Dietary Omega-3 Polyunsaturated Fatty Acids Research Articles

Vitamin D Deficiency in Community-Dwelling Elderly Is Not Associated with Age-Related Macular Degeneration1–3

Background: Elderly persons are at elevated risk of vitamin D deficiency, which is involved in various health problems. However, its relation with age-related macular degeneration (AMD) is debated.Objectives: We investigated factors associated with plasma 25-hydroxyvitamin D [25(OH)D] deficiency and the associations between plasma 25(OH)D concentrations and AMD in elderly subjects.Methods: Antioxydants, Lipides Essentiels, Nutrition et maladies OculaiRes (ALIENOR) is a population-based study on eye diseases performed in elderly residents of Bordeaux, France. Plasma 25(OH)D concentrations were assessed from blood samples and categorized as <25 nmol/L (deficiency), 25–49 nmol/L (insufficiency), or ≥50 nmol/L (sufficiency). AMD was classified as: no AMD, early AMD, and late AMD. Associations between baseline characteristics and plasma 25(OH)D status were examined with multinomial logistic regression analysis. Associations between AMD and plasma 25(OH)D status were estimated using generalized estimating equation logistic regressions.Results: Six hundred ninety-seven subjects with complete data were included. The prevalence of plasma 25(OH)D deficiency and insufficiency were 27.3% and 55.9%, respectively. In multivariate analysis, 25(OH)D deficiency was significantly associated with older age (P = 0.0007), females (P = 0.0007), absence of physical activity (P = 0.01), absence of vitamin D supplementation (P < 0.0001), higher plasma total cholesterol (P = 0.007), use of fibrates (P < 0.0001), lower alcohol consumption (P = 0.02), and season of blood sampling (P < 0.0001). After adjustment for these covariates and dietary omega-3 polyunsaturated fatty acid intake, smoking, and body mass index, no significant associations were found between early AMD and 25(OH)D insufficiency or deficiency (OR: 0.71, P = 0.12; OR: 0.73, P = 0.23, respectively) or with late AMD (OR: 1.04, P = 0.93; OR: 0.74, P = 0.59, respectively).Conclusion: These findings underline the very high prevalence of plasma 25(OH)D deficiency in this elderly population but do not support a specific role for vitamin D in AMD.

Eicosapentaenoic acid but not docosahexaenoic acid restores skeletal muscle mitochondrial oxidative capacity in old mice.

Mitochondrial dysfunction is often observed in aging skeletal muscle and is implicated in age-related declines in physical function. Early evidence suggests that dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) improve mitochondrial function. Here, we show that 10 weeks of dietary eicosapentaenoic acid (EPA) supplementation partially attenuated the age-related decline in mitochondrial function in mice, but this effect was not observed with docosahexaenoic acid (DHA). The improvement in mitochondrial function with EPA occurred in the absence of any changes in mitochondrial abundance or biogenesis, which was evaluated from RNA sequencing, large-scale proteomics, and direct measurements of muscle mitochondrial protein synthesis rates. We find that EPA improves muscle protein quality, specifically by decreasing mitochondrial protein carbamylation, a post-translational modification that is driven by inflammation. These results demonstrate that EPA attenuated the age-related loss of mitochondrial function and improved mitochondrial protein quality through a mechanism that is likely linked with anti-inflammatory properties of n-3 PUFAs. Furthermore, we demonstrate that EPA and DHA exert some common biological effects (anticoagulation, anti-inflammatory, reduced FXR/RXR activation), but also exhibit many distinct biological effects, a finding that underscores the importance of evaluating the therapeutic potential of individual n-3 PUFAs.

Balancing omega-6 and omega-3 fatty acids in ready-to-use therapeutic foods (RUTF).

