Flaxseed oil and fish-oil capsule consumption alters human red blood cell n-3 fatty acid composition: a multiple-dosing trial comparing 2 sources of n-3 fatty acid

Current Insights into the Effects of Dietary α-Linolenic Acid Focusing on Alterations of Polyunsaturated Fatty Acid Profiles in Metabolic Syndrome

The plant-derived α-linolenic acid (ALA) is an essential n-3 acid highly susceptible to oxidation, present in oils of flaxseeds, walnuts, canola, perilla, soy, and chia. After ingestion, it can be incorporated in to body lipid pools (particularly triglycerides and phospholipid membranes), and then endogenously metabolized through desaturation, elongation, and peroxisome oxidation to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with a very limited efficiency (particularly for DHA), beta-oxidized as an energy source, or directly metabolized to C18-oxilipins. At this moment, data in the literature about the effects of ALA supplementation on metabolic syndrome (MetS) in humans are inconsistent, indicating no effects or some positive effects on all MetS components (abdominal obesity, dyslipidemia, impaired insulin sensitivity and glucoregulation, blood pressure, and liver steatosis). The major effects of ALA on MetS seem to be through its conversion to more potent EPA and DHA, the impact on the n-3/n-6 ratio, and the consecutive effects on the formation of oxylipins and endocannabinoids, inflammation, insulin sensitivity, and insulin secretion, as well as adipocyte and hepatocytes function. It is important to distinguish the direct effects of ALA from the effects of EPA and DHA metabolites. This review summarizes the most recent findings on this topic and discusses the possible mechanisms.

Validation of Nutritional Approaches to Modulate Cardiovascular and Diabetic Risk Factors in Patients with Hypertriglyceridemia or Prediabetes-The MoKaRi II Randomized Controlled Study

Hypertriglyceridemia and diabetes mellitus type 2 are among the most important metabolic diseases globally. Diet plays a vital role in the development and progression of both clinical pictures. For the 10-week randomized, controlled, intervention study, 67 subjects with elevated plasma triglyceride (TG) concentrations (≥1.7 mmol/L) and 69 subjects with elevated fasting glucose concentrations (≥5.6 < 7.0 mmol/L) were recruited. The intervention groups received specially developed, individualized menu plans and regular counseling sessions to lower (A) TG or (B) fasting glucose and glycated hemoglobin A1c as well as other cardiovascular and diabetic risk factors. The hypertriglyceridemia intervention group was further supplemented with fish oil (3.5 g/d eicosapentaenoic acid + docosahexaenoic acid). The two control groups maintained a typical Western diet. Blood samples were taken every 2 weeks, and anthropometric data were collected. A follow-up examination was conducted after another 10 weeks. In both intervention groups, there were comparable significant reductions in blood lipids, glucose metabolism, and anthropometric parameters. These results were, with a few exceptions, significantly more pronounced in the intervention groups than in the corresponding control groups (comparison of percentage change from baseline). In particular, body weight was reduced by 7.4% (6.4 kg) and 7.5% (5.9 kg), low-density lipoprotein cholesterol concentrations by 19.8% (0.8 mmol/L) and 13.0% (0.5 mmol/L), TG concentrations by 18.2% (0.3 mmol/L) and 13.0% (0.2 mmol/L), and homeostatic model assessment for insulin resistance by 31.8% (1.1) and 26.4% (0.9) (p < 0.05) in the hypertriglyceridemia and prediabetes intervention groups, respectively. Some of these changes were maintained until follow-up. In patients with elevated TG or fasting glucose, implementing individualized menu plans in combination with regular counseling sessions over 10 weeks led to a significant improvement in cardiovascular and diabetic risk factors.

Evaluation of Influencing Factors on Metabolism of Land-Based n-3 Poly Unsaturated Fatty Acids-The KoALA Study

This study aimed to investigate the impact of influencing factors (sex, eicosapentaenoic acid (EPA) status at baseline, linoleic acid (LA) intake, milk fat intake) on the conversion of α-linolenic acid (ALA) obtained from linseed oil into its long-chain metabolites. In addition, the effect of ALA on cardiovascular risk markers was investigated. This study used a parallel design approach by randomly assigning the 134 subjects to one of four diets (high in LA (HLA); low in LA (LLA); high in milk fat (MF); control (Western diet)) each enriched with linseed oil (10 en%, 22-27 mL ≙ 13-16 g ALA). Blood samples were taken at baseline and after 4, 8, and 12 weeks of dietary intervention. The study was fully completed by 105 subjects (57.4 ± 12.1 years; 65.7% female). Results showed that ALA (296-465%), C-20:4n3 (54-140%), and EPA (37-73%) concentrations in erythrocytes increased in all groups (p < 0.01). In contrast, docosahexaenoic acid (19-35%, p < 0.01) and n-3 index (10-21%, p < 0.05) dropped in the HLA, LLA, and control groups. An increase in C-22:5n3 was only observed in the MF (36%) and control groups (11%) (p < 0.05). In addition, an increase in LA (7-27%) was found in the HLA, LLA, and control groups, whereas C-20:3n6 (16-22%), arachidonic acid (10-16%), C-22:4n6 (12-30%), and C-22:5n6 (32-47%) decreased (p < 0.01). The conversion into EPA was higher in men than in women (69 vs. 39%, p = 0.043) and in subjects with low EPA status compared to participants with high EPA status (79 vs. 29%, p < 0.001). A high LA status attenuates the conversion rate. In line with the literature, no clear effects on blood lipids and parameters of glucose metabolism were found in relation to ALA supplementation.

Effect of the inclusion of extruded flaxseed in the diet of fattening pigs on performance parameters and blood parameters

The aim of the study was to determine the effect of the inclusion of 2%, 4% and 6% extruded flaxseed in the diet of fattening pigs on their growth performance parameters, carcass parameters, and selected blood parameters. The experiment was conducted on 160 weaners (from about 30 kg to about 110 kg BW) assigned to four experimental groups of 40 animals each (5 replicates with 8 individuals each). The animals in control group received a diet in which the source of fat was soybean oil. The other groups received extruded flaxseed (FE) in place of soybean meal in the amount of 2% (group 2FE); 4% (group 4FE) and 6% (group 6FE). Soybean oil was added to the diets in the experimental treatments to obtain equal amounts of fat. The inclusion of 2% and 4% extruded flaxseed in the diet of fatteners in place of soybean meal significantly improved the digestibility of basic nutrients, i.e. ether extract (by about 5%) and dietary fibre (by more than 20%) and led to better growth performance (higher BW by about 11%; higher ADG by about 20% and lower FCR by about 12%) vs group C. In the groups with 2% and 4% extruded flaxseed there was also an increase in the lean meat content of the carcasses (by about 6%) and the thickness of the backfat (by about 6.5%) vs group C. The inclusion of extruded flaxseed did not affect the animals' condition, as indicated by the haematological and biochemical parameters of the blood, which were within reference ranges. The results for production, nutrient digestibility and carcass analysis between groups 2FE and 4FE were similar, and at this stage of research indicate that the use of 2% extruded flaxseed is economically more justified.

