Source Of Alpha-linolenic Acid Research Articles

Fatty Acid Profiling and Physiochemical Characterization of Chlorella sorokiniana Potentially Used for Biofuel Production

Rising oil prices and climate change have resulted in more emphasis on research into renewable biofuels. In this study, different water samples were collected from local vicinities for the isolation of local isolates of microalgae to check their potential towards the production of biofuel by the addition of different chemical substrates. Five different concentrations of ascorbic acid and iron (III) chloride (0, 1, 2.5, 5 & 10 µM) are used as substrates. Microscopic analysis evaluated that samples belong to genus Chlorella and further molecular identification showed that the samples are C. sorokiniana. Among all the concentrations of ascorbic acid 2.5 µM is most effective against the C. sorokiniana strain 1 (Safari Wildlife Park, Lahore) and C. sorokiniana strain 2 (Bahria Town, Lahore) while C. sorokiniana Strain 3 (SukhChane Society, Lahore) responded at 2.5 & 5 µM in term of biomass production. FeCl3 (2.5 µM) is effective against C. sorokiniana strain 1 while the growth of C. sorokiniana strain 2 and C. sorokiniana Strain 3 is inhibited. Lipid content analysis showed that only the C. sorokiniana strain 1 shows effective results at 1 & 2.5 µM of ascorbic acid and FeCl3, respectively. Those concentrations which give the significant results of lipid production were preceded for fatty acid profiling. Results indicate that the C. sorokiniana strain 1 can be considered as a source of alpha-linolenic acid; the basic constituent of biofuel production. In this study, it is concluded that C. sorokiniana strain 1 is useful for the production of environment friendly biofuel.

Linseed and Its Basic Composition

The archaeological evidence of flax cultivation dates back to >6000 BC and it is considered as one of the oldest and most useful crops. Components of flax have diverse uses. Cultivar development of flax is currently focused on enhancing the oil content and nutritional value to meet the demand of nutraceutical market supply, as an alternate source of fish oil, a rich source of eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6). Growing awareness about the role of diet and quest for human wellness has fuelled interest in ‗Functional foods‘ and functional attributes of many traditional foods are being reinvented. Flaxseed is cultivated in many parts of world for fiber, oil as well as for medicinal purposes and also as nutritional product. Flax continues to surge forward in its recognition as a functional food. It is the richest known source of alpha-linolenic acid, the phytoestrogen, lignans, as well as being a good source of soluble fiber. Flax is also very important fibrous bast plant, both for valuable textile fibres and composites applications and for bioactive compounds used in folk medicine, nutraceuticals and functional food. Flax seeds are rich in valuable fatty acids, amino-acids, phytoestrogens, cyclolinopeptides, lecithin, waxes, lignin, pectin, mucilage, etc. ω-3 and ω-6 polyunsaturated fatty acids (PUFA) are effective preventing cardiovascular and heart diseases. The flax seed has been shown to possess significant antioxidant and anti-inflammatory functions. In this review, composition, essential fatty acids,omega-3 fatty acid, alpha linolienic acid, proteins, vitamins and minerals, lignans, dietary fiber and uses of flaxseed are discussed.

Study on Portulaca Oleracea Native Species as Vegetal Source of Omega-3 and Omega-6 Fatty Acids

Fatty grass, grasita or purslane (Portulaca oleracea L.) is an important plant identified as a natural weed in field crops and lawns. Purslane is widespread worldwide and is popular as edible plants in many areas of Europe, Asia and the Mediterranean region. This plant possesses mucilaginous substances of great medicinal importance. It is a rich source of potassium, magnesium and calcium and has the potential to be used as a vegetal source of omega-3 and omega-6. It is very good as a source of alpha-linolenic acid (ALA) and gamma-linolenic acid (GLA) and contains the highest amount compared to any other green leafy vegetables. It also contains significant amounts of alpha-tocopherol and ascorbic acid, as well as an increased content of oxalate in fresh leaves. The antioxidant value and nutritional content of purslane are important for human consumption. It reveals a huge nutritional potential and indicates the potential for future use of this plant in food industry, dietary supplements, drugs, cosmetics and products for body care.

