 1.27–5.24) greater odds for a limitation in climbing stairs.

Conclusions:

Our pilot investigation found that low daily linoleic acid intake could be associated with physical function in older adults. Dietitians working with older patients may want to consider the importance of daily linoleic acid intake for health and certain physical function tasks.

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

Red blood cell (RBC) fatty acid (FA) patterns are becoming recognized as long-term biomarkers of tissue FA composition, but different analytical methods have complicated inter-study and international comparisons. Here we report RBC FA data, with a focus on the Omega-3 Index (EPA + DHA in% of total FAs in RBC), from samples of seven countries (USA, Canada, Italy, Spain, Germany, South Korea, and Japan) including 167,347 individuals (93% of all samples were from the US). FA data were generated by a uniform methodology from a variety of interventional and observational studies and from clinical laboratories. The cohorts differed in size, demographics, health status, and year of collection. Only the Canadian cohort was a formal, representative population-based survey. The mean Omega-3 Index of each country was categorized as desirable (>8%), moderate (>6% to 8%), low (>4% to 6%), or very low (≤4%). Only cohorts from Alaska (treated separately from the US), South Korea and Japan showed a desirable Omega-3 Index. The Spanish cohort had a moderate Omega-3 Index, while cohorts from the US, Canada, Italy, and Germany were all classified as low. This study is limited by the use of cohorts of convenience and small sample sizes in some countries. Countries undertaking national health status studies should utilize a uniform method to measure Omega-3 FA levels.

Omega-3 Fatty Acids Improve Functionality of High-Density Lipoprotein in Individuals With High Cardiovascular Risk: A Randomized, Parallel, Controlled and Double-Blind Clinical Trial

Omega-3 (ω-3) fatty acids have been extensively studied for primary and secondary prevention of cardiovascular health, but their ability to modulate HDL functionality remains unclear. The purpose of this study was to investigate the role of ω-3, rich in eicosapentaenoic (EPA) and docosahexaenoic (DHA), on HDL functionality. For that, 147 individuals with high cardiovascular risk were randomized in ω-3 (1 g of fish oil each - 370 mg of EPA and 230 mg of DHA, 3 times per day total EPA+DHA = 1,800 mg) or ω-6 groups (1 g of sunflower oil each - 760 mg of linoleic acid, 3 times per day; total linoleic acid = 2,280 mg). Fasting blood samples were collected at baseline time and after 8 weeks of follow-up and, and the lipid profile and glucose metabolism were evaluated from plasma. From HDL, the fatty acid profile, apolipoproteins (Apo AI, CII and CIII), paraoxonase-1 (PON1), cholesteryl ester transfer protein (CETP), subfractions and antioxidant activity were investigated. Omega-3 improved large HDL (HDL = 28.7%) and reduced small HDL (HDL10 = −10.6%) and the non-esterified fatty acids in HDL (NEFAs-HDL) level (−16.2%). A significant reduction in CETP activity was observed in the ω-3group (Δ ω-6 = 3.60 pmol/ul/h and Δ ω-3 = −1.99 pmol/ul/h; p = 0.044). The antioxidant capacity estimated by Lag time analysis did not change after the ω-3intervention. Changes in PON1 and Apo AI were inversely associated with increased incorporation of EPA (AOR = 0.446; IC = 0.200–0.994) and DHA (AOR = 0.351; IC = 0.150–0.821) in HDL, respectively. Cardioprotective profile obtained by pooled fatty acids analysis was related to a decrease in Apo CIII (r = −0.638; p = 0.002) and CETP (r = −0.341; p = 0.012) and an increase in Apo CII (r = 0.448; p = 0.042) and PON1 (r = 0.388; p = 0.003). In conclusion, omega-3 was effective in the reduction of cardiovascular risk associated with HDL functionality by size improvement and changes in its lipid, antioxidant and enzyme composition.

Molecular Deficits Relevant to Concussion Are Prevalent in Top-Ranked Football Players Entering the National Football League Draft

ABSTRACT

Kunces, LJ, Keenan, J, Schmidt, CM, and Schmidt, MA. Molecular deficits relevant to concussion are prevalent in top-ranked football players entering the National Football League draft. J Strength Cond Res XX(X): 000-000, 2021-Characterization of blood variants in athletes entering the highly competitive contact environment of professional football can help us understand the risk for brain injury. When coupled with longitudinal follow-up of future concussion incidence and trajectory, it may provide additional insight into factors that influence brain injury. We observed the metabolic phenotype of collegiate football players entering the 2016 National Football League (NFL) draft. The principal aims were to characterize the molecular status of individual athletes and quantify the prevalence of athletes with multiple concurrent molecular deficits. Blood was taken from 30 elite American collegiate football players 7 weeks before the NFL scouting combine and 15 weeks before entering the NFL draft. Average results revealed suboptimal values in Omega-3 Index (avg ± std, 4.66 ± 1.16%), arachidonic acid:eicosapentaenoic acid fatty acid ratio (29.13 ± 10.78), homocysteine (11.4 ± 3.4 µmol·L-1), vitamin D (30 ± 11.4 ng·ml-1), and red blood cell magnesium (4.1 ± 0.8 mg·dl-1). Using sport-optimized reference ranges from previously published research, 10% presented with 3, 40% presented with 4, and 50% of athletes presented with 5 suboptimal values at once. We conclude molecular deficits in this cohort entering the NFL draft were common, with a significant number of athletes presenting with multiple suboptimal levels. The significant commonality of the suboptimal biomarkers is relevance to brain health and function. This data warrant extensive metabolic phenotyping and consideration of prophylactic precision nutrition countermeasures by the multidisciplinary staff for athletes entering contact environments.

Dietary Control of Inflammation and Resolution

The healing of any injury requires a dynamic balance of initiation and resolution of inflammation. This hypothesis-generating review presents an overview of the various nutrients that can act as signaling agents to modify the metabolic responses essential for the optimal healing of injury-induced inflammation. In this hypothesis-generating review, we describe a defined nutritional program consisting of an integrated interaction of a calorie-restricted anti-inflammatory diet coupled with adequate levels of omega-3 fatty acids and sufficient levels of dietary polyphenols that can be used in clinical trials to treat conditions associated with insulin resistance. Each dietary intervention works in an orchestrated systems-based approach to reduce, resolve, and repair the tissue damage caused by any inflammation-inducing injury. The orchestration of these specific nutrients and their signaling metabolites to facilitate healing is termed the Resolution Response. The final stage of the Resolution Response is the activation of intracellular 5' adenosine monophosphate-activated protein kinase (AMPK), which is necessary to repair tissue damaged by the initial injury-induced inflammation. The dietary optimization of the Resolution Response can be personalized to the individual by using standard blood markers. Once each of those markers is in their appropriate ranges, activation of intracellular AMPK will be facilitated. Finally, we outline how the resulting activation of AMPK will affect a diverse number of other intercellular signaling systems leading to an extended healthspan.

Tissue and Circulating Fatty Acids as Biomarkers to Evaluate Long-Term Fat Intake Are Tissue and Sex Dependent in CD-1 Mice

BACKGROUND

There is currently no consensus on which tissues are optimal for assessing specific diet-derived fatty acids (FAs) as biomarkers for long-term dietary studies.