Ready-to-use therapeutic foods (RUTFs) are a key component of a life-saving treatment for young children who present with uncomplicated severe acute malnutrition in resource limited settings. Increasing recognition of the role of balanced dietary omega-6 and omega-3 polyunsaturated fatty acids (PUFA) in neurocognitive and immune development led two independent groups to evaluate RUTFs. Jones et al. (BMC Med 13:93, 2015), in a study in BMC Medicine, and Hsieh et al. (J Pediatr Gastroenterol Nutr 2015), in a study in the Journal of Pediatric Gastroenterology and Nutrition, reformulated RUTFs with altered PUFA content and looked at the effects on circulating omega-3 docosahexaenoic acid (DHA) status as a measure of overall omega-3 status. Supplemental oral administration of omega-3 DHA or reduction of RUTF omega-6 linoleic acid using high oleic peanuts improved DHA status, whereas increasing omega-3 alpha-linolenic acid in RUTF did not. The results of these two small studies are consistent with well-established effects in animal studies and highlight the need for basic and operational research to improve fat composition in support of omega-3-specific development in young children as RUTF use expands.Please see related article: http://www.biomedcentral.com/1741-7015/13/93

Dietary fatty acids affect semen quality: a review.

Mammalian spermatozoa are characterized by a high proportion of polyunsaturated fatty acids (PUFA) which play a crucial role in fertilization. This review focuses on analysis of sperm fatty acid profiles and the effects of omega-3, saturated and trans dietary and sperm fatty acids on sperm parameters. Two major points have been pivotal points of investigation in the field of sperm fatty acid profiles: first, the comparison between fatty acid profiles of fertile and infertile men and second, the effect of dietary fatty acids on sperm fatty acid profiles as well as sperm quality and quantity. Docosahexaenoic acid (DHA, C22:6n-3), and palmitic acid (C16:0) are the predominant PUFA and saturated fatty acids, respectively, in human sperm cells. Higher levels of DHA are concentrated on the sperm's head or tail varying among different species. However, the human sperm head contains a higher concentration of DHA. Dietary fatty acids influence on sperm fatty acid profiles and it seems that sperm fatty acid profiles are most sensitive to dietary omega-3 PUFA. Although improvements in sperm parameters are a response to omega-3 sources after more than 4 weeks of supplementation in the male diet, time-dependent and dose-dependent responses may explain the failure in some experiments. In human spermatozoa, elevated saturated or trans fatty acid concentration and a low DHA level is a concern. The regulations of the sperm fatty acid mean melting point as well as expression regulation of peroxisome proliferator-activated receptor gamma (PPARG) alongside with spermatozoon assembly, anti-apoptosis effects, eicosanoid formation, and hormone activity are the putative key factors that induce a response by inclusion of omega-3 PUFA.

Validation of endogenous reference genes in Buglossoides arvensis for normalizing RT-qPCR-based gene expression data.

Selection of a stably expressed reference gene (RG) is an important step for generating reliable and reproducible quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) gene expression data. We, in this study, have sought to validate RGs for Buglossoides arvensis, a high nutraceutical value plant whose refined seed oil is entering the market under the commercial trade name Ahiflower™. This weed plant has received attention for its natural ability to significantly accumulate the poly-unsaturated fatty acid (PUFA) stearidonic acid (SDA, C18:4n-3) in its seeds, which is uncommon for most plant species. Ten candidate RGs (β-Act, 18S rRNA, EF-1a, α-Tub, UBQ, α-actin, CAC, PP2a, RUBISCO, GAPDH) were isolated from B. arvensis and TaqMan™ compliant primers/probes were designed for RT-qPCR analysis. Abundance of these gene transcripts was analyzed across different tissues and growth regimes. Two of the most widely used algorithms, geNorm and NormFinder, showed variation in expression levels of these RGs. However, combinatorial analysis of the results clearly identified CAC and α-actin as the most stable and unstable RG candidates, respectively. This study has for the first time identified and validated RGs in the non-model system B. arvensis, a weed plant projected to become an important yet sustainable source of dietary omega-3 PUFA.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-0952-4) contains supplementary material, which is available to authorized users.