Optimization of jackfruit seed starch-soya protein isolate ratio and process variables for flaxseed oil encapsulation

The attribution as functional food ingredient of omega-3 fatty acid encouraged food researchers and industry for development of foods enriched with omega-3 fatty acids. Flaxseed oil (FSO) is the prolific vegetarian source of alpha linolenic acid (ω-3) for food enrichment, but its direct incorporation in food is problematic due to its high oxidation susceptibility. Microencapsulation of FSO using spray drying with jack fruit seed starch (JSS)-soya protein isolate (SPI) coating combination was studied as it is widely used approach to address the issue. The study was aimed at optimization of JSS-SPI ratio and process variables for microencapsulation of FSO with goals of maximization of encapsulation efficiency (EE), minimization of peroxide value (PV) and desired range of moisture content (MC:3-5, % wb) using Response surface methodology (RSM). The Box Behnken design (3k) was used to plan the experiments with three independent variables, viz. JSS-SPI ratio (1:1, 3:1 and 5:1), oil loading (20, 25 and 30%) of total solids in emulsion and inlet air temperature (160, 170 and 180°C) of spray dryer. Response surface methodology was used for analysis of responses (EE, PV and MC) and second order polynomial models were found significantly fitted to the responses with high coefficient of determination. The JSS:SPI ratio of 3.24:1, 23.8% oil loading and 175°C dryingair temperature were selected as the optimum conditions after numerical optimization and model validation.

Effects of Flaxseed Oil Consumption on Anthropometric Parameters in the Patients with Metabolic Syndrome: A Randomized Clinical Trial

Background: Flaxseed oil, as the main source of Alpha linolenic acid (ALA), decreases the production of Arachidonic acid (AA) from linoleic acid (LA) that plays an important role in the development of metabolic syndrome (MS). The aim of the present study was to compare the effects of flaxseed oil and sunflower oil on anthropometric parameters in patients suffering from MS. Materials and Methods: In this randomized clinical trial, 60 participants aged 30-60 years who suffered from MS were selected according to ATP III definition and were divided into two even groups receiving flaxseed oil and sunflower oil. Each group received 25 ml of the specified oil on a daily basis for 7 weeks. The anthropometric measures were evaluated on the first and last days of the study. Results: No significant differences were observed between the two groups regarding weight. However, waist circumference reduced significantly in the flaxseed oil group compared to the control group (P=0.001). Conclusions: The ALA might prevent the increase in adipose tissues. Therefore, it seems that flaxseed oil has beneficial effects on MS. [GMJ.2017;6(1):44-51]

Providing Flaxseed Oil but Not Menhaden Oil Protects against OVX Induced Bone Loss in the Mandible of Sprague-Dawley Rats.

Higher intakes of polyunsaturated fatty acids (PUFA) are associated with benefits at several skeletal sites in postmenopausal women and in rodent models, but the effect of PUFA-containing oils on tooth-supporting alveolar bone of the mandible has not been studied. Moreover, direct comparison of the effect of flaxseed oil (a source of alpha-linolenic acid (ALA)) and menhaden oil (a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) is unknown. One-month old female Sprague-Dawley rats (n = 48) were randomized to and fed a diet containing flaxseed oil or menhaden oil from one to six months of age. At three months of age, rats were randomized to receive SHAM or ovariectomy (OVX) surgery (n = 12/diet). The inter-radicular septum below the first molar of the mandible was imaged at 6 months of age (study endpoint) using micro-computed tomography (μCT) at a resolution of 9 μm. As expected, OVX significantly reduced percent bone volume (BV/TV), connectivity density (Conn. D.), trabecular number (Tb. N.), and increased trabecular separation (Tb. Sp.) compared to SHAM rats (p < 0.001). However, post hoc analysis revealed these differences were present in rats fed menhaden oil but not those fed flaxseed oil. These results suggest that providing flaxseed oil, possibly through its high ALA content, provides protection against the OVX-induced alveolar bone loss in rats.