OBJECTIVES

This study measured the content of unique diet-derived FAs from dairy, echium, and fish in tissues (adipose, muscle, liver, erythrocyte membranes, and plasma phospholipids, cholesterol esters, triglycerides, and free fatty acids) after long-term feeding in CD-1 mice.

METHODS

Beginning at weaning, mice (n = 10-11/sex/diet) were fed 1 of 4 diets (40% kcal/total energy) that only differed in FA composition: control fat blend (CON), reflecting the FA profile of the average US American diet, or CON supplemented with 30% of fish oil (FO), dairy fat (DF), or echium oil (EO). After 13 mo, tissues were collected to determine FAs via gas-liquid chromatography. Tissue FAs were analyzed via 2-factor ANOVA, and relationships between FA intake and tissue content were assessed with Spearman correlations.

RESULTS

As anticipated, 20:5n-3 (ω-3) tissue content was ≤32-fold greater in FO- compared with CON-fed mice (P < 0.05). In addition, 20:5n-3 intake strongly correlated with its content in all tissues (ρ = 0.67-0.76; P < 0.05). Echium oil intake also influenced tissue FA content in mice as expected. For example, 18:3n-6 was ≤25-fold greater in adipose, muscle, and liver tissues of EO-fed compared with CON-fed mice (P < 0.05). Tissue content of FAs typically considered biomarkers of dairy fat intake (15:0, 16:1 t9, and 17:0) was often not greater in mice fed DF than other diet groups, although 18:2 c9, t11 content was ≤6-fold greater in tissues from DF-fed compared with CON-fed mice (P < 0.05). The content of dairy-derived FAs in blood fractions of females was up to 2-fold greater compared with males, whereas docosapentaenoic acid content was up to 1-fold greater in all blood fractions and in liver tissue of males compared with females (P < 0.05). In adipose, muscle, and liver tissue, the content of γ-linolenic acid and stearidonic acid was less than 1-fold greater in females than in males (P < 0.05).

CONCLUSIONS

Our study indicates that the distribution of dietary FAs is tissue and sex dependent in aged CD-1 mice. Research using FA biomarkers should assess a combination of FA biomarkers to accurately validate patterns of FA intake and source.

Aspirin and omega-3 fatty acid status interact in the prevention of cardiovascular diseases in Framingham Heart Study

BACKGROUND

The roles of omega-3 (n3) fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] and low-dose aspirin in the primary prevention of ischemic cardiovascular disease (CVD) are controversial. Since omega-3 (n3) fatty acids and aspirin affect cyclooxygenase activity in platelets, there could be a clinically-relevant effect of aspirin combined with a particular n3 fatty acid level present in each individual.

METHODS

RBC EPA+DHA, arachidonic acid (AA) and docosapentaenoic acid (DPA) were measured in 2500 participants without known CVD in the Framingham Heart Study. We then tested for interactions with reported aspirin use (1004 reported use and 1494 did not) on CVD outcomes. The median follow-up was 7.2 years.

RESULTS

Having RBC EPA+DHA in the second quintile (4.2-4.9% of total fatty acids) was associated with significantly reduced risk for future CVD events (relative to the first quintile, <4.2%) in those who did not take aspirin (HR 0.54 (0.30, 0.98)), but in those reporting aspirin use, risk was significantly increased (HR 2.16 (1.19, 3.92)) in this quintile. This interaction remained significant when adjusting for confounders. Significant interactions were also present for coronary heart disease and stroke outcomes using the same quintiles. Similar findings were present for EPA and DHA alone but not for DPA and AA.

CONCLUSIONS

There is a complex interaction between aspirin use and RBC EPA+DHA levels on CVD outcomes. This suggests that aspirin use may be beneficial in one omega-3 environment but harmful in another, implying that a personalized approach to both aspirin use and omega-3 supplementation may be needed.

Blood Omega-3 Fatty Acids Are Inversely Associated With Albumin-Creatinine Ratio in Young and Healthy Adults (The Omega-Kid Study)

Background: Omega-3 fatty acids are associated with a lower risk of cardiovascular disease (CVD) and with beneficial effects on CV risk factors. The albumin-creatinine ratio (ACR) is a risk factor for CVD, all-cause mortality and accelerated glomerular filtration rate (GFR) decline in the general population. We aimed to investigate the association between n-3 PUFAS and ACR in heathy individuals with preserved GFR. Design and Methods: The present cross-sectional analysis is part of the GAPP study, a population-based cohort of healthy adults aged 25-41 years. Individuals with known CVD, diabetes, or a BMI >35 kg/m² were excluded. eGFR was calculated according to the combined Creatinine/Cystatin C CKD-EPI formula. ACR was obtained from a fasting morning urine sample. The Omega-3 Index (relative amount of EPA and DHA of total fatty acids in %) was obtained from whole blood aliquots. Results: Overall, 2001 participants (median age 37 years IQR 31; 40, 53% female) were included in this analysis. Median Omega-3 Index was 4.59 (IQR 4.06; 5.25) and median eGFR 111 ml/min/1.73 m² (IQR 103; 118). Median ACR was 0.14 mg/mmol (IQR 0; 0.43). We found a significant inverse association of the Omega-3 Index with ACR (ratio 0.84, 95%CI 0.73-0.96; p = 0.011) which remained after comprehensive adjustment (ratio 0.86, 95%CI 0.74-1.00; p = 0.048). No association of the Omega-3 Index with eGFR was found. The adjusted difference in eGFR per 1-unit increase in Omega3-Index was -0.21 (95%CI -0.76; 0.35; p = 0.47). Conclusions: A higher Omega-3 Index was significantly associated with lower ACR in this young and healthy population with preserved eGFR. Omega-3 fatty acids may exhibit cardio- and nephroprotective effects in healthy individuals through modulation of ACR.

Fatty acid desaturase activity in mature red blood cells and implications for blood storage quality

BACKGROUND

Increases in the red blood cell (RBC) degree of fatty acid desaturation are reported in response to exercise, aging, or diseases associated with systemic oxidant stress. However, no studies have focused on the presence and activity of fatty acid desaturases (FADS) in the mature RBC.

STUDY DESIGN AND METHODS

Steady state metabolomics and isotope-labeled tracing experiments, immunofluorescence approaches, and pharmacological interventions were used to determine the degree of fatty acid unsaturation, FADS activity as a function of storage, oxidant stress, and G6PD deficiency in human and mouse RBCs.

RESULTS

In 250 blood units from the REDS III RBC Omics recalled donor population, we report a storage-dependent accumulation of free mono-, poly-(PUFAs), and highly unsaturated fatty acids (HUFAs), which occur at a faster rate than saturated fatty acid accumulation. Through a combination of immunofluorescence, pharmacological inhibition, tracing experiments with stable isotope-labeled fatty acids, and oxidant challenge with hydrogen peroxide, we demonstrate the presence and redox-sensitive activity of FADS2, FADS1, and FADS5 in the mature RBC. Increases in PUFAs and HUFAs in human and mouse RBCs correlate negatively with storage hemolysis and positively with posttransfusion recovery. Inhibition of these enzymes decreases accumulation of free PUFAs and HUFAs in stored RBCs, concomitant to increases in pyruvate/lactate ratios. Alterations of this ratio in G6PD deficient patients or units supplemented with pyruvate-rich rejuvenation solutions corresponded to decreased PUFA and HUFA accumulation.

