Influence of dietary supplementation with long-chain n-3 or n-6 polyunsaturated fatty acids on blood inflammatory cell populations and functions and on plasma soluble adhesion molecules in healthy adults

Different profiles of fatty acids between leukocytes and whole blood in children with idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (INS) is the most common pediatric glomerular disease, characterized by proteinuria, hypoalbuminemia and edema and caused by an immune dysregulation of T and B cells. Fatty acids (FA) are involved in immune response, with omega-6 prevailing in pro-inflammatory states and omega-3 promoting anti-inflammatory effects. While previous studies of INS assessed FA profile in blood or serum, which may be influenced by many systemic and dietary factors, the intracellular FA metabolism in white blood cells of children with INS, critical to immune cell activation, remains still unexplored. This pilot study compares the FA profile within leukocytes (endo-leukocyte, EL) and whole blood in 35 children with INS and 34 matched controls. INS patients were stratified by steroid sensitivity vs. steroid resistance and by remission vs. proteinuric state. EL FA profiles were analyzed via gas chromatography and dietary habits were evaluated by the Kid Med questionnaire. While blood FA profile of patients demonstrated both elevated omega-6 and omega-3 levels (P-value < 0.005), EL show an inflammatory dominance, with increased omega-6 (P-value < 0.005), but similar omega-3 levels, compared to controls. Furthermore, EL profiles showed reduced saturated FA and palmitic acid but elevated oleic acid levels (P-value < 0.005), possibly indicating a compensatory anti-inflammatory response. This study suggests that EL FA profile may provide unique insights into intracellular mechanisms of inflammation in INS, complementing data arising from blood FA analysis. Despite some limitations, including the small sample size, the study of FA inside the cellular population directly involved in INS underscores its potential in increasing diagnostic precision of FA anomalies in the course of nephrotic syndrome. This new approach may also represent the prerequisite for a clearcut evaluation of the effectiveness of pharmacologic and dietary therapies, like the supplementation with omega 3 metabolites and a diet rich in omega-3.

Systemic immune inflammation mediates the association of serum omega-3 and omega-6 polyunsaturated fatty acids with biological aging: a national population-based study

OBJECTIVE

This study aimed to explore the association between serum omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) and biological aging, along with the potential mediating role of systemic immune inflammation (SII).

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were used for analyses. Accelerated aging in participants was assessed by calculating the difference between phenotypic age (PhenoAge) and chronological age. Weighted multivariate linear regression models and subgroup analysis were used to investigate the correlation between serum n-3 and n-6 PUFAs and accelerated aging, and restricted cubic spline (RCS) model was applied to explore potential nonlinear relationships. We further conducted mediation analyses to assess the role of SII in these relationships. Additionally, weighted quantile sum (WQS) regression and quantile g-computation (QGC) models were conducted to investigate the mixed effects of serum PUFAs and identify the key contributor.

RESULTS

A total of 3376 participants were enrolled in this study. In multivariate linear regression models, eight of the twelve individual serum PUFAs showed a significantly negative association with PhenoAge acceleration, Specifically, per-unit increases in linoleic acid (LA), gamma-linolenic acid (GLA), arachidonic acid (AA), alpha-linolenic acid (ALA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosapentaenoic acid (n-3 DPA), and docosahexaenoic acid (DHA) were all associated with reduced PhenoAge acceleration (P < 0.05, respectively). Subgroup analysis demonstrated robust consistence results when stratified by age, sex, and race/ethnicity. L-shaped nonlinear relationships were observed between PhenoAge acceleration with total n-6 PUFAs, LA and ALA (all P for nonlinear < 0.05). Mediation analyses indicated that SII mediated the relationship between serum PUFAs and reduced PhenoAge acceleration. Mixed-effects analysis using WQS and QGC models revealed that the combined effect of serum PUFAs on reducing PhenoAge acceleration, with DHA showing the strongest significant contribution.

CONCLUSIONS

This study demonstrated that higher levels of certain PUFAs were associated with a reduction in PhenoAge acceleration either individually or in combination, with DHA having the most prominent effect in mixed effects. The SII mediated these relationships, suggesting that PUFAs may slow biological aging by reducing inflammation. These findings highlighted the potential role of PUFAs in mitigating accelerated aging and their implications for aging-related health interventions.

Algal lipids: A review on current status and future prospects in food processing

The consumer demand for functional foods derived from natural sources has been enhanced due to health-promoting effects. Algae are widely available globally as a sustainable source of proteins, lipids, and carbohydrates. Algal lipids are underexplored natural sources that exhibit several nutraceutical effects and applications in fortification, cosmetics, and pharmaceuticals. Both macro- and microalgae are composed of high-quality lipids. These latter involve polar lipids, nonpolar lipids, and essential fatty acids. Therefore, this review aimed to bring out knowledge on the chemistry of various lipids isolated and identified from micro- and macroalgae. Further, their extraction using traditional thermal (solid-liquid, and liquid-liquid) and advanced nonthermal (supercritical fluid, microwave-, ultrasound-, and enzyme-assisted) techniques has been explored. Along with this, bioactivities of algal lipids have been discussed. This study explored algal lipids in advancing sustainable food processing technologies that contribute positively to environmental sustainability and global health, in line with United Nations Sustainable Development GroupUnited Nations Sustainable Development Group UNSDGs.

Effects of flaxseed supplementation on inflammatory biomarkers: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials

Several studies reported the benefits of flaxseed on inflammatory biomarkers, while others reported conflicting findings. Thus, the aim of this meta-analysis was to assess the impacts of flaxseed on inflammatory biomarkers in adults. Databases including Embase, PubMed, Scopus, and Web of Sciences were searched till February 2024. The 54 RCTs were included in the final analysis, which involved 3000 individuals from 12 countries. Overall, the flaxseed supplementation had a significant reduction in C-reactive protein (CRP) (SMD = -0.46; 95 % CI: -0.70, -0.23, P < 0.001; I2 = 82.9 %, P < 0.001), and interleukin 6 (IL-6) (SMD = -0.64, 95 % CI: -1.13, -0.16, P = 0.010; I2 = 92.7, P < 0.001). Furthermore, flaxseed did not significantly change the concentration of tumor necrosis factor α (TNF-α) (SMD = -0.17; 95 % CI: -0.63, 0.29, P = 0.467; I2 = 92, P < 0.001). Flaxseed supplementation significantly decreased serum concentrations of CRP and IL-6, but not TNF-a. Thus, this meta-analysis suggests that the current evidence supports the potential benefits of flaxseed in managing inflammatory conditions.

Effects of Omega-3 Polyunsaturated Fatty Acids on the Formation of Adipokines, Cytokines, and Oxylipins in Retroperitoneal Adipose Tissue of Mice

Oxylipins and specialized pro-resolving lipid mediators (SPMs) derived from polyunsaturated fatty acids (PUFAs) are mediators that coordinate an active process of inflammation resolution. While these mediators have potential as circulating biomarkers for several disease states with inflammatory components, the source of plasma oxylipins/SPMs remains a matter of debate but may involve white adipose tissue (WAT). Here, we aimed to investigate to what extent high or low omega (n)-3 PUFA enrichment affects the production of cytokines and adipokines (RT-PCR), as well as oxylipins/SPMs (liquid chromatography-tandem mass spectrometry) in the WAT of mice during lipopolysaccharide (LPS)-induced systemic inflammation (intraperitoneal injection, 2.5 mg/kg, 24 h). For this purpose, n-3 PUFA genetically enriched mice (FAT-1), which endogenously synthesize n-3 PUFAs, were compared to wild-type mice (WT) and combined with n-3 PUFA-sufficient or deficient diets. LPS-induced systemic inflammation resulted in the decreased expression of most adipokines and interleukin-6 in WAT, whereas the n-3-sufficient diet increased them compared to the deficient diet. The n-6 PUFA arachidonic acid was decreased in WAT of FAT-1 mice, while n-3 derived PUFAs (eicosapentaenoic acid, docosahexaenoic acid) and their metabolites (oxylipins/SPMs) were increased in WAT by genetic and nutritional n-3 enrichment. Several oxylipins/SPMs were increased by LPS treatment in WAT compared to PBS-treated controls in genetically n-3 enriched FAT-1 mice. Overall, we show that WAT may significantly contribute to circulating oxylipin production. Moreover, n-3-sufficient or n-3-deficient diets alter adipokine production. The precise interplay between cytokines, adipokines, and oxylipins remains to be further investigated.