Association Between Omega‐3 Index and Type 2 Diabetes in Older Overweight/Obese People is Sex Dependent

The association between dietary omega‐3 polyunsaturated fatty acid (n‐3PUFA) deficiency and insulin resistance, and type 2 diabetes (T2D) is unclear. The aim of this study was to determine whether there is an association between erythrocyte n‐3PUFA levels (Omega‐3 Index) and T2D in older adults.A cross‐sectional sample of older adults aged 65‐95 years (n=548) was analysed. Outcome measures included: Omega‐3 index (O3I; %EPA + %DHA); fasting blood glucose; plasma insulin; and HbA1c. HOMA‐IR was calculated to determine insulin sensitivity. Odds ratio (OR) for T2D was calculated for each quartile of O3I using the lowest quartile as a reference.There was a significant inverse association between O3I and T2D in overweight and obese females, with an OR for T2D for the first to fourth quartiles respectively: 1.0 (reference), 0.82 (95% CI, 0.31‐2.18), 0.56 (95% CI, 0.21‐1.52), 0.22 (95% CI, 0.06‐0.82) (P‐trend=0.015). Similar trends were seen in overweight males however the relationship did not reach significance. After adjusting for BMI, no associations were found between O3I and fasting blood glucose, insulin, HbA1c or HOMA‐IR.Higher erythrocyte n‐3PUFA status may be protective against obesity‐related insulin resistance and T2D in females. Further research is warranted to further elucidate sex differences and determine whether dietary interventions to improve the O3I may delay or prevent the development of T2D.

Omega-3 polyunsaturated fatty acids and brain aging.

The literature on the influence of dietary omega-3 polyunsaturated fatty acid (ω-3 PUFA) on brain aging has grown exponentially during the last decade. Many avenues have been explored but no global picture or clear evidence has emerged. Experimental studies have shown that ω-3 PUFA is involved in many neurobiological processes that are involved in neurotransmission and neuroprotection, indicating that these PUFAs may prevent age-related brain damage. Human studies have revealed only a weak link between ω-3 PUFA status and cognitive aging, whereas interventional studies have yet to confirm it. The purpose of this review is to analyze the developments in the area during the last 2 years. Human brain MRI studies have confirmed previous findings that ω-3 PUFA can protect the brain during aging; two intervention studies obtained clear evidence. We also analyzed the experimental data clarifying the involvement of ω-3 PUFA in neurotransmission, neuroprotection (including prevention of peroxidation, inflammation, and excitotoxicity), and neurogenesis, thereby helping the brain cope with aging. These recent human and experimental studies provide support for and clarification of how ω-3 PUFA protect against brain aging and highlight the main lines for future research.

The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: A systematic review and commentary

This paper presents a systematic review of human studies investigating the effect of altering dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) alpha-linolenic acid (ALA) and omega-6 polyunsaturated fatty acid (n-6 PUFA) linoleic acid (LA) intakes on n-3 long-chain polyunsaturated fatty acid (LCPUFA) status in adult humans. The results suggest that it is possible to increase n-3 LCPUFA status by reducing LA and/or increasing ALA intake in humans, although decreasing LA intake to below 2.5%E may be required to specifically increase levels of the n-3 LCPUFA docosahexaenoic acid (DHA). The majority of studies in this area to date have been relatively poor in quality, which limits the ability to draw robust conclusions, and we present a series of recommendations to improve the quality of future studies in fatty acid nutrition in humans.

Endogenous Generation and Signaling Actions of Omega-3 Fatty Acid Electrophilic Derivatives

Dietary omega-3 polyunsaturated fatty acids (PUFAs) are beneficial for a number of conditions ranging from cardiovascular disease to chronic airways disorders, neurodegeneration, and cancer. Growing evidence has shown that bioactive oxygenated derivatives are responsible for transducing these salutary effects. Electrophilic oxo-derivatives of omega-3 PUFAs represent a class of oxidized derivatives that can be generated via enzymatic and nonenzymatic pathways. Inflammation and oxidative stress favor the formation of these signaling species to promote the resolution of inflammation within a fine autoregulatory loop. Endogenous generation of electrophilic oxo-derivatives of omega-3 PUFAs has been observed in in vitro and ex vivo human models and dietary supplementation of omega-3 PUFAs has been reported to increase their formation. Due to the presence of an α,β-unsaturated ketone moiety, these compounds covalently and reversibly react with nucleophilic residues on target proteins triggering the activation of cytoprotective pathways, including the Nrf2 antioxidant response, the heat shock response, and the peroxisome proliferator activated receptor γ (PPARγ) and suppressing the NF-κB proinflammatory pathway. The endogenous nature of electrophilic oxo-derivatives of omega-3 PUFAs combined with their ability to simultaneously activate multiple cytoprotective pathways has made these compounds attractive for the development of new therapies for the treatment of chronic disorders and acute events characterized by inflammation and oxidative stress.