CONCLUSION

Fatty acid desaturases are present and active in mature RBCs. Their activity is sensitive to oxidant stress, storage duration, and alterations of the pyruvate/lactate ratio.

Effects of menopausal hormone therapy on erythrocyte n-3 and n-6 PUFA concentrations in the Women's Health Initiative randomized trial

BACKGROUND

The factors other than dietary intake that determine tissue concentrations of EPA and DHA remain obscure. Prior studies suggested that, in women, endogenous estrogen may accelerate synthesis of DHA from ɑ-linolenic acid (ALA), but the effects of exogenous estrogen on RBC n-3 (ɷ-3) PUFA concentrations are unknown.

OBJECTIVE

We tested the hypothesis that menopausal hormone therapy (HT) would increase RBC n-3 PUFA concentrations.

METHODS

Postmenopausal women (ages 50-79 y) were assigned to HT or placebo in the Women's Health Initiative (WHI) randomized trial. The present analyses included a subset of 1170 women (ages 65-79 y) who had RBC PUFA concentrations measured at baseline and at 1 y as participants in the WHI Memory Study. HT included conjugated equine estrogens (E) alone for women without a uterus (n = 560) and E plus medroxyprogesterone acetate (P) for those with an intact uterus (n = 610). RBC n-3 and n-6 (ɷ-6) PUFAs were quantified.

RESULTS

Effects of E alone and E+P on PUFA profiles were similar and were thus combined in the analyses. Relative to the changes in the placebo group after 1 y of HT, docosapentaenoic acid (DPA; n-3) concentrations decreased by 10% (95% CI: 7.3%, 12.5%), whereas DHA increased by 11% (95% CI: 7.4%, 13.9%) in the HT group. Like DHA, DPA n-6 increased by 13% from baseline (95% CI: 10.0%, 20.3%), whereas linoleic acid decreased by 2.0% (95% CI: 1.0%, 4.1%; P values at least <0.01 for all). EPA and arachidonic acid concentrations were unchanged.

CONCLUSIONS

HT increased RBC concentrations of the terminal n-3 and n-6 PUFAs (DHA and DPA n-6). These findings are consistent with an estrogen-induced increase in DHA and DPA n-6 synthesis, which is consistent with an upregulation of fatty acid elongases and/or desaturases in the PUFA synthetic pathway. The clinical implications of these changes require further study. The Women's Health Initiative Memory Study is registered at clinicaltrials.gov as NCT00685009. Note that the data presented here were not planned as part of the original trial, and therefore are to be considered exploratory.

Blood omega-3 fatty acids and death from COVID-19: A pilot study

Very-long chain omega-3 fatty acids (EPA and DHA) have anti-inflammatory properties that may help reduce morbidity and mortality from COVID-19 infection. We conducted a pilot study in 100 patients to test the hypothesis that RBC EPA+DHA levels (the Omega-3 Index, O3I) would be inversely associated with risk for death by analyzing the O3I in banked blood samples drawn at hospital admission. Fourteen patients died, one of 25 in quartile 4 (Q4) (O3I ≥5.7%) and 13 of 75 in Q1-3. After adjusting for age and sex, the odds ratio for death in patients with an O3I in Q4 vs Q1-3 was 0.25, p = 0.07. Although not meeting the classical criteria for statistical significance, this strong trend suggests that a relationship may indeed exist, but more well-powered studies are clearly needed.

Associations Between Systemic Omega-3 Fatty Acid Levels With Moderate-to-Severe Dry Eye Disease Signs and Symptoms at Baseline in the Dry Eye Assessment and Management Study

PURPOSE

Omega-3 (n-3) fatty acid supplementation is used to treat systemic inflammatory diseases, but the role of n-3 in the pathophysiology and therapy of dry eye disease (DED) is not definitive. We evaluated the relationship of systemic n-3 levels with signs and symptoms at baseline in the Dry Eye Assessment and Management (DREAM) Study.

METHODS

Blood samples from participants at baseline were analyzed for n-3 and n-6, measured as relative percentage by weight among all fatty acids in erythrocytes. Symptoms were evaluated using the Ocular Surface Disease Index. Signs including conjunctival staining, corneal staining, tear breakup time (TBUT), and Schirmer's test with anesthesia were also evaluated.

RESULTS

There was no correlation between the systemic n-3 levels and DED symptoms. When the associations with signs of DED were assessed, lower DHA levels were associated with higher conjunctival staining, with mean scores of 3.31, 2.96, and 2.82 for low, medium, and high levels of DHA, respectively (linear trend P=0.007). None of the other signs were associated with DHA or the other measures of n-3.

CONCLUSION

Previous studies have found varying results on the role of n-3 supplementation with the signs and symptoms of DED. Among patients with DED enrolled in the DREAM Study, lower systemic n-3 levels were not associated with worse symptoms and most signs of DED.

Foveal macular pigment dip in offspring of age-related macular degeneration patients is inversely associated with omega-3 index

Background

Offspring of parent(s) with age-related macular degeneration (AMD) have a 45% lifetime risk of developing the disease. High foveal macular pigment optical density (MPOD) is protective, whereas individuals with a “foveal macular pigment dip” (FMPD) are at increased risk. Shortage of the dietary carotenoids lutein, zeaxanthin as well as fish consumption are reported AMD risk factors. This Early Biomarkers of AMD (EBAMD) study evaluates serum factors that protect foveal MPOD architecture in Caucasian offspring of parent(s) with AMD.

Methods

N = 130 subjects [mean (SD) age 62.8 (8.6) years; 36/94 male/female] were recruited from Scripps Health/ Scripps Memorial Hospital/ Scripps Mericos Eye Institute between 2012 and 2017. Macula pigment 3D topography was evaluated using specular reflectance. Buccal genetic cheek swab, circulating serum dietary carotenoids and long-term RBC omega-3 fatty acid status, as well as common secondary clinical structural and vision function parameters were obtained.

Results

41 % of offspring of AMD parent(s) presented with FMPD. These offspring were about 4 years younger than those without FMPD (controls; P = 0.012) and had thinner foveas (P = 0.010). There were no differences in gender, BMI, % body fat, visual acuity or contrast sensitivity between those with and without FMPD. % RBC membrane docosahexaenoic acid (DHA) was reduced in FMPD offspring vs. control offspring (P = 0.04). The Omega-3 Index was significantly decreased in the FMPD group (P = 0.03).

Conclusions

The percentage of FMPD in AMD offspring is nearly twice that reported for the general population in the scientific literature. Offspring presenting FMPD had similar AMD genetic risk, but significantly reduced % RBC membrane omega-3 fatty acids and thinner foveas compared with those without FMPD. Our data supports the importance of ‘essential fatty’ acids as an independent AMD risk factor.

Higher omega-3 index is associated with more rapid heart rate recovery in healthy men and women

BACKGROUND

Previous studies have suggested that omega-3 polyunsaturated fatty acids (n-3 PUFA) can favorably influence cardiac autonomic tone. However, data regarding n-3 PUFA status and heart rate recovery (HRR) in healthy adults are sparse.

PURPOSE

To examine the association between n-3 PUFA status and HRR.