Causal link between metabolic related factors and osteoarthritis: a Mendelian randomization investigation

Introduction

Metabolic syndrome (MetS) is significantly associated with osteoarthritis (OA), especially in MetS patients with blood glucose abnormalities, such as elevated fasting blood glucose (FG), which may increase OA risk. Dietary modifications, especially the intake of polyunsaturated fatty acids (PUFAs), are regarded as a potential means of preventing MetS and its complications. However, regarding the effects of FG, Omega-3s, and Omega-6s on OA, the research conclusions are conflicting, which is attributed to the complexity of the pathogenesis of OA. Therefore, it is imperative to thoroughly evaluate multiple factors to fully understand their role in OA, which needs further exploration and clarification.

Methods

Two-sample univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) were employed to examine the causal effect of metabolic related factors on hip OA (HOA) or knee OA (KOA). The exposure and outcome datasets were obtained from Open GWAS IEU. All cases were independent European ancestry data. Three MR methods were performed to estimate the causal effect: inverse-variance weighting (IVW), weighted median method (WMM), and MR-Egger regression. Additionally, the intercept analysis in MR-Egger regression is used to estimate pleiotropy, and the IVW method and MR-Egger regression are used to test the heterogeneity.

Results

The UVMR analysis revealed a causal relationship between FG and HOA. By MVMR analysis, the study discovered a significant link between FG (OR = 0.79, 95%CI: 0.64∼0.99, p = 0.036) and KOA after accounting for body mass index (BMI), age, and sex hormone-binding globulin (SHBG). However, no causal effects of FG on HOA were seen. Omega-3s and Omega-6s did not have a causal influence on HOA or KOA. No significant evidence of pleiotropy was identified.

Discussion

The MR investigation showed a protective effect of FG on KOA development but no causal relationship between FG and HOA. No causal effect of Omega-3s and Omega-6s on HOA and KOA was observed. Shared genetic overlaps might also exist between BMI and age, SHBG and PUFAs for OA development. This finding offers a novel insight into the treatment and prevention of KOA from glucose metabolism perspective. The FG cutoff value should be explored in the future, and consideration should be given to demonstrating the study in populations other than Europeans.

The effects of omega-3 fatty acids supplementation on hemoglobin, hematocrit, and platelet levels of patients with ESRD condition undergoing dialysis

Background

Concomitant inflammation may boost the cardiovascular complications in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). Omega-3 fatty acids may have certain health benefits in HD patients. The aim of this study was to investigate the effects of omega-3 fatty acids supplementation on hematocrit (HCT), hemoglobin (HB) level and platelet (PLT) counts of HD patients.

Methods

A randomized controlled trial was conducted on HD patients at a private dialysis center in Rasht, Iran. Three omega-3 fatty acid supplement capsules (3 g/d) were administered daily for two months to patients in the intervention group (n = 55). The control group (n = 60) were given three placebo capsules containing medium chain triglyceride (MCT) oil, similar to the supplemental dose of the intervention group at the same period. Three parameters of HCT, HB and PLT were measured at baseline and after the intervention.

Results

The PLT count decreased in the intervention group compared to the control group (173.38 ± 74.76 vs. 227.68 ± 86.58 103/mm3, F = 4.83, P = 0.03). No significant change was found on the levels of HCT and HB parameters between the two groups after the intervention.

Conclusion

Omega-3 supplementation in HD patients may decrease the risk of forming blood clots in the blood vessels. Further studies are warranted.

Fish oil supplementation in obese rats ameliorates metabolic syndrome response

Accumulation of visceral adipose tissue is associated with metabolic syndrome (MS), insulin resistance, and dyslipidemia. Here we examined several morphometric and biochemical parameters linked to MS in a rodent litter size reduction model, and how a 30-day fish oil (FO) supplementation affected these parameters. On day 3 post-birth, pups were divided into groups of ten or three. On day 22, rats were split into control (C) and small litter (SL) until 60 days old. Then, after metabolic disturbance and obesity were confirmed, FO supplementation started for 30 days and the new groups were named control (C), FO supplemented (FO), obese (Ob), and obese FO supplemented (ObFO). Comparison was performed by Student t-test or 2-way ANOVA followed by Tukey post hoc test. At the end of the 60-day period, SL rats were hyperphagic, obese, hypoinsulinemic, normoglycemic, and had high visceral fat depot and high interleukin (IL)-6 plasma concentration. Obese rats at 90 days of age were fatter, hyperphagic, hyperglycemic, hypertriacylgliceromic, hipoinsulinemic, with low innate immune response. IL-6 production ex vivo was higher, but in plasma it was not different from the control group. FO supplementation brought all biochemical changes to normal values, normalized food intake, and reduced body weight and fat mass in obese rats. The innate immune response was improved but still not as efficient as in lean animals. Our results suggested that as soon MS appears, FO supplementation must be used to ameliorate the morpho- and biochemical effects caused by MS and improve the innate immune response.

Effects of marine-derived n-3 PUFA supplementation on soluble adhesion molecules: A systematic review and dose-response meta-analysis of randomized controlled trials

Long-chain n-3 poly unsaturated fatty acids have anti-inflammatory effects but their effects on serum levels of adhesion molecules are inconsistent and contradictory. In this updated systematic review and meta-analysis, marine sources of omega-3 fatty acids were pooled up to determine the effects of omega-3 supplementation on adhesion molecules. PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to April 2023) were searched and all RCTs investigating the effects of marine sources of omega-3, on blood concentrations of adhesion molecules were included and a meta-analysis undertaken. Forty-two RCTs were included involving 3555 participants aged from 18 to 75 years. Meta-analysis of 38 arms from 30 RCTs reporting serum concentrations of vascular cell adhesion molecule-1 (VCAM-1) showed a significant reduction after omega-3 supplementation (WMD: -1.26, 95% CI: -1.88 to -0.64 ng/mL, P < 0.001). Meta-analysis of 40 arms from 30 RCTs reporting serum concentrations of intercellular adhesion molecule-1 (ICAM-1) revealed a reduction following omega-3 supplementation, although it was not significant (WMD: -1.76, 95%CI: -3.68 to 0.16 ng/mL, P = 0.07). Meta-analysis of 27 arms from 21 trials showed no effect on E-selectin (WMD: 0.01, 95%CI: -0.02 to 0.04 ng/mL, P = 0.62). Pooling 15 arms from 11 RCTs showed a marginally significant reducing effect on P-selectin concentrations (WMD: -2.67, 95%CI: -5.53 to 0.19 ng/mL, P = 0.06). A considerable decrease in VCAM concentration was observed after omega-3 supplementation in this meta-analysis with a trend to decreases in both ICAM and P-selectin levels, with effects that may be significant depending on study design, and there was no effect on E-selectin.

Mendelian Randomization Analysis Reveals Causal Effects of Polyunsaturated Fatty Acids on Subtypes of Diabetic Retinopathy Risk

Polyunsaturated fatty acids (PUFAs) affect several physiological processes, including visual acuity, but their relationship with diabetic retinopathy (DR) remains elusive. The aim of this study was to determine whether PUFAs have a causal effect on DR. PUFAs- (total and omega-3 [FAw3] and omega-6 [FAw6] fatty acids and their ratio) and DR-associated single nucleotide polymorphisms derived from genome-wide association studies; sample sizes were 114,999 for fatty acids and 216,666 for any DR (ADR), background DR (BDR), severe non-proliferative DR (SNPDR), and proliferative DR (PDR). We hypothesized that the intra-body levels of PUFAs have an impact on DR and conducted a two-sample Mendelian randomization (MR) study to assess the causality. Pleiotropy, heterogeneity, and sensitivity analyses were performed to verify result reliability. High levels of PUFAs were found to be associated with reduced risk of both ADR and PDR. Moreover, FAw3 was associated with a decreased risk of PDR, whereas FAw6 demonstrated an association with lowered risks of both BDR and PDR. Our findings provide genetic evidence, for the first time, for a causal relationship between PUFAs and reduced DR risk. Consequently, our comprehensive MR analysis strongly urges further investigation into the precise functions and long-term effects of PUFAs, FAw3, and FAw6 on DR.

