Individual Polyunsaturated Fatty Acids Research Articles

The associations of erythrocyte membrane polyunsaturated fatty acids with skeletal muscle loss: A prospective cohort study

Polyunsaturated fatty acids (PUFAs) may play a vital role in maintaining skeletal muscle mass in the aged population. This study investigated the longitudinal relationship between the concentrations of erythrocyte membrane PUFAs and age-related changes in skeletal muscle mass over an average 6.5 years of follow-up in a Chinese middle-aged and older adult population. A total of 1494 participants aged 57.4±4.7 years were included in this study. Skeletal muscle mass was determined using dual-energy X-ray absorptiometry. Per year percent changes in the skeletal muscle index (Δ% SMI), appendicular skeletal muscle index (Δ% ASMI), and total body lean mass index (Δ% TBLMI) from baseline were calculated. Concentrations of total and individual cis-n-3 and cis-n-6 PUFAs of the erythrocyte membrane were determined using gas-liquid chromatography. Fully adjusted linear regression models showed that per unit increases in the concentrations of C18:2 n-6, C20:4 n-6, C22:4 n-6, and total n-6 PUFAs resulted in increases of 0.022%-0.155% in the Δ% SMI (P for linearity: <0.001-0.006). Restricted cubic spline analysis revealed an inverted U-shaped relationship between the concentrations of C20:2 n-6, C22:5 n-3, C22:6 n-3, and total n-3 PUFAs and the Δ% SMI (P for non-linearity: <0.001-0.036). In addition, an inverted U-shaped curve was also detected for the relationships of the linoleic acid/α-linolenic acid ratio (P for non-linearity=0.010) and n-6/n-3 PUFA ratio (P for non-linearity=0.013) with the Δ% SMI, with the Δ% SMI peaking at respective ratios of 124.96 and 3.69. Similar associations were revealed by the Bayesian kernel machine regression model. No interaction effect was detected between the individual PUFAs for the Δ% SMI in the bivariate exposure-response analysis. Overall, similar results were observed for the Δ% ASMI and Δ% TBLMI. The associations between different individual PUFAs and age-related muscle loss in middle-aged and older adults may be different. Our results suggest that high concentrations of erythrocyte membrane n-6 PUFAs may be correlated with less skeletal muscle mass loss, whereas extremely high concentrations of n-3 PUFAs may be correlated with more muscle loss.

Potential sex differences in human milk fatty acids and their association with atopic dermatitis: Results of the Ulm SPATZ health study.

Polyunsaturated fatty acids (PUFAs) in human milk are essential in immune system maturation and might play a role in the development of allergic conditions, such as atopic dermatitis (AD) in infants. Immune system responses are modulated by sex, but data on the sex-specific associations with PUFAs are limited. We therefore explored sex-specific differences in human milk PUFAs and their association with AD up to 2 years. PUFAs were measured in human milk samples from the Ulm SPATZ Health Study at 6 weeks (n = 512) and 6 months (n = 367). Associations with AD up to 2 years were evaluated using crude and multivariable logistic regression. Interactions between infant sex and PUFAs were explored by including the product term. No significant associations were observed with 6-week data. At 6 months, the median relative proportion of docosahexaenoic acid (DHA) was significantly higher in milk for female than male infants (p = .001). Female infants whose milk was lower in quintile proportions of alpha-linolenic acid (ALA) at 6 months had lower odds of AD compared to males [first vs. fifth quintile OR (95% confidence interval): 0.13 (0.02, 0.66), p = .02]. This interaction was not significant when correcting for multiple testing (α threshold: p = .004). No other statistically significant associations were observed. Individual quintile PUFA proportions in human milk were not associated with AD, overall and in a sex-specific manner. More comprehensive and statistically powered longitudinal studies are needed to determine whether potential sex differences in human milk, if any, could be of clinical relevance for infants including the investigation of mediating factors.