METHODS

Participants included 13,912 patients who underwent a comprehensive examination at the Cooper Clinic, Dallas TX. Fitness was determined from a maximal exercise test. HRR was calculated by subtracting the heart rate at 1, 3, and 5 min of an active recovery period from the maximal heart rate. Participants were categorized as having a low (<4%), normal (4-8%) or optimal (>8%) Omega-3 Index (O3I) (i.e., erythrocyte levels of eicosapentaenoic and docosahexaenoic acids). Multiple linear regression was used to model the association between O3I and HRR adjusting for age, maximal METs, body mass index, and smoking by sex.

RESULTS

Higher categories of O3I were associated with greater HRR at 1 min (men: 23.7, 23.9, 24.6 beats/min; women: 23.9, 24.6, 25.9 and 3 min (men: 52.4, 52.9, 53.6 beats/min; women: 51.9, 53.4, 54.6), p trend <0.01 for all. Corresponding HRR at 5 min were (men: 60.0, 60.2, 60.7 beats/min, p trend=0.09; women: 59.4, 60.8, 61.6, p trend <0.001). The HRR gradients across O3I categories were steeper in women than men at 1, 3, and 5 min (p<0.03 for all sex x O3I category interactions with HRR).

CONCLUSIONS

A direct relationship between HRR and O3I values was observed in both men and women, with a steeper gradient in women. These findings suggest a potential cardioprotective mechanism for n-3 PUFA.

Higher Increase in Plasma DHA in Females Compared to Males Following EPA Supplementation May Be Influenced by a Polymorphism in ELOVL2: An Exploratory Study

Young adult females have higher blood docosahexaenoic acid (DHA), 22:6n-3 levels than males, and this is believed to be due to higher DHA synthesis rates, although DHA may also accumulate due to a longer half-life or a combination of both. However, sex differences in blood fatty acid responses to eicosapentaenoic acid (EPA), 20:5n-3 or DHA supplementation have not been fully investigated. In this exploratory analysis, females and males (n = 14-15 per group) were supplemented with 3 g/day EPA, 3 g/day DHA, or olive oil control for 12 weeks. Plasma was analyzed for sex effects at baseline and changes following 12 weeks' supplementation for fatty acid levels and carbon-13 signature (δ¹³ C). Following EPA supplementation, the increase in plasma DHA in females (+23.8 ± 11.8, nmol/mL ± SEM) was higher than males (-13.8 ± 9.2, p < 0.01). The increase in plasma δ¹³ C-DHA of females (+2.79 ± 0.31, milliUrey (mUr ± SEM) compared with males (+1.88 ± 0.44) did not reach statistical significance (p = 0.10). The sex effect appears driven largely by increased plasma DHA in the AA genotype of females (+58.8 ± 11.5, nmol/mL ± SEM, n = 5) compared to GA + GG in females (+4.34 ± 13.5, n = 9) and AA in males (-29.1 ± 17.2, n = 6) for rs953413 in the ELOVL2 gene (p < 0.001). In conclusion, EPA supplementation increases plasma DHA levels in females compared to males, which may be dependent on the AA genotype for rs953413 in ELOVL2.

Polyunsaturated fatty acid biosynthesis pathway and genetics. implications for interindividual variability in prothrombotic, inflammatory conditions such as COVID-19✰,✰✰,★,★★

COVID-19 symptoms vary from silence to rapid death, the latter mediated by both a cytokine storm and a thrombotic storm. SARS-CoV (2003) induces Cox-2, catalyzing the synthesis, from highly unsaturated fatty acids (HUFA), of eicosanoids and docosanoids that mediate both inflammation and thrombosis. HUFA balance between arachidonic acid (AA) and other HUFA is a likely determinant of net signaling to induce a healthy or runaway physiological response. AA levels are determined by a non-protein coding regulatory polymorphisms that mostly affect the expression of FADS1, located in the FADS gene cluster on chromosome 11. Major and minor haplotypes in Europeans, and a specific functional insertion-deletion (Indel), rs66698963, consistently show major differences in circulating AA (>50%) and in the balance between AA and other HUFA (47-84%) in free living humans; the indel is evolutionarily selective, probably based on diet. The pattern of fatty acid responses is fully consistent with specific genetic modulation of desaturation at the FADS1-mediated 20:3→20:4 step. Well established principles of net tissue HUFA levels indicate that the high linoleic acid and low alpha-linoleic acid in populations drive the net balance of HUFA for any individual. We predict that fast desaturators (insertion allele at rs66698963; major haplotype in Europeans) are predisposed to higher risk and pathological responses to SARS-CoV-2 could be reduced with high dose omega-3 HUFA.

Relationships of Fatty Acids, Delta-5 Desaturase Activity, and Lipid Profiles in Men with Acute Coronary Syndrome

AIMS

We evaluated the relationship between the ratios of eicosapentaenoic acid and arachidonic acid (EPA/AA), docosahexaenoic acid (DHA)/AA, and delta-5 desaturase activity (D5D) and atherogenic lipid profiles (ALP) and coronary atherosclerosis.

METHODS

Polyunsaturated fatty acids (PUFA) and ALP were assessed in 436 men with the first episode of acute coronary syndrome (ACS) not take any lipid-lowering drugs. D5D was estimated as the ratio of AA to dihomogamma-linolenic acid (DGLA). These biomarkers were compared between the lower and higher levels of EPA/AA (0.41) or DHA/AA (0.93) according to the levels in Japanese general population. The thrombolysis in myocardial infarction flow (TIMI) grade of the culprit coronary artery was visually estimated during the initial angiography.

RESULTS

Approximately 70% of patients had low EPA/AA or DHA/AA. Serum levels of LDL-cholesterol, apolipoprotein B (apoB), and remnant lipoprotein cholesterol (RL-C) were significantly higher in the low EPA/AA or DHA/AA groups, while those of triglycerides and malondialdehyde-modified LDL (MDA-LDL) were significantly higher in the low EPA/AA group alone. The levels of EPA, EPA/AA, DHA/AA, and HbA1c increased and those of DGLA and apoA1 decreased with increasing number of stenotic vessels. Patients with three stenotic coronary vessels or TIMI grade ≥ 1 had significantly higher EPA levels compared with the others. The levels of LDL-cholesterol, non-HDL-cholesterol, triglycerides, small dense LDL-cholesterol, RL-C, MDA-LDL, apoB, and apoE decreased progressively and those of EPA, DHA, EPA/AA and HDL-cholesterol increased as D5D increased.

CONCLUSIONS

The EPA/AA is a superior risk marker than DHA/AA in term of correlation with ALP in ACS patients.

