The importance of a balanced ω-6 to ω-3 ratio in the prevention and management of obesity

Fatty Acids and Cardiovascular Risk. Evidence, Lack of Evidence, and Diligence

One of the most controversial areas of nutrition research relates to fats, particularly essential fatty acids, in the context of cardiovascular disease risk. A critical feature of dietary fatty acids is that they incorporate into the plasma membrane, modifying fluidity and key physiological functions. Importantly, they can reshape the bioavailability of eicosanoids and other lipid mediators, which direct cellular responses to external stimuli, such as inflammation and chronic stress conditions. This paper provides an overview of the most recent evidence, as well as historical controversies, linking fat consumption with human health and disease. We underscore current pitfalls in the area of fatty acid research and critically frame fatty acid intake in the larger context of diet and behavior. We conclude that fundamental research on fatty acids and lipids is appropriate in certain areas, but the rigor and reproducibility are lacking in others. The pros and cons are highlighted throughout the review, seeking to guide future research on the important area of nutrition, fat intake, and cardiovascular disease risk.

Fructose, Omega 3 Fatty Acids, and Vitamin E: Involvement in Pediatric Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most common form of liver disease in both adults and children, becoming the leading cause for liver transplant in many countries. Its prevalence has increased considerably in recent years, mainly due to the explosive increase in pediatric obesity rates. NAFLD is strongly associated with central obesity, diabetes, dyslipidemia and insulin resistance, and it has been considered as the hepatic manifestation of the metabolic syndrome. Its complex pathophysiology involves a series of metabolic, inflammatory and oxidative stress processes, among others. Given the sharp increase in the prevalence of NAFLD and the lack of an appropriate pharmacological approach, it is crucial to consider the prevention/management of the disease based on lifestyle modifications such as the adoption of a healthy nutrition pattern. Herein, we review the literature and discuss the role of three key nutrients involved in pediatric NAFLD: fructose and its participation in metabolism, Omega-3 fatty acids and its anti-inflammatory effects and vitamin E and its action on oxidative stress.

The Importance of Maintaining a Low Omega-6/Omega-3 Ratio for Reducing the Risk of Inflammatory Cytokine Storms

Inflammatory cytokine storms in the lungs are a potential consequence of RNA viruses. One issue that may increase the risk of developing inflammatory cytokine storms in the lungs during viral infections is an imbalance in the dietary omega-6/3 ratio. Indeed, over the past 100 years the omega-6/3 ratio in the Western world has increased from approximately 4:1 to 20:1. This has increased the production of pro-inflammatory metabolites from omega-6 and reduced the anti-inflammatory metabolites from omega-3s. A high dietary omega-6/3 ratio may promote excessive inflammation, which may be contributing to inflammatory cytokine storms in the lungs during viral infections.

Genetic diversity of SAD and FAD genes responsible for the fatty acid composition in flax cultivars and lines

BACKGROUND

Flax (Linum usitatissimum L.) is grown for fiber and seed in many countries. Flax cultivars differ in the oil composition and, depending on the ratio of fatty acids, are used in pharmaceutical, food, or paint industries. It is known that genes of SAD (stearoyl-ACP desaturase) and FAD (fatty acid desaturase) families play a key role in the synthesis of fatty acids, and some alleles of these genes are associated with a certain composition of flax oil. However, data on genetic polymorphism of these genes are still insufficient.

RESULTS

On the basis of the collection of the Institute for Flax (Torzhok, Russia), we formed a representative set of 84 cultivars and lines reflecting the diversity of fatty acid composition of flax oil. An approach for the determination of full-length sequences of SAD1, SAD2, FAD2A, FAD2B, FAD3A, and FAD3B genes using the Illumina platform was developed and deep sequencing of the 6 genes in 84 flax samples was performed on MiSeq. The obtained high coverage (about 400x on average) enabled accurate assessment of polymorphisms in SAD1, SAD2, FAD2A, FAD2B, FAD3A, and FAD3B genes and evaluation of cultivar/line heterogeneity. The highest level of genetic diversity was observed for FAD3A and FAD3B genes - 91 and 62 polymorphisms respectively. Correlation analysis revealed associations between particular variants in SAD and FAD genes and predominantly those fatty acids whose conversion they catalyze: SAD - stearic and oleic acids, FAD2 - oleic and linoleic acids, FAD3 - linoleic and linolenic acids. All except one low-linolenic flax cultivars/lines contained both the substitution of tryptophan to stop codon in the FAD3A gene and histidine to tyrosine substitution in the FAD3B gene, while samples with only one of these polymorphisms had medium content of linolenic acid and cultivars/lines without them were high-linolenic.

CONCLUSIONS

Genetic polymorphism of SAD and FAD genes was evaluated in the collection of flax cultivars and lines with diverse oil composition, and associations between particular polymorphisms and the ratio of fatty acids were revealed. The achieved results are the basis for the development of marker-assisted selection and DNA-based certification of flax cultivars.

The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders

Most of the global population is deficient in long-chain marine omega-3s. In particular, docosahexaenoic acid (DHA), a long-chain omega-3 fatty acid, is important for brain and eye development. Additionally, DHA plays a significant role in mental health throughout early childhood and even into adulthood. In the brain, DHA is important for cellular membrane fluidity, function and neurotransmitter release. Evidence indicates that a low intake of marine omega-3s increases the risk for numerous mental health issues, including Attention Deficit Hyperactivity Disorder (ADHD), autism, bipolar disorder, depression and suicidal ideation. Studies giving supplemental marine omega-3s have shown promise for improving numerous mental health conditions. This paper will review the evidence surrounding marine omega-3s and mental health conditions.