Effect of flaxseed supplementation on blood pressure: a systematic review, and dose-response meta-analysis of randomized clinical trials

Many clinical trials have revealed that flaxseed supplementation might exert a potent antihypertensive influence, but the findings are inconsistent. In this regard, a meta-analysis was carried out to provide a more accurate estimate of the impact of flaxseed supplementation on blood pressure. We searched international databases including PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Google Scholar till July 2022. A random-effects model was used to calculate weighted mean differences (WMDs). Non-linear dose-response analysis and meta-regression were performed. Meta-analysis of 33 trials (comprising 43 treatment arms) with 2427 participants revealed significant reductions in both systolic (WMD: -3.19 mmHg; 95% CI: -4.15 to -2.24, p < 0.001; I² = 92.5%, p < 0.001) and diastolic blood pressure (WMD = -2.61 mmHg; 95% CI: -3.27, -1.94, p < 0.001; I² = 94.1%, p < 0.001) following flaxseed supplementation. Greater effects on SBP and DBP were found in trials with an intervention duration of >20 weeks, ≥30 g day^-1 of flaxseed, subjects with BMI 25-30 kg m^-2, and in patients with hypertension. Supplementation with various flaxseed products significantly reduced SBP and DBP levels, confirming the hypothesis that flaxseed could be used as an effective supplement for blood pressure management, alongside routine medications.

Human Milk Lipid Profiles around the World: A Systematic Review and Meta-Analysis

Reported breast milk lipid concentrations may vary with geographical region, postnatal age, and year of sample collection. In this review, we summarized data on the concentrations of total fat, total phospholipids, cholesterol, and fatty acids in human milk worldwide and their variation according to lactation stage, study area, and sample collection year. A systematic literature search was performed using the PubMed, Embase, Web of Science, and Medline databases for English-language papers and Wanfang and China National Knowledge Infrastructure databases for Chinese-language papers. A total of 186 studies evaluating the human milk lipid profiles were included. According to random-effects models based on worldwide data, the summarized means (95% CIs) as percentages of total fat were 42.2% (41.1%, 43.3%) for SFAs, 36.6% (35.6%, 37.5%) for MUFAs, and 21.0% (19.3%, 22.7%) for PUFAs. However, the study heterogeneity was high for most types of fatty acids (I2 > 99%). Human milk from Western countries had higher concentrations of MUFAs and 18:1n-9 (ω-9), but lower concentrations of PUFAs, 18:2n-6, 20:4n-6, 18:3n-3, 20:5n-3, 22:6n-3, and total n-6 PUFA compared with those from non-Western countries (P < 0.001-0.011). Significant lactation stage differences were observed for total fat and some individual fatty acids. The concentrations of SFAs and 16:0 were significantly negatively correlated with sampling year (P < 0.001-0.028). In contrast, a significant positive correlation between the concentrations of 18:2n-6 and 18:3n-3 and sampling year was observed (P < 0.001-0.035). Our results suggest that the pooling of data on human milk lipid profiles in different studies should be done with caution due to the high between-study heterogeneity. The concentration of lipids, including total fat, cholesterol, and specific fatty acids, differs in human milk according to lactation stage, geographical region, and year of sample collection.

Vegan nutrition: a preliminary guide for health professionals

Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.

The Effect of Flaxseed Oil Supplementation on Body Composition and Inflammation Indices in Overweight Adults With Pre-Diabetes

Background:

Flaxseed has rich content of alpha linolenic acid for preventing pro inflammatory process. The aim of present study is exploring the effect of flaxseed oil supplementation on inflammatory biomarkers and body composition in overweight adults with pre-diabetes.

Material and methods:

this double-blind randomized clinical trial conducted with 80 overweight pre-diabetic patients in 2 clusters (flaxseed oil group (2000-mg daily) and control group) across a 14-week period. Anthropometric indices, body composition and inflammatory indices were measured between 2 groups before and after the treatment.

Result:

this study found a significant decrease in visceral fat level in the intervention group (P = .009) and control group (P = .004) at the end of the survey. However, the mean change of it (P = .06) was not significant. Also, this study showed that percentage of body fat (P = .31) and its mean change (P = .6) did not have significantly different between the 2 groups at the 14th week. The skeletal muscle% had a significant rise in the intervention group (P = .005) and control group (P = .003) by the end of 14th week. However, the mean change of it (P = .19) was not significant between the 2 groups. In addition, there was no significant change in the fasting blood glucose (P = . 7), C reactive protein (P = .12) and TNF-α (P = .22) between the 2 groups at the end of study.

Conclusion:

It showed that flaxseed oil supplementation cannot improve body composition and inflammation.

n-3 index is associated with cardiometabolic risk factors but is not improved by walnut intake in free-living elderly: a single-blind, randomised controlled trial

n-3 index, the erythrocyte proportion of the EPA + DHA fatty acids is a clinical marker of age-related disease risk. It is unclear whether regular intake of α-linolenic acid (ALA), a plant-derived n-3 polyunsaturated fatty acid, raises n-3 index in older adults. Of the 356 participants at the Loma Linda, CA centre from the original study, a randomly selected subset (n 192) was included for this secondary analysis (mostly Caucasian women, mean age 69 years). Participants were assigned to either the walnut (15 % of daily energy from walnuts) or the control group (usual diet, no walnuts) for 2 years. Erythrocyte fatty acids were determined at baseline and 1-year following intervention. No differences were observed for erythrocyte EPA, but erythrocyte DHA decreased albeit modestly in the walnut group (-0·125 %) and slightly improved in the control group (0·17 %). The change in n-3 index between the walnut and control groups was significantly different only among fish consumers (those who ate fish ≥ once/month). Longitudinal analyses combining both groups showed significant inverse association between the 1-year changes of the n-3 index and fasting plasma TAG (ß = -10), total cholesterol (ß = -5·59) and plasma glucose (ß = -0·27). Consuming ALA-rich walnuts failed to improve n-3 index in elders. A direct source of EPA/DHA may be needed to achieve desirable n-3 index, as it is inversely associated with cardiometabolic risk. Nevertheless, incorporating walnuts as part of heart healthy diets is still encouraged.

Omega-3 Polyunsaturated Fatty Acids Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials

Background

Current evidence might support the use of omega‐3 fatty acids (preferably docosahexaenoic acid and eicosapentaenoic acid) for lowering blood pressure (BP), but the strength and shape of the dose‐response relationship remains unclear.

Methods and Results

This study included randomized controlled trials published before May 7, 2021, that involved participants aged ≥18 years, and examined an association between omega‐3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid, or both) and BP. A random‐effects 1‐stage cubic spline regression model was used to predict the average dose‐response association between daily omega‐3 fatty acid intake and changes in BP. We also conducted stratified analyses to examine differences by prespecified subgroups. Seventy‐one trials were included, involving 4973 individuals with a combined docosahexaenoic acid+eicosapentaenoic acid dose of 2.8 g/d (interquartile range, 1.3 g/d to 3.6 g/d). A nonlinear association was found overall or in most subgroups, depicted as J‐shaped dose‐response curves. The optimal intake in both systolic BP and diastolic BP reductions (mm Hg) were obtained by moderate doses between 2 g/d (systolic BP, −2.61 [95% CI, −3.57 to −1.65]; diastolic BP, −1.64 [95% CI, −2.29 to −0.99]) and 3 g/d (systolic BP, −2.61 [95% CI, −3.52 to −1.69]; diastolic BP, −1.80 [95% CI, −2.38 to −1.23]). Subgroup studies revealed stronger and approximately linear dose‐response relations among hypertensive, hyperlipidemic, and older populations.

Conclusions

This dose‐response meta‐analysis demonstrates that the optimal combined intake of omega‐3 fatty acids for BP lowering is likely between 2 g/d and 3 g/d. Doses of omega‐3 fatty acid intake above the recommended 3 g/d may be associated with additional benefits in lowering BP among groups at high risk for cardiovascular diseases.