Changes in Erythrocyte Omega-3 Fatty Acids in German Employees upon Dietary Advice by Corporate Health

Background: The erythrocyte ratio of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) over total fatty acids, the omega-3 index (O3I), has been suggested as an overall health marker and to motivate corporate health recommendations. We set out to assess the O3I status in a working population, the differences between normal and rotating shift employees, the consumption of omega-3 rich food and whether recommendations to increase intake of omega-3 rich foods can improve the O3I. Methods: Employees registered for their occupational health check-up were offered to participate in a pre-post study at the Ludwigshafen (Germany) site including an assessment of their O3I at baseline and after 4 months (follow-up) and two subsequent food frequency questionnaires. For those with O3I below 8%, a recommendation was provided to increase the intake of omega-3 fatty acid rich food and to take advantage of the employees’ catering service with its enhanced fatty seafood offer during the study period. Dietary intake of EPA and DHA, erythrocyte fatty acid profiles, clinical and lifestyle parameters were assessed. Results: In 500 employees (26.6% female, 21–64 years, median age: 47 years [IQR: 37–53]), at baseline the overall mean O3I was 4.1 ± 1.1% (99.6% of O3I assessed were below 8%), higher in women, in participants with “normal” body weight, upper employment grade, and non-smokers, but not different between regular and rotating shift workers. The three fifths of the cohort also participating in the follow-up increased their EPA and DHA intake by 0.1 g/d and their O3I by 0.5 percentage points. Conclusion: This study provides essential data on omega-3 erythrocyte concentrations in a clinically healthy German working population and the challenges of increasing the O3I with dietary recommendations even in study participants motivated to follow up on their omega-3 status.

The Erythrocyte Membrane Lipidome of Healthy Dogs: Creating a Benchmark of Fatty Acid Distribution and Interval Values

Molecular-based approaches are rapidly developing in medicine for the evaluation of physiological and pathological conditions and discovery of new biomarkers in prevention and therapy. Fatty acid diversity and roles in health and disease in humans are topical subjects of lipidomics. In particular, membrane fatty acid-based lipidomics provides molecular data of relevance in the study of human chronic diseases, connecting metabolic, and nutritional aspects to health conditions. In veterinary medicine, membrane lipidomics, and fatty acid profiles have not been developed yet in nutritional approaches to health and in disease conditions. Using a protocol widely tested in human profiling, in the present study erythrocyte membrane lipidome was examined in 68 clinically healthy dogs, with different ages, sex, and sizes. In particular, a cluster composed of 10 fatty acids, present in membrane glycerophospholipids and representative of structural and functional properties of cell membrane, was chosen, and quantitatively analyzed. The interval values and distribution for each fatty acid of the cluster were determined, providing the first panel describing the healthy dog lipidomic membrane profile, with interesting correlation to bodyweight increases. This molecular information can be advantageously developed as benchmark in veterinary medicine for the evaluation of metabolic and nutritional status in healthy and diseased dogs.

Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Current evidence on associations between intakes of linoleic acid (LA), the predominant n-6 (ω-6) fatty acid, and mortality is inconsistent and has not been summarized by a systematic review and meta-analysis.

OBJECTIVE

The aim was to perform a systematic review and meta-analysis of prospective cohort studies to examine associations between LA intake and mortality.

METHODS

We conducted a comprehensive search of MEDLINE and EMBASE databases through 31 July 2019 for prospective cohort studies reporting associations of LA (assessed by dietary surveys and/or LA concentrations in adipose tissue or blood compartments) with mortality from all causes, cardiovascular disease (CVD), and cancer. Multivariable-adjusted RRs were pooled using random-effects meta-analysis.

RESULTS

Thirty-eight studies reporting 44 prospective cohorts were identified; these included 811,069 participants with dietary intake assessment (170,076 all-cause, 50,786 CVD, and 59,684 cancer deaths) and 65,411 participants with biomarker measurements (9758 all-cause, 6492 CVD, and 1719 cancer deaths). Pooled RRs comparing extreme categories of dietary LA intake (high vs low) were 0.87 (95% CI: 0.81, 0.94; I2 = 67.9%) for total mortality, 0.87 (95% CI: 0.82, 0.92; I2 = 3.7%) for CVD mortality, and 0.89 (95% CI: 0.85, 0.93; I2 = 0%) for cancer mortality. Pooled RRs for each SD increment in LA concentrations in adipose tissue/blood compartments were 0.91 (95% CI: 0.87, 0.95; I2 = 64.1%) for total mortality, 0.89 (95% CI: 0.85, 0.94; I2 = 28.9%) for CVD mortality, and 0.91 (95% CI: 0.84, 0.98; I2 = 26.3%) for cancer mortality. Meta-regressions suggested baseline age and dietary assessment methods as potential sources of heterogeneity for the association between LA and total mortality.

CONCLUSIONS

In prospective cohort studies, higher LA intake, assessed by dietary surveys or biomarkers, was associated with a modestly lower risk of mortality from all causes, CVD, and cancer. These data support the potential long-term benefits of PUFA intake in lowering the risk of CVD and premature death.

Effects of Fish Oil Monotherapy on Depression and Prefrontal Neurochemistry in Adolescents at High Risk for Bipolar I Disorder: A 12-Week Placebo-Controlled Proton Magnetic Resonance Spectroscopy Trial

Objectives: To evaluate the clinical and neurochemical effects of 12-week fish oil, a source of omega-3 polyunsaturated fatty acids (n-3 PUFAs), in depressed adolescents with a family history of bipolar I disorder. Methods: Adolescents with a current Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision diagnosis of Major Depressive Disorder or Depressive Disorder not otherwise specified, a Childhood Depression Rating Scale-Revised (CDRS-R) Version raw score of ≥40, and at least one biological parent with bipolar I disorder were randomized to double-blind treatment with fish oil (2100 mg/day) or placebo for 12 weeks. The primary outcome measure was change in CDRS-R total score, and secondary outcomes measures were change in manic symptoms (Young Mania Rating Scale), global symptom and functioning measures (Clinical Global Impression-Severity [CGI-S] /CGI Improvement [CGI-I], Children's Global Assessment Scale, and Child Behavior Checklist), safety and laboratory measures, and anterior cingulate cortex (ACC) and bilateral ventrolateral prefrontal cortex neurometabolite concentrations using proton magnetic resonance spectroscopy at 4 T. Results: Fifty-six patients were randomized, and 42 completed the 12-week trial (placebo: n = 21; fish oil, n = 21). Subjects randomized to fish oil, but not placebo, exhibited a significant baseline to endpoint increase in erythrocyte n-3 PUFAs. Reductions in CDRS-R scores did not differ between treatment groups (p = 0.15), and similar remission (p = 0.58) and response (p = 0.77) rates were observed. Fish oil produced a significantly greater decrease in CGI-S (p = 0.0042) and CGI-I (p = 0.036) scores compared with placebo. Baseline to endpoint change in ACC creatine (p = 0.004) and ACC choline (Cho) (p = 0.024) differed significantly between groups. Baseline ACC Cho levels were inversely correlated with baseline and baseline to endpoint change in CDRS-R scores, and baseline to endpoint change in ACC Cho correlated with baseline-endpoint change in CDRS-R scores and n-3 PUFA. There were no group differences in safety and tolerability ratings or laboratory measures. Conclusions: Fish oil monotherapy was not superior to placebo for reducing depressive symptoms in high-risk youth as assessed by the CDRS-R, but was safe and well tolerated and superior to placebo on clinician ratings of global symptom improvement. Associations among ACC Cho levels, depression symptom severity, and n-3 PUFA warrant additional investigation.