Effects of Exercise and Omega-3-Supplemented, High-Protein Diet on Inflammatory Markers in Serum, on Gene Expression Levels in PBMC, and after Ex Vivo Whole-Blood LPS Stimulation in Old Adults

Inflammaging is related to cell senescence and reflects an erratic immune system, which promotes age-associated diseases. Exercise and nutrition, particularly omega-3 fatty acids, are able to affect inflammation. Therefore, we examined the effects of an 8-week exercise and dietary intervention on the inflammatory response in community-dwelling old adults. All participants received weekly vibration and home-based resistance exercise. Furthermore, participants were randomized to either a control, high-protein (1.2-1.5 g/kg), or high-protein, omega-3-enriched (2.2 g/day) diet. Before and after treatment, inflammatory markers in fasting serum and after whole-blood ex vivo lipopolysaccharide (LPS) stimulation were assessed. Gene expression levels of inflammatory markers were quantified in peripheral blood mononuclear cells (PBMC). Sixty-one participants (age: 70.6 ± 4.7 years; 47% men) completed the study. According to generalized linear mixed models, a high-protein, omega-3-enriched diet decreased circulating anti-inflammatory interleukin (IL-) 10 and IL-1 receptor antagonist (IL-1RA). Sex-stratified analyses showed also significantly reduced pro-inflammatory markers in men with a high-protein, omega-3-enriched diet. Gene expression of IL-1RA was significantly reduced after both protein-enriched diets compared with controls. In comparison to a high-protein diet, exercise alone showed lower LPS-induced release of c-c motif chemokine ligand-2 (CCL-2), which tended to be more pronounced in men compared with women. Eight weeks of a high-protein, omega-3-enriched diet combined with exercise decreased circulating anti-inflammatory markers, and pro-inflammatory markers in men. A high-protein diet attenuated anti-inflammatory markers on gene expression level in PBMC. Exercise alone resulted in a lower pro-inflammatory response to LPS-exposure in whole-blood cultures.

Recent insights into dietary ω-6 fatty acid health implications using a systematic review

The American Heart Association suggests that consuming ω-6 fatty acids (5-10% of total energy) can prevent cardiovascular disease by improving lipoprotein profiles. However, some studies warn of deleterious effects of these due to eicosanoid biosynthesis. We explored the five years for clinical evidence of ω-6 fatty acids on several diseases including inflammation, cancer, cardiovascular disease, and metabolic syndrome. Predefined criteria identified a total of 21 articles in 5 databases. Some studies indicated that dietary arachidonic acid was not related to increase of pro-inflammatory cytokines. In cohort studies, ω-6 fatty acids prevented the onset of digestive and lung cancer. ω-6 Fatty acids improved blood lipoprotein profiles. Moreover, consuming ω-6 fatty acids delayed diabetes mellitus and chronic renal disease and had positive effects on muscle recovery and glaucoma. In conclusion, ω-6 fatty acids have beneficial effects on cancers, blood lipoprotein profiles, diabetes, renal disease, muscle function, and glaucoma without inflammation response.

Associations of serum n-3 and n-6 polyunsaturated fatty acids with prevalence and incidence of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver diseases worldwide, and lifestyle and diet are significant factors in its development. Recent studies have suggested that dietary fat quality is associated with the development of NAFLD.

OBJECTIVES

Our purpose was to investigate the cross-sectional and longitudinal associations of serum n-3 (ω-3) and n-6 (ω-6) PUFAs with NAFLD among middle-aged and older men and women from eastern Finland. We also investigated the associations of estimated Δ5-desaturase and Δ6-desaturase activities, enzymes involved in PUFA metabolism, with NAFLD.

METHODS

After exclusions, the cross-sectional analyses included 1533 men examined in 1984-1989 and 674 men and 870 women examined in 1998-2001 in the Kuopio Ischaemic Heart Disease Risk Factor Study. The longitudinal analyses included 520 men examined in 1991-1993 and 301 men and 466 women examined in 2005-2008. Fatty liver index (FLI) was used as a surrogate for NAFLD. Hepatic steatosis was defined as FLI >60. ANCOVA and logistic regression were used for analyses.

RESULTS

In the longitudinal analyses, participants with higher serum concentrations of total n-6 PUFA and linoleic acid, the major n-6 PUFA, had markedly lower FLI and lower odds for hepatic steatosis (e.g., odds ratios for incident hepatic steatosis in the highest compared with lowest quartiles were ≤0.41), whereas serum γ-linolenic acid concentration was associated with a higher FLI and higher odds for hepatic steatosis. The associations with the other PUFAs were generally weaker and nonsignificant. In the cross-sectional analyses, also the long-chain n-3 PUFAs had inverse associations. In most analyses, high estimated Δ5-desaturase activity was associated with lower risk and high estimated Δ6-desaturase activity with higher risk for NAFLD.

CONCLUSIONS

In middle-aged and older Finnish adults, higher serum concentrations of total n-6 PUFAs and linoleic acid were associated with lower odds for future NAFLD.

Balancing the health effect between risks of methylmercury and benefits of nutrients in consumption of Chinese mitten crab (Eriocheir sinensis) in China

Aquatic products contain both beneficial substances such as polyunsaturated fatty acids and harmful compounds such as methylmercury, and their combined health effects should be assessed at a common end point for a rational analysis. We used a risk-benefit model to assess net IQ point gain from consumption of Chinese mitten crabs (Eriocheir sinensis) from Jiangsu Province. Levels of methylmercury in the edible parts of the crabs ranged from 0.79 to 69.47 μg/kg (mean: 26.88 ± 15.09 μg/kg). Levels of methylmercury did not differ by sampling location. In aquaculture experiments, we simulated artificial pond farming using either iced trash fish or formulated feed. Crabs fed iced trash fish contained 28.72 ± 2.30 mg/g of eicosapentaenoic acid and docosahexaenoic acid and crabs fed formulated feed contained 19.64 ± 3.62 mg/g of eicosapentaenoic acid and docosahexaenoic acid. Model calculations estimated a gain of 7.52 IQ points from consumption of crabs fed formulated feed and 11.00 IQ points from consumption of crabs fed iced trash fish. They are all above the maximum theoretical IQ point gain value. Chinese mitten crab is a kind of high-quality food which is beneficial to the neural development of infants. Our findings may assist in improving crab farming methods and consumption patterns, accelerating the sustainable development of the Chinese mitten crab industry.

Perilla Fruit Oil-Fortified Soybean Milk Intake Alters Levels of Serum Triglycerides and Antioxidant Status, and Influences Phagocytotic Activity among Healthy Subjects: A Randomized Placebo-Controlled Trial

This study aimed to develop perilla fruit oil (PFO)-fortified soybean milk (PFO-SM), identify its sensory acceptability, and evaluate its health outcomes. Our PFO-SM product was pasteurized, analyzed for its nutritional value, and had its acceptability assessed by an experienced and trained descriptive panel (n = 100) based on a relevant set of sensory attributes. A randomized clinical trial was conducted involving healthy subjects who were assigned to consume deionized water (DI), SM, PFO-SM, or black sesame-soybean milk (BS-SM) (n = 48 each, 180 mL/serving) daily for 30 d. Accordingly, health indices and analyzed blood biomarkers were recorded. Consequently, 1% PFO-SM (1.26 mg ALA rich) was generally associated with very high scores for overall acceptance, color, flavor, odor, taste, texture, and sweetness. We observed that PFO-SM lowered levels of serum triglycerides and erythrocyte reactive oxygen species, but increased phagocytosis and serum antioxidant activity (p < 0.05) when compared to SM and BS-SM. These findings indicate that PFO supplementation in soybean milk could enhance radical-scavenging and phagocytotic abilities in the blood of healthy persons. In this regard, it was determined to be more efficient than black sesame supplementation. We are now better positioned to recommend the consumption of PFO-SM drink for the reduction of many chronic diseases. Randomized clinical trial registration (Reference number 41389) by IRSCTN Registry.

The effects of Mediterranean diet on hepatic steatosis, oxidative stress, and inflammation in adolescents with non-alcoholic fatty liver disease: A randomized controlled trial

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in children and adolescents. The optimal dietary strategy to improve hepatic stetatosis and reduce oxidative stress and inflammation in adolescents is unknown.

OBJECTIVE

This study was conducted to evaluate the effect of Mediterranean diet (MD) versus low-fat diet (LFD) on hepatic steatosis, inflammation, and oxidative stress in adolescents with obesity and NAFLD.

METHODS

Adolescents diagnosed with NAFLD between the ages of 11-18 years were randomized to either a MD or conventional LFD (control diet) for 12 weeks. Dietary status, anthropometry, body composition, and biochemical parameters were evaluated. Hepatic steatosis was determined by ultrasonography.