DHA Disorders Raft-Like Domains as Revealed by Solid State 2H NMR

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs), such as docosahexaenoic acid (DHA, 22:6), have a wide variety of health benefits. However, the origin of the benefits at the molecular level is yet to be elucidated. A membrane-mediated mechanism in which n-3 PUFAs are incorporated into phospholipids and modulate molecular organization is one possibility. Cellular membranes are inhomogeneous where structurally diverse lipids can exist in separate domains. Regions rich in sphingomyelin (SM) and cholesterol, commonly called lipid rafts, contain important signaling proteins. In a recent solid-state 2H nuclear magnetic resonance (2H NMR) study of a model membrane composed of 1-[2H31] palmitoyl-2-docosahexaenoyl-phosphatidylcholine (PDPC-d31), a deuterated analog of a DHA-containing phospholipid, in mixtures with SM and cholesterol, we discovered that DHA could significantly enter raft-like domains. How DHA affects the molecular organization within the raft-like domains is addressed here by observing PSM-d31, an analog of SM with a perdeuterated N-palmitoyl chain. The 2H NMR spectra for PSM-d31 in mixtures with PDPC and cholesterol exhibit two spectral components, a larger more ordered component that we attribute to raft-like domains and a smaller less ordered component that we attribute to non-raft-like domains. On average, the order of PSM-d31 is reduced and, thus, disordering of PSM-d31 by PDPC is indicated. Our observations confirm that DHA can infiltrate rafts and affect molecular organization, which has implications for the signaling of raft and non-raft proteins. Furthermore, these results are consistent with in vivo studies showing that DHA infiltrates rafts.

Understanding diet and modeling changes in the omega-3 and omega-6 fatty acid composition of U.S. garrison foods for active duty personnel.

Research indicates that dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) are important in reducing the risk of mental illness. We used the DoD Survey of Health Related Behaviors among Active Duty Military Personnel (HRBS) to assess current military dietary patterns and meal locations. We used the Lands Equation to model PUFAs in a sample Garrison diet and the nutritional impact of substitution of foods higher in omega-3 PUFAs and lower in omega-6 PUFAs on tissue composition. The military diet was very poor quality compared to 2010 Healthy People Guidelines. A representative Garrison diet does not meet our estimated healthy n-3 HUFA intake at 3.5 g/d, corresponding with a tissue composition of 60% n-3 in HUFA (i.e., 40% n-6 in HUFA). Substitution of n-3 rich eggs, poultry, pork and other food commodities, combined with use on low linoleic acid oils, may contribute significantly to attaining healthier n-6/n-3 proportions in the tissue.

Omega-3 fatty acids and stress-induced immune dysregulation: implications for wound healing.

Stress-related immune alterations can be consequential for health; they can enhance susceptibility to infectious agents and influence the severity of infectious disease, diminish the strength of immune responses to vaccines, reactivate latent viruses, and slow wound healing. Furthermore, stressful events and negative emotions promote systemic proinflammatory cytokine production while reducing beneficial local production of proinflammatory cytokines at the wound site that are important for wound healing. Dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) also influence systemic inflammation; high proportions of omega-6 to omega-3 boost inflammation, while omega-3 has anti-inflammatory properties. Additionally, the limited evidence thus far suggests that omega-3 PUFA may enhance local inflammatory responses at wound sites. Moreover, an individual's dietary proportion of omega-3 to omega-6 may influence the magnitude of inflammatory responses to stressful events. Thus, wound healing and surgery provide exemplars of how stress and depression can interact with the diet to influence important clinical outcomes.

Dietary omega-3 and omega-6 fatty acids compete in producing tissue compositions and tissue responses.