Polyunsaturated fatty acids changes during electroconvulsive therapy in major depressive disorder

Polyunsaturated fatty acids (PUFAs) have important electrochemical properties and have been implicated in the pathophysiology of major depressive disorder (MDD) and its treatment. However, the relation of PUFAs with electroconvulsive therapy (ECT) has never been investigated. Therefore, we aimed to explore the associations between PUFA concentrations and response to ECT in patients with MDD. We included 45 patients with unipolar MDD in a multicentre study. To determine PUFA concentrations, we collected blood samples at the first (T0) and twelfth (T12) ECT-session. We assessed depression severity using the Hamilton Rating Scale for Depression (HAM-D) at T0, T12 and at the end of the ECT-course. ECT-response was defined as ‘early response’ (at T12), ‘late response’ (after ECT-course) and ‘no’ response (after the ECT-course). The PUFA chain length index (CLI), unsaturation index (UI) and peroxidation index (PI) and three individual PUFAs (eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA] and nervonic acid [NA]) were associated with response to ECT using linear mixed models. Results showed a significant higher CLI in ‘late responders’ compared to ‘non responders’. For NA, ‘late responders’ showed significantly higher concentrations compared to ‘early’- and ‘non responders’. In conclusion, this study provides the first indication that PUFAs are associated with the efficacy of ECT. This indicates that PUFAs' influence on neuronal electrochemical properties and neurogenesis may affect ECT outcomes. Thereby, PUFAs form a potentially modifiable factor predicting ECT outcomes, that warrants further investigation in other ECT-cohorts.

Nano and natural zeolite feed supplements for dairy goats: Feed intake, ruminal fermentation, blood metabolites, and milk yield and fatty acids profile

Zeolite particle size can affect its characteristics as a rumen modifier, thus its form may not only affects the goats' health during the transition period but also their milk quantity and quality. Our objectives of this study were to evaluate the effects of zeolite supplementation either in its natural or nano form on ruminal fermentation characteristics, blood biochemical parameters, and milk production and chemical composition of dairy goats. Thirty-nine late pregnant Damascus goats (initial body waight: 26.1 ± 0.93 kg, mean ± SD) were randomly assigned to three experimental dietary treatments (n = 13/ treatment) for 90 days of an experimental period: The control treatment was fed a basal diet without feed additives, natural zeolite [supplemented at 20 g/kg of dry matter (DM) to the basal diet], and nano zeolite (supplemented at 0.4 g/kg DM to the basal diet). Both zeolite forms increased (P < 0.05) ruminal pH, total protozoal count, Diplodinium spp ciliates, and reduced (P < 0.01) ammonia, while nano zeolite enhanced the total short-chain fatty acids concentration compared to the control. Supplementation of nano zeolite increased (P = 0.01) the blood calcium and reduced (P < 0.05) total cholesterol, total lipids, aspartate aminotransferase, alanine aminotransferase activities compared to other diets. Goats fed nano zeolite produced higher (P < 0.01) milk yield without affecting the feed intake, while both zeolite forms resulted in similar reductions (P < 0.05) in milk fat, protein, lactose, solid not fat, and somatic cell count. No differences were detected in milk total saturated fatty acids and total odd and branched-chain fatty acids among treatments while, nano zeolite reduced (P = 0.03) milk concentration of eicosanoic acid (C20:0). Natural zeolite tended to reduce (P = 0.08) the concentrations of total mono-unsaturated fatty acids in milk, while nano zeolite resulted in higher (P = 0.04) miristoleic (C14:1-Cis9; omega 5) than the control. No differences were detected in the total and individual polyunsaturated fatty acids compared to the control. In conclusion, nano zeolite was more pronounced as a feed additive than its natural form to support goats through late pregnancy to early lactation and to enhance milk quality.

Circulating Polyunsaturated Fatty Acids and Pain Intensity in Five Chronic Pain Conditions

Pain intensity is well-known to be influenced by a wide range of biobehavioral variables. Nutritional factors, however, have not been generally considered for their potential importance. This cross-sectional study examined associations between erythrocyte omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) and pain intensity in 605 adults. Pain intensity was computed on a 0 to 100 numeric rating scale from questions about 5 chronic pain conditions: orofacial pain, headache, low back pain, irritable bowel syndrome, and bodily pain. For each pain condition, multiple linear regression tested the hypothesis that a higher ratio of n-6 arachidonic acid to the sum of n-3 eicosapentaenoic acid and docosahexaenoic acid (AA/(EPA+DHA) was associated with greater pain intensity. In covariate-adjusted analysis, orofacial pain intensity increased 5.7 points (95% CI: 1.4, 9.9) per unit increase in n-6/n-3 PUFA ratio. Likewise, a 1 unit increase in n-6/n-3 PUFA ratio was associated with significant increases in pain intensity (range 5–8 points) of headache pain, low back pain, and bodily pain, but not abdominal pain. Separate multiple linear regression models investigated the independent strength of association of individual PUFAs to the intensity of each pain condition. Overall, n-3 docosahexaenoic acid was most strongly, and inversely, associated with pain intensity. PerspectiveA higher ratio of n-6/n-3 long-chain polyunsaturated fatty acids was associated greater pain intensity for orofacial pain, headache, low back pain, and bodily pain, but not abdominal pain. The n-6/n-3 PUFA ratio was more consistently associated with pain intensity than any individual constituent of the long-chain PUFA ratio.