RESULTS

A total of 44 participants completed the study. At the end of the study, severity of hepatic steatosis, serum transaminase levels, and insulin resistance decreased significantly in both groups with no significant differences between groups except for aspartate aminotransferase (AST). The amount of decrease in AST levels in the MD group was greater than the LFD group (p < 0.05). In the MD group, serum total antioxidant capacity, paraoxanase-1, and glutathione peroxidase levels increased (p < 0.05); it did not change in the LFD group compared to baseline (p > 0.05). C-Reactive Protein (CRP) levels decreased only in the MD group (p = 0.008), interleukine-6 decreased only in the LFD group (p = 0.031).

CONCLUSION

Consumption of MD and LFD for 12 weeks in adolescents with obesity and NAFLD reduced BMI, fat mass, hepatic steatosis, and insulin resistance, improved high transaminase levels, and had positive effects on inflammation and oxidative stress. Registered under ClinicalTrials.gov Identifier no. NCT04845373.

The associations of circulating common and uncommon polyunsaturated fatty acids and modification effects on dietary quality with all-cause and disease-specific mortality in NHANES 2003-2004 and 2011-2012

BACKGROUND

Associations of dietary or supplementary intake of several unsaturated fatty acids and mortality have been widely studied but the results were still hitherto inconsistent or limited. It is still need to explore the effects of these fatty acids by using the objective biomarkers.

OBJECTIVE

We aimed to investigate the relevancy of several serum n-3 and n-6 fatty acids with all-cause and disease-specific mortality to confirm their health effects and effects on the associations between dietary quality and all-cause mortality.

METHODS

A total of 4132 people from NHANES 2003-2004 and 2011-2012 and the mortality information was confirmed from the NDI. CPH models adjusted for known risk factors were conducted to explore the associations between circulating n-3 and n-6 fatty acids and all-cause or CVD or cancer mortality under complex sampling. We further evaluated their effects on association between dietary quality and all-cause mortality.

RESULTS

A total of 437 deaths occurred during the mean follow-up of 83.34 months, including 157 CVD death and 100 cancer death. Serum LA, ALA, EPA and DHA were associated with all-cause mortality (HR in quintile5: LA:0.584, 95%CI: 0.387-0.882, Ptrend = 0.011; ALA:0.626, 95%CI: 0.432-0.907, Ptrend = 0.008; EPA:0.535, 95%CI: 0.375-0.764, Ptrend = 0.001; DHA:0.669, 95%CI: 0.468-0.955, Ptrend = 0.031). Additionally, serum EPA and ALA were respectively related to CVD and cancer mortality (Q5 HR: EPA:0.450, 95%CI: 0.23-0.854, Ptrend = 0.009; ALA:0.387, 95%CI: 0.167-0.900, Ptrend = 0.022). Serum AA, GLA, DGLA and SDA were not associated with any risk of mortality. The effect on all-cause mortality of the lower AHEI scores can be improved by adherence to a higher serum LA, EPA and DHA (in the lowest AHEI strata, LA in tertile3 compared to tertile1 HR:0.596, 95%CI: 0.366-0.970; EPA:0.660, 95%CI: 0.454-0.959; DHA:0.666, 95%CI; 0.444-1.000).

CONCLUSIONS

Our results support the recent dietary recommendations to increase the intake of plant-derived and marine-derived n-6 and n-3 to improve the ability of primary and secondary prevention.

Plasma metabolites changes in male heroin addicts during acute and protracted withdrawal

BACKGROUND

Heroin addiction and withdrawal have been associated with an increased risk for infectious diseases and psychological complications. However, the changes of metabolites in heroin addicts during withdrawal remain largely unknown.

METHODS

A total of 50 participants including 20 heroin addicts with acute abstinence stage, 15 with protracted abstinence stage and 15 healthy controls, were recruited. We performed metabolic profiling of plasma samples based on ultraperformance liquid chromatography coupled to tandem mass spectrometry to explore the potential biomarkers and mechanisms of heroin withdrawal.

RESULTS

Among the metabolites analyzed, omega-6 polyunsaturated fatty acids (linoleic acid, dihomo-gamma-linolenic acid, arachidonic acid, n-6 docosapentaenoic acid), omega-3 polyunsaturated fatty acids (docosahexaenoic acid, docosapentaenoic acid), aromatic amino acids (phenylalanine, tyrosine, tryptophan), and intermediates of the tricarboxylic acid cycle (oxoglutaric acid, isocitric acid) were significantly reduced during acute heroin withdrawal. Although majority of the metabolite changes could recover after months of withdrawal, the levels of alpha-aminobutyric acid, alloisoleucine, ketoleucine, and oxalic acid do not recover.

CONCLUSIONS

In conclusion, the plasma metabolites undergo tremendous changes during heroin withdrawal. Through metabolomic analysis, we have identified links between a framework of metabolic perturbations and withdrawal stages in heroin addicts.

Alpha-linolenic acid regulates the gut microbiota and the inflammatory environment in a mouse model of endometriosis

PROBLEM

This study aims to investigate the effects of alpha-linolenic acid (ALA) on the gut microbiota (GM) and the abdominal environment in mice with endometriosis (EMS).

METHODS

The effects of faecal microbiota transplantation (FMT) from EMS mice on mice treated with antibiotic cocktail were conducted. The 16S rRNA sequencing and PICRUSt software were used to detect the structure and function of GM respectively. The protein levels of Claudin 4 and ZO-2 in the intestinal wall were detected using the western blotting. The level of LPS in the abdominal cavity was detected using enzyme-linked immunosorbent assay (ELISA). The content of macrophages in the abdominal cavity was detected using flow cytometry.

RESULTS

The exogenous supplementation of ALA could restore the abundance of Firmicutes and Bacteroidota in EMS mice. After the ALA treatment, the abundance of 125 functional pathways and 50 abnormal enzymes related to GM in EMS mice was significantly improved (p < .05). The expression of the ZO-2 protein in the intestinal wall was decreased, and the level of LPS in the abdominal cavity was significantly increased after FMT from EMS mice (p < .05). ALA could increase the expression of the ZO-2 protein in the intestinal wall of EMS mice, reduce the level of LPS in the abdominal cavity (p < .05) and reduce the aggregation of peritoneal macrophages (p < .05).

CONCLUSION

Alpha-linolenic acid can improve the GM, intestinal wall barrier and abdominal inflammatory environment and reduce the level of LPS in mice with EMS.

Associations of Arachidonic Acid Synthesis with Cardiovascular Risk Factors and Relation to Ischemic Heart Disease and Stroke: A Univariable and Multivariable Mendelian Randomization Study

Arachidonic acid (AA), a major long-chain omega-6 polyunsaturated fatty acid, is associated with ischemic heart disease (IHD) and stroke. We assessed bi-directional associations of AA synthesis reflected by plasma phospholipid AA with CVD risk factors, and identified mediators of associations of AA with IHD and stroke using Mendelian randomization (MR). We used two-sample MR to assess bi-directional associations of AA synthesis with lipids, blood pressure, adiposity, and markers of inflammation and coagulation. We used multivariable MR to assess mediators of associations of AA with IHD and stroke. Genetically predicted AA (% of total fatty acids increase) was positively associated with apolipoprotein B (ApoB, 0.022 standard deviations (SD), 95% confidence interval (CI) 0.010, 0.034), high-density (0.030 SD, 95% CI 0.012, 0.049) and low-density lipoprotein cholesterol (LDL-C, 0.016 SD, 95% CI 0.004, 0.027) and lower triglycerides (-0.031 SD, 95% CI -0.049, -0.012) but not with other traits. Genetically predicted these traits gave no association with AA. The association of AA with IHD was attenuated adjusting for ApoB or LDL-C. Genetically predicted AA was associated with lipids but not other traits. Given ApoB is thought to be the key lipid in IHD, the association of AA with IHD is likely mediated by ApoB.

Effect of Omega-3 on Recurrent Aphthous Stomatitis and Improvement Quality of Life

Objective

Recurrent aphthous stomatitis is one of the most common chronic inflammatory diseases in oral mucosa. Beneficial effects of omega-3 supplements on some inflammatory diseases have been proved. The aim of present study was to evaluate the effect of omega-3 supplements in recurrent aphthous stomatitis management and improve oral health-related quality of life.

Methods

In this double-blind clinical trial, 40 patients with minor recurrent aphthous stomatitis were randomly divided into case and control groups. The case group received 1000 mg capsules of omega-3, while the control group received placebo capsules for 6 months. The questionnaires of the ulcer severity score and the chronic oral mucosal disease questionnaire were filled by the patients in three steps, at the baseline session, after 3 months, and after 6 months. The data were analyzed by SPSS 22 software through ANOVA, Mann-Whitney, and chi-square tests. P < 0.05 was considered as significant.