Metabolic profiling of organic and fatty acids in chronic and autoimmune diseases

Metabolomics is a powerful tool of omics that permits the simultaneous identification of metabolic perturbations in several autoimmune and chronic diseases. Several parameters can affect a metabolic profile, from the population characteristics to the selection of the analytical method. In the current chapter, we summarize the main analytical methods and results of the metabolic profiling of fatty and organic acids performed in human metabolomic studies for asthma, COPD, psoriasis and Hashimoto's thyroiditis. We discuss the most significant metabolic alterations associated with these diseases, after comparison of either a single patient's group with healthy controls or several patient's subgroups of different disease severity and phenotype with healthy controls or of a patient's group before and after treatment. Finally, we present critical metabolic patterns that are associated with each disease and their potency for the unraveling of disease pathogenesis, prediction, diagnosis, patient stratification and treatment selection.

Proximate analysis and fatty acid of Corbicula fluminea (C. fluminea) tissue in Kelantan, Malaysia

Corbicula fluminea (C. fluminea) is one of the mollusc species commonly eaten as a popular snack in Kelantan, Malaysia. This species contributes to the local economic activity. However, the handling process of C. fluminea at different processing stages (raw, smoke and selling stages) is believed to have affected the nutritional value in their soft tissue. Hence, this study aims to provide information about the chemical content (moisture, crude fat, ash, crude protein and carbohydrate) of C. fluminea and fatty acid of smoked C. fluminea at different processing stages. Samples were collected from Pasir Mas and Tumpat, Kelantan, Malaysia. The chemical content analysis was carried out based on the Association of Official Analytical Chemists (AOAC) standard procedures. The results have indicated that moisture (80.93 ± 0.37%) and crude fat (10.82 ± 0.21%) in C. fluminea were significantly higher (p < 0.05) at the raw stage. On the other hand, the ash (2.09 ± 0.03%) and crude protein (9.45 ± 0.42%) were significantly higher (p < 0.05) at smoked stage. Meanwhile, carbohydrate (3.39 ± 0.49%) was significantly higher (p < 0.05) at the selling stage. The fatty acid percentage of smoked C. fluminea indicates that the total saturated fatty acid (SFA) content was higher than the total of both monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). The obtained data indicates that the composition percentage of omega-6 (n-6) in PUFA is significantly greater than omega-3 (n-3). The n-6/n-3 ratio of smoked C. fluminea is 2.95-3.11 and therefore can be considered as a healthy diet. The findings of this study can improve consumers' health through sufficient nutrient consumption and also provide economic benefits by increasing sellers' income in Kelantan.

Evidence of the Role of Omega-3 Polyunsaturated Fatty Acids in Brain Glucose Metabolism

In mammals, brain function, particularly neuronal activity, has high energy needs. When glucose is supplemented by alternative oxidative substrates under different physiological conditions, these fuels do not fully replace the functions fulfilled by glucose. Thus, it is of major importance that the brain is almost continuously supplied with glucose from the circulation. Numerous studies describe the decrease in brain glucose metabolism during healthy or pathological ageing, but little is known about the mechanisms that cause such impairment. Although it appears difficult to determine the exact role of brain glucose hypometabolism during healthy ageing or during age-related neurodegenerative diseases such as Alzheimer’s disease, uninterrupted glucose supply to the brain is still of major importance for proper brain function. Interestingly, a body of evidence suggests that dietary n-3 polyunsaturated fatty acids (PUFAs) might play significant roles in brain glucose regulation. Thus, the goal of the present review is to summarize this evidence and address the role of n-3 PUFAs in brain energy metabolism. Taken together, these data suggest that ensuring an adequate dietary supply of n-3 PUFAs could constitute an essential aspect of a promising strategy to promote optimal brain function during both healthy and pathological ageing.

Effect of probiotics on obesity-related markers per enterotype: a double-blind, placebo-controlled, randomized clinical trial

Background

Prevention and improvement of disease symptoms are important issues, and probiotics are suggested as a good treatment for controlling the obesity. Human gut microbiota has different community structures. Because gut microbial composition is assumed to be linked to probiotic function, this study evaluated the efficacy of probiotics on obesity-related clinical markers according to gut microbial enterotype.

Methods

Fifty subjects with body mass index over 25 kg/m² were randomly assigned to either the probiotic or placebo group. Each group received either unlabeled placebo or probiotic capsules for 12 weeks. Body weight, waist circumference, and body composition were measured every 3 weeks. Using computed tomography, total abdominal fat area and visceral fat area were measured. Blood and fecal samples were collected before and after the intervention for biochemical parameters and gut microbial compositions analysis.

Results

Gut microbial compositions of all the subjects were classified into two enterotypes according to Prevotella/Bacteroides ratio. The fat percentage, blood glucose, and insulin significantly increased in the Prevotella-rich enterotype of the placebo group. The obesity-related markers, such as waist circumference, total fat area, visceral fat, and ratio of visceral to subcutaneous fat area, were significantly reduced in the probiotic group. The decrease of obesity-related markers was greater in the Prevotella-rich enterotype than in the Bacteroides-rich enterotype.

Conclusion

Administration of probiotics improved obesity-related markers in obese people, and the efficacy of probiotics differed per gut microbial enterotype and greater responses were observed in the Prevotella-dominant enterotype.