Associations between omega-3 fatty acids and insulin resistance and body composition in women with polycystic ovary syndrome.

BackgroundPolycystic ovary syndrome (PCOS) is strongly associated with abdominal obesity and insulin resistance and effective approaches to nutrition (e.g., omega-3 fatty acids intake) might improve the cardiometabolic risk profile. This study aimed to examine the associations of dietary and serum omega-3 fatty acids with insulin resistance (IR) and body composition among PCOS patients.MethodsA total of 185 patients with PCOS were included in our analysis. Dietary information was collected through face-to-face interviews using a 102-item food frequency questionnaire (FFQ). Serum omega-3 fatty acid levels were measured with the gas chromatography method. Body composition was measured by both dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance (BIA) methods. The multivariable linear regression model was applied to analyze the associations of dietary and serum omega-3 fatty acids with the levels of Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) and body composition parameters among PCOS patients.ResultsOur results indicated that the dietary long-chain omega-3 polyunsaturated fatty acids (PUFA) intakes were negatively associated with HOMA-IR (β = –0.089, P = 0.040), fat mass (β = –0.022, P = 0.047), and body fat percentage (β = –0.026, P = 0.032). For serum biomarkers, higher total omega-3 PUFAs levels (β = –0.158, P = 0.021) and long-chain omega-3 PUFAs levels (β = –0.187, P < 0.001), particularly eicosapentaenoic acid (EPA) (β = –164, P = 0.011) and docosahexaenoic acid (DHA) (β = –0.158, P = 0.001) were also associated with decreased HOMA-IR. In addition, generally, dietary and serum long-chain omega-3 PUFA levels, DPA, and DHA levels were both positively associated with muscle mass measured by DXA; whereas serum total, long-chain and individual omega-3 PUFA levels (e.g., DPA, EPA, and DHA) were all negatively associated with fat mass and body fat percentage. These findings were further confirmed by the findings for body composition measured by the BIA method.ConclusionHigher levels of dietary and serum omega-3 PUFAs, particularly long-chain omega PUFAs (DPA and DHA), might have beneficial effects on metabolic parameters and body composition among PCOS patients.

Omega-3 polyunsaturated fatty acid biomarkers and risk of type 2 diabetes, cardiovascular disease, cancer, and mortality

Considerable attention has focused on the role of omega-3 polyunsaturated fatty acids (PUFA) in the prevention of cardiometabolic diseases, which has led to dietary recommendations to increase omega-3 fatty acid intake. A meta-analysis was conducted to summarize evidence from prospective studies regarding associations between omega-3 PUFA biomarkers and risk of developing major chronic diseases. Four electronic databases were searched for articles from inception to March 1, 2022. Random-effects model was used to estimate the pooled relative risk (RR) and 95% confidence intervals (CIs) for the association of omega-3 PUFAs, including α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA), with risk of developing type 2 diabetes (T2D), cardiovascular disease (CVD), including coronary heart disease (CHD) and stroke, cancer, and mortality. The Grades of Recommendation, Assessment, Development and Evaluation assessment tool was used to rates the confidence in estimates. A total of 67 prospective studies comprised of 310,955 participants were identified. Individual omega-3 PUFAs showed divergent associations with the study outcomes of interest. A significant inverse association with T2D risk was observed across categories of ALA (relative risk [RR]: 0.89, 95% confidence interval [CI]: 0.82-0.96), EPA (RR: 0.85, 95% CI: 0.72-0.99) and DPA (RR: 0.84, 95% CI: 0.73-0.96) biomarkers. The marine-origin omega-3 fatty acids biomarkers but not ALA was significantly associated with lower risks of total CVD, CHD, and overall mortality, with RRs ranging from 0.70 for DHA-CHD association to 0.85 for EPA-CHD association. A lower risk of colorectal cancer was observed at higher levels of DPA (RR: 0.76, 95% CI: 0.59-0.98) and DHA (RR: 0.80; 95% CI: 0.65-0.99), whereas no association was noted for other outcomes. In addition, a dose-response relationship was observed between an increasing level of EPA, DPA, or DHA biomarker and lower risk of CVD. Higher concentrations of marine-derived omega-3 PUFA biomarkers were associated with a significantly reduced risk of total CVD, CHD, and total mortality. Levels of ALA were inversely associated with a lower risk of T2D but not CVD-related outcomes. These data support the dietary recommendations advocating the role of omega-3 PUFAs in maintaining an overall lower risk of developing cardiovascular disease and premature deaths.