Effects of marine-derived and plant-derived omega-3 polyunsaturated fatty acids on erythrocyte fatty acid composition in type 2 diabetic patients

Background

Dietary fatty acids intake affects the composition of erythrocyte fatty acids, which is strongly correlated with glycolipid metabolism disorders. This study aimed at investigating the different effects of marine-derived and plant-derived omega-3 polyunsaturated fatty acid (n-3 PUFA) on the fatty acids of erythrocytes and glycolipid metabolism in patients with type 2 diabetes mellitus (T2DM).

Methods

The randomized double-blinded trial that was performed on 180 T2DM patients. The participants were randomly assigned to three groups for the six-month intervention. The participants were randomly assigned to three groups for the six-month intervention. The fish oil (FO) group was administered with FO at a dose of 3 g/day containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the perilla oil (PO) group was administered with PO at a dose of 3 g/day containing α-linolenic (ALA), the linseed and fish oil (LFO) group was administered with mixed linseed and fish oil at a dose of 3 g/day containing EPA, DHA and ALA. Demographic information were collected and anthropometric indices, glucose and lipid metabolism indexes, erythrocyte fatty acid composition were measured. Statistical analyses were performed using two-way ANOVA.

Results

A total of 150 patients finished the trial, with 52 of them in the FO group, 50 in the PO group and 48 in the LFO group. There were significant effects of time × treatment interaction on fast blood glucose (FBG), insulin, HOMA-IR and C-peptide, TC and triglyceride (TG) levels (P < 0.001). Glucose and C-peptide in PO and LFO groups decreased significantly and serum TG in FO group significantly decreased (P < 0.001) after the intervention. Erythrocyte C22: 5 n-6, ALA, DPA, n-6/n-3 PUFA, AA/EPA levels in the PO group were significantly higher than FO and LFO groups, while EPA, total n-3 PUFA and Omega-3 index were significantly higher in the FO and LFO groups compared to PO group.

Conclusion

Supplementation with perilla oil decreased FBG while fish oil supplementation decreased the TG level. Marine-based and plant-based n-3 PUFAs exhibit different effects on fatty acid compositions of erythrocytes and regulated glycolipid metabolism.

Trial registration

This trial was recorded under Chinese Clinical Trial Registry Center (NO: ChiCTR-IOR-16008435) on May 28 2016.

Dietary alpha-linolenic acid reduces platelet activation and collagen-mediated cell adhesion in sickle cell disease mice

BACKGROUND

Sickle cell disease (SCD) is a genetic hemoglobinopathy associated with high morbidity and mortality. The primary cause of hospitalization in SCD is vaso-occlusive crisis (VOC), mediated by alteration of red blood cells, platelets, immune cells and a pro-adhesive endothelium.

OBJECTIVES

We investigated the potential therapeutic use of the plant-derived omega-3 alpha-linolenic acid (ALA) in SCD.

METHODS

Berkeley mice were fed a low- or high-ALA diet for 4 weeks, followed by analysis of liver fibrosis, endothelial activation, platelet activation and formation of platelet-neutrophils aggregates. Aggregation of platelets over collagen under flow after high-ALA was compared to a blocking P-selectin Fab.

RESULTS

Dietary high-ALA was able to reduce the number of sickle cells in blood smear, liver fibrosis, and the expression of adhesion molecules on the endothelium of aorta, lungs, liver and kidneys (VCAM-1, ICAM-1 and vWF). Specific parameters of platelet activation were blunted after high-ALA feeding, notably P-selectin exposure and the formation of neutrophil-platelet aggregates, along with a correspondingly reduced expression of PSGL-1 on neutrophils. By comparison, in vivo treatment of SCD mice with the anti-P-selectin Fab was able to similarly reduce the formation of neutrophil-platelet aggregates, but did not reduce GpIbα shedding nor the activation of the αIIb β3 integrin in response to thrombin. Both ALA feeding and P-selectin blocking significantly reduced collagen-mediated cell adhesion under flow.

CONCLUSIONS

Dietary ALA is able to reduce the pro-inflammatory and pro-thrombotic state occurring in the SCD mouse model and may represent a novel, inexpensive and readily available therapeutic strategy for SCD.

Perilla seed oil in combination with the nobiletin-rich ponkan powder enhances cognitive function in healthy elderly Japanese individuals: Possible supplement for brain health in the elderly

Perilla (Perilla frutescens) seed oil (PO), rich in α-linolenic acid (ALA), can improve cognitive function in healthy elderly Japanese people. Here, supplements containing either PO alone or PO with nobiletin-rich...

Effect of Dietary Flaxseed Oil Supplementation on the Redox Status, Haematological and Biochemical Parameters of Horses' Blood

Simple Summary

Flaxseed oils have long been used in animal feeding and human nutrition due to the beneficial effects of their biologically active substances, especially omega-3 polyunsaturated fatty acids (PUFA). This study aimed to evaluate the effect of the replacement of soybean oil (SO) with flaxseed oil (FO) in the horses’ diet on biochemical, haematological, and redox status parameters of the blood. We found FO contributed to an improvement of lipid profile, haematological parameters of the blood and enhanced antioxidant defence mechanisms of horses. This suggests that substitution of SO with FO in the diet of horses is beneficial for their health status.

Abstract

This study compared the effect of two dietary vegetable oils on plasma biochemical indices, haematological parameters, and redox status of horses. Forty riding horses (20 mares and 20 stallions) of the Malopolski breed were divided equally into two groups that were similar in terms of age, sex, and body weight (on average 530 ± 30 kg). The horses received soybean oil (SO) or flaxseed oil (FO) in the amount of 25 mL per 100 kg BW/day. After 60 days, blood was collected for biochemical and haematological analyses. The results show that horses receiving FO as compared to the SO group had significantly lower plasma levels of glucose, low density lipoprotein cholesterol, total cholesterol/high-density lipoprotein (HDL) ratio and triacylglycerols, as well as the activities of alanine aminotransferase and alkaline phosphatase. In turn, %HDL-TC and lactate dehydrogenase activity were significantly higher in the FO group. The inclusion of FO in the diet contributed to an increase in antioxidant indices: creatinine, vitamin C, copper, and zinc contents and also superoxide dismutase and catalase activities. The level of the end product of lipid peroxidation, i.e., malonyl dialdehyde, in the FO group as compared to the SO group was significantly lower. Moreover, FO caused an elevation in red blood cell indicators, lymphocyte count and lysozymes. In conclusion, FO exerts a beneficial effect by stimulating antioxidant defence mechanisms of horses and reducing the severity of oxidative stress. FO also improved the lipid profile and haematological parameters of the blood. The replacement of SO by FO is recommended based on these findings.

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.

Effect of flaxseed oil supplementation on the erythrocyte membrane fatty acid composition and endocannabinoid system modulation in patients with coronary artery disease: a double-blind randomized controlled trial

Background

The endocannabinoid system (ECS) overactivation, associated with increased inflammatory process, may act as a risk factor for coronary artery disease (CAD). Dietary fat may influence the ECS tone. The aim of the present study was to investigate the effect of flaxseed oil on the erythrocyte membrane fatty acid profile and ECS activity by the measurement of serum N-arachydonoil ethanolamine (AEA) and cannabinoid receptor type-1 (CB1), cannabinoid receptor type-2 (CB2), and fatty acid amide hydrolase (FAAH) mRNA expression.