Results

In the omega-3 group, the ulcer severity score showed significant reduction by three-month and six-month follow-ups (P < 0.0001, P < 0.0001, respectively). The mean score of the chronic oral mucosal disease questionnaire significantly improved by three-month and six-month follow-ups in the omega-3-receiving group.

Conclusion

Use of omega-3 oral supplements decreased the severity of aphthous ulcer and improved oral health-related quality of life.

Dietary Regulation of the Crosstalk between Gut Microbiome and Immune Response in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), a chronic, recurring inflammatory response, is a growing global public health issue. It results from the aberrant crosstalk among environmental factors, gut microbiota, the immune system, and host genetics, with microbiota serving as the core of communication for differently-sourced signals. In the susceptible host, dysbiosis, characterized by the bloom of facultative anaerobic bacteria and the decline of community diversity and balance, can trigger an aberrant immune response that leads to reduced tolerance against commensal microbiota. In IBD, such dysbiosis has been profoundly proven in animal models, as well as clinic data analysis; however, it has not yet been conclusively ascertained whether dysbiosis actually promotes the disease or is simply a consequence of the inflammatory disorder. Better insight into the complex network of interactions between food, the intestinal microbiome, and host immune response will, therefore, contribute significantly to the diagnosis, treatment, and management of IBD. In this article, we review the ways in which the mutualistic circle of dietary nutrients, gut microbiota, and the immune system becomes anomalous during the IBD process, and discuss the roles of bacterial factors in shaping the intestinal inflammatory barrier and adjusting immune capacity.

The ratio of eicosapentaenoic acid to docosahexaenoic acid as a modulator for the cardio-metabolic effects of omega-3 supplements: A meta-regression of randomized clinical trials

BACKGROUND

A large number of studies have demonstrated the effects of omega- 3 supplements containing mixtures of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), known to favorably affect many modifiable risk factors of coronary heart disease (CHD). These studies have used diverse ratios and doses of EPA and DHA. However, it is not known whether the ratio of EPA to DHA in omega-3 supplements affect their efficacy as modulators for cardiovascular risk factors. This meta-regression aimed to investigate the effect of different ratios of EPA to DHA on risk factors associated with CHD including lipid profile, blood pressure, heart rate, and inflammation.

METHOD

A regression analysis was carried out on 92 clinical trials with acceptable quality (Jadad score ≥ 3) that were previously identified from two databases (PubMed and Cochrane Library).

RESULTS

Data from studies that met the inclusion criteria for this analysis showed that the ratio of EPA to DHA was not associated with lipid profile, diastolic blood pressure, or heart rate. With all studies, the ratio of EPA to DHA was associated with C-reactive protein (CRP) (β = -1.3121 (95 % CI: -1.6610 to -0.9543), that is, the higher the EPA to DHA ratio, the greater the reduction. Using only studies that supplied EPA and DHA in the range of 2 g-6 g, the ratio of EPA to DHA was also associated with CRP (β = -2.10429 and 95 % CI: -3.89963 to -0.30895); that is, an even more pronounced reduction in CRP with a higher EPA to DHA ratio. Systolic blood pressure was only associated with an increasing EPA to DHA ratio in the 2 g-6 g range (β = 5.47129 and 95 % CI: 0.40677-10.53580), that is, a higher EPA to DHA ratio within this dose range, the greater the increase in SBP.

CONCLUSION

Current data suggest that the EPA to DHA ratio only correlates to the modulation of CRP by omega-3 supplementation of EPA and DHA, and SBP in studies that supplemented EPA and DHA in the range of 2 g-6 g, shedding light on potential differential effects of EPA vs. DHA on inflammation and systolic blood pressure.

High Dietary Intake of Vegetable or Polyunsaturated Fats Is Associated With Reduced Risk of Hepatocellular Carcinoma

BACKGROUND & AIMS

We investigated associations of intake of total fats, specific dietary fats, and fats from different food sources with risk of hepatocellular carcinoma (HCC) using data from the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS).

METHODS

We analyzed data from a total of 138,483 women and men who participated in the NHS or HPFS. A validated semi-quantitative food frequency questionnaire was sent to NHS participants in 1980, 1984, 1986, and every 4 years thereafter; dietary information was collected from participants in the HPFS in 1986 and every 4 years thereafter. Multivariable hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards regression.

RESULTS

After an average follow-up time of 26.6 years, 160 incident HCC cases were documented. Although there was a non-significant association between total fat intake and HCC, intake of vegetable fats reduced risk of HCC (HR for the highest vs lowest quartile, 0.61; 95% CI, 0.39-0.96; Ptrend = .02), but not animal or dairy fats. Replacing animal or dairy fats with an equivalent amount of vegetable fats was associated with a lower risk of HCC (HR per 1 standard deviation, 0.79; 95% CI, 0.65-0.97). Among fat subtypes, monounsaturated and polyunsaturated fatty acids, including n-3 (HR, 0.63; 95% CI, 0.41-0.96; Ptrend = .14) and n-6 polyunsaturated fatty acids (HR, 0.54; 95% CI, 0.34-0.86; Ptrend = .02), were inversely associated with risk of HCC. Higher ratios of monounsaturated or polyunsaturated fat to saturated fat were inversely associated with HCC risk (all Ptrend ≤ .02). In addition, when replacing saturated fats with monounsaturated or polyunsaturated fats, the HR per 1 standard deviation was 0.77 (95% CI, 0.64-0.92).

CONCLUSIONS

In an analysis of data from 2 large cohort studies, we found higher intake of vegetable fats and polyunsaturated fats to be associated with lower risk of HCC. Replacing animal or dairy fats with vegetable fats, or replacing saturated fats with monounsaturated or polyunsaturated fats, was associated with reduced risk of HCC.

Modulatory Effect of Dietary Polyunsaturated Fatty Acids on Immunity, Represented by Phagocytic Activity

Lately, dietary polyunsaturated fatty acids (PUFAs) have shown substantial importance in human and animal nutrition, especially those of the n-3 group. Development and optimal functioning of the immune system are directed affected by diet. These dietary fatty acids have an important impact on the health and immune competence of various species including human beings. They are essential for the modulation of immune responses in health and disease. Fatty acid composition of immune cells can be modulated by the action of dietary fats and the outcomes in the composition can produce functional effects on reactivity and functioning of immune cells in a short period. There are several mechanisms involved in impacting dietary fatty acids on immune function; however, lipid mediator synthesis from PUFAs is of great importance in terms of inflammation. The objectives of this article are reviewing studies on the impact of PUFA in the diet on phagocytosis of chickens, murine, rats, ruminants, and humans. It also sheds light on the possible mechanism by which this immunomodulation occurs.

Anti-Inflammatory Potential of n-3 Polyunsaturated Fatty Acids Enriched Hen Eggs Consumption in Improving Microvascular Endothelial Function of Healthy Individuals-Clinical Trial

The effects of consumption of n-3 polyunsaturated fatty acids (n-3 PUFAs) enriched hen eggs on endothelium-dependent and endothelium-independent vasodilation in microcirculation, and on endothelial activation and inflammation were determined in young healthy individuals. Control group (N = 21) ate three regular hen eggs/daily (249 mg n-3 PUFAs/day), and n-3 PUFAs group (N = 19) ate three n-3 PUFAs enriched hen eggs/daily (1053 g n-3 PUFAs/day) for 3 weeks. Skin microvascular blood flow in response to iontophoresis of acetylcholine (AChID; endothelium-dependent) and sodium nitroprusside (SNPID; endothelium-independent) was assessed by laser Doppler flowmetry. Blood pressure (BP), body composition, body fluid status, serum lipid and free fatty acids profile, and inflammatory and endothelial activation markers were measured before and after respective dietary protocol. Results: Serum n-3 PUFAs concentration significantly increased, AChID significantly improved, and SNPID remained unchanged in n-3 PUFAs group, while none was changed in Control group. Interferon-γ (pro-inflammatory) significantly decreased and interleukin-10 (anti-inflammatory) significantly increased in n-3 PUFAs. BP, fat free mass, and total body water significantly decreased, while fat mass, interleukin-17A (pro-inflammatory), interleukin-10 and vascular endothelial growth factor A significantly increased in the Control group. Other measured parameters remained unchanged in both groups. Favorable anti-inflammatory properties of n-3 PUFAs consumption potentially contribute to the improvement of microvascular endothelium-dependent vasodilation in healthy individuals.