Circulating Polyunsaturated Fatty Acids and COVID-19: A Prospective Cohort Study and Mendelian Randomization Analysis.

Higher circulating polyunsaturated fatty acids (PUFAs), especially omega-3 fatty acids, have been linked to a better prognosis in patients of coronavirus disease 2019 (COVID-19). However, the effects and causality of pre-infection PUFA levels remain unclear. This study aimed to investigate the observational and causal associations of circulating PUFAs with COVID-19 susceptibility and severity. We first performed a prospective cohort study in UK Biobank, with 20,626 controls who were tested negative and 4,101 COVID-19 patients, including 970 hospitalized ones. Plasma PUFAs at baseline (blood samples collected from 2007 to 2010) were measured by nuclear magnetic resonance, including total PUFAs, omega-3 PUFAs, omega-6 PUFAs, docosahexaenoic acid (DHA), linoleic acid (LA), and the omega-6/omega-3 ratio. Moreover, going beyond UK Biobank, we leveraged summary statistics from existing genome-wide association studies to perform bidirectional two-sample Mendelian randomization (MR) analyses to examine the causal associations of eight individual PUFAs, measured in either plasma or red blood cells, with COVID-19 susceptibility and severity. In the observational association analysis of each PUFA measure separately, total, omega-3, and omega-6 PUFAs, DHA, and LA were associated with a lower risk of severe COVID-19. Omega-3 PUFAs and DHA were also associated with a lower risk of testing positive for COVID-19. The omega-6/omega-3 ratio was positively associated with risks of both susceptibility and severity. When omega-6, omega-3, and their ratio are jointly analyzed, only omega-3 PUFAs remained significantly and inversely associated with both susceptibility and severity. The forward MR analysis indicated that docosapentaenoic acid (DPA-n3) and arachidonic acid (AA) might be causally associated with a lower risk of severe COVID-19, with OR (95% CI) per one SD increase in the plasma level as 0.89 (0.81, 0.99) and 0.96 (0.94, 0.99), respectively. The reverse MR analysis did not support any causal effect of COVID-19 on PUFAs. Our observational analysis supported that higher circulating omega-3 PUFAs, especially DHA, may lower the susceptibility to and alleviate the severity of COVID-19. Our MR analysis further supported causal associations of DPA-n3 and AA with a lower risk of severe COVID-19.

Dietary omega-3 polyunsaturated fatty acids and fish intake and risk of age-related macular degeneration

Epidemiologic studies are inconsistent regarding the association of dietary omega-3 polyunsaturated fatty acids (PUFA) and/or fish intake with risk of age-related macular degeneration (AMD) incidence and progression. The objective was to determine these associations by conducting a meta-analysis of available studies. Three electronic databases were searched for studies that quantified dietary omega-3 PUFA and/or fish intake from inception to December 2020 without language restriction. Three investigators independently assessed for inclusion and extracted data. Study-specific risk estimates were combined using random-effects model. Potential dose-response associations were explored with the use of generalized least-squares trend estimation. 21 studies were included in the meta-analysis. Higher dietary intakes of omega-3 PUFA was significantly associated with 14% (relative risk [RR]: 0.86, 95% confidence interval [CI]: 0.77, 0.96) and 29% (RR: 0.71, 95% CI: 0.55, 0.91) lower risk of early and late AMD, respectively. The dose-response analysis showed a 6% and 22% decrease in the risk of early and late AMD for each additional 1g/d omega-3 PUFA intake. For individual omega-3 PUFA, the intake of eicosapentaenoic acid and docosahexaenoic acid was inversely associated with lower AMD risk, whereas no association was found for the alpha-linolenic acid. Consistent inverse associations were also found between fish intake and AMD. The pooled RRs comparing extreme categories of fish intake were 0.79 (95% CI: 0.70, 0.90) and 0.71 (95% CI: 0.60, 0.85) for early and late AMD risk, respectively. Every 15g/d of fish consumption was associated with 13% and 14% lower early and late AMD. In addition, fish intake was associated with a significantly reduced risk of AMD progression (RR: 0.73, 95% CI: 0.53, 1.00). A high intake of dietary omega-3 PUFA or fish was associated with a reduced risk of developing of AMD, which further supports that consumption of omega-3 PUFA-rich foods may be a new avenue nutritional approach to preventing AMD.