Methods

This clinical trial was performed on 44 patients with CAD. The intervention group received 1.5% fat milk supplemented with flaxseed oil (containing 2.5 g α-linolenic acid or ALA), while the placebo group received 1.5% fat milk for 10 weeks. The fatty acid profile of erythrocyte membrane phospholipids was measured by gas chromatography. The AEA level was determined using an ELISA kit, and real-time PCR was performed to measure CB1, CB2, and FAAH mRNA expression pre- and post-intervention.

Results

Flaxseed oil supplementation resulted in a significant increase in the ALA content and a significant reduction in linoleic acid (LA) content of membrane phospholipids, compared to the placebo group (MD = − 0.35 and 2.89, respectively; P < 0.05). The within group analysis showed that flaxseed oil supplementation caused a significant reduction in both LA and arachidonic acid (MD = − 4.84 and − 4.03, respectively; P < 0.05) and an elevation in the ALA (MD = 0.37, P < 0.001) content of membrane phospholipids compared with the baseline. In the intervention group, a marked reduction was observed in the serum AEA level after 10 weeks of intervention, compared with the placebo group (MD = 0.64, P = 0.016). Changes in CB2 mRNA expression in the flaxseed oil group were significant (fold change = 1.30, P = 0.003), compared with the placebo group.

Conclusion

Flaxseed oil supplementation could attenuate the ECS tone by decreasing the AEA level and increasing CB2 mRNA expression. Therefore, flaxseed oil may be considered a promising agent with cardioprotective properties.

Flaxseed and Its Components in Treatment of Hyperlipidemia and Cardiovascular Disease

This paper describes the effects of flaxseed and its components (flax oil, secoisolariciresinoldiglucoside[SDG], flax lignan complex [FLC], and flax fibers] on serum lipids (total cholesterol [TC], low-density lipoprotein-cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides [TG]) in animals and humans. Ordinary flaxseed reduces TG, TC, LDL-C, and TC/HDL-C levels in a dose-dependent manner in animals. In humans, it reduces serum lipids in hypercholesterolemicpatients but has no effects in normocholesterolemicpatients. Flax oil has variable effects on serum lipids in normo- and hypercholesterolemic animals. Flax oil treatment, with a dosage containing greater than 25 g/day of α-linolenic acid, reduces serum lipids in humans. Although FLC reduces serum lipids and raises serum HDL-C in animals, its effects on serum lipids in humans are small and variable. Flax fibers exert small effects on serum lipids in humans. Crop Development Centre (CDC)-flaxseed, which contains low concentrations of α-linolenic acid, has significant lipid lowering effects in animals. Pure SDG has potent hypolipidemic effects and raises HDL-C. In conclusion, flaxseed and pure SDG have significant lipid-lowering effects in animals and humans, while other components of flaxseed have small and variable effects.

Impact of whole dairy matrix on musculoskeletal health and aging-current knowledge and research gaps

Dairy products are included in dietary guidelines worldwide, as milk, yoghurt, and cheese are good sources of calcium and protein, vital nutrients for bones and muscle mass maintenance. Bone growth and mineralization occur during infancy and childhood, peak bone mass being attained after early adulthood. A low peak bone mass has consequences later in life, including increased risk of osteoporosis and fractures. Currently, more than 200 million people worldwide suffer from osteoporosis, with approximately 9 million fractures yearly. This poses a tremendous economic burden on health care. Between 5% and 10% of the elderly suffer from sarcopenia, the loss of muscle mass and strength, further increasing the risk of fractures due to falls. Evidence from interventional and observational studies support that fermented dairy products in particular exert beneficial effects on bone growth and mineralization, attenuation of bone loss, and reduce fracture risk. The effect cannot be explained by single nutrients in dairy, which suggests that a combined or matrix effect may be responsible similar to the matrix effects of foods on cardiometabolic health. Recently, several plant-based beverages and products have become available and marketed as substitutes for dairy products, even though their nutrient content differs substantially from dairy. Some of these products have been fortified, in efforts to mimic the nutritional profile of milk, but it is unknown whether the additives have the same bioavailability and beneficial effect as dairy. We conclude that the dairy matrix exerts an effect on bone and muscle health that is more than the sum of its nutrients, and we suggest that whole foods, not only single nutrients, need to be assessed in future observational and intervention studies of health outcomes. Furthermore, the importance of the matrix effect on health outcomes argues in favor of making future dietary guidelines food based.

Biomarkers of meat and seafood intake: an extensive literature review

Meat, including fish and shellfish, represents a valuable constituent of most balanced diets. Consumption of different types of meat and fish has been associated with both beneficial and adverse health effects. While white meats and fish are generally associated with positive health outcomes, red and especially processed meats have been associated with colorectal cancer and other diseases. The contribution of these foods to the development or prevention of chronic diseases is still not fully elucidated. One of the main problems is the difficulty in properly evaluating meat intake, as the existing self-reporting tools for dietary assessment may be imprecise and therefore affected by systematic and random errors. Dietary biomarkers measured in biological fluids have been proposed as possible objective measurements of the actual intake of specific foods and as a support for classical assessment methods. Good biomarkers for meat intake should reflect total dietary intake of meat, independent of source or processing and should be able to differentiate meat consumption from that of other protein-rich foods; alternatively, meat intake biomarkers should be specific to each of the different meat sources (e.g., red vs. white; fish, bird, or mammal) and/or cooking methods. In this paper, we present a systematic investigation of the scientific literature while providing a comprehensive overview of the possible biomarker(s) for the intake of different types of meat, including fish and shellfish, and processed and heated meats according to published guidelines for biomarker reviews (BFIrev). The most promising biomarkers are further validated for their usefulness for dietary assessment by published validation criteria.

Importance of Flaxseed and its Components in the Management of Hypertension

This review paper describes the effects of flaxseed and its components (flax oil, secoisolariciresinol diglucoside [SDG], flax lignan complex [FLC], and flaxseed protein hydrolysate [FPH]) on blood pressure (BP) in Sprague Dawley rats (SDR), spontaneously hypertensive rats (SHR), and humans. Flaxseed, flax oil, and FLC had variable effects on BP in humans, while SDG and FPH significantly reduced the BP in SDR and SHR. The effect of SDG was dose-dependent and long lasting. The lowering of BP is mediated through inhibition of soluble epoxide by α -linolenic acid in flax oil, stimulation of guanylate cyclase and inhibition of angiotensin converting enzyme (ACE) by SDG, and inhibition of renin and ACE activity by FPH. Flaxseed, flax oil, and FLC have variable effects on BP (none, slight, and significant). They are effective in lowering BP in individuals with hypertension and metabolic syndrome but ineffective in healthy individuals' ineffectiveness of flaxseed and its compounds in lowering BP may be due to their low doses, long interval of dosing, short duration of consumption, and patient status. In conclusion, the data at present suggest that flaxseed, flax oil, and FLC cannot serve as therapeutic agents for the treatment of hypertension. However, they can be used as an adjunct in the treatment of hypertension. A clinical trial should be conducted of these agents with higher doses which would be given twice daily for long duration. Pure SDG and FPS may serve as therapeutic agents for the treatment of hypertension but they have not been tried in humans.

