The lipid compositions of barophilic bacterial strains which contained docosahexaenoic acid (DHA [22:6n-3]) were examined, and the adaptive changes of these compositions were analyzed in response to growth pressure. In the facultatively barophilic strain 16C1, phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) were major components which had the same fatty acid chains. However, in PE, monounsaturated fatty acids such as hexadecenoic acid were major components, and DHA accounted for only 3.7% of the total fatty acids, while in PG, DHA accounted for 29.6% of the total fatty acids. In response to an increase in growth pressure in strain 16C1, the amounts of saturated fatty acids in PE were reduced, and these decreases were mainly balanced by an increase in unsaturated fatty acids, including DHA. In PG, the decrease in saturated fatty acids was mainly balanced by an increase in DHA. Similar adaptive changes in fatty acid composition were observed in response to growth pressure in obligately barophilic strain 2D2. Furthermore, these adaptive changes in response were also observed in response to low temperature in strain 16C1. These results confirm that the general shift from saturated to unsaturated fatty acids including DHA is one of the adaptive changes in response to increases in pressure and suggest that DHA may play a role in maintaining the proper fluidity of membrane lipids under high pressure.
We devised a new method (the dorayaki method) using marine agar under in situ pressures to isolate barophilic bacteria from the intestinal contents of three deep-sea fishes (two Coryphaenoides yaquinae samples and one Ilyophis sp. sample) retrieved from depths of 4,700 to 6,100 m in the Northwest Pacific Ocean. All 10 strains isolated from one sample (C. yaquinae) were obligately barophilic. One of the 10 strains did not grow at atmospheric pressure and 103.4 MPa but did grow well between 20.7 and 82.7 MPa, with optimal growth at 41.4 MPa. This method is useful for isolating psychrophilic and barophilic deep-sea bacteria.
The intestinal floras of seven deep-sea fish retrieved at depths of from 3,200 to 5,900 m were examined for population sizes and growth responses to pressure. Large populations of culturable bacteria, ranging from 1.1 x 10(sup6) to 3.6 x 10(sup8) cells per ml of contents, were detected when samples were incubated at conditions characteristic of those of the deep sea. Culturable cell counts at in situ pressures were greater than those at atmospheric pressure in all samples. Most of the strains isolated by the spread-plating method at atmospheric pressure later proved barophilic. Barophilic bacteria were the predominant inhabitants of the abyssal fish intestines.
The fatty acid composition of the membrane lipids in 11 deep-sea bacterial isolates was determined. The fatty acids observed were typical of marine vibrios except for the presence of large amounts of long-chain polyunsaturated fatty acids (PUFAs). These long-chain PUFAs were previously thought to be absent in procaryotes, with the notable exception of a single marine Flexibacter sp. In three barophilic strains tested at 2°C, there was a general increase in the relative amount of PUFAs as pressure was increased from a low growth pressure towards the optimal growth pressure. In Vibrio marinus MP-1, a psychrophilic strain, PUFAs were found to increase as a function of decreasing temperature at constant atmospheric pressure. These results suggest the involvement of PUFAs in the maintenance of optimal membrane fluidity and function over environmentally relevant temperatures and pressures. Furthermore, since these lipids are essential nutrients for higher taxa and are found in large amounts in the lipids of deep-sea vertebrates and invertebrates, an important, specific role for deep-sea bacteria in abyssal food webs is implicated.