Current Trends on Seaweeds: Looking at Chemical Composition, Phytopharmacology, and Cosmetic Applications

Seaweeds have received huge interest in recent years given their promising potentialities. Their antioxidant, anti-inflammatory, antitumor, hypolipemic, and anticoagulant effects are among the most renowned and studied bioactivities so far, and these effects have been increasingly associated with their content and richness in both primary and secondary metabolites. Although primary metabolites have a pivotal importance such as their content in polysaccharides (fucoidans, agars, carragenans, ulvans, alginates, and laminarin), recent data have shown that the content in some secondary metabolites largely determines the effective bioactive potential of seaweeds. Among these secondary metabolites, phenolic compounds feature prominently. The present review provides the most remarkable insights into seaweed research, specifically addressing its chemical composition, phytopharmacology, and cosmetic applications.

Effects of abomasal infusion of essential fatty acids and conjugated linoleic acid on performance and fatty acid, antioxidative, and inflammatory status in dairy cows

The objective of this study was to test the effects of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) supplementation on fatty acid (FA) composition, performance, and systemic and hepatic antioxidative and inflammatory responses in dairy cows. Four cows (126 ± 4 d in milk) were investigated in a 4 × 4 Latin square and were abomasally infused with 1 of the following for 6 wk: (1) coconut oil (control treatment, CTRL; 38.3 g/d; providing saturated FA), (2) linseed and safflower oil (EFA treatment; 39.1 and 1.6 g/d, respectively; providing mainly α-linolenic acid), (3) Lutalin (BASF, Ludwigshafen, Germany; CLA treatment; cis-9,trans-11 and trans-10,cis-12 CLA, 4.6 g/d each), (4) or EFA+CLA. The initial dosage was doubled every 2 wk, resulting in 3 dosages (dosage 1, 2, and 3). Cows were fed a corn silage-based total mixed ration with a high n-6/n-3 FA ratio. Dry matter intake and milk yield were recorded daily, and milk composition was measured weekly. The FA compositions of milk fat and blood plasma were analyzed at wk 0, 2, 4, and 6. The plasma concentration and hepatic mRNA abundance of parameters linked to the antioxidative and inflammatory response were analyzed at wk 0 and 6 of each treatment period. Infused FA increased in blood plasma and milk of the respective treatment groups in a dose-dependent manner. The n-6/n-3 FA ratio in milk fat was higher in CTRL and CLA than in EFA and EFA+CLA. The sum of FA <C16 in milk fat decreased in CLA and EFA+CLA in a dosage-dependent manner. Energy-corrected milk and milk fat decreased in CLA and EFA+CLA in a dosage-dependent manner and were higher in EFA and CTRL than in CLA at dosages 2 and 3. Energy balance tended to be highest in CLA cows. Milk protein content was lower in CLA and EFA+CLA than in CTRL. Milk urea concentration decreased in CLA and EFA+CLA in a dosage-dependent manner and was lower in CLA and EFA+CLA than in EFA and CTRL at dosages 2 and 3. Milk citrate concentration increased in CLA in a dosage-dependent manner and was higher in CLA and EFA+CLA than in EFA and CTRL. Glutathione peroxidase activity in blood plasma was lower in CTRL than in EFA, and plasma concentration of β-carotene increased in EFA and EFA+CLA with dosage. Increased milk citrate pointed at reduced de novo FA synthesis and a better antioxidative status in milk due to CLA treatment. Supplementation with CLA may also affect milk protein synthesis, but EFA and CLA treatment did not influence the inflammatory status in a consistent manner in mid-lactating cows.

Omega-3, omega-6, and total dietary polyunsaturated fat for prevention and treatment of type 2 diabetes mellitus: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To assess effects of increasing omega-3, omega-6, and total polyunsaturated fatty acids (PUFA) on diabetes diagnosis and glucose metabolism.

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

Medline, Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and trials in relevant systematic reviews.

ELIGIBILITY CRITERIA

Randomised controlled trials of at least 24 weeks' duration assessing effects of increasing α-linolenic acid, long chain omega-3, omega-6, or total PUFA, which collected data on diabetes diagnoses, fasting glucose or insulin, glycated haemoglobin (HbA_1c), and/or homoeostatic model assessment for insulin resistance (HOMA-IR).

DATA SYNTHESIS

Statistical analysis included random effects meta-analyses using relative risk and mean difference, and sensitivity analyses. Funnel plots were examined and subgrouping assessed effects of intervention type, replacement, baseline risk of diabetes and use of antidiabetes drugs, trial duration, and dose. Risk of bias was assessed with the Cochrane tool and quality of evidence with GRADE.

RESULTS

83 randomised controlled trials (mainly assessing effects of supplementary long chain omega-3) were included; 10 were at low summary risk of bias. Long chain omega-3 had little or no effect on likelihood of diagnosis of diabetes (relative risk 1.00, 95% confidence interval 0.85 to 1.17; 58 643 participants, 3.7% developed diabetes) or measures of glucose metabolism (HbA_1c mean difference -0.02%, 95% confidence interval -0.07% to 0.04%; plasma glucose 0.04, 0.02 to 0.07, mmol/L; fasting insulin 1.02, -4.34 to 6.37, pmol/L; HOMA-IR 0.06, -0.21 to 0.33). A suggestion of negative outcomes was observed when dose of supplemental long chain omega-3 was above 4.4 g/d. Effects of α-linolenic acid, omega-6, and total PUFA on diagnosis of diabetes were unclear (as the evidence was of very low quality), but little or no effect on measures of glucose metabolism was seen, except that increasing α-linolenic acid may increase fasting insulin (by about 7%). No evidence was found that the omega-3/omega-6 ratio is important for diabetes or glucose metabolism.

CONCLUSIONS

This is the most extensive systematic review of trials to date to assess effects of polyunsaturated fats on newly diagnosed diabetes and glucose metabolism, including previously unpublished data following contact with authors. Evidence suggests that increasing omega-3, omega-6, or total PUFA has little or no effect on prevention and treatment of type 2 diabetes mellitus.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017064110.