Treatment with flaxseed oil induces apoptosis in cultured malignant cells

Flaxseed oil is widely recognized for its exceptional nutritional value, high concentration of fiber-based lignans and large amounts of ω-fatty acids. It is one of a generic group of functional foods that is often taken by cancer patients as a potential treatment. We have examined the anti-cancer effects of flaxseed oil by studying its direct effects on cancer cell growth in vitro. Treatment of a variety of cancer cell lines with flaxseed oil decreased their growth in a dose-dependent manner while non-malignant cell lines showed small increases in cell growth. Cells treated with a mixture of fatty acids, including α-linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid and lignans including enterodiol and enterolactone was also able to decrease the growth of cancer cells. Treatment of B16-BL6 murine melanoma and MCF-7 breast cancer cells with flaxseed oil induced apoptosis as determined by changes in cell morphology, annexin V staining, DNA fragmentation and/or caspase activation. In addition, treatment with flaxseed oil also disrupted mitochondrial function in B16-BL6 and MCF-7 cells. These results indicate that flaxseed oil can specifically inhibit cancer cell growth and induce apoptosis in some cancer cells and suggests it has further potential in anti-cancer therapy.

Biomarkers of food intake for nuts and vegetable oils: an extensive literature search

Nuts and vegetable oils are important sources of fat and of a wide variety of micronutrients and phytochemicals. Following their intake, several of their constituents, as well as their derived metabolites, are found in blood circulation and in urine. As a consequence, these could be used to assess the compliance to a dietary intervention or to determine habitual intake of nuts and vegetable oils. However, before these metabolites can be widely used as biomarkers of food intake (BFIs), several characteristics have to be considered, including specificity, dose response, time response, stability, and analytical performance. We have, therefore, conducted an extensive literature search to evaluate current knowledge about potential BFIs of nuts and vegetable oils. Once identified, the strengths and weaknesses of the most promising candidate BFIs have been summarized. Results from selected studies have provided a variety of compounds mainly derived from the fatty fraction of these foods, but also other components and derived metabolites related to their nutritional composition. In particular, α-linolenic acid, urolithins, and 5-hydroxyindole-3-acetic acid seem to be the most plausible candidate BFIs for walnuts, whereas for almonds they could be α-tocopherol and some catechin-derived metabolites. Similarly, several studies have reported a strong association between selenium levels and consumption of Brazil nuts. Intake of vegetable oils has been mainly assessed through the measurement of specific fatty acids in different blood fractions, such as oleic acid for olive oil, α-linolenic acid for flaxseed (linseed) and rapeseed (canola) oils, and linoleic acid for sunflower oil. Additionally, hydroxytyrosol and its metabolites were the most promising distinctive BFIs for (extra) virgin olive oil. However, most of these components lack sufficient specificity to serve as BFIs. Therefore, additional studies are necessary to discover new candidate BFIs, as well as to further evaluate the specificity, sensitivity, dose-response relationships, and reproducibility of these candidate biomarkers and to eventually validate them in other populations. For the discovery of new candidate BFIs, an untargeted metabolomics approach may be the most effective strategy, whereas for increasing the specificity of the evaluation of food consumption, this could be a combination of different metabolites.

Omega-3 Polyunsaturated Fatty Acid Deficiency and Progressive Neuropathology in Psychiatric Disorders: A Review of Translational Evidence and Candidate Mechanisms

Meta-analytic evidence indicates that mood and psychotic disorders are associated with both omega-3 polyunsaturated fatty acid (omega-3 PUFA) deficits and progressive regional gray and white matter pathology. Although the association between omega-3 PUFA insufficiency and progressive neuropathological processes remains speculative, evidence from translational research suggests that omega-3 PUFA insufficiency may represent a plausible and modifiable risk factor not only for enduring neurodevelopmental abnormalities in brain structure and function, but also for increased vulnerability to neurodegenerative processes. Recent evidence from human neuroimaging studies suggests that lower omega-3 PUFA intake/status is associated with accelerated gray matter atrophy in healthy middle-aged and elderly adults, particularly in brain regions consistently implicated in mood and psychotic disorders, including the amygdala, anterior cingulate, hippocampus, prefrontal cortex, and temporal cortex. Human neuroimaging evidence also suggests that both low omega-3 PUFA intake/status and psychiatric disorders are associated with reductions in white matter microstructural integrity and increased rates of white matter hyperintensities. Preliminary evidence suggests that increasing omega-3 PUFA status is protective against gray matter atrophy and deficits in white matter microstructural integrity in patients with mood and psychotic disorders. Plausible mechanisms mediating this relationship include elevated pro-inflammatory signaling, increased synaptic regression, and reductions in cerebral perfusion. Together these associations encourage additional neuroimaging research to directly investigate whether increasing omega-3 PUFA status can mitigate neuropathological processes in patients with, or at high risk for, psychiatric disorders.

The effect of camelina sativa oil and fish intakes on fatty acid compositions of blood lipid fractions

BACKGROUND AND AIMS

Blood lipid fractions serve as objective biomarkers of dietary fat intake. It is unclear which fatty acid pool most accurately reflects the dietary intakes of different n-3 PUFAs. We aimed to investigate the effect of fish and camelina sativa oil (CSO) intakes on fatty acid composition of erythrocyte membranes (EM), plasma phospholipids (PL), cholesteryl esters (CE) and triglycerides (TG). We also aimed to identify the most appropriate blood lipid fraction for assessing n-3 PUFA intake.

METHODS AND RESULTS

Altogether 79 volunteers with impaired glucose metabolism were randomly assigned either to CSO, fatty fish, lean fish or control groups for 12 weeks. Fatty acid compositions of lipid pools were measured by gas chromatography. The proportion of alpha-linolenic acid (ALA) increased in all lipid pools in the CSO group (false discovery rate (FDR) p < 0.001 for all). Similarly, the proportions of EPA and DHA increased in all lipid fractions in the fatty fish group (FDR p < 0.001 for EM, PL and CE; FDR p = 0.005 for TG; FDR p < 0.001 for EM, PL, CE; FDR p < 0.007 for TG, respectively). Changes in the dietary intakes of ALA, EPA and DHA correlated with the changes in their proportions in all lipid pools (r = 0.3-0.5, p < 0.05).

CONCLUSION

There is no difference in the ability of blood lipid fractions in reflecting the dietary intake of different n-3 PUFAs over a time period of 12 weeks in subjects with high baseline omega-3 index. This trial was registered in Clinicaltrials.gov (NCT01768429).

Eight-week hempseed oil intervention improves the fatty acid composition of erythrocyte phospholipids and the omega-3 index, but does not affect the lipid profile in children and adolescents with primary hyperlipidemia

Children affected by primary hyperlipidemia have a high risk of developing cardiovascular diseases (CVDs) during adulthood. Several studies have reported a positive association between the intake of polyunsaturated fatty acids (PUFAs) and improvements in lipid markers and CVD risk. Dietary supplements may represent a potential strategy in the management of hyperlipidemia. In this context, the effectiveness of hempseed oil (HSO) rich in PUFAs (particularly linoleic acid (LA) and α-linolenic acid (ALA)) in the modulation of hyperlipidemia has been poorly investigated. The present pilot study aimed to explore the impact of HSO supplementation on the serum lipid profile and fatty acid (FA) composition of red blood cells (RBCs) in children and adolescents with primary hyperlipidemia. A randomized, 8 week long, parallel dietary intervention study was performed. Thirty-six hyperlipidemic probands (6-16 years) on diet therapy were randomized into two groups: the HSO group, receiving 3 g of HSO providing 1.4 g of LA and 0.7 g/day of ALA, and the control group. Both groups received specific dietary guidelines. Before and after the intervention, blood samples were collected and the serum lipid profile, FA composition of RBCs and omega-3-index were analyzed. Eight weeks of supplementation with HSO significantly (p < .01) reduced the RBC content of total saturated and monounsaturated FAs (-5.02 ± 7.94% and - 2.12 ± 2.23%, respectively), increased the levels of total n-3 and n-6 PUFAs (+1.57 ± 1.96% and + 5.39 ± 7.18%, respectively) and the omega-3 index (+1.18 ± 1.42%), but failed to affect the serum lipid profile compared to the control group. In conclusion, our findings seem to support the contribution of HSO supplementation in improving the RBC phospholipid composition and omega-3 index, while no effect was observed regarding modulation of the lipid profile. Further controlled studies are necessary to achieve a complete understanding of the effects of HSO in the modulation of hyperlipidemia and CVD risk in this and other target groups.