Effect of Supplementation Purslane (Portulaca oleracea) as a Source of Alpha-Linolenic Acid on Production Performance and Physical Quality of Egg of Laying Hens

The aim of the study was to evaluate the effects of inclusion plant source of n 3 fat in the form of alpha-linolenic acid (ALA, 18:3n-3) on the diets of layers on production performance and physical quality of eggs. A total of 125 Hy-Line Brown hens (38 weeks old) were placed at individual cages and assigned to five dietary treatments. The dietary treatments were supplemented with 0, 1.5, 3.0, 4.5 and 6.0% purslane meal. Laying hens were fed for five weeks following a seven day adaptation period. Water and feed were provided ad libitum. Feed intake (FI) measured weekly and feed consumption ratio (FCR) was calculated at the end of the trial. A total of 25 egg yolk samples of day 35 (n = 5 egg yolks for each treatment) were collected to analyse physical quality of eggs. The data were analyzed using Analysis of Variance (ANOVA). Differences between treatment means were further analyzed using Duncan's New Multiple Range Test (DMRT). Results showed that the incorporation of plants rich in ALA did not modify FI, FCR, and egg production. Supplementation of purslane meal in the diets had no effect on physical quality of eggs, including egg weight, yolk weight, albumen index, yolk index and Haugh Unit (HU). The average of egg weight and yolk weight were 60,5 and 15.3 g, respectively. Diet containing purslane meal increased yolk colour. In conclusion, laying hens that fed diet supplemented with purslane meal rich in ALA improved yolk colour and did not change the production performance of the laying hens or the qualities of the eggs.

Effect of Supplementation Purslane (Portulaca oleracea) as a Source of Alpha-Linolenic Acid on Production Performance and Physical Quality of Egg of Laying Hens

The aim of the study was to evaluate the effects of inclusion plant source of n 3 fat in the form of alpha-linolenic acid (ALA, 18:3n-3) on the diets of layers on production performance and physical quality of eggs. A total of 125 Hy-Line Brown hens (38 weeks old) were placed at individual cages and assigned to five dietary treatments. The dietary treatments were supplemented with 0, 1.5, 3.0, 4.5 and 6.0% purslane meal. Laying hens were fed for five weeks following a seven day adaptation period. Water and feed were provided ad libitum. Feed intake (FI) measured weekly and feed consumption ratio (FCR) was calculated at the end of the trial. A total of 25 egg yolk samples of day 35 (n = 5 egg yolks for each treatment) were collected to analyse physical quality of eggs. The data were analyzed using Analysis of Variance (ANOVA). Differences between treatment means were further analyzed using Duncan's New Multiple Range Test (DMRT). Results showed that the incorporation of plants rich in ALA did not modify FI, FCR, and egg production. Supplementation of purslane meal in the diets had no effect on physical quality of eggs, including egg weight, yolk weight, albumen index, yolk index and Haugh Unit (HU). The average of egg weight and yolk weight were 60,5 and 15.3 g, respectively. Diet containing purslane meal increased yolk colour. In conclusion, laying hens that fed diet supplemented with purslane meal rich in ALA improved yolk colour and did not change the production performance of the laying hens or the qualities of the eggs.

A new source of alpha-linolenic acid (ALA)

A new source of alpha-linolenic acid (ALA)

Effect of shortening replacement with flaxseed oil on physical, sensory, fatty acid and storage characteristics of cookies.