Multi-omic analysis in transgenic mice implicates omega-6/omega-3 fatty acid imbalance as a risk factor for chronic disease

An unbalanced increase in dietary omega-6 (n-6) polyunsaturated fatty acids (PUFA) and decrease in omega-3 (n-3) PUFA in the Western diet coincides with the global rise in chronic diseases. Whether n-6 and n-3 PUFA oppositely contribute to the development of chronic disease remains controversial. By using transgenic mice capable of synthesizing PUFA to eliminate confounding factors of diet, we show here that alteration of the tissue n-6/n-3 PUFA ratio leads to correlated changes in the gut microbiome and fecal and serum metabolites. Transgenic mice able to overproduce n-6 PUFA and achieve a high tissue n-6/n-3 PUFA ratio exhibit an increased risk for metabolic diseases and cancer, whereas mice able to convert n-6 to n-3 PUFA, and that have a lower n-6/n-3 ratio, show healthy phenotypes. Our study demonstrates that n-6 PUFA may be harmful in excess and suggests the importance of a low tissue n-6/n-3 ratio in reducing the risk for chronic diseases.

Protective Effects of Omega-3 Fatty Acids in Cancer-Related Complications

Omega-3 polyunsaturated fatty acids (PUFAs) are considered immunonutrients and are commonly used in the nutritional therapy of cancer patients due to their ample biological effects. Omega-3 PUFAs play essential roles in cell signaling and in the cell structure and fluidity of membranes. They participate in the resolution of inflammation and have anti-inflammatory and antinociceptive effects. Additionally, they can act as agonists of G protein-coupled receptors, namely, GPR40/FFA1 and GPR120/FFA4. Cancer patients undergo complications, such as anorexia-cachexia syndrome, pain, depression, and paraneoplastic syndromes. Interestingly, the 2017 European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines for cancer patients only discuss the use of omega-3 PUFAs for cancer-cachexia treatment, leaving aside other cancer-related complications that could potentially be managed by omega-3 PUFA supplementation. This critical review aimed to discuss the effects and the possible underlying mechanisms of omega-3 PUFA supplementation in cancer-related complications. Data compilation in this critical review indicates that further investigation is still required to assess the factual benefits of omega-3 PUFA supplementation in cancer-associated illnesses. Nevertheless, preclinical evidence reveals that omega-3 PUFAs and their metabolites might modulate pivotal pathways underlying complications secondary to cancer, indicating that this is a promising field of knowledge to be explored.

Diet Supplementation in ω3 Polyunsaturated Fatty Acid Favors an Anti-Inflammatory Basal Environment in Mouse Adipose Tissue

Oxylipins are metabolized from dietary ω3 and ω6 polyunsaturated fatty acids and are involved in an inflammatory response. Adipose tissue inflammatory background is a key factor of metabolic disorders and it is accepted that dietary fatty acids, in terms of quality and quantity, modulate oxylipin synthesis in this tissue. Moreover, it has been reported that diet supplementation in ω3 polyunsaturated fatty acids resolves some inflammatory situations. Thus, it is crucial to assess the influence of dietary polyunsaturated fatty acids on oxylipin synthesis and their impact on adipose tissue inflammation. To this end, mice fed an ω6- or ω3-enriched standard diet (ω6/ω3 ratio of 30 and 3.75, respectively) were analyzed for inflammatory phenotype and adipose tissue oxylipin content. Diet enrichment with an ω3 polyunsaturated fatty acid induced an increase in the oxylipins derived from ω6 linoleic acid, ω3 eicosapentaenoic, and ω3 docosahexaenoic acids in brown and white adipose tissues. Among these, the level of pro-resolving mediator intermediates, as well as anti-inflammatory metabolites, were augmented. Concomitantly, expressions of M2 macrophage markers were increased without affecting inflammatory cytokine contents. In vitro, these metabolites did not activate macrophages but participated in macrophage polarization by inflammatory stimuli. In conclusion, we demonstrated that an ω3-enriched diet, in non-obesogenic non-inflammatory conditions, induced synthesis of oxylipins which were involved in an anti-inflammatory response as well as enhancement of the M2 macrophage molecular signature, without affecting inflammatory cytokine secretion.

Transgenic and Genome Editing Approaches for Modifying Plant Oils

Vegetable oils are important for human and animal nutrition and as renewable resources for chemical feedstocks. We provide an overview of transgenic and genome editing approaches for modifying plant oils, describing useful model and crop systems and different strategies for transgenic modifications. We also describe new genome editing approaches that are beginning to be applied to oilseed plants and crops. These approaches are illustrated with examples for modifying the nutritional quality of vegetable oils by altering fatty acid desaturation, producing non-native fatty acids in oilseeds, and enhancing the overall accumulation of oil in seeds and leaves.

Application of metabolomics part II: Focus on fatty acids and their metabolites in healthy adults

Fatty acids (FAs) play critical roles in health and disease. The detection of FA imbalances through metabolomics can provide an overview of an individual’s health status, particularly as regards chronic inflammatory disorders. In this study, we aimed to establish sensitive reference value ranges for targeted plasma FAs in a well-defined population of healthy adults. Plasma samples were collected from 159 participants admitted as outpatients. A total of 24 FAs were analyzed using gas chromatography-mass spectrometry, and physiological values and 95% reference intervals were calculated using an approximate method of analysis. The differences among the age groups for the relative levels of stearic acid (P=0.005), the omega-6/omega-3 ratio (P=0.027), the arachidonic acid/eicosapentaenoic acid ratio (P<0.001) and the linoleic acid-produced dihomo-gamma-linolenic acid (P=0.046) were statistically significant. The majority of relative FA levels were higher in males than in females. The levels of myristic acid (P=0.0170) and docosahexaenoic acid (P=0.033) were signifi-cantly different between the sexes. The reference values for the FAs examined in this study represent a baseline for further studies examining the reproducibility of this methodology and sensitivities for nutrient deficiency detection and investigating the biochemical background of pathological conditions. The application of these values to clinical practice will allow for the discrimination between health and disease and contribute to early prevention and treatment.