ISSFAL Official Statement Number 6: The importance of measuring blood omega-3 long chain polyunsaturated fatty acid levels in research

A statement on measuring blood omega-3 long chain polyunsaturated fatty acid levels was developed and edited based on input from ISSFAL members and accepted by vote of the ISSFAL Board of Directors. Summary of Statement: Omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) levels at baseline and post-intervention should be assessed and reported in future research to evaluate the efficacy of n-3 LCPUFA supplementation: b ecause; 1. there are numerous factors that affect n-3 LCPUFA levels in humans as described in the systematic literature review [1]; 2. assessing intake of n-3 LCPUFA from the diet and/or supplements is not sufficient to accurately determine n-3 LCPUFA levels in humans; 3. some studies do not provide sufficient doses of n-3 LCPUFA to produce a significant impact on bloodstream/organ content and there is substantial variability in the uptake of n-3 LPCUFA into tissues between individuals. In secondary analyses, clinical trials should consider the influence of fatty acid status (baseline, endpoint and change from baseline to endpoint) on the outcome variables.

Metabolic indices of polyunsaturated fatty acids: current evidence, research controversies, and clinical utility

The n-3 and n-6 polyunsaturated fatty acids (PUFA) are among the most studied nutrients in human metabolism. In the past few decades, prospective studies and controlled trials have supported the view that the effects of these essential fatty acids are clinically relevant. PUFA profiles in different blood compartments are reflections of both diet and metabolism, and their levels may be related to disease risk. Despite widespread interest, there is no consensus regarding which biomarkers best reflect PUFA status in the body. The measurement of PUFA levels is not straight-forward, and a wide variety of indices have been used in clinical studies, producing conflicting results. A major source of heterogeneity among studies is associated with research design, sampling, and laboratory analyses. To date, the n-3 index, n-6/n-3 ratio, and arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio are the most promising biomarkers associated with PUFA metabolism. Although hotly debated, these indices may be considered at least markers, if not risk factors, for several diseases, especially cardiovascular events and brain disorders. Here, we summarize the most updated evidence of n-3 and n-6 PUFA effects on human health, reviewing current controversies on the aforementioned indices and whether they can be considered valuable predictors of clinical outcomes.

Survey of the erythrocyte EPA+DHA levels in the heart attack/stroke belt

BACKGROUND

The Omega-3 Index (O3I; erythrocyte EPA+DHA as a percent of total fatty acids) is inversely related to risk for cardiovascular disease (CVD). The cardioprotective target O3I is 8%-12%. O3I levels in American regions with high CVD risk are poorly characterized.

PURPOSE

To determine the O3I in individuals participating in a Seafood Nutrition Partnership (SNP) survey in seven US cities in the CVD "belt."

METHODS

Fingerstick blood samples were analyzed for the O3I.

RESULTS

The SNP cohort (n = 2177) had a mean (SD) O3I of 4.42% (1.12%). Only 1.2% were in the desirable range, whereas 42% had an undesirable (<4%) O3I. The mean (SD) O3I in a subset of 772 SNP subjects who were matched for age and sex with the Framingham study was 4.6% (1.2%) compared 5.3% (1.6%) in the Framingham cohort (p < 0.0001).

CONCLUSIONS

Individuals in the CVD "belt" had relatively low O3I levels. Since in other settings, a low O3I is associated with increased risk for CVD, this may be one factor contributing to the higher risk for CVD in this region of the US.

Omega-3 PUFA metabolism and brain modifications during aging

In Canada, 5.5 million (16% of Canadians) adults are >65 years old and projections suggest this number will be approximately 20% of Canadians by 2024. A major concern regarding old age is a decline in health, especially if this entails a loss of self-sufficiency and independence caused by a decline in cognition. The brain contains 60% of fat and is one of the most concentrated organs in long chain omega-3 fatty acids such as docosahexaenoic acid (DHA). During aging, there are physiological modifications in the metabolism of lipids that could also have consequences on brain structure and levels of DHA. This review will hence discuss the physiological modifications in the metabolism of lipids during aging with a focus on long chain omega-3 and omega-6 fatty acids and also outline the structural and functional modifications of the brain during aging including brain lipid modifications and its relation to higher levels of DHA and cognition. Therefore, in this review, we outline the importance of collecting more data on the biology of aging since it might highly improve our understanding about what are «normal» modifications occurring during aging and what can become pathological.

Translating plasma eicosapentaenoic acid concentrations into erythrocyte percentages of eicosapentaenoic acid plus docosahexaenoic acid during treatment with icosapent ethyl

BACKGROUND

The Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT) study demonstrated that 4 g/d of eicosapentaenoic acid (EPA) ethyl esters (icosapent ethyl [IPE]) reduced risk for major cardiovascular events by 25% in statin-treated patients with residual hypertriglyceridemia. How this treatment affected red blood cell (RBC) EPA and docosahexaenoic acid (DHA) levels (ie, the Omega-3 Index [O3I]) was not reported, but effects on plasma EPA concentrations were reported.

OBJECTIVE

The aim of the study was to estimate baseline and final O3I levels in REDUCE-IT.

METHODS

First, deidentified data from our laboratory on RBC and plasma EPA and DHA from 2311 patients with similar lipid profiles as those in REDUCE-IT were used to generate a regression equation, which was then used to estimate the O3I from plasma FA concentrations. Second, previously published data on the effects of IPE on RBC FA concentrations were also converted to the O3I.

RESULTS

Both approaches (from calculations and prior publications) suggested that baseline and follow-up O3I levels were about 5% and 7%, respectively. In addition, plasma EPA levels (but not the O3I) were noted to be influenced by triglyceride levels.

CONCLUSION

For patients using 4 g of IPE, an estimated O3I value of about 7% reflects a cardioprotective state. Plasma EPA concentrations may be ill-suited as treatment targets because they are confounded by triglyceride levels.

Evaluation of a Rapid Assessment Questionnaire Using a Biomarker for Dietary Intake of n-3 Fatty Acids

While there is considerable evidence supporting health benefits of consuming diets high in omega-3 (n-3) fatty acids, there is no quick and effective tool to measure n-3 intake. The objective of this study was to evaluate the accuracy of a rapid assessment questionnaire (the Omega-3 Checklist) used to quantify intake of n-3 fatty acids. This was done by comparing n-3 intakes to blood biomarkers of n-3 exposure in a population of healthy men and women. In addition, a separate analysis was run including covariates age, sex, and weight, which have been shown to affect n-3 biomarker levels. Reported intake of eicosapentaenoic acid (EPA), docoshexaenoic acid (DHA), and EPA + DHA was correlated with erythrocyte EPA (Spearman's rank correlation r_s  = 0.51, p < 0.001), DHA (r_s  = 0.54, p < 0.001), and the Omega-3 Index (r_s  = 0.57, p < 0.001). These associations remained significant when controlling for age, sex, and weight. Therefore, the Omega-3 Checklist can be a useful, rapid assessment tool to estimate individuals' EPA and DHA intake.