Near-Infrared Reflectance Spectroscopy for Predicting the Phospholipid Fraction and the Total Fatty Acid Composition of Freeze-Dried Beef.

Research on fatty acids (FA) is important because their intake is related to human health. NIRS can be a useful tool to estimate the FA of beef but due to the high moisture and the high absorbance of water makes it difficult to calibrate the analyses. This work evaluated near-infrared reflectance spectroscopy as a tool to assess the total fatty acid composition and the phospholipid fraction of fatty acids of beef using freeze-dried meat. An average of 22 unrelated pure breed young bulls from 15 European breeds were reared on a common concentrate-based diet. A total of 332 longissimus thoracis steaks were analysed for fatty acid composition and a freeze-dried sample was subjected to near-infrared spectral analysis. 220 samples (67%) were used as a calibration set with the remaining 110 (33%) being used for validation of the models obtained. There was a large variation in the total FA concentration across the animals giving a good data set for the analysis and whilst the coefficient of variation was nearly 68% for the monounsaturated FA it was only 27% for the polyunsaturated fatty acids (PUFA). PLS method was used to develop the prediction models. The models for the phospholipid fraction had a low R2p and high standard error, while models for neutral lipid had the best performance, in general. It was not possible to obtain a good prediction of many individual PUFA concentrations being present at low concentrations and less variable than other FA. The best models were developed for Total FA, saturated FA, 9c18:1 and 16:1 with R2p greater than 0.76. This study indicates that NIRS is a feasible and useful tool for screening purposes and it has the potential to predict most of the FA of freeze-dried beef.

Relationships between inflammatory markers and suicide risk status in major depression

Pro-inflammatory status has been implicated in depression and suicidal behaviors. Polyunsaturated fatty acids (PUFAs) and cytokines, two types of inflammatory biomarkers, have been associated with suicide, independent of depression severity. How these biomarkers relate to each other is less clear. We measured plasma phospholipid levels of arachidonic acid (AA%), docosahexaenoic acid (DHA%), and eicosapentaenoic acid (EPA%) as a percentage of total phospholipids, as well as serum interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α), in 80 patients with major depressive disorder (MDD) and 24 healthy controls (HC). Individual PUFA and cytokine species were compared using ANOVA across four suicide risk-stratified groups: 1) highest-risk, recent (within 5 years) suicide attempters (n = 20); 2) high-risk, severe current suicidal ideators (having intent or plan) with no recent attempt history (n = 22); 3) low-risk, current non-ideators who were also lifetime non-attempters (n = 38); and 4) HC (n = 24). None of the participants were enrolled following an acute suicide attempt. Of biomarkers studied, only DHA% (p = 0.012) and IL-1β (p = 0.002) differed between groups. In post-hoc testing, DHA% was lower in attempters than ideators (p = 0.018) or MDD non-ideators (trend level, p = 0.073). IL-1β was lowest in attempters, differentiating them from ideators (p = 0.009) and HC (p = 0.004). Recent suicide attempt, one of the most powerful predictors of suicide risk, was also most closely tied to inflammatory indices in this study. Low DHA% as an indicator of suicide risk is consistent with previous reports; however, lower IL-1β was unexpected and may relate to acuity/chronicity of inflammation. There is a need for prospective studies of immune status with respect to suicidal behaviors.

The role of linoleic and α-linolenic acids and their metabolites in maintaining chronic inflammation and developing colorectal cancer

For many years it has been postulated the role of dietary factors, in particular the consumption of fatty acids, in the development of cancer. It has been confirmed in numerous epidemiological observations, as well as the experimental studies on cell lines. Despite numerous studies the role of various fatty acids and their metabolites, has not been clearly established. Among others there are still under investigation on the importance of linoleic acid, belonging to the group of polyunsaturated omega-6. Because of the diversity of scientific reports authors of this publication are trying to make a critical synthesis analysis of current knowledge of the postulated role of linoleic acid in development of colon cancer. And they also attempt to draw practical conclusions from them. The ability to modify their lifestyle, including dietary habits, and their real impact on the development of malignancies is a very important area of research, and can have an impact on the cancer epidemiology. Based on currently available data, dietary recommendations can be made for individual polyunsaturated fatty acid. It is recommended that in adults the LA share was 4% of the energy value of the diet, while the α-linolenic acid share was 0.5% of the energy value of the diet. In addition, in order to provide the right amount of docosahexaenoic acid and eicosapentaenoic acid, it is recommended to include at least 2 portions of fish per week, including 1 portion of oily fish.