Use of a Smartphone Application Can Improve Assessment of High-Fat Food Consumption in Overweight Individuals

BACKGROUND

We evaluated the feasibility of an application for measuring the frequency of consumption of high-fat foods and compared this application with standard methods.

METHODS

Twenty-six females and thirty six males aged 20⁻40 were enrolled in Poland. Participants completed the Block Screening Questionnaire for Fat Intake (BSQF; Q1) and a second questionnaire (Q2) with additional high-fat foods. The participants were then monitored for ten days in a real-time manner using a smartphone application that employed the same lists of food as Q2.

RESULTS

Most subjects (84%) gave replies to at least three prompts on at least 5 days. The results from Q1 and the application were correlated (r = 0.42, p < 0.001). Energy intake and the frequency of consumption of high-fat foods were correlated in the overweight/obese group (r = 0.83, p < 0.001). The mean differences between Q2 and the app were similar in both groups but the agreement limits were wider in the overweight/obese group than in the normal weight group.

CONCLUSIONS

An application for mobile devices is a feasible tool for capturing the frequency of high-fat food consumption and it seems to improve the measured variable, especially in overweight or obese people.

Aerobic Physical Activity and a Low Glycemic Diet Reduce the AA/EPA Ratio in Red Blood Cell Membranes of Patients with NAFLD

Omega-6 Polyunsaturated Fatty Acids (PUFAs), through the eicosanoids derived from arachidonic acid (AA), are able to modulate the inflammatory processes, whereas omega-3 PUFAs, such as eicosapentaenoic acid (EPA), exert anti-oxidant and anti-inflammatory effects. An unbalanced AA/EPA ratio in favor of AA leads to the development of different metabolic disorders, including non-alcoholic fatty liver disease (NAFLD). The aim of the present study was to evaluate the effects of different diets, alone and in combination with two physical activity programs, on the AA/EPA ratio value in erythrocyte membranes of patients with NAFLD. One hundred forty-two subjects with NAFLD were enrolled in the study and randomized into six treatment groups. AA/EPA ratio was significantly reduced after 90 days of treatment with only a program of aerobic activity. However, it appears that the combination of physical activity and a Low Glycemic Index Mediterranean Diet (LGIMD) was more efficacious in reducing AA/EPA levels, at 45 days of treatment, even if this effect was not maintained over time. The combined effect of diet and physical activity reduced the AA/EPA ratio value improving the score of steatosis. Dietary intake of omega-3 PUFAs, in association with a healthy lifestyle, may be used in the prevention protocols for many chronic diseases, including NAFLD.

Effects of dietary omega-3 PUFAs on growth and development: Somatic, neurobiological and reproductive functions in a murine model

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) are relevant to fetal and infant growth and development. Objective: to assess whether long-term exposure to dietary ω-3 PUFA imbalance alters pre- and/or postnatal pups' development and reproductive function later in life. Mice dams were fed with ω-3 PUFA Control (soybean oil, 7%), Deficient (sunflower oil, 7%) or Excess (blend oil; 4.2% cod-liver+2.8% soybean) diet before conception and throughout gestation-lactation and later on, their pups received the same diet from weaning to adulthood. Offspring somatic, neurobiological and reproductive parameters were evaluated. Excess pups were lighter during the preweaning period and shorter in length from postnatal day (PND) 7 to 49, compared to Control pups (P<.05). On PND14, the percentage of pups with eye opening in Excess group was lower than those from Control and Deficient groups (P<.05). In Excess female offspring, puberty onset (vaginal opening and first estrus) occurred significantly later and the percentage of parthenogenetic oocytes on PND63 was higher than Control and Deficient ones (P<.05). Deficient pups were shorter in length (males: on PND14, 21, 35 and 49; females: on PND14, 21 and 42) compared with Control pups (P<.05). Deficient offspring exhibited higher percentage of bending spermatozoa compared to Control and Excess offspring (P<.05). These results show that either an excessively high or insufficient ω-3 PUFA consumption prior to conception until adulthood seems inadvisable because of the potential risks of short-term adverse effects on growth and development of the progeny or long-lasting effects on their reproductive maturation and function.

Comparative Effect between Sardine Oil and Fish Oil Rich in Omega-3 Fatty Acids on Hypertension and the Membrane Composition of Adipocytes in SHR Rats

Omega-3 polyunsaturated fatty acids, have an important role in reducing hypertriglyceridemia, these acids decrease the mortality for Coronary Heart Disease. Very important is the relationship between fatty acid biosynthesis and distribution in organs and tissues involved in insulin resistance and hypertension due to its role in the production of vasoactive eicosanoids and their effects on insulin sensitivity; which is estimated with the HOMA-IR index, which relates the physiological and metabolic behavior of glucose and insulin in the body. The aim of this project was to compare the effect of sardine oil and omega-3 oils rich in polyunsaturated fatty acids: EPA (≈30%) and DHA (≈50%) administered for 6 to 8 wk respectively; on the lipid composition of the plasma membrane of epididymal adipocytes in spontaneously hypertensive rats (SHR) and their relation to obesity, insulin resistance and hypertension. The administration of omega-3 enriched oil significantly decreased the HOMA criteria as an insulin resistance indicator compared to the sardine oil.