Double-blind, randomized, multicenter phase 2 study of SC411 in children with sickle cell disease (SCOT trial)

Blood cell membranes in sickle cell disease (SCD) have low docosahexaenoic acid (DHA). DHA treatment reduces sickle cell crisis (SCC) rate and ameliorates the inflammation, oxidative stress, and hypercoagulable state of SCD. SC411 is a novel DHA ethyl ester formulation with a proprietary delivery platform (Advanced Lipid Technology) that enhances DHA bioavailability. The SCOT trial investigated the effect of 3 different doses of SC411 on clinical and biochemical endpoints in 67 children with SCD (5-17 years old). Seventy-six percent of subjects were also receiving hydroxyurea. After 4 weeks of treatment with SC411 at 20, 36, and 60 mg DHA/kg per day or placebo a statistically significant (P < .001) mean percentage increase of blood cell membrane DHA and eicosapentaenoic acid was seen vs baseline: 109.0% (confidence interval [CI], 46.7-171.3), 163.8% (CI, 108.3-219.2), 170.8% (CI, 90.2-251.4), and 28.6% (CI, 250.1 to 107.3), respectively. After 8 weeks of treatment, statistically significant changes vs placebo were also observed in D-dimer (P = .025) and soluble E-selectin (P = .0219) in subjects exposed to 36 mg/kg. A significant increase in hemoglobin was observed against placebo in subjects receiving 20 mg DHA/kg per day (P = .039). SC411 significantly reduced electronic diary recorded SCC, analgesic use at home, and days absent from school because of sickle cell pain. The lower rate of clinical SCC observed in the pooled active groups vs placebo did not reach statistical significance (rate ratio, 0.47; 95% CI, 0.20-1.11; P = .07). All tested doses were safe and well tolerated. This trial was registered at www.clinicaltrials.gov as #NCT02973360.

Association of reported fish intake and supplementation status with the omega-3 index

BACKGROUND

An Omega-3 Index (O3I; EPA+DHA as a % of erythrocyte total fatty acids) in the desirable range (8%-12%) has been associated with improved heart and brain health.

OBJECTIVE

To determine the combination of fish intake and supplement use that is associated with an O3I of >8%.

DESIGN

Two cross-sectional studies comparing the O3I to EPA+DHA/fish intake.

PARTICIPANTS/SETTING

The first study included 28 individuals and assessed their fish and EPA+DHA intake using both a validated triple-pass 24-hr recall dietary survey and a single fish-intake question. The second study used de-identified data from 3,458 adults (84% from US) who self-tested their O3I and answered questions about their fish intake and supplement use.

STATISTICAL ANALYSES PERFORMED

Study 1, chi-squared, one-way ANOVA, and Pearson correlations were computed. In Study 2, multi-variable regression models were used to predict O3I levels from reported fish/supplement intakes.

RESULTS

The mean ± SD O3I was 4.87 ± 1.32%, and 5.99 ± 2.29% in the first and second studies, respectively. Both studies showed that for every increase in fish intake category the O3I increased by 0.50-0.65% (p < 0.0001). In the second study, about half of the population was taking omega-3 supplements, 32% reported no fish intake and 17% reported eating fish >2 times per week. Taking an EPA+DHA supplement increased the O3I by 2.2% (p < 0.0001). The odds of having an O3I of ≥8% were 44% in the highest intake group (≥3 servings/week and supplementation) and 2% in the lowest intake group (no fish intake or supplementation); and in those consuming 2 fish meals per week but not taking supplements (as per recommendations), 10%.

CONCLUSIONS

Current AHA recommendations are unlikely to produce a desirable O3I. Consuming at least 3 fish servings per week plus taking an EPA+DHA supplement markedly increases the likelihood of achieving this target level.

Fish Oil Increases Specialized Pro-resolving Lipid Mediators in PAD (The OMEGA-PAD II Trial)

BACKGROUND

N-3 polyunsaturated fatty acid (PUFA) supplementation has been associated with reduced mortality and inflammation in patients with cardiovascular disease. There are limited data on the effects of n-3 PUFA supplementation in patients with peripheral artery disease (PAD).

MATERIALS AND METHODS

The OMEGA-PAD II trial was a double-blinded, randomized, placebo-controlled trial to assess the effect of 3 mo of high-dose oral n-3 PUFA supplementation on inflammation, endothelial function, and walking ability in patients with PAD.

RESULTS

Twenty-four patients with claudication received 4.4 g/d of fish oil or placebo for 3 mo. Outcomes measured included high-sensitivity C-reactive protein levels, the omega-3 index, endothelial function as measured via flow-mediated vasodilation, walking impairment questionnaire, and a 6-min walk test. Plasma levels of specialized pro-resolving lipid mediators (SPMs) were measured by liquid-chromatography-tandem mass spectrometry. In patients treated with fish oil, the absolute mean omega-3 index significantly increased from baseline (fish oil: 7.2 ± 1.2%, P < 0.001; placebo: -0.4 ± 0.9%, P = 0.31; between-group P < 0.001). Furthermore, there were significant increases in several pathway markers of SPM biosynthesis, including several mono-hydroxyeicosapentaenoic acids and mono-hydroxydocosahexaenoic acids. We also observed significant increases in the SPM lipoxin A₅ (fish oil: 0.57 ± 0.70 pg/mL, P = 0.05; placebo: 0.01 ± 0.38 pg/mL, P = 0.93; between-group P = 0.04) and resolvin E3 (fish oil: 154 ± 171 pg/mL, P = 0.04; placebo: 32 ± 54 pg/mL, P = 0.08; between-group P = 0.04). There were no significant changes in high-sensitivity C-reactive protein, flow-mediated vasodilation, walking impairment questionnaire, or 6-min walk test in the fish oil group.

CONCLUSIONS

Fish oil increases SPMs in plasma of patients with PAD. Further studies are required to determine whether these early changes translate to clinical improvements in patients with PAD.

Non-dietary factors associated with n-3 long-chain PUFA levels in humans - a systematic literature review

Numerous health benefits are attributed to the n-3 long-chain PUFA (n-3 LCPUFA); EPA and DHA. A systematic literature review was conducted to investigate factors, other than diet, that are associated with the n-3 LCPUFA levels. The inclusion criteria were papers written in English, carried out in adult non-pregnant humans, n-3 LCPUFA measured in blood or tissue, data from cross-sectional studies, or baseline data from intervention studies. The search revealed 5076 unique articles of which seventy were included in the qualitative synthesis. Three main groups of factors potentially associated with n-3 LCPUFA levels were identified: (1) unmodifiable factors (sex, genetics, age), (2) modifiable factors (body size, physical activity, alcohol, smoking) and (3) bioavailability factors (chemically bound form of supplements, krill oil v. fish oil, and conversion of plant-derived α-linolenic acid (ALA) to n-3 LCPUFA). Results showed that factors positively associated with n-3 LCPUFA levels were age, female sex (women younger than 50 years), wine consumption and the TAG form. Factors negatively associated with n-3 LCPUFA levels were genetics, BMI (if erythrocyte EPA and DHA levels are &lt;5·6 %) and smoking. The evidence for girth, physical activity and krill oil v. fish oil associated with n-3 LCPUFA levels is inconclusive. There is also evidence that higher ALA consumption leads to increased levels of EPA but not DHA. In conclusion, sex, age, BMI, alcohol consumption, smoking and the form of n-3 LCPUFA are all factors that need to be taken into account in n-3 LCPUFA research.

The omega-3 index in patients with heart failure: A prospective cohort study

BACKGROUND

Epidemiologic studies on the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in heart failure are scarce, while one large intervention trial demonstrated a modest benefit.