Effect ofα-linolenic acid on 24-h ambulatory blood pressure in untreated high-normal and stage I hypertensive subjects

Results of intervention studies on the effects ofα-linolenic acid (ALA; C18 : 3n-3) on blood pressure (BP) are conflicting. Discrepancies between studies may be due to differences in study population, as subjects with increased baseline BP levels may be more responsive. Therefore, we examined specifically the effects of ALA on 24-h ambulatory blood pressure (ABP) in (pre-)hypertensive subjects. In a double-blind, randomised, placebo-controlled parallel study, fifty-nine overweight and obese adults (forty males and nineteen females) with (pre-)hypertension (mean age of 60 (sd8) years) received daily 10 g refined cold-pressed flaxseed oil, providing 4·7 g (approximately 2 % of energy) ALA (n29) or 10 g of high-oleic sunflower oil as control (n30) for 12 weeks. Compliance was excellent as indicated by vial count and plasma phospholipid fatty-acid composition. Compared with control, the changes of –1·4 mmHg in mean arterial pressure (MAP; 24 h ABP) after flaxseed oil intake (95 % CI –4·8, 2·0 mmHg,P=0·40) of –1·5 mmHg in systolic BP (95 % CI –6·0, 3·0 mmHg,P=0·51) and of –1·4 mmHg in diastolic BP (95 % CI –4·2, 1·4 mmHg,P=0·31) were not statistically significant. Also, no effects were found for office BP and for MAP, systolic BP, and diastolic BP when daytime and night-time BP were analysed separately and for night-time dipping. In conclusion, high intake of ALA, about 3–5 times recommended daily intakes, for 12 weeks does not significantly affect BP in subjects with (pre-)hypertension.

Green leafy vegetables in diets with a 25:1 omega-6/omega-3 fatty acid ratio modify the erythrocyte fatty acid profile of spontaneously hypertensive rats

Background

In addition to the actual composition of the diet (i.e. nutrient composition, food groups), the omega-6/omega-3 fatty acid ratio has been demonstrated to influence the tissue fatty acid profile and subsequently the risk for cardiovascular and other diseases. Likewise, the consumption of green leafy vegetables (GLVs) may favorably reduce the risks associated with disease. Although an ~ 3:1 omega-6/omega-3 fatty acid ratio (ω-6/ω-3 FAR) is recommended, the typical American diet has an ~ 25:1 ω-6/ω-3 FAR. Previous research affirms the ability of collard greens (CG), purslane (PL), and sweet potato greens (SPG) to improve the hepatic profile of spontaneously hypertensive rats (SHRs). The aim of the present study was to determine the influence of GLVs, incorporated (4%) into diets with a 25:1 ω-6/ω-3 FAR, on the erythrocyte fatty acid profile of male SHRs.

Methods

SHRs (N = 50) were randomly assigned to one of five dietary groups – standardized control (AIN-76A), Control (25:1 ω-6/ω-3 FAR), CG (25:1 ω-6/ω-3 FAR + 4% CG), PL (25:1 ω-6/ω-3 FAR + 4% PL) or SPG (25:1 ω-6/ω-3 FAR + 4% SPG). Following 6 weeks consumption of diets, SHRs erythrocyte fatty acid profiles were determined by gas-liquid chromatography.

Results

Significantly lower percentages of total saturated fatty acids (p < 0.05) and greater percentages of polyunsaturated fatty acids were present among SHR erythrocytes following the consumption of diets containing CG, PL and SPG. Total polyunsaturated fatty acids were greatest among SHRs consuming diets containing purslane.

Conclusions

The present study demonstrates the ability of GLVs to mitigate the potential effects of an elevated ω-6/ω-3 FAR, which may contribute to an atherogenic fatty acid profile, inflammation and disease pathogenesis. Dietary recommendations for disease prevention should consider the inclusion of these GLVs, particularly among those consuming diets with an ω-6/ω-3 FAR that may promote disease.

Effect of supplementation with flaxseed oil and different doses of fish oil for 2 weeks on plasma phosphatidylcholine fatty acids in young women

Background/objectives

Although assumed, it remains unclear that fatty acid (FA) biomarkers of n-3 long-chain PUFA reflect wide ranges of intake. However, to be utilised as biomarkers, to predict dietary intake, dose–response curves that cover a spectrum of intakes are required. The aim of the study was to investigate whether the FA composition of plasma phosphatidylcholine (PC) is a sensitive biomarker of n-3 FAs from fish oil, across a range of supplementation doses, and alpha-linolenic acid (ALA) supplementation, in young, healthy women.

Subjects/methods

A total of 303 young women were randomised to intakes ranging between 0.33 and 4.50 g EPA+DHA/day from fish oil (not all doses used in each year) or flaxseed oil (5.90–6.60 g/d) daily for 14 days in a series of trials, over 5 years. Fasting blood was collected at baseline (day 0) and day 14 and plasma PC FA composition, total and HDL-cholesterol and triglyceride concentrations measured.

Results

Fourteen days supplementation with fish oil significantly (P < 0.01) increased, in a dose-dependent fashion, plasma PC EPA, DPA and DHA at all doses except 1 and 3 mL/day. For the combined group of women who consumed any fish oil there was a 16% (P < 0.01) decrease in plasma triacylglycerol concentrations after 14 days supplementation. Flaxseed oil supplementation for 14 day resulted in significant (P < 0.01) increases in ALA, EPA and DPA, whilst DHA remained unchanged.

Conclusion

Our data demonstrate plasma PC is a sensitive biomarker of n-3 FA intake and reflects changes within 14 days across a range of intakes.

Unsaturated Fatty Acids Improve Atherosclerosis Markers in Obese and Overweight Non-diabetic Elderly Patients

BACKGROUND

Several studies have demonstrated the benefits of replacing trans and saturated fats with unsaturated fatty acids on cardiovascular diseases. We aimed to demonstrate the effect of polyunsaturated and monounsaturated fat supplementation on the biochemical and endothelial markers of atherosclerotic disease in obese or overweight non-diabetic elderly patients.

METHOD

Seventy-nine patients were randomly divided into three groups: flaxseed oil, olive oil, and sunflower oil; patients in each group received 30 mL of oil for 90 days. Patients were subjected to anthropometric and bioimpedance assessments; biochemical and endothelial evaluations were performed through ultrasonography of the brachial artery and carotid artery for endothelium-dependent dilation and intima-media thickness assessment, respectively, before and after the intervention. The participants' usual diet remained unchanged.

RESULTS

The flaxseed oil group had improved ultra-sensitive C-reactive protein levels (p = 0.074) and reduced carotid intima-media thickness (CIMT) (p = 0.028); the olive oil group exhibited an improved apolipoprotein (Apo)B/ApoA ratio (p = 0.021), reduced CIMT (p = 0.028), and improved flow-mediated vasodilation (FMV) (p = 0.054); and similarly, the sunflower oil group showed an improved ApoB/ApoA ratio (p = 0.024), reduced CIMT (p = 0.048), and improved FMV (p = 0.001).