Omega-3 fatty acid imparted good evidence of health benefits. Flaxseed oil, being the richest vegetarian source of alpha linolenic acid (omega-3 fatty acid), was incorporated in cookies by replacing shortening at level of 5%, 10%, 20%, 30%, 40% and 50%. Effect of shortening replacement with flaxseed oil on physical, textural and sensory attributes were investigated. Spread ratio and breaking strength of cookies increased as flaxseed oil level increased. Sensory score was not significantly affected up to 30% shortening replacement with flaxseed oil as compared with the control cookies. Above 30% flaxseed oil, sensory score was adversely affected. Fatty acid profile confirmed the enhancement of omega-3 fatty acid from 0 (control) to 14.14% (30% flaxseed oil cookies). The poly-unsaturated to saturated fatty acid ratio (P/S) increased from 0.088 (control) to 0.57 while ω - 6 to ω -3 fatty acid ratio of flaxseed oil cookies decreased from 4.51 (control) to 0.65 in the optimized cookies. The data on storage characteristics of the control and 30% flaxseed oil cookies showed that there was significant change in the moisture content, Peroxide value (PV) and overall acceptability (OAA) up to 28days of storage at 45°C packed in polyethylene bags. Flaxseed oil cookies were acceptable up to 21days of storage and afterwards noticeable off flavour was perceived.

Influence of defatted flaxseed diet on insulin sensitivity, vascular permeability and lipid profile in a rat model of type 2 diabetes mellitus

The impact of flaxseed (FSD) intake, a rich source of alpha linolenic acid (ALA), fiber and lignans, on the cardiovascular system is well documented. However, mechanisms by which flaxseed improve cardiovascular health are not clear. The aim of this study was to investigate the effects of dietary flaxseed on vascular permeability and endothelial function in streptozotocin-induced type 2 diabetes in rats. Type 2 diabetes mellitus (T2DM) was induced in male Sprague-Dawley rats by intraperitoneal injection of streptozotocin (35 mg/kg body weight) after short term feeding of high fructose diet. Diabetic rats were divided into three groups, one group fed standard diet, second group fed standard diet supplemented with defatted flaxseed powder (FSD), and third group received Metformin (200 mg/kg BW (body weight)) for 8 weeks. Fasting serum concentrations of glucose (FPG), insulin, vascular endothelial growth factor (VEGF), nitric oxide (NO), uric acid (UA) and lipid profile were measured. Vascular permeability index (VPI) was assessed at the end of experiment by quantifying the extravasation of albumin-bound Evans blue (EB) dye in the heart. Dietary FSD supplementation is comparable to Metformin in modulating blood lipid profiles, insulin and FPG levels. FSD intake was associated with significant reductions in serum insulin (-66%), glucose (-68%), VEGF levels (-66.8%) and UA (-63%), and NO (-37.5%) as compared to diabetic group without FSD supplementation. There were also improvements in lipid profile, vascular permeability index (VPI), insulin resistance and atherogenic indices in diabetic rats supplemented with flaxseed. These results suggest that dietary FSD supplementation may reduce the incidence of diabetic vascular complications through improvement of insulin sensitivity, vascular permeability and lipid profile. Key words: Diabetes mellitus, cardiovascular diseases, vascular permeability, endothelial dysfunction, insulin resistance, vascular endothelial growth factor, nitric oxide.