Fish oil in infancy protects against food allergy in Iceland-Results from a birth cohort study

BACKGROUND

Consumption of oily fish or fish oil during pregnancy, lactation and infancy has been linked to a reduction in the development of allergic diseases in childhood.

METHODS

In an observational study, Icelandic children (n = 1304) were prospectively followed from birth to 2.5 years with detailed questionnaires administered at birth and at 1 and 2 years of age, including questions about fish oil supplementation. Children with suspected food allergy were invited for physical examinations, allergic sensitization tests, and a double-blind, placebo-controlled food challenge if the allergy testing or clinical history indicated food allergy. The study investigated the development of sensitization to food and confirmed food allergy according to age and frequency of postnatal fish oil supplementation using proportional hazards modelling.

RESULTS

The incidence of diagnosed food sensitization was significantly lower in children who received regular fish oil supplementation (relative risk: 0.51, 95% confidence interval: 0.32-0.82). The incidence of challenge-confirmed food allergy was also reduced, although not statistically significant (0.57, 0.30-1.12). Children who began to receive fish oil in their first half year of life were significantly more protected than those who began later (P = .045 for sensitization, P = .018 for allergy). Indicators of allergy severity decreased with increased fish oil consumption (P = .013). Adjusting for parent education and allergic family history did not change the results.

CONCLUSION

Postnatal fish oil consumption is associated with decreased food sensitization and food allergies in infants and may provide an intervention strategy for allergy prevention.

Cardioprotection by Cocoa Polyphenols and ω-3 Fatty Acids: A Disease-Prevention Perspective on Aging-Associated Cardiovascular Risk

Cardiovascular disease (CVD) remains the leading cause of death today. Many of the biochemical alterations associated with the pathophysiology of CVD can be modified by adequate intakes of bioactive nutrients through a correct diet or supplementation. Recently, there has been growing public and clinical interest in cocoa polyphenols (CPs) and omega-3 (ω-3) fatty acids. A plethora of nutritional intervention trials and experimental studies demonstrates that consumption of these bioactive food compounds is beneficial to promote cardiovascular health. The purpose of this review is to summarize the major cardioprotective effects of CPs and ω-3 fatty acids, providing a scientific rationale for incorporating the combination of these molecules as a nutritional intervention in the prevention of CVD. Although several studies have shown the individual cardioprotective nature of these compounds, a combination treatment with CPs and ω-3 fatty acids may be a promising approach to enhance the preventive value of these molecules and reduce cardiovascular risk factors associated with aging. Therefore, this article also reviews some of the key studies on the interaction between CPs and the metabolism of ω-3 fatty acids.

Fucoxanthin and Polyunsaturated Fatty Acids Co-Extraction by a Green Process

By their autotrophic nature and their molecular richness, microalgae are serious assets in the context of current environmental and societal challenges. Some species produce both omega-3 long chain polyunsaturated fatty acids (PUFAs) and xanthophylls, two molecular families widely studied for their bioactivities in the fields of nutrition and cosmetics. Whereas most studies separately deal with the two families, synergies could be exploited with extracts containing both PUFAs and xanthophylls. The purpose of our work was to determine cost effective and eco-friendly parameters for their co-extraction. The effect of several parameters (solvent, solvent/biomass ratio, temperature, duration) were studied, using two microalgal species, the non-calcifying Haptophyta Tisochrysis lutea, and the diatom Phaeodactylum tricornutum, that presents a silicified frustule. Analyses of PUFAs and fucoxanthin (Fx), the main xanthophyll, allowed to compare kinetics and extraction yields between experimental protocols. Co-extraction yields achieved using 96% ethanol as solvent were 100% for Fx and docosahexaenoic acid (DHA) in one hour from T. lutea biomass, and respectively 95% and 89% for Fx and eicosapentaenoic acid (EPA) in eight hours from P. tricornutum. These conditions are compatible with industrial applications.

Obesity, Inflammation, Toll-Like Receptor 4 and Fatty Acids

Obesity leads to an inflammatory condition that is directly involved in the etiology of cardiovascular diseases, type 2 diabetes mellitus, and certain types of cancer. The classic inflammatory response is an acute reaction to infections or to tissue injuries, and it tends to move towards resolution and homeostasis. However, the inflammatory process that was observed in individuals affected by obesity and metabolic syndrome differs from the classical inflammatory response in certain respects. This inflammatory process manifests itself systemically and it is characterized by a chronic low-intensity reaction. The toll-like receptor 4 (TLR4) signaling pathway is acknowledged as one of the main triggers of the obesity-induced inflammatory response. The aim of the present review is to describe the role that is played by the TLR4 signaling pathway in the inflammatory response and its modulation by saturated and omega-3 polyunsaturated fatty acids. Studies indicate that saturated fatty acids can induce inflammation by activating the TLR4 signaling pathway. Conversely, omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid, exert anti-inflammatory actions through the attenuation of the activation of the TLR4 signaling pathway by either lipopolysaccharides or saturated fatty acids.

Impact of dietary ω3 polyunsaturated fatty acid supplementation on brown and brite adipocyte function

The recent characterization of functional brown adipose tissue in adult humans has opened new perspectives for regulation of energy expenditure with respect to obesity and diabetes. Furthermore, dietary recommendations have taken into account the insufficient dietary intake of ω3 PUFAs and the concomitant excessive intake of ω6 PUFA associated with the occurrence of overweight/obesity. We aimed to study whether ω3 PUFAs could play a role in the recruitment and function of energy-dissipating brown/brite adipocytes. We show that ω3 PUFA supplementation has a beneficial effect on the thermogenic function of adipocytes. In vivo, a low dietary ω6:ω3 ratio improved the thermogenic response of brown and white adipose tissues to β3-adrenergic stimulation. This effect was recapitulated in vitro by PUFA treatment of hMADS adipocytes. We pinpointed the ω6-derived eicosanoid prostaglandin (PG)F2α as the molecular origin because the effects were mimicked with a specific PGF2α receptor agonist. PGF2α level in hMADS adipocytes was reduced in response to ω3 PUFA supplementation. The recruitment of thermogenic adipocytes is influenced by the local quantity of individual oxylipins, which is controlled by the ω6:ω3 ratio of available lipids. In human nutrition, energy homeostasis may thus benefit from the implementation of a more balanced dietary ω6:ω3 ratio.