CONCLUSION

Unsaturated fatty acid supplementation using the three vegetable oils attenuated pro-inflammatory properties and improved prothrombotic conditions. Therefore, introducing or replacing saturated and trans fat with unsaturated fatty acids is beneficial for cardiovascular risk reduction in obese or overweight non-diabetic elderly people. Further studies are needed to determine which unsaturated fat best prevents cardiovascular disease in elderly patients.

Plasma n-3 and n-6 Fatty Acids Are Differentially Related to Carotid Plaque and Its Progression: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

ω-3 (n-3) fatty acids (FAs) have long been considered healthful dietary components, yet recent clinical trials have questioned their cardiovascular benefits. By contrast, the ω-6 (n-6) FAs have been considered harmful, proatherogenic macronutrients, despite an absence of empirical evidence supporting this hypothesis. We aimed to determine whether plasma n-3 and n-6 FAs are related to risk of carotid plaque and its progression in 3327 participants of MESA (Multi-Ethnic Study of Atherosclerosis).

APPROACH AND RESULTS

Carotid plaque was assessed using ultrasonography at baseline and after a median period of 9.5 years. Plasma phospholipid n-3 and n-6 FAs were determined using gas chromatography-flame ionization detection. Relative risk regression analyses assessed the relations of FAs with the presence or progression of carotid plaque adjusted for typical cardiovascular disease risk factors. At baseline, it was found that participants in the fourth quartile of n-3 docosahexaenoic acid showed a 9% lower risk of carotid plaque (P=0.05), whereas those in the second quartile of n-3 α-linolenic acid showed an 11% greater risk compared with respective referent quartiles (P=0.02). In prospective analyses, individuals in the top quartile of docosahexaenoic acid showed a 12% lower risk of carotid plaque progression during 9.5 years compared with those in the referent quartile (P=0.002). No significant relations were observed among n-6 FAs and plaque outcomes. No significant race/ethnicity interactions were found.

CONCLUSIONS

These findings support docosahexaenoic acid as an atheroprotective macronutrient, whereas null findings for n-6 FAs challenge the view that they promote atherosclerosis.

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.

Hospital Diet Enriched With Rapeseed or Sunflower Oils Is Associated With a Decrease in Plasma 16:1n-7 and Some Metabolic Disorders in the Elderly

We recently demonstrated that the prevalence of dysglycemia was high among hospitalized elderly people who were fed a low fat diet (27.7% of energy) and was positively associated with plasma 16:1n-7, an indicator of de novo lipogenesis (DNL). Fatty acids in the DNL pathway have been shown to be associated with a higher risk of metabolic syndrome (MetS). The purpose of this study was to investigate the potential beneficial effects of fat enrichment (up to 34.1%en) of the hospital diet in 111 patients (30 men and 81 women, 84 ± 7 years) during 6 weeks. Based on gender, they were randomly given a diet supplemented either with rapeseed oil (RO) or with sunflower oil (SO). Fatty acids of cholesteryl esters and erythrocyte phospholipids and markers of metabolic disorders were evaluated before and after dietary intervention. Both enriched diets significantly, and to a similar extent, decreased (1) the overall prevalence of dysglycemia (by 25-33%) and MetS (by 31-43%) and (2) plasma 16:1n-7 mol% in men and women. Dysglycemia prevalence adjusted by the diets was reduced in men versus baseline; no change was found in women. Enrichment of the diet with RO or SO resulted in a difference in fatty acid compositions, that is, EPA (mol%) and the omega-3 index increased with RO, while proportions of 18:1n-7, 18:1n-9, and EPA decreased with SO. These findings highlight the need for adequate fat intake in the elderly. For supplementation of the hospital diet, RO, which led to a higher proportion of circulating n-3 polyunsaturated fatty acids (PUFA) and is known to be beneficial, may be preferred to SO.

Effects of a 12-week high-α-linolenic acid intervention on EPA and DHA concentrations in red blood cells and plasma oxylipin pattern in subjects with a low EPA and DHA status

The essential omega-3 fatty acid alpha-linolenic acid (ALA, 18:3n3) can be converted into EPA and DHA.

Glutamate homeostasis in the adult rat prefrontal cortex is altered by cortical docosahexaenoic acid accrual during adolescence: An in vivo1H MRS study

Major psychiatric disorders are associated with dysregulated glutamate homeostasis and deficits in the omega-3 fatty acid docosahexaenoic acid (DHA). This study determined the effects of dietary-induced alterations in brain DHA accrual on cortical glutamate homeostasis in the adult rat brain. Adolescent rats were fed a control diet (n = 20), a n-3 fatty acid-deficient diet (DEF, n = 20), or a fish oil-fortified diet containing preformed DHA (FO, n = 20). In adulthood ¹H MRS scans were performed with voxels in the prefrontal cortex (PFC) and thalamus. Compared with controls, erythrocyte, PFC, and thalamus DHA levels were significantly lower in DEF rats and significantly higher in FO rats. In the PFC, but not the thalamus, glutamate was significantly elevated in DEF rats compared with controls and FO rats. Glutamine did not differ between groups and the glutamine/glutamate ratio was lower in DEF rats. No differences were observed for markers of excitotoxicity (NAA, GFAP), or astrocyte glutamate transporter (GLAST, GLT-1) or glutamine synthetase expression. Across diet groups, PFC DHA levels were inversely correlated with PFC glutamate levels and positively correlated with GLAST expression. Together these findings demonstrate that rat cortical DHA accrual during adolescence impacts glutamate homeostasis in the adult PFC.

The effect of flaxseed supplementation on body weight and body composition: a systematic review and meta-analysis of 45 randomized placebo-controlled trials

Flaxseed consumption may be inversely associated with obesity; however, findings of available randomized controlled trials (RCTs) are conflicting. The present study aimed to systematically review and analyse RCTs assessing the effects of flaxseed consumption on body weight and body composition. PubMed, Medline via Ovid, SCOPUS, EMBASE and ISI Web of Sciences databases were searched up to November 2016. Mean changes in body composition indices including body weight, body mass index (BMI) and waist circumference were extracted. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity between studies was assessed with the I² test. Publication bias and subgroup analyses were also performed. The quality of articles was assessed via the Jadad scale. A total of 45 RCTs were included. Meta-analyses suggested a significant reduction in body weight (WMD: -0.99 kg, 95% CI: -1.67, -0.31, p = 0.004), BMI (WMD: -0.30 kg m^-2 , 95% CI: -0.53, -0.08, p = 0.008) and waist circumference (WMD: -0.80 cm, 95% CI: -1.40, -0.20, p = 0.008) following flaxseed supplementation. Subgroup analyses showed that using whole flaxseed in doses ≥30 g d^-1 , longer-term interventions (≥12 weeks) and studies including participants with higher BMI (≥ 27 kg m^-2 ) had positive effects on body composition. Whole flaxseed is a good choice for weight management particularly for weight reduction in overweight and obese participants.