Effect of Flax Addition on the Flavor Profile and Acceptability of Bagels

Bakery products containing flaxseed, a rich source of alpha linolenic acid (ALA), may provide health benefits. However, the effect of adding flaxseed, especially in the high amounts required for use as the food supplement in clinical trials (23% by weight of the raw ingredients), may affect the flavor characteristics and consumer acceptability. Sensory attributes of bagels containing 30 g of milled flaxseed were evaluated by a 9 member trained panel using a descriptive test and by 89 participants using a consumer test. Grain/flax aroma and flavor were significantly higher for the flax bagels compared to the nonflax bagels. The cinnamon raisin bagel had significantly lower grain/flax aroma and flavor and significantly higher sweet aroma and taste compared to the plain and sunflower sesame types. Older consumers rated the appearance, color, and flavor of the bagels significantly higher than the younger consumers possibly leading to higher compliance in clinical studies for this age group. Bagels with flax showed a significantly lower mean value for flavor acceptability, overall acceptability, and frequency of eating compared to bagels without flax. Appearance, color, and texture acceptability showed no significant differences. The cinnamon raisin bagel had significantly higher flavor acceptance compared to sunflower sesame and plain bagels. In conclusion, for bagels containing 6 g ALA in the form of milled flaxseed, cinnamon raisin appears to be a promising flavoring alternative for ALA fortification for use in clinical trials or as part of the daily diet. Consumers are seeking functional foods that contain omega-3 fatty acids. Bagels made with 23% milled flaxseed (approximately 2 times the amount in regular flax baked products) provided 6 g ALA, an amount high enough to test the efficacy of ALA in human subjects without causing gastrointestinal distress. This study showed that flaxseed aroma and flavor were detected in fortified compared to nonfortified bagels but bagels with this high flaxseed amount were still acceptable with the addition of cinnamon raisin flavoring. Commercial bakeries can use these results to formulate healthy, tasty, and convenient products.

Flax Seed: A Potential Medicinal Food

Growing awareness about the role of diet and quest for human wellness has fuelled interest in ‘Functional foods’ and functional attributes of many traditional foods are being reinvented. Flax continues to surge forward in its recognition as a functional food and has recently gained attention in the area of cardiovascular disease primarily because it is the richest known source of alpha-linolenic acid, the phytoestrogen, lignans, as well as being a good source of soluble fiber. Lignans have diverse range of biological activities and flax seeds contain a lignin derivative, secoisolariciresinol diglucoside which get metabolized into the mammalian lignans. The flax lignans influence the early risk markers of mammary and colonic carcinogenesis in animal models. Regular consumption of flaxseed products can affect serum total and low-density lipoprotein cholesterol concentrations, reduce postprandial glucose absorption, decrease some markers of inflammation and raise serum levels of the omega-3 fatty acids, ALA and eicosapentaenoic acid. The flax seed has been shown to possess significant antioxidant and anti-inflammatory functions in experimental as well as human studies. The flax seed supplementation in diet revealed potential health benefits in situations like cardiovascular risk, certain types of cancers and other metabolic disorders. There are number of studies indicating the role of raw flaxseed and its baked products in health promotion and disease prevention. This review highlights the potential of ‘flax seed’ as a ‘neutraceutical’ and its role as a protective and therapeutic medicinal food.

FlaxLic supplementation improves growth performance of Angus bulls

Introduction Nutrition can affect bull fertility. Omega-3 fatty acids such as alpha linolenic, eicosapentaenoic, and docosahexaenoic acids can affect motility and morphology of sperm. Flaxseed is an excellent source of alpha linolenic acid and has been shown to increase tissue concentrations of both alpha linolenic acid and eicosapentaenoic acid, which are involved in synthesis of important reproductive hormones. Flax can be difficult to transport, process, and store, but the FlaxLic block (New Generation Feeds, Belle Fourche, SD) is stable and easy to handle, contains high levels of omega-3 fatty acids, and may be a useful supplement for developing beef bulls. In a previous study at Kansas State University, feeding FlaxLic blocks to developing bulls for 61 days prior to breeding soundness examinations increased rate of gain and percentages of motile and normal sperm.