Anti-aging potential of tree nuts with a focus on the phytochemical composition, molecular mechanisms and thermal stability of major bioactive compounds

Tree nuts, complete functional foods, contain macro- and micronutrients of high biological value.

Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies

BACKGROUND

The metabolic effects of omega-6 polyunsaturated fatty acids (PUFAs) remain contentious, and little evidence is available regarding their potential role in primary prevention of type 2 diabetes. We aimed to assess the associations of linoleic acid and arachidonic acid biomarkers with incident type 2 diabetes.

METHODS

We did a pooled analysis of new, harmonised, individual-level analyses for the biomarkers linoleic acid and its metabolite arachidonic acid and incident type 2 diabetes. We analysed data from 20 prospective cohort studies from ten countries (Iceland, the Netherlands, the USA, Taiwan, the UK, Germany, Finland, Australia, Sweden, and France), with biomarkers sampled between 1970 and 2010. Participants included in the analyses were aged 18 years or older and had data available for linoleic acid and arachidonic acid biomarkers at baseline. We excluded participants with type 2 diabetes at baseline. The main outcome was the association between omega-6 PUFA biomarkers and incident type 2 diabetes. We assessed the relative risk of type 2 diabetes prospectively for each cohort and lipid compartment separately using a prespecified analytic plan for exposures, covariates, effect modifiers, and analysis, and the findings were then pooled using inverse-variance weighted meta-analysis.

FINDINGS

Participants were 39 740 adults, aged (range of cohort means) 49-76 years with a BMI (range of cohort means) of 23·3-28·4 kg/m2, who did not have type 2 diabetes at baseline. During a follow-up of 366 073 person-years, we identified 4347 cases of incident type 2 diabetes. In multivariable-adjusted pooled analyses, higher proportions of linoleic acid biomarkers as percentages of total fatty acid were associated with a lower risk of type 2 diabetes overall (risk ratio [RR] per interquintile range 0·65, 95% CI 0·60-0·72, p<0·0001; I2=53·9%, pheterogeneity=0·002). The associations between linoleic acid biomarkers and type 2 diabetes were generally similar in different lipid compartments, including phospholipids, plasma, cholesterol esters, and adipose tissue. Levels of arachidonic acid biomarker were not significantly associated with type 2 diabetes risk overall (RR per interquintile range 0·96, 95% CI 0·88-1·05; p=0·38; I2=63·0%, pheterogeneity<0·0001). The associations between linoleic acid and arachidonic acid biomarkers and the risk of type 2 diabetes were not significantly modified by any prespecified potential sources of heterogeneity (ie, age, BMI, sex, race, aspirin use, omega-3 PUFA levels, or variants of the FADS gene; all pheterogeneity≥0·13).

INTERPRETATION

Findings suggest that linoleic acid has long-term benefits for the prevention of type 2 diabetes and that arachidonic acid is not harmful.

FUNDING

Funders are shown in the appendix.

Impact of Biological Feedback and Incentives on Blood Fatty Acid Concentrations, Including Omega-3 Index, in an Employer-Based Wellness Program

Eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3) are important fatty acids for the retina and brain. More than 95% of Americans have suboptimal EPA + DHA blood concentrations. This cross-sectional employer-based study assessed whole blood fatty acid levels of volunteers participating in an onsite wellness biometric screening program and was designed to determine if an incentive, a $5 coupon for a 90-day supply of fish oil supplement typically costing $18-30, stimulated incremental dietary behavior change relative to nutritional status assessment alone to increase EPA + DHA concentrations. Volunteers completed a dietary survey and finger stick blood samples were collected to be analyzed for fatty acid composition. In addition, 636 individuals participated in the initial onsite biometric screening. Three months later, and without prior knowledge, all employees were invited to a second screening. At the second screening, 198 employees volunteered for the first time and 149 employees had a second test (17.9%). At baseline, the average age (n = 834) was 45 year and omega-3 index was 5.0% with 41% female. EPA + DHA concentration, i.e., omega-3 index, was significantly lower in men (4.8%) than women (5.2%), as were DHA and linoleic acid (LA) concentrations (p < 0.05). Baseline omega-3 index was positively and linearly associated with omega-3 intake. Only 4% of volunteers had an omega-3 index >8% on initial screening. Among the 149 individuals with two measurements, omega-3 intake from supplements, but not food, increased significantly from 258 to 445 mg/d (p < 0.01) at the second test as did the omega-3 index (+0.21, p < 0.02). In this employed population, only 1% redeemed a coupon for an omega-3 supplement.