Enriching Diet with n-3 PUFAs to Help Prevent Cardiovascular Diseases in Healthy Adults: Results from Clinical Trials

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are believed to be important for cardiovascular health. Many investigations have been carried out in an attempt to examine the effect of n-3 PUFAs intake, in the form of supplementation or fortified foods, for the management of cardiovascular disease (CVD) and risk factors for CVD, whereas less is known about the effect on healthy individuals. The present study reviews the available literature in order to examine the relationship between n-3 PUFAs intake, either via supplementation or enriched food, and the prevention of CVD among healthy adults. Interventional clinical trials on subjects aged >18 years old with none of the established risk factors for CVD have been considered for review. n-3 PUFAs supplementation or enriched food may positively regulate triglycerides and some lipoprotein subsets, as well as several vascular and coagulation parameters, even in healthy patients, presenting no risk factors for CVD, suggesting a protective effect. Diet enrichment with omega-3 is likely to be useful in helping to lower the risk of developing CVD in healthy individuals, but still offers no strong evidence of a tangible benefit on a population level. Additional studies are needed to determine the optimal daily intake, especially to prevent the unfavorable effects of PUFAs over-consumption.

Effects of the flavonol quercetin and α-linolenic acid on n-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial

Increased dietary intake and tissue status of the long-chain n-3 PUFA, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. We investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. Subjects (n 74) were randomised to receive at least 3·3 g/d ALA with either 190 mg/d quercetin (ALA+quercetin) or placebo (ALA+placebo) in a double-blinded, placebo-controlled, crossover trial with 8-week intervention periods separated by an 8-week washout period. A total of seven subjects dropped out for personal reasons. Data from the remaining sixty-seven subjects (thirty-four males and thirty-three females) were included in the analysis. Both interventions significantly increased serum phospholipid ALA (ALA+placebo: +69·3 %; ALA+quercetin: +55·8 %) and EPA (ALA+placebo: +37·3 %; ALA+quercetin: +25·5 %). ALA + quercetin slightly decreased DHA concentration by 9·3 %. Erythrocyte ALA and EPA significantly increased with both interventions, whereas DHA decreased. Fatty acid composition did not differ between sexes. We found no effect of quercetin. Intake of 3·6 g/d ALA over an 8-week period resulted in increased ALA and EPA, but not DHA, in serum phospholipids and erythrocytes. Neither quercetin supplementation nor sex affected the increment of ALA and relative proportions of n-3 PUFA in serum phospholipids and erythrocytes.

Polyunsaturated fatty acids and recurrent mood disorders: Phenomenology, mechanisms, and clinical application

A body of evidence has implicated dietary deficiency in omega-3 polyunsaturated fatty acids (n-3 PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in the pathophysiology and etiology of recurrent mood disorders including major depressive disorder (MDD) and bipolar disorder. Cross-national and cross-sectional evidence suggests that greater habitual intake of n-3 PUFA is associated with reduced risk for developing mood symptoms. Meta-analyses provide strong evidence that patients with mood disorders exhibit low blood n-3 PUFA levels which are associated with increased risk for the initial development of mood symptoms in response to inflammation. While the etiology of this n-3 PUFA deficit may be multifactorial, n-3 PUFA supplementation is sufficient to correct this deficit and may also have antidepressant effects. Rodent studies suggest that n-3 PUFA deficiency during perinatal development can recapitulate key neuropathological, neurochemical, and behavioral features associated with mood disorders. Clinical neuroimaging studies suggest that low n-3 PUFA biostatus is associated with abnormalities in cortical structure and function also observed in mood disorders. Collectively, these findings implicate dietary n-3 PUFA insufficiency, particularly during development, in the pathophysiology of mood dysregulation, and support implementation of routine screening for and treatment of n-3 PUFA deficiency in patients with mood disorders.

A new genotype of flax (Linum usitatissimum L.) with decreased susceptibility to fat oxidation: consequences to hematological and biochemical profiles of blood indices

BACKGROUND

Flaxseed is an alternative to marine products that provide the traditional dietary sources of ω-fatty acids. A new genotype of flax, W92, is rich in natural antioxidants as well as having a reduced content of α-linolenic acid and therefore shows decreased susceptibility to fat oxidation. The objective of this study was to evaluate the effect of a diet supplemented with W92 flaxseed on hematological and biochemical blood indices.

RESULTS

A positive impact of diet with the addition of flaxseed was observed on erythrocyte indices, including red blood cell (RBC), hematocrit (HCT), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) values. There were no significant differences for white blood cell (WBC), total protein and glucose values. Aspartate aminotransferase and alanine aminotransferase estimations in serum were also carried out and no obvious toxicity to the liver was shown. Moreover, a lipid profile was performed in serum samples and a decrease in total cholesterol and low-density lipoprotein cholesterol (LDL-C), accompanied by an increase in high-density lipoprotein cholesterol (HDL-C), was observed in rabbits fed flaxseed diets.

CONCLUSION

Based on the results obtained, it appeared that the inclusion of a new genetically modified type of flaxseed in the diet altered cholesterol metabolism and could reduce the possibility of cardiovascular diseases. Diet enrichment with W92 flaxseed may be a solution to the health issues that are a result of improper diet in humans and animals. © 2016 Society of Chemical Industry.

Monoacylglycerol-enriched oil increases EPA/DHA delivery to circulatory system in humans with induced lipid malabsorption conditions

It was hypothesized that under induced lipid malabsorption/maldigestion conditions, an enriched sn-1(3)-monoacylglycerol (MAG) oil may be a better carrier for n-3 long-chain PUFAs (LC-PUFAs) compared with triacylglycerol (TAG) from fish oil. This monocentric double blinded clinical trial examined the accretion of EPA (500 mg/day) and DHA (300 mg/day) when consumed as TAG or MAG, into the erythrocytes, plasma, and chylomicrons of 45 obese (BMI ≥30 kg/m² and ≤40 kg/m²) volunteers who were and were not administered Orlistat, an inhibitor of pancreatic lipases. Intake of MAG-enriched oil resulted in higher accretion of LC-PUFAs than with TAG, the concentrations of EPA and DHA in erythrocytes being, respectively, 72 and 24% higher at 21 days (P < 0.001). In addition, MAG increased the plasma concentration of EPA by 56% (P < 0.001) as compared with TAG. In chylomicrons, MAG intake yielded higher levels of EPA with the area under the curve (0-10 h) of EPA being 55% greater (P = 0.012). In conclusion, in obese human subjects with Orlistat-induced lipid maldigestion/malabsorption conditions, LC-PUFA MAG oil increased LC-PUFA levels in erythrocytes, plasma, and chylomicrons to a greater extent than TAG. These results indicate that MAG oil might require minimal enzymatic digestion prior to intestinal uptake and transfer across the epithelial barrier.

Maternal Malnutrition in the Etiopathogenesis of Psychiatric Diseases: Role of Polyunsaturated Fatty Acids

Evidence from human studies indicates that maternal metabolic state and malnutrition dramatically influence the risk for developing psychiatric complications in later adulthood. In this regard, the central role of polyunsaturated fatty acids (PUFAs), and particularly n-3 PUFAs, is emerging considering that epidemiological evidences have established a negative correlation between n-3 PUFA consumption and development of mood disorders. These findings were supported by clinical studies indicating that low content of n-3 PUFAs in diet is linked to an increased susceptibility to psychiatric disorders. PUFAs regulate membrane fluidity and exert their central action by modulating synaptogenesis and neurotrophic factor expression, neurogenesis, and neurotransmission. Moreover, they are precursors of molecules implicated in modulating immune and inflammatory processes in the brain. Importantly, their tissue concentrations are closely related to diet intake, especially to maternal consumption during embryonal life, considering that their synthesis from essential precursors has been shown to be inefficient in mammals. The scope of this review is to highlight the possible mechanisms of PUFA functions in the brain during pre- and post-natal period and to evaluate their role in the pathogenesis of psychiatric diseases.