Characterization of cis-9 trans-11 trans-15 C18:3 in milk fat by GC and covalent adduct chemical ionization tandem MS

Rumen biohydrogenation of dietary alpha-linolenic acid gives rise in ruminants to accumulation of fatty acid intermediates, some of which may be transferred into milk. Rumelenic acid [cis-9 trans-11 cis-15 C18:3 (RLnA)] has recently been characterized, but other C18:3 minor isomers are still unknown. The objective of this work was to identify a new isomer of octatridecenoic acid present in milk fat from ewes fed different sources of alpha-linolenic acid. Structural characterization of this fatty acid was achieved by GC-MS. Analysis of dimethyloxazoline and picolinyl ester derivatives allowed for location of the double bond positions. Covalent adduct chemical ionization tandem mass spectrometry confirmed the positional structure 9-11-15, identical to RLnA, and helped to establish double bond geometry (cis-trans-trans). This new C18:3 isomer could be formed by isomerization of cis-15 bond of RLnA and subsequently converted by hydrogenation to trans-11 trans-15 C18:2, an octadecadienoic acid also detected in this study.

Flaxseed and Cardiovascular Risk Factors: Results from a Double Blind, Randomized, Controlled Clinical Trial

Objective: Flaxseed is a rich source of alpha linolenic acid (ALA), fiber and lignans, making it a potentially attractive functional food for modulating cardiovascular risk. We studied the effects of flaxseed on markers of cardiovascular risk in hypercholesterolemic adults.Methods: Sixty-two men and post-menopausal women with pre-study low density lipoprotein cholesterol (LDL-C) between 130 and 200 mg/dl were randomized to 40g/day of ground flaxseed-containing baked products or matching wheat bran products for 10 weeks while following a low fat, low cholesterol diet. Fasting lipoproteins, measures of insulin resistance, inflammation, oxidative stress, and safety were assessed at 0, 5 and 10 weeks.Results: Flaxseed was well-tolerated, and increased serum levels of ALA (p < 0.001). Compared to wheat, flaxseed significantly reduced LDL-C at 5 weeks (−13%, p < 0.005), but not at 10 weeks (−7%, p = 0.07). Flaxseed reduced lipoprotein a (Lp[a]) by a net of 14% (p = 0.02), and reduced the homeostatic model assessment of insulin resistance (HOMA-IR) index by 23.7% (p = 0.03) compared to wheat at 10 weeks, but did not affect markers of inflammation (IL-6, Hs-CRP) or oxidative stress (ox LDL, urinary isoprostanes) at any time points. In men, flaxseed reduced HDL-C concentrations by a net of 16% (p = 0.03) and 9% (p = 0.05) at 5 and 10 weeks, respectively.Conclusions: Ground flaxseed has a modest but short lived LDL-C lowering effect, yet reduces Lp(a) and improves insulin sensitivity in hyperlipidemic adults. The HDL-C lowering effect of flaxseed in men warrants additional study.

Ácidos graxos poliinsaturados ômega-3 e ômega-6: importância e ocorrência em alimentos

Os ácidos graxos poliinsaturados abrangem as famílias de ácidos graxos ômega-3 e ômega-6. Os ácidos graxos de cadeia muito longa, como os ácidos araquidônico e docosaexaenóico, desempenham importantes funções no desenvolvimento e funcionamento do cérebro e da retina. Esse grupo de ácidos graxos não pode ser obtido pela síntese de novo, mas pode ser sintetizado a partir dos ácidos linoléico e alfa-linolênico presentes na dieta. Neste artigo são considerados os principais fatores que podem inibir a atividade das enzimas dessaturases envolvidas na síntese dos ácidos graxos de cadeia muito longa. São apresentadas as recomendações da razão ômega-6/ômega-3 na dieta, propostas em diversos países, sendo verificada a convergência para o intervalo de 4 a 5:1. São relacionados alimentos que podem contribuir para aumentar a ingestão do ácido alfa-linolênico e dos ácidos graxos de cadeia muito longa. A essencialidade dos ácidos graxos de cadeia muito longa é muito dependente do metabolismo do indivíduo, sendo que a razão n-6/n-3 da dieta exerce grande influência nesse sentido.