Serious food-related health disorders may be prevented by recognizing the molecular processes that connect the dietary intake of vitamin-like fatty acids to tissue accumulation of precursors of potent hormone-like compounds that cause harmful tissue responses. Conversion of dietary 18-carbon omega-3 and omega-6 polyunsaturated fatty acids to tissue 20- and 22-carbon highly unsaturated fatty acids (HUFAs) is catalyzed by promiscuous enzymes that allow different types of fatty acid to compete among each other for accumulation in tissue HUFA. As a result, food choices strongly influence the types of accumulated tissue HUFA. However, the conversion of tissue HUFA to active hormones and their receptor-mediated actions occurs with discriminating enzymes and receptors that give more intense responses for the omega-6 and omega-3 hormones. Undesired chronic health disorders, which are made worse by excessive omega-6 hormone actions, can be prevented by eating more omega-3 fats, less omega-6 fats, and fewer calories per meal.

Experimental reduction in dietary omega-3 polyunsaturated fatty acids depresses sperm competitiveness.

The health benefits of diets containing rich sources of long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) are well documented and include reductions in the risk of several diseases typical of Western societies. The dietary intake of n-3 LC-PUFA has also been linked to fertility, and there is abundant evidence that a range of ejaculate traits linked to fertility in humans, livestock and other animals depend on an adequate intake of n-3 LC-PUFA from dietary sources. However, relatively few studies have explored how n-3 LC-PUFA influence reproductive fitness, particularly in the context of sexual selection. Here, we show that experimental reduction in the level of n-3 LC-PUFA in the diet of guppies (Poecilia reticulata) depresses a male's share of paternity when sperm compete for fertilization, confirming that the currently observed trend for reduced n-3 LC-PUFA in western diets has important implications for individual reproductive fitness.

Dietary omega-3 polyunsaturated fatty acids plus aspirin decreases plasma lipids and increases pro-resolving lipid mediators in apoE-deficient mice

Dietary omega-3 polyunsaturated fatty acids plus aspirin decreases plasma lipids and increases pro-resolving lipid mediators in apoE-deficient mice

The effect of dietary omega-3 polyunsaturated fatty acids on plasma lipids and lipoproteins of C57BL/6 mice is age and sex specific

There is clear evidence of the effects of sex and age on the prevalence of cardiovascular disease. We investigated the interactions of dietary omega (n)-3 polyunsaturated fatty acids (PUFA), sex, and age on plasma lipids and lipoproteins in the offspring of C57BL/6 mice exposed to high, medium, or low n-3 PUFA at weaning and 16 weeks postweaning. There was an increase in plasma triglycerides from weaning to 16 weeks in male and female offspring; however, the high n-3 PUFA group showed a reduction in triglycerides in both sexes at 16 weeks. High n-3 PUFA caused an increase in plasma LDL-cholesterol from weaning to 16 weeks in male offspring; however, the LDL particle size was significantly larger in the high n-3 PUFA group. Plasma from male mice showed higher cholesterol efflux compared to females; high n-3 PUFA increased cholesterol efflux. Thus the effects of n-3 PUFA are age and sex dependent.

The effect of docosahexaenoic acid on bone microstructure in young mice and bone fracture in neonates

BackgroundAs low bone mineral density is a risk factor for fracture in childhood, optimizing age appropriate bone mass is recommended and might lower the impact of bone loss related to age. Consumption of omega-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic and docosahexaenoic (DHA) acids have been shown to beneficially modulate bone metabolism. The objective of this study was to determine the incidence of fracture in neonates receiving a fish compared with soybean oil–based intravenous lipid emulsion and evaluate the effect of varying dietary omega-3 PUFA consumption on growing bone in young mice. Materials and methodsEligibility criteria for the clinical study included gestational age ≤37 wk and parenteral nutrition–dependence for ≥4 wk. Radiographs were reviewed after lipid initiation to identify radiologic bone fracture. The animal study evaluated female C57/Bl6 mice randomized into one of five groups from age 3–12 wk, at which time femurs were harvested for micro–computed tomography and light microscopy analysis. ResultsA lower incidence of bone fracture was found in neonates maintained on fish compared with soybean oil. In the animal study, findings suggest the DHA diet provides the best protection against trabecular bone loss as evidenced by increased bone volume fraction, increased trabecular number, and decreased trabecular separation on micro–computed tomography. These protective effects appeared to affect the bone microstructure alone. ConclusionsThe lower fracture risk observed in fish oil fed neonates in combination with the protective effects of DHA observed in the femurs of young C57/BL6 mice suggest an important role for omega-3 PUFAs on bone growth.