Polyunsaturated Fatty Acids in Newborn Bloodspots: Associations With Autism Spectrum Disorder and Correlation With Maternal Serum Levels.

We conducted a population-based case-control study to examine newborn polyunsaturated fatty acid (PUFA) levels in association with autism spectrum disorder (ASD) and assess PUFA correlation across two time points. ASD cases (n = 200) were identified through the Department of Developmental Services and matched to live-birth population controls (n = 200) on birth month, year (2010-2011), and sex. Nonesterified PUFAs were measured by isotope dilution liquid chromatography-high resolution mass spectrometry from archived newborn dried blood spots and maternal mid-pregnancy serum samples. Crude and adjusted conditional logistic regression models were used to examine the association between neonatal PUFA levels, categorized in quartiles and according to distributional extremes, and ASD. Cubic splines were utilized to examine nonlinear relationships between continuous neonatal PUFAs and ASD. The correlation between neonatal and maternal levels was examined using Pearson correlation coefficients. In adjusted analyses of neonatal PUFA levels, no clear trends emerged, though there was an elevated odds ratio of ASD for the third quartile of linoleic acid, relative to the first (adjusted odds ratio = 2.49, 95% confidence interval: 1.31, 4.70). Cubic spline analysis suggested a nonlinear association between linoleic acid and ASD, though this was not robust to sensitivity analyses. While individual PUFAs were significantly correlated with one another within a given time point, aside from docohexaseanoic acid, PUFAs were not correlated across maternal and neonatal samples. Overall, our findings do not support an association between neonatal PUFA levels and ASD. Future work should confirm and expand these findings by examining associations with phenotypic subgroups and considering PUFAs in other time points. LAY SUMMARY: In this study, we examined whether levels of fats known as polyunsaturated fatty acids, measured in newborns, were related to later child diagnosis of autism spectrum disorder (ASD). Overall, we did not find strong evidence for hypothesized reduction in risk of ASD based on newborn levels of these fats. Future studies in larger samples and considering other time points may be useful to explain whether these fats are important in brain development related to ASD. Autism Res 2020, 13: 1601-1613. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.

A prospective study of erythrocyte polyunsaturated fatty acids and risk of colorectal serrated polyps and conventional adenomas.

The influence of polyunsaturated fatty acids (PUFAs) on risk of colorectal cancer precursors remains largely unknown. We examined the associations of erythrocyte PUFAs, including n-3 and n-6 PUFAs, with risk of colorectal conventional adenomas and serrated polyps in 4517 participants from three US prospective cohorts who had provided a blood sample and undergone at least one endoscopic examination. We calculated the multivariable odds ratios (ORs) per 1 SD increment in individual PUFAs and the ratio of n-6/n-3 PUFAs. We considered P < .005 statistically significant to account for multiple testing. During a median of 20 years of follow-up, we documented 493 conventional adenomas and 316 serrated polyps. After adjusting for various CRC risk factors, no associations for PUFAs achieved the stringent statistical significance for either conventional adenomas or serrated polyps (ORs per 1 SD ranged from 0.90 to 1.14). Some associations achieved nominal significance (P < .05), including the association of dihomogammalinolenic acid (DGLA) (20:3, n-6) with lower risk of conventional adenomas (OR = 0.91; 95% confidence interval [CI] = 0.83-1.00), total n-6 PUFAs with higher risk of proximal serrated polyps (OR = 1.32; 95% CI = 1.01-1.74) and eicosadienoic acid (20:2, n-6) and DGLA with lower risk of advanced adenomas (OR = 0.83; 95% CI = 0.71-0.97 and OR = 0.84; 95% CI = 0.72-0.98, respectively). Our findings indicate that erythrocyte PUFAs in a typical American diet are unlikely to have a substantial influence on risk of colorectal cancer precursors. The subgroup associations require further confirmation.