Flaxseed for Health and Disease: Review of Clinical Trials

BACKGROUND

Flaxseed (Linum usitatissimum) is an oil-based seed that contains high amounts of alpha-linolenic acid, linoleic acid, lignans, fiber and many other bioactive components which is suggested for a healthier life. Nowadays, flaxseed is known as a remarkable functional food with different health benefits for humans and protects against cardiovascular disease, diabetes, dyslipidemia, obesity and altogether metabolic syndrome.

METHODS

To review the bioactive components of flaxseed and their potential health effects, PubMed and Scopus were searched from commencement to July 2019. Keywords including: "flaxseed", "Linum usitatissimum", "metabolic syndrome", "obesity", "inflammation", "insulin resistance", "diabetes", "hyperlipidemia" and "menopause" were searched in the databases with varying combinations.

CONCLUSION

Consumption of flaxseed in different forms has valuable effects and protects against cardiovascular disease, hypertension, diabetes, dyslipidemia, inflammation and some other complications. Flaxseed can serve as a promising candidate for the management of metabolic syndrome to control blood lipid levels, fasting blood sugar, insulin resistance, body weight, waist circumference, body mass and blood pressure.

Effects of omega-3 fatty acids on immune, health and growth variables in veal calves

Under the present intensive rearing conditions, calves face a series of stressors and multiple pathogens often necessitating antimicrobial use. Multiple feed additives are currently explored for their ability to prevent disease and limit the use of antimicrobials. Supplementation of the polyunsaturated long chain n-3 fatty acids eicosapentaenoic (EPA) and docohexaenoic (DHA) from marine origin has been proposed as a strategy to improve immune function and prevent excessive inflammation reactions. The aim of this randomized clinical trial was to explore the effects of n-3 fatty acids (PUFAs) used as feed supplement on health, production and immune variables in a veal calf setting. One hundred-seventy calves were randomly assigned to 3 treatment groups: microalgae (MA, n = 57, 2.5 g DHA/animal/day), fish oil (FO, n = 57, 2.5 g EPA + DHA/animal/day)] and a control group (CON, n = 56). Average daily gain (ADG), bodyweight at 12 weeks on feed and slaughter weight were determined. Health monitoring consisted of recording of clinical signs and repeated thoracic ultrasonography. After 5, 8 and 11 weeks of supplementation, the function of neutrophils, monocytes and peripheral blood mononuclear cells (PBMCs) was evaluated ex vivo by measuring reactive oxygen species (ROS) production by neutrophils and monocytes and proliferation of and cytokine release by PBMCs. Under the field conditions of this study, dietary supplementation of MA and FO showed very limited immunomodulatory effects. Feeding MA led to increased ROS production by neutrophils, Estimate (E) = 0.38, Standard Error (SE) = 0.14; P < 0.05, compared to the control calves after 5 weeks of in-feed supplementation. FO reduced IL-6 secretion E= -0.29, SE= 0.11; P < 0.05 compared to MA treated animals after 11 weeks on feed. Health and production variables were unaffected by treatments. The doses of EPA and DHA used in this study did not cause immunomodulatory changes in highly stressed calves to such an extent that this led to better health or growth of animals.

α-Linolenic Acid-Rich Diet Influences Microbiota Composition and Villus Morphology of the Mouse Small Intestine

α-Linolenic acid (ALA) is well-known for its anti-inflammatory activity. In contrast, the influence of an ALA-rich diet on intestinal microbiota composition and its impact on small intestine morphology are not fully understood. In the current study, we kept adult C57BL/6J mice for 4 weeks on an ALA-rich or control diet. Characterization of the microbial composition of the small intestine revealed that the ALA diet was associated with an enrichment in Prevotella and Parabacteroides. In contrast, taxa belonging to the Firmicutes phylum, including Lactobacillus, Clostridium cluster XIVa, Lachnospiraceae and Streptococcus, had significantly lower abundance compared to control diet. Metagenome prediction indicated an enrichment in functional pathways such as bacterial secretion system in the ALA group, whereas the two-component system and ALA metabolism pathways were downregulated. We also observed increased levels of ALA and its metabolites eicosapentanoic and docosahexanoic acid, but reduced levels of arachidonic acid in the intestinal tissue of ALA-fed mice. Furthermore, intestinal morphology in the ALA group was characterized by elongated villus structures with increased counts of epithelial cells and reduced epithelial proliferation rate. Interestingly, the ALA diet reduced relative goblet and Paneth cell counts. Of note, high-fat Western-type diet feeding resulted in a comparable adaptation of the small intestine. Collectively, our study demonstrates the impact of ALA on the gut microbiome and reveals the nutritional regulation of gut morphology.

Impacts of replacement of dietary fish oil by vegetable oils on growth performance, anti-oxidative capacity, and inflammatory response in large yellow croaker Larimichthys crocea

A 12-week feeding trial was conducted to evaluate the effects of replacement of dietary fish oil by palm and linseed oils on the growth performance, anti-oxidative capacity, and inflammatory responses of large yellow croaker (initial body weight: 36.82 ± 0.29 g). The control diet was designed to contain 6.5% of fish oil, and named as FO. On the basis of the control diet, the fish oil was 100% replaced by palm and linseed oils, and these two diets were named as PO and LO, respectively. Results showed that the specific growth rate significantly reduced in the PO and LO groups. Crude lipid content in liver of fish fed FO was significantly lower than that in the PO and LO groups. Fatty acid composition in liver reflected the dietary input. Compared with the FO group, palm oil inclusion significantly decreased expressions of superoxide dismutase 1, catalase, and nuclear factor erythroid 2-related factor 2 in liver, while linseed oil inclusion significantly increased expressions of above genes. However, both of the PO and LO groups had a significantly lower total anti-oxidative capacity in liver than the fish fed FO. Dietary palm and linseed oils significantly decreased expressions of arginase I and interleukin 10, and increased expressions of tumor necrosis factor α, interleukin 1β, toll-like receptor 22, and myeloid differentiation factor 88 in liver. In conclusion, total replacement of dietary fish oil by palm and linseed oils could suppress growth performance and liver anti-oxidative capacity, and induce inflammatory responses of large yellow croaker.

The Influence of Dietary Fatty Acids on Immune Responses

Diet-derived fatty acids (FAs) are essential sources of energy and fundamental structural components of cells. They also play important roles in the modulation of immune responses in health and disease. Saturated and unsaturated FAs influence the effector and regulatory functions of innate and adaptive immune cells by changing membrane composition and fluidity and by acting through specific receptors. Impaired balance of saturated/unsaturated FAs, as well as n-6/n-3 polyunsaturated FAs has significant consequences on immune system homeostasis, contributing to the development of many allergic, autoimmune, and metabolic diseases. In this paper, we discuss up-to-date knowledge and the clinical relevance of the influence of dietary FAs on the biology, homeostasis, and functions of epithelial cells, macrophages, dendritic cells, neutrophils, innate lymphoid cells, T cells and B cells. Additionally, we review the effects of dietary FAs on the pathogenesis of many diseases, including asthma, allergic rhinitis, food allergy, atopic dermatitis, rheumatoid arthritis, multiple sclerosis as well as type 1 and 2 diabetes.

Immunosenescence and Its Hallmarks: How to Oppose Aging Strategically? A Review of Potential Options for Therapeutic Intervention

Aging is accompanied by remodeling of the immune system. With time, this leads to a decline in immune efficacy, resulting in increased vulnerability to infectious diseases, diminished responses to vaccination, and a susceptibility to age-related inflammatory diseases. An age-associated immune alteration, extensively reported in previous studies, is the reduction in the number of peripheral blood naïve cells, with a relative increase in the frequency of memory cells. These two alterations, together with inflamm-aging, are considered the hallmarks of immunosenescence. Because aging is a plastic process, it is influenced by both nutritional and pharmacological interventions. Therefore, the role of nutrition and of immunomodulation in immunosenescence is discussed, due to the multifactorial influence on these hallmarks. The close connection between nutrition, intake of bioactive nutrients and supplements, immune function, and inflammation demonstrate the key role of dietary strategies as regulators of immune response and inflammatory status, hence as possible modulators of the rate of immunosenescence. In addition, potential options for therapeutic intervention are clarified. In particular, the use of interleukin-7 as growth factor for naïve T cells, the function of checkpoint inhibitors in improving T cell responses during aging and, the potential of drugs that inhibit mitogen-activated protein kinases and their interaction with nutrient signaling pathways are discussed. Finally, it is suggested that the inclusion of appropriate combinations of toll-like receptor agonists may enhance the efficacy of vaccination in older adults.