Highlights on Functional Foods, with Special Reference to Flaxseed

Functional food is any food or food ingredients that may provide a health benefit through prevention or treatment of diseases and disorders. Flaxseed is emerging as one of the key sources of nutrients and phytochemicals in the functional food arena. It is a leading source of alpha linolenic acid. Flaxseed also contains soluble fiber, gum, high quality protein and phenolic compound, lignans, therefore it is considered as a rich source of functional food ingredients that may have specific health advantages. It has potential health benefits in reducing the incidence of obesity, cardiovascular diseases, diabetes and cancer. It also has beneficial effects on platelet aggregation and immune function. Flaxseed protein can be used as physiologic functional foods for patients with malnutrition during chronic liver diseases. Flaxseed lignans can control renal diseases and combat menopause symptoms.

Effect of randomized supplementation with high dose olive, flax or fish oil on serum phospholipid fatty acid levels in adults with attention deficit hyperactivity disorder

Dietary intake of omega-3 fatty acids has been positively correlated with cardiovascular and neuropsychiatric health in several studies. The high seafood intake by the Japanese and Greenland Inuit has resulted in low ratios of the omega-6 fatty acid arachidonic acid (AA, 20:4n-6) to eicosapentaenoic acid (EPA, 20:5n-3), with the Japanese showing AA:EPA ratios of approximately 1.7 and the Greenland Eskimos showing ratios of approximately 0.14. It was the objective of this study to determine the effect of supplementation with high doses (60 g) of flax and fish oils on the blood phospholipid (PL) fatty acid status, and AA/EPA ratio of individuals with Attention Deficit Hyperactivity Disorder (ADHD), commonly associated with decreased blood omega-3 fatty acid levels. Thirty adults with ADHD were randomized to 12 weeks of supplementation with olive oil (< 1% omega-3 fatty acids), flax oil (source of alpha-linolenic acid; 18:3n-3; alpha-LNA) or fish oil (source of EPA and docosahexaenoic acid; 22:6n-3; DHA). Serum PL fatty acid levels were determined at baseline and at 12 weeks. Flax oil supplementation resulted in an increase in alpha-LNA and a slight decrease in the ratio of AA/EPA, while fish oil supplementation resulted in increases in EPA, DHA and total omega-3 fatty acids and a decrease in the AA/EPA ratio to values seen in the Japanese population. These data suggest that in order to increase levels of EPA and DHA in adults with ADHD, and decrease the AA/EPA ratio to levels seen in high fish consuming populations, high dose fish oil may be preferable to high dose flax oil. Future study is warranted to determine whether correction of low levels of long-chain omega-3 fatty acids is of therapeutic benefit in this population.

Compartmental modeling to quantify α-linolenic acid conversion after longer term intake of multiple tracer boluses

To estimate in vivo alpha-linolenic acid (ALA; C18:3n-3) conversion, 29 healthy subjects consumed for 28 days a diet providing 7% of energy from linoleic acid (C18:2n-6) and 0.4% from ALA. On day 19, subjects received a single bolus of 30 mg of uniformly labeled [(13)C]ALA and for the next 8 days 10 mg twice daily. Fasting plasma phospholipid concentrations of (12)C- and (13)C-labeled ALA, eicosapentaenoic acid (EPA; C20:5n-3), docosapentaenoic acid (DPA; C22:5n-3), and docosahexaenoic acid (DHA; C22:6n-3) were determined on days 19, 21, 23, 26, 27, and 28. To estimate hepatic conversion of n-3 fatty acids, a tracer model was developed based on the averaged (13)C data of the participants. A similar tracee model was solved using the averaged (12)C values, the kinetic parameters derived from the tracer model, and mean ALA consumption. ALA incorporation into plasma phospholipids was estimated by solving both models simultaneously. It was found that nearly 7% of dietary ALA was incorporated into plasma phospholipids. From this pool, 99.8% was converted into EPA and 1% was converted into DPA and subsequently into DHA. The limited incorporation of dietary ALA into the hepatic phospholipid pool contributes to the low hepatic conversion of ALA into EPA. A low conversion of ALA-derived EPA into DPA might be an additional obstacle for DHA synthesis.