Effects of fatty acids and vitamin E in larval diets on development and performance of Queensland fruit fly

Tephritid fruit flies are commonly reared on artificial larval diets for laboratory studies and for sterile insect technique pest management programs. While significant effort has been invested in developing artificial larval diets, surprisingly little is known about the specific nutritional requirements of tephritid flies. Recently developed gel larval diets have provided new opportunities for nutritional studies in Queensland fruit fly, Bactrocera tryoni (‘Q-fly’). Wheat germ oil (WGO) is the main source of fatty acids and vitamin E in this diet, and is key for production of high-quality adults. To identify the importance of nutritional components of WGO for Q-fly productivity and quality, linoleic, linolenic, oleic and palmitic fatty acids as well as α-tocopherol (vitamin E) were included in the diet individually and in combination. Diets that included all of the tested fatty acids or just unsaturated fatty acids performed as well as diets containing WGO in most quality control parameters except fecundity, and addition of vitamin E reduced the pupal productivity. Considering individual fatty acids, larval diets containing only linolenic acid produced adults with higher percentage of fliers than did larval diets containing only palmitic acid or oleic acid. Compared with diets containing WGO, nutritional requirements for egg production in Q-fly were not entirely met by either grouped fatty acids or individual polyunsaturated, monounsaturated or saturated fatty acids, however, diets containing linoleic acid alone produced more eggs than any other fatty acid. The present study is a significant advance in understanding of the role of fatty acids as a component of WGO in larval diet in meeting the needs of developing Q-fly for somatic performance, but highlight also that other, untested, components of WGO appear to be important for reproduction.

Exploring the Physiological Roles of Unsaturated Fatty Acids Using C. elegans

Monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), classified broadly as unsaturated fatty acids, are macronutrients that have a wide range of physiological effects. It is known that unsaturated fatty acids play a crucial role in a diet, but it is unclear which specific MUFAs and PUFAs are required and what the physiological consequences of having different amounts of these fatty acids and their metabolites in the body are. Specific omega‐3 and omega‐6 PUFAs have been shown to be beneficial to human diseases, such as cardiovascular disease, inflammatory conditions, and certain cognitive impairments. This study aims to investigate the physiological roles of individual MUFAs and PUFAs. From this study, we will gain the preliminary knowledge for making dietary and treatment suggestions for patients with various disease states and in normal aging. To do this, we will use the model organism C. elegans because of its short lifespan and abundance of genetic tools available (including single and multiple genetic knockouts of fatty acid desaturase enzymes). Additionally, findings from studies in C. elegans reliably translate to human disease. Preliminary data suggests that specific MUFAs and PUFAs are essential for normal lifespan, physiological functions, and neurodevelopment. This study will expand on this by examining every available genetic knockout of fatty acid desaturase enzyme in the worm. We will conduct lifespan assays in order to observe changes in the median and maximum lifespans of different genetic knockouts compared to the wild type as well as thrashing assays, a measure of physical fitness. We hypothesize that certain unsaturated fatty acids play more important physiologic roles than others and the corresponding downstream metabolites are important lipid signaling molecules. Preliminary results from the lab confirm these hypotheses, as the genetic strains tested thus far show variations in lifespan and fitness.Support or Funding InformationThis project was funded by the MSU Startup Fund, NIEHS ‐ R00 ES024806, and NSF ‐DMS‐1761320.

Abstract P239: Longitudinal Measurement Of Maternal Plasma Polyunsaturated Fatty Acids In Relation To Physical Activity Throughout Pregnancy-a Prospective Study Within The Nichd Fetal Growth Studies

Background: Physical activity (PA) is a key components of energy expenditure and can alter fat metabolism. Maternal polyunsaturated fatty acids (PUFA), particularly endogenous PUFA, plays critical roles on maternal health and fetal development. However, studies investigating the longitudinal association of PA with PUFA during pregnancy are scarce. Objective: To examine the prospective associations of PA with PUFA among pregnant women. Methods: This study used longitudinal data from a nested gestational diabetes mellitus case-control study (n=321) within the NICHD Fetal Growth Studies-Singletons. Plasma phospholipid PUFA and PA were measured at 4 time-points during pregnancy (10-14, 15-26, 23-31, and 33-39 GW). Total PA was calculated as energy expenditure in metabolic equivalent (METs-hour) and physically active was defined as spending ≥150 min on moderate-to-vigorous exercise per week. Associations of PA with total n-3, n-6, and individual PUFAs were examined using generalized linear models where the sample was weighted to represent the entire cohort. Results: Total PA was positively associated with EDA, but inversely associated with ALA and GLA, independent of maternal age, race, parity, pre-pregnancy BMI, and dietary intake of FA. Being physically active was inversely associated with total n-3 PUFA but positively associated with total n-6 PUFA. However, the direction of the associations of individual PUFA varied: an inverse association for ALA (n-3) and LA (n-6); a positive association for DHA (n-3), AA (n-6) and DPA (n-6). Conclusions: Findings from this study indicate that PA may alter PUFA metabolism in pregnant women. The inverse association between total PA and GLA (an endogenous PUFA) is novel and merits confirmation in future studies.