Effect of flaxseed oil on muscle protein loss and carbohydrate oxidation impairment in a pig model after lipopolysaccharide challenge

Flaxseed oil is rich in α-linolenic acid (ALA), which is the metabolic precursor of EPA and DHA. The present study investigated the effect of flaxseed oil supplementation on lipopolysaccharide (LPS)-induced muscle atrophy and carbohydrate oxidation impairment in a piglet model. Twenty-four weaned pigs were used in a 2 × 2 factorial experiment including dietary treatment (5 % maize oil v. 5 % flaxseed oil) and LPS challenge (saline v. LPS). On day 21 of treatment, the pigs were injected intraperitoneally with 100 μg/kg body weight LPS or sterile saline. At 4 h after injection, blood, gastrocnemius muscle and longissimus dorsi muscle were collected. Flaxseed oil supplementation increased ALA, EPA, total n-3 PUFA contents, protein:DNA ratio and pyruvate dehydrogenase complex quantity in muscles (P < 0·05). In addition, flaxseed oil reduced mRNA expression of toll-like receptor (TLR) 4 and nucleotide-binding oligomerisation domain protein (NOD) 2 and their downstream signalling molecules in muscles and decreased plasma concentrations of TNF-α, IL-6 and IL-8, and mRNA expression of TNF-α, IL-1β and IL-6 (P < 0·05). Moreover, flaxseed oil inclusion increased the ratios of phosphorylated protein kinase B (Akt) 1:total Akt1 and phosphorylated Forkhead box O (FOXO) 1:total FOXO1 and reduced mRNA expression of FOXO1, muscle RING finger (MuRF) 1 and pyruvate dehydrogenase kinase 4 in muscles (P < 0·05). These results suggest that flaxseed oil might have a positive effect on alleviating muscle protein loss and carbohydrates oxidation impairment induced by LPS challenge through regulation of the TLR4/NOD and Akt/FOXO signalling pathways.

The Physiological Effect of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) Intake and Exercise on Hemorheology, Microvascular Function, and Physical Performance in Health and Cardiovascular Diseases; Is There an Interaction of Exercise and Dietary n-3 PUFA Intake?

Physical activity has a beneficial effect on systemic hemodynamics, physical strength, and cardiac function in cardiovascular (CV) patients. Potential beneficial effects of dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs), such as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on hemorheology, vascular function, inflammation and potential to improve physical performance as well as other CV parameters are currently investigated. Recent meta-analysis suggests no effect of n-3 PUFA supplementation on CV function and outcomes of CV diseases. On the other hand, some studies support beneficial effects of n-3 PUFAs dietary intake on CV and muscular system, as well as on immune responses in healthy and in CV patients. Furthermore, the interaction of exercise and dietary n-3 PUFA intake is understudied. Supplementation of n-3 PUFAs has been shown to have antithrombotic effects (by decreasing blood viscosity, decreasing coagulation factor and PAI-1 levels and platelet aggregation/reactivity, enhancing fibrinolysis, but without effects on erythrocyte deformability). They decrease inflammation by decreasing IL-6, MCP-1, TNFα and hsCRP levels, expression of endothelial cell adhesion molecules and significantly affect blood composition of fatty acids. Treatment with n-3 PUFAs enhances brachial artery blood flow and conductance during exercise and enhances microvascular post-occlusive hyperemic response in healthy humans, however, the effects are unknown in cardiovascular patients. Supplementation of n-3 PUFAs may improve anaerobic endurance and may modulate oxygen consumption during intense exercise, may increase metabolic capacity, enhance endurance capacity delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function in humans and animal models. In addition, n-3 PUFAs have anti-inflammatory and anti-nociceptive effects and may attenuate delayed-onset muscle soreness and muscle stiffness, and preserve joint mobility. On the other hand, effects of n-3 PUFAs were variably observed in men and women and they vary depending on dietary protocol, type of supplementation and type of sports activity undertaken, both in healthy and cardiovascular patients. In this review we will discuss the physiological effects of n-3 PUFA intake and exercise on hemorheology, microvascular function, immunomodulation and inflammation and physical performance in healthy persons and in cardiovascular diseases; elucidating if there is an interaction of exercise and diet.

A systematic review of the effects of increasing arachidonic acid intake on PUFA status, metabolism and health-related outcomes in humans

We conducted a systematic review of randomised controlled trials (RCT) of increased intake of arachidonic acid (ARA) on fatty acid status and health outcomes in humans. We identified twenty-two articles from fourteen RCT. Most studies were conducted in adults. These used between 80 and 2000 mg ARA per d and were of 1-12 weeks duration. Supplementation with ARA doses as low as 80 mg/d increased the content of ARA in different blood fractions. Overall there seem to be few marked benefits for adults of increasing ARA intake from the typical usual intake of 100-200 mg/d to as much as 1000 mg/d; the few studies using higher doses (1500 or 2000 mg/d) also report little benefit. However, there may be an impact of ARA on cognitive and muscle function which could be particularly relevant in the ageing population. The studies reviewed here suggest no adverse effects in adults of increased ARA intake up to at least 1000-1500 mg/d on blood lipids, platelet aggregation and blood clotting, immune function, inflammation or urinary excretion of ARA metabolites. However, in many areas there are insufficient studies to make firm conclusions, and higher intakes of ARA are deserving of further study. Based on the RCT reviewed, there are not enough data to make any recommendations for specific health effects of ARA intake.

The effect of different sources of fish and camelina sativa oil on immune cell and adipose tissue mRNA expression in subjects with abnormal fasting glucose metabolism: a randomized controlled trial

Background/Objectives

Molecular mechanisms linking fish and vegetable oil intakes to their healthy metabolic effects may involve attenuation of inflammation. Our primary aim was to examine in a randomized controlled setting whether diets enriched in fatty fish (FF), lean fish (LF) or ALA-rich camelina sativa oil (CSO) differ in their effects on the mRNA expression response of selected inflammation-related genes in peripheral blood mononuclear cells (PBMCs) and subcutaneous adipose tissue (SAT) in subjects with impaired fasting glucose.

Subjects/Methods

Samples from 72 participants randomized to one of the following 12-week intervention groups, FF (n = 19), LF (n = 19), CSO (n = 17) or a control group (n = 17), were available for the PBMC study. For SAT, 39 samples (n = 8, n = 10, n = 9, n = 12, respectively) were available. The mRNA expression was measured at baseline and 12 weeks by TaqMan® Low Density Array.

Results

In PBMCs, LF decreased ICAM1 mRNA expression (P < 0.05), which was different (P = 0.06, Bonferroni correction) from the observed increase in the FF group (P < 0.05). Also, compared to the control group, LF decreased ICAM1 mRNA expression (P < 0.05). Moreover, the change in ICAM1 mRNA expression correlated positively with the intake of FF (P < 0.05) and negatively with the intake of LF (P < 0.05), independently of study group. A diet enriched in CSO, a rich source of alpha-linolenic acid (ALA), decreased PBMC IFNG mRNA expression (P < 0.01). The intake of CSO in the CSO group, but not the increase in plasma ALA proportions, correlated inversely with the IFNG mRNA expression in PBMCs (P = 0.08). In SAT, when compared with the control group, the effect of FF on decreasing IL1RN mRNA expression was significant (P < 0.03).

Conclusion

We propose that CSO intake may partly exert its benefits through immuno-inflammatory molecular regulation in PBMCs, while modulation of ICAM1 expression, an endothelial/vascular-related gene, may be more dependent on the type of fish consumed.

Omega-6 fatty acids and inflammation

Inflammation is a normal process that is part of host defence and tissue healing. However, excessive or unresolved inflammation can lead to uncontrolled tissue damage, pathology and disease. In humans on a Western diet, the omega-6 polyunsaturated fatty acid arachidonic acid (ARA) makes a significant contribution to the fatty acids present in the membrane phospholipids of cells involved in inflammation. ARA is a precursor to a number of potent pro-inflammatory mediators including well described prostaglandins and leukotrienes, which has led to the development of anti-inflammatory pharmaceuticals that target the ARA pathway to successfully control inflammation. Hence, it is commonly believed that increasing dietary intake of the omega-6 fatty acids ARA or its precursor linoleic acid (LA) will increase inflammation. However, studies in healthy human adults have found that increased intake of ARA or LA does not increase the concentrations of many inflammatory markers. Epidemiological studies have even suggested that ARA and LA may be linked to reduced inflammation. Contrastingly, there is also evidence that a high omega-6 fatty acid diet inhibits the anti-inflammatory and inflammation-resolving effect of the omega-3 fatty acids. Thus, the interaction of omega-3 and omega-6 fatty acids and their lipid mediators in the context of inflammation is complex and still not properly understood.