B10.RIII and B10.G mice were transferred from a diet of laboratory rodent chow to a standard diet in which all the fat (5% by weight) was supplied as either fish oil (17% eicosapentaenoic acid [EPA], 12% docosahexaenoic acid [DHA], 0% arachidonic acid [AA], and 2% linoleic acid) or corn oil (0% EPA, 0% DHA, 0% AA, and 65% linoleic acid). The fatty acid composition of the macrophage phospholipids from mice on the chow diet was similar to that of mice on a corn oil diet. Mice fed the fish oil diet for only 1 wk showed substantial increases in macrophage phospholipid levels of the omega-3 fatty acids (of total fatty acid 4% was EPA, 10% docosapentaenoic acid [DPA], and 10% DHA), and decreases in omega-6 fatty acids (12% was AA, 2% docosatetraenoic acid [DTA], and 4% linoleic acid) compared to corn oil-fed mice (0% EPA, 0% DPA, 6% DHA, 20% AA, 9% DTA, and 8% linoleic acid). After 5 wk this difference between the fish oil-fed and corn oil-fed mice was even more pronounced. Further small changes occurred at 5-9 wk. We studied the prostaglandin (PG) and thromboxane (TX) profile of macrophages prepared from mice fed the two diets just before being immunized with collagen. Irrespective of diet, macrophages prepared from female mice and incubated for 24 h had significantly more PG and TX in the medium than similarly prepared macrophages from male mice. The increased percentage of EPA and decreased percentage of AA in the phospholipids of the macrophages prepared from the fish oil-fed mice was reflected in a reduction in the amount of PGE2 and PGI2 in the medium relative to identically incubated macrophages prepared from corn oil-fed mice. When this same fish oil diet was fed to B10.RIII mice for 26 d before immunization with type II collagen, the time of onset of arthritis was increased, and the incidence and severity of arthritis was reduced compared to arthritis induced in corn oil-fed mice. The females, especially those on the fish oil diet, tended to have less arthritis than the males. These alterations in the fatty acid pool available for PG and leukotriene synthesis suggest a pivotal role for the macrophage and PG in the immune and/or inflammatory response to type II collagen.
Dietary long-chain polyunsaturated fatty acids (LC-PUFA) are of crucial importance for the development of neural tissues. The aim of this study was to evaluate the impact of a dietary supplementation in n-3 fatty acids in female rats during gestation and lactation on fatty acid pattern in brain glial cells phosphatidylethanolamine (PE) and phosphatidylserine (PS) in the neonates.
Sprague-Dawley rats were fed during the whole gestation and lactation period with a diet containing either docosahexaenoic acid (DHA, 0.55%) and eicosapentaenoic acid (EPA, 0.75% of total fatty acids) or α-linolenic acid (ALA, 2.90%). At two weeks of age, gastric content and brain glial cell PE and PS of rat neonates were analyzed for their fatty acid and dimethylacetal (DMA) profile. Data were analyzed by bivariate and multivariate statistics.
In the neonates from the group fed with n-3 LC-PUFA, the DHA level in gastric content (+65%, P < 0.0001) and brain glial cell PE (+18%, P = 0.0001) and PS (+15%, P = 0.0009) were significantly increased compared to the ALA group. The filtered correlation analysis (P < 0.05) underlined that levels of dihomo-γ-linolenic acid (DGLA), DHA and n-3 docosapentaenoic acid (DPA) were negatively correlated with arachidonic acid (ARA) and n-6 DPA in PE of brain glial cells. No significant correlation between n-3 and n-6 LC-PUFA were found in the PS dataset. DMA level in PE was negatively correlated with n-6 DPA. DMA were found to occur in brain glial cell PS fraction; in this class DMA level was correlated negatively with DHA and positively with ARA.
The present study confirms that early supplementation of maternal diet with n-3 fatty acids supplied as LC-PUFA is more efficient in increasing n-3 in brain glial cell PE and PS in the neonate than ALA. Negative correlation between n-6 DPA, a conventional marker of DHA deficiency, and DMA in PE suggests n-6 DPA that potentially be considered as a marker of tissue ethanolamine plasmalogen status. The combination of multivariate and bivariate statistics allowed to underline that the accretion pattern of n-3 LC-PUFA in PE and PS differ.
Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5) and DHA (C22:6) and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.
Docosahexaenoic acid; DHA; Eicosapentaenoic acid; EPA; Microalgae; Omega-3 fatty acids; Polyunsaturated fatty acids
Long chain fatty acids influence inflammation through a variety of mechanisms; many of these are mediated by, or at least associated with, changes in fatty acid composition of cell membranes. Changes in these compositions can modify membrane fluidity, cell signaling leading to altered