Good Fats versus Bad Fats: A Comparison of Fatty Acids in the Promotion of Insulin Resistance, Inflammation, and Obesity

Recently, debate has erupted in both the scientific community and throughout the lay public around whether a low-fat or low-carbohydrate diet is better for weight loss. In other words, is it better to cut fat or cut carbohydrate for weight loss. However, going beyond this debate (fat versus carbohydrate), are questions around whether certain fatty acids are worse for promoting insulin resistance, inflammation, and obesity. The overall evidence in the literature suggests that medium-chain saturated fats (such as lauric acid, found in coconut oil) and monounsaturated fat (oleic acid, found in olive oil) are less likely to promote insulin resistance, inflammation, and fat storage compared to long-chain saturated fatty acids (such as stearic acid found in large quantities in butter, but particularly palmitic acid found in palm oil) especially when consumed on top of a diet moderate in refined carbohydrates. Compared to long-chain saturated fats, lauric acid and oleic acid have an increased fatty acid oxidation rate, are more likely to be burned for energy and less likely to be stored in adipose tissue, and thus promote increased energy expenditure. Omega-6 polyunsaturated fatty acids (PUFAs), such as linoleic acid, as found in vegetable oils may contribute to obesity, whereas omega-3 PUFA may be protective. Importantly, both olive oil as part of a Mediterranean diet, and omega-3 from fish and fish oil have been proven to reduce risk of cardiovascular (CV) events.

High dietary arachidonic acid levels induce changes in complex lipids and immune-related eicosanoids and increase levels of oxidised metabolites in zebrafish (Danio rerio)

This study explores the effect of high dietary arachidonic acid (ARA) levels (high ARA) compared with low dietary ARA levels (control) on the general metabolism using zebrafish as the model organism. The fatty acid composition of today's 'modern diet' tends towards higher n-6 PUFA levels in relation to n-3 PUFA. Low dietary n-3:n-6 PUFA ratio is a health concern, as n-6 PUFA give rise to eicosanoids and PG, which are traditionally considered pro-inflammatory, especially when derived from ARA. Juvenile zebrafish fed a high-ARA diet for 17 d had a lower whole-body n-3:n-6 PUFA ratio compared with zebrafish fed a low-ARA (control) diet (0·6 in the control group v. 0·2 in the high-ARA group). Metabolic profiling revealed altered levels of eicosanoids, PUFA, dicarboxylic acids and complex lipids such as glycerophospholipids and lysophospholipids as the most significant differences compared with the control group. ARA-derived hydroxylated eicosanoids, such as hydroxy-eicosatetraenoic acids, were elevated in response to high-ARA feed. In addition, increased levels of oxidised lipids and amino acids indicated an oxidised environment due to n-6 PUFA excess in the fish. To conclude, our results indicate that an ARA-enriched diet induces changes in complex lipids and immune-related eicosanoids and increases levels of oxidised lipids and amino acids, suggesting oxidative stress and lipid peroxidation.

Plasma ω-3 fatty acids in pregnancy are inversely associated with postpartum weight retention in a multiethnic Asian cohort

Background: Studies have demonstrated associations between polyunsaturated fatty acids (PUFAs) and adiposity. It is unclear whether PUFAs in pregnancy have an effect on maternal weight retention after childbirth, which can contribute to long-term obesity.Objective: We examined the association of maternal plasma PUFAs in pregnancy with 18-mo postpartum weight retention (PPWR) in a multiethnic Asian cohort.Design: We studied pregnant women (n = 653) recruited between June 2009 and September 2010 from a prospective cohort. At 26-28 wk of gestation, plasma phosphatidylcholine PUFA concentrations were measured and determined as percentages of total fatty acids (FAs). PPWR was calculated based on the difference between measured weight at the first antenatal clinic visit and at 18 mo postpartum.Results: The median retained weight of women was 0.90 kg (IQR: -1.40, 3.25) at 18 mo postpartum. Of 653 women, 544 women (83.3%) had PPWR of <5 kg and 109 (16.7%) had PPWR of ≥5 kg. In adjusted linear regression models, higher plasma eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total ω-3 (n-3) PUFA concentrations were associated with lower PPWR [EPA: β = -0.62 kg/1% increase of total FAs (95% CI: -1.18, -0.05); DHA: β = -0.24 kg/1% increase (95% CI: -0.45, -0.02); total ω-3 PUFAs: β = -0.20 kg/1% increase (95% CI: -0.36, -0.03)], whereas a higher ratio of plasma ω-6-to-ω-3 PUFAs was associated with a higher PPWR [β = 0.21 kg/unit increase (95% CI: 0.05, 0.36)].Conclusions: Higher plasma percentages of ω-3 PUFAs and a lower ratio of ω-6-to-ω-3 PUFAs in the late-second trimester of pregnancy are associated with less weight retention at 18 mo postpartum. This may offer an alternative strategy to assist postpartum weight reduction by increasing EPA and DHA status together with a decreased ratio of ω-6-to-ω-3 PUFA through diet or fish-oil supplementation during pregnancy. This study was registered at clinicaltrials.gov as NCT01174875.

n-3 Polyunsaturated Fatty Acids and Cardiovascular Disease: Principles, Practices, Pitfalls, and Promises - A Contemporary Review

Amidst voluminous literature, inconsistencies and opposing results have confused rather than clarified cardiologists' ability to assess the potential benefits of n-3 polyunsaturated fatty acids (n-3 PUFA). In perspective, there are common themes that emerge from n-3 PUFA studies, even as imperfect as they may be. The approach taken was to identify and unite these themes into a manageable, cohesive, evidence-based, yet useful synthesis. In all reviews and meta-analyses, the selection of component studies and assumptions influences outcomes. This overarching principle must be combined with the totality of the data, particularly when evidence is incompletely understood and gaps in knowledge must be bridged. Both the older literature and the most recent rigorous meta-analyses indicate that n-3 PUFA are highly pleiotropic agents with many documented positive physiological effects. Concordance among preclinical, observational, randomized clinical trials and meta-analyses is impressive. These agents have modest, statistically significant benefits which accrue over time. Given their favorable safety profile, a risk reduction of about 10% justifies their potential use in cardiovascular disease.