Serum n-6 polyunsaturated fatty acids and risk of death: the Kuopio Ischaemic Heart Disease Risk Factor Study

Background

The cardioprotective properties of linoleic acid (LA), a major n-6 (ω-6) polyunsaturated fatty acid (PUFA), have been recognized, but less is known about its associations with other causes of death. Relatively little is also known about how the minor n-6 PUFAs-γ-linolenic acid (GLA), dihomo-γ-linolenic acid (DGLA), and arachidonic acid (AA)-relate to mortality risk.

Objective

We investigated the associations of serum n-6 PUFAs, an objective biomarker of exposure, with risk of death in middle-aged and older men and whether disease history modifies the associations.

Design

We included 2480 men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study, aged 42-60 y at baseline in 1984-1989. The stratified analyses by baseline disease status included 1019 men with a history of cardiovascular disease (CVD), cancer, or diabetes and 1461 men without a history of disease.

Results

During the mean follow-up of 22.4 y, 1143 deaths due to disease occurred. Of these, 575 were CVD deaths, 317 were cancer deaths, and 251 were other-cause deaths. A higher serum LA concentration was associated with a lower risk of death from any cause (multivariable-adjusted HR for the highest compared with the lowest quintile: 0.57; 95% CI: 0.46, 0.71; P-trend < 0.001) and with deaths due to CVD (extreme-quintile HR: 0.54; 95% CI: 0.40, 0.74; P-trend < 0.001) and non-CVD or noncancer causes (HR: 0.48; 95% CI: 0.30, 0.76; P-trend = 0.001). Serum AA had similar, although weaker, inverse associations. Serum GLA and DGLA were not associated with risk of death, and none of the fatty acids were associated with cancer mortality. The results were generally similar among those with or without a history of major chronic disease (P-interaction > 0.13).

Conclusions

Our findings showed an inverse association of a higher biomarker of LA intake with total and CVD mortality and little concern for risk, thus supporting the current dietary recommendations to increase LA intake for CVD prevention. The finding of an inverse association of serum AA with the risk of death needs replication in other populations.

Standard Reference Material (SRM) 2378 fatty acids in frozen human serum. Certification of a clinical SRM based on endogenous supplementation of polyunsaturated fatty acids

Dietary fatty acids can be both beneficial and detrimental to human health depending on the degree and type of saturation. Healthcare providers and research scientists monitor the fatty acid content of human plasma and serum as an indicator of health status and diet. In addition, both the Centers for Disease Control & Prevention (CDC) and the National Institutes of Health - Office of Dietary Supplements are interested in circulating fatty acids (FAs) because they may be predictive of coronary heart disease. The National Institute of Standards and Technology (NIST) provides a wide variety of reference materials (RMs) and Standard Reference Materials® (SRM®s) including blood, serum, plasma, and urine with values assigned for analytes of clinical interest. NIST SRM 2378 Fatty Acids in Frozen Human Serum was introduced in 2015 to help validate methods used for the analysis of FAs in serum, and consists of three different pools of serum acquired from (1) healthy donors who had taken fish oil dietary supplements (at least 1000 mg per day) for at least one month (level 1 material), (2) healthy donors who had taken flaxseed oil dietary supplements (at least 1000 mg per day) for at least one month (level 2 material), and (3) healthy donors eating "normal" diets who had not taken dietary supplements containing fish or plant oils (level 3 material). The use of dietary supplements by donors provided SRMs with natural endogenous ranges of FAs at concentrations observed in human populations. Results from analyses using two methods at NIST, including one involving a novel microwave-assisted acid hydrolysis procedure, and one at the CDC are presented here. These results and their respective uncertainties were combined to yield certified values with expanded uncertainties for 12 FAs and reference values with expanded uncertainties for an additional 18 FAs.

Arachidonic acid supplementation modulates blood and skeletal muscle lipid profile with no effect on basal inflammation in resistance exercise trained men

Arachidonic acid (ARA), an omega-6 polyunsaturated fatty acid (PUFA), is the metabolic precursor to the eicosanoid family of lipid mediators. Eicosanoids have potent pro-inflammatory actions, but also act as important autocrine/paracrine signaling molecules in skeletal muscle growth and development. Whether dietary ARA is incorporated into skeletal muscle phospholipids and the resulting impact on intramuscular inflammatory and adaptive processes in-vivo is not known. In the current study, resistance trained men (≥1 year) received dietary supplementation with 1.5g/day ARA (n=9, 24 ± 1.5 years) or placebo (n=10, 26 ± 1.3 years) for 4-weeks while continuing their normal training regimen. Plasma and vastus lateralis muscle biopsies were collected in an overnight fasted state at baseline and week 4. ARA supplementation increased plasma content of ARA and gamma-linolenic acid, while decreasing relative abundance of linoleic acid, eicosapentaenoic acid, and dihomo-gamma-linolenic acid. In skeletal muscle, ARA and dihomo-gamma-linolenic acid content increased, whereas alpha-linolenic-acid was reduced. Compared to placebo, ARA supplementation reduced circulating platelet and monocyte number, and decreased the mRNA expression of the immune cell surface markers; neutrophil elastase/CD66b and interleukin 1-beta, in peripheral blood mononuclear cells. In muscle, ARA supplementation increased mRNA expression of the myogenic regulatory factors; MyoD and myogenin, but had no effect on a range of immune cell markers or inflammatory cytokines. These data show that dietary ARA supplementation can rapidly and safely modulate plasma and muscle fatty acid profile and promote myogenic gene expression in resistance trained men, without a risk of increasing basal systemic or intramuscular inflammation.

The associations of serum n-6 polyunsaturated fatty acids with serum C-reactive protein in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND/OBJECTIVES

There are concerns that high intake of n-6 polyunsaturated fatty acids (PUFA) may promote inflammation, because the end-product of n-6 PUFA metabolism, arachidonic acid, is a precursor for pro-inflammatory eicosanoids. Our aim was to investigate cross-sectional associations of the serum n-6 PUFAs, objective biomarkers for exposure, with serum high-sensitivity C-reactive protein (CRP), a key inflammation marker.

SUBJECTS/METHODS

The study included 1287 generally healthy men aged 42-60 years from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study, examined in 1984-1989. ANCOVA and logistic regression were used for analyses.

RESULTS

In the multivariable-adjusted analyses, both serum total n-6 PUFA and linoleic acid, the predominant n-6 PUFA, were associated with lower CRP. The mean CRP concentrations in quartiles of linoleic acid were 1.86, 1.51, 1.53, and 1.37 mg/L (P-trend = 0.001). The odds ratio for elevated CRP (>3 mg/L) in the highest vs. the lowest quartile was 0.47 (95% confidence interval (CI) 0.25-0.87, P-trend = 0.01). Arachidonic acid or the mainly endogenously produced n-6 PUFAs, gamma-linolenic acid and dihomo-gamma-linolenic acid, were not associated with higher CRP, either. Age, body mass index, or serum long-chain n-3 PUFA concentration did not modify the associations (P-interactions > 0.14).

CONCLUSIONS

Serum n-6 PUFAs were not associated with increased inflammation in men. In contrast, the main n-6 PUFA linoleic acid had a strong inverse association with the key inflammation marker, CRP.

Health relevance of the modification of low grade inflammation in ageing (inflammageing) and the role of nutrition

Ageing of the global population has become a public health concern with an important socio-economic dimension. Ageing is characterized by an increase in the concentration of inflammatory markers in the bloodstream, a phenomenon that has been termed "inflammageing". The inflammatory response is beneficial as an acute, transient reaction to harmful conditions, facilitating the defense, repair, turnover and adaptation of many tissues. However, chronic and low grade inflammation is likely to be detrimental for many tissues and for normal functions. We provide an overview of low grade inflammation (LGI) and determine the potential drivers and the effects of the "inflamed" phenotype observed in the elderly. We discuss the role of gut microbiota and immune system crosstalk and the gut-brain axis. Then, we focus on major health complications associated with LGI in the elderly, including mental health and wellbeing, metabolic abnormalities and infections. Finally, we discuss the possibility of manipulating LGI in the elderly by nutritional interventions. We provide an overview of the evidence that exists in the elderly for omega-3 fatty acid, probiotic, prebiotic, antioxidant and polyphenol interventions as a means to influence LGI. We conclude that slowing, controlling or reversing LGI is likely to be an important way to prevent, or reduce the severity of, age-related functional decline and the onset of conditions affecting health and well-being; that there is evidence to support specific dietary interventions as a strategy to control LGI; and that a continued research focus on this field is warranted.