Вплив ω-3 поліненасичених жирних кислот на показники функціонування мітохондрій міокарда при ізопротереноліндукованому пошкодженні серця

We have studied the functional parameters of mitochondria from hearts after isopreterenol-induced injury (two subcutaneous injections of isopreterenol at the dose 60 mg/kg/day). We investigated the influence of dietary omega-3 polyunsaturated fatty acids (omega-3 PUFAs) administered to rats (Epadol, 0.1 mg/100 gr of weight for 4 weeks) on these parameters. Isoproterenol-induced heart injury leads to a decreased parameters of respiration of isolated mitochondria in the presence of succinate. Administration of omega-3 PUFAs significantly restored the respiration rate of mitochondria: the state 3 respiration was increased by 70.12%, the state 4 by 39.87% and the respiratory control ratio by 45.19% compared to the corresponding parameters of experimental group. Also, it was shown the ability of omega-3 PUFAs to decrease mitochondria swelling (by 60%) in nominally free calcium solution. The results of the study indicate that omega-3 PUFAs improve the altered functions of the heart mitochondria evoked by isoproterenol-induced injury.

Omega-3 Fatty Acids: A Growing Ocean of Choices

There has been increasing interest in the health benefits of supplemental and/or dietary omega-3 polyunsaturated fatty acids (PUFAs), particularly in their role in disease prevention. This interest escalated once their effects on cardiovascular health were observed from numerous observational studies in populations whose diet consisted mainly of fish. Research has since been undertaken on omega-3 PUFAs to investigate their health benefits in a vast array of medical conditions, including primary and secondary prevention. This article discusses the evidence and controversies concerning omega-3 PUFAs in various health conditions. In addition to the effects on cardiovascular health, omega-3 PUFAs have been shown to prevent the development of dementia, reduce systemic inflammatory diseases, prevent prostate cancer, and possibly have a role in the treatment of depression and bipolar disorder.

Effects of dietary omega-3 polyunsaturated fatty acids on growth and immune response of weanling pigs.

The recognition that omega-3 polyunsaturated fatty acids (n-3 PUFA) possess potent anti-inflammatory properties in human models has prompted studies investigating their efficacy for animal growth and immunity. This study examined the effect of feeding an n-3 PUFA-enriched diet on growth and immune response of weanling piglets. Newly weaned pigs (averaging 27 ± 2 days of age and 8.1 ± 0.7 kg of body weight) were assigned randomly to receive a control (3% vegetable oil, n = 20) or n-3 PUFA-supplemented (3% marine n-3 PUFA, n = 20) diet for 28 day after weaning. Female pigs consuming the n-3 PUFA-enriched diet were lighter at week 4 post-weaning than those fed the vegetable oil supplement. Weanling pigs gained more weight, consumed more feed and had better growth to feed ratios between days 14 and 28 than between days 0 and 14 post-weaning. Plasma insulin-like growth factor I (IGF-I) decreased between days 0 (87.2 ± 17.0 ng/mL) and 14 (68.3 ± 21.1 ng/mL) after weaning and then increased again by day 28 (155.2 ± 20.9 ng/mL). In piglets consuming the vegetable oil-enriched diet, plasma tumor necrosis factor alpha (TNF-α) increased from 37.6 ± 14.5 to 102.9 ± 16.6 pg/mL between days 0 and 14 post-weaning and remained high through day 28 (99.0 ± 17.2 pg/mL). The TNF-α increase detected in the piglets fed vegetable oil was not observed in the piglets fed n-3 PUFA. Results indicate that weaning induces considerable immune stress in piglets and that this stress can be mitigated by dietary supplementation of n-3 PUFA.