Rumen bacterial community responses to DPA, EPA and DHA in cattle and sheep: A comparative in vitro study

The role of marine lipids as modulators of ruminal biohydrogenation of dietary unsaturated fatty acids may be explained by the effects of their n-3 polyunsaturated fatty acids (PUFA) on the bacterial community. However, the impact of individual PUFA has barely been examined, and it is uncertain which bacteria are truly involved in biohydrogenation. In addition, despite interspecies differences in rumen bacterial composition, we are not aware of any direct comparison of bovine and ovine responses to dietary PUFA. Therefore, rumen fluid from cannulated cattle and sheep were used as inocula to examine in vitro the effect of 20:5n-3 (EPA), 22:5n-3 (DPA), and 22:6n-3 (DHA) on the bacterial community. Amplicon 16 S rRNA sequencing suggested that EPA and DHA had a greater contribution to the action of marine lipids than DPA both in cattle and sheep. Certain effects were exclusive to each ruminant species, which underlines the complexity of rumen microbial responses to dietary fatty acids. Based on changes in bacterial abundance, Barnesiella, Prevotella, Paraprevotella, Hallela, Anaerovorax, Succiniclasticum, Ruminococcus and Ruminobacter may be involved in the ruminal response in biohydrogenation to the addition of marine lipids, but further research is necessary to confirm their actual role in ruminal lipid metabolism.

Biosynthesis of Triacylglycerol Molecules with a Tailored PUFA Profile in Industrial Microalgae

The composition of polyunsaturated fatty acids (PUFAs) in triacylglycerols (TAGs) is key to health benefits and for oil applications, yet the underlying genetic mechanism remains poorly understood. In this study, by in silico, ex vivo, and in vivo profiling of type-2 diacylglycerol acyltransferases (DGAT2s) in Nannochloropsis oceanica we revealed two novel PUFA-preferring enzymes that discriminate individual PUFA species in TAG assembly, with NoDGAT2J for linoleic acid (LA) and NoDGAT2K for eicosapentaenoic acid (EPA). The LA and EPA composition of TAG molecules is mediated in vivo via the functional partitioning between NoDGAT2J and 2K, both of which are localized in the chloroplast envelope. By modulating transcript abundance of the DGAT2s, an N. oceanica strain bank was created, where proportions of LA and EPA in TAG vary by 18.7-fold (between 0.21% and 3.92% dry weight) and 34.7-fold (between 0.09% and 3.12% dry weight), respectively. These findings lay the foundation for producing designer TAG molecules with tailored health benefits or for biofuel applications in industrial microalgae and higher-plant crops.

An Invasive Shrimp Species, Machrobrachium nipponense, in Anzali Wetland Demonstrated a Potential Source for Commercial Fishing

ABSTRACT The proximate content, fatty acids composition, and nutritional quality index (NQI) of Macrobrachium nipponense at three habitats in the Anzali wetland in Iran were investigated as a potential source for human consumption. The highest amounts of protein, lipid, ash, and energy contents in muscle of M. nipponense were showed in autumn (non-reproductive season) (p < 0.05). The main monounsaturated fatty acids (MUFA) were oleic acid (C18:1 n9 C, C18:1 ω9 T) and palmitoleic acid (C16:1). Moreover, the main polyunsaturated fatty acids (PUFA) were docosahexaenoic acid (DHA, C22:6 n3), eicosapentaenoic acid (EPA, C20:5n3), arachidonic acid (ARA, C20:4 n6), linoleic acid (LA, C18:2 ω6), and α-linolenic acid (ALA, C18:3 n3). The predominant individual saturated fatty acid (SFA) was palmitic acid (0.07–13.4%), while oleic acid (14.7–26.3%), EPA (3.5–12.7%) and linoleic acid (0.04–14.9%) represented the most abundant individual MUFA and PUFA in M. nipponense. The highest mean value of EPA+DHA (14.0), n3/n6 (1.02), ΣMUFA/ΣSFA (1.05), ΣPUFA/ΣSFA (1.04), and EPA/DHA (3.8) ratios in M. nipponense was in autumn. The range of atherogenicity index (AI) and thrombogenicity index (TI) was much lower, from 0.42 to 0.6 and from 0.33 to 0.57, respectively, in terms of season. The results obtained in the present study show that M. nipponense is an excellent nutritional food source in the Anzali wetland.