METHODS

This is a secondary analysis from the Interdisciplinary Network Heart Failure (INH) program. Patients hospitalized for systolic heart failure were enrolled and followed for 36 months. At baseline, whole blood samples from 899 patients were analyzed for fatty acid composition using a standardized analytical procedure (HS-Omega-3 Index®, O3-I). Associations of the O3-I with markers of heart failure severity, clinical characteristics, biomarkers, and mortality were analyzed.

RESULTS

The mean O3-I was 3.7 ± 1.0%. Patient mean age was 68 ± 12 years (72% male, 43% in New York Heart Association (NYHA) class III or IV, mean LVEF 30 ± 8%). During follow-up 258 patients (28.7%) died. After adjustment for potential confounders, the O3-I showed weak associations with uncured malignancy, end-systolic diameter of the left atrium, left ventricular end-diastolic and end-systolic diameters, and blood lipids and other laboratory parameters (all p < 0.05), but not with NYHA class, left ventricular ejection fraction, and the underlying cause of heart failure. The O3-I did not predict the 3-year mortality risk.

CONCLUSIONS

Our results show a marked depletion of omega-3 fatty acids in patients hospitalized for decompensated heart failure (suggested target range 8-11%). Although the O3-I was associated with a panel of established risk indicators in heart failure, it did not predict mortality risk.

CLINICAL TRIAL REGISTRATION

www.controlled-trials.com; ISRCTN23325295.

A Prenatal DHA Test to Help Identify Women at Increased Risk for Early Preterm Birth: A Proposal

Fish intake and docosahexaenoic acid (DHA), a nutrient found in fish, have been favorably linked to several pregnancy outcomes. The risk of early preterm birth (ePT, <34 weeks gestation) is associated with low fish intake and DHA blood levels and can be reduced by supplemental DHA. Here, we summarize the evidence linking blood DHA levels with risk for ePT birth, and based on the available studies, propose that women who are pregnant or trying to become pregnant aim for a red blood cell (RBC) DHA value of at least 5% (of total RBC fatty acids). In the US, ~70% of women of childbearing age are likely below this cut-point, and dietary intake data suggest that this group, including pregnant women, consumes ~60 mg/day DHA and that >90% of this group do not take an omega-3 supplement. Since the recommendations for women to consume fish and to take a 200 mg DHA supplement during pregnancy are not being heeded generally, there is a need to motivate practitioners and pregnant women to attend to these recommendations. Having an objective prenatal blood DHA test could provide such motivation. More research is needed to test the clinical utility of this proposed target prenatal DHA level.

Intake of Saturated Fatty Acids Affects Atherogenic Blood Properties in Young, Caucasian, Overweight Women Even without Influencing Blood Cholesterol

Despite a general relation between fat intake and cardiovascular risk factors, the association is often not observed in studies conducted in heterogenic populations, as for population groups, it may differ. The aim of the study was to analyze the associations between dietary fat intake and lipoprotein cholesterol fractions, as well as atherogenic blood properties, in young and middle-aged overweight Caucasian women. In a group of 138 overweight women, the three-day dietary records were assessed, under-reporters were excluded, and lipoprotein cholesterol fractions were analyzed. For the included 24 young (aged 20–40) and 42 middle-age women (aged 40–60), the intakes of fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and cholesterol, as well as the PUFA/SFA ratio, were assessed. Afterwards, the analysis of associations with blood levels of total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglyceride, as well as the TC/HDL ratio, HDL/LDL, ratio and Atherogenic Index of Plasma (AIP), were conducted. It was stated that the influence of the dietary fat level on lipoprotein cholesterol fractions as well as atherogenic blood properties in overweight Caucasian women is age dependent. For young, overweight, Caucasian women, the influence of the dietary fat level on the lipoprotein cholesterol fractions was not observed; however, SFA intake influenced atherogenic blood properties. For middle-aged, overweight, Caucasian women, the PUFA intake had an especially important influence in increasing the HDL cholesterol level. For overweight Caucasian women, not only should lipoprotein cholesterol fractions be controlled, but also the AIP calculated—especially for younger women.

Cardiometabolic risks and omega-3 index in recent-onset bipolar I disorder

OBJECTIVES

The aims of the present study were to characterize cardiometabolic risk factors in a cohort of bipolar disorder patients with limited exposure to psychotropic medications, and to evaluate their associations with mood symptoms and omega-3 polyunsaturated fatty acid (PUFA) blood levels.

METHODS

Cardiometabolic risk assessments were compared in individuals with bipolar I disorder experiencing a first manic or mixed episode or an early depressive episode (n=117) and healthy subjects (n=56). Patients were medication free at assessment and had no or limited exposure to mood-stabilizer or antipsychotic medications prior to the current admission. Associations among cardiometabolic parameters and Clinical Global Impression-Severity scale (CGI-S), manic (Young Mania Rating Scale [YMRS]), and depressive (Hamilton Depression Rating Scale [HDRS]) symptom ratings were evaluated within the bipolar group.

RESULTS

Following adjustment for demographic variables (i.e., age, gender, and parental education), significantly higher fasting triglyceride levels were observed in the bipolar group compared to the healthy group (121.7 mg/dL vs 87.0 mg/dL; P<.01). There were no clear trends for other metabolic indicators, including blood pressure, body mass index, and fasting glucose. Nineteen percent of the bipolar group and 6% of the healthy group met the criteria for metabolic syndrome (P=.23). The omega-3 index was lower in the bipolar group (3.4% vs 3.9%; P<.01). Within the bipolar group, no associations were found between the cardiometabolic parameters and CGI-S, YMRS, and HDRS symptom ratings.

CONCLUSIONS

Recent-onset medication-free bipolar disorder is associated with higher triglyceride levels. These findings are suggestive of early metabolic dysregulation prior to long-term psychotropic medication exposure. Lower omega-3 PUFA levels in individuals with bipolar I disorder represent a potential therapeutic target for additional investigation.

Associations between Fatty Acid Intake and Status, Desaturase Activities, and FADS Gene Polymorphism in Centrally Obese Postmenopausal Polish Women

Fatty acid (FA) status is associated with the risk of several diet-related diseases. Since postmenopausal women are at increased risk of cardiometabolic disturbances, determinants of FA metabolism should be fully understood in this group. We hypothesize that FA metabolism in postmenopausal Polish women may depend on current macronutrient intake and on fatty acid desaturase (FADS) gene polymorphism. One-hundred-and-twenty-eight postmenopausal women with central obesity were recruited to the study and their dietary intake, FA composition in red blood cells (RBC), and rs174556, rs174561, rs174547, and rs3834458 polymorphism of the FADS gene were analyzed. Higher levels of 18:2n-6t level in RBC were associated with higher protein or fat intake or with lower carbohydrate intake. The minor allele carriers of rs174561 of the fatty acid desaturase 1 (FADS1) gene had 9.7% lower concentration of 20:4n⁻6 in RBC (p < 0.05), but there were no other associations between other FA in RBC levels and FADS1 or fatty acid desaturase 2 (FADS2) polymorphisms. The mean D5D value was 15.3⁻17.9% lower in the minor allele carriers of each SNPs. We concluded that protein and carbohydrate intake may be associated with FA concentrations in RBC in centrally obese postmenopausal Polish women. The D5D value may be affected by FADS1 or FADS2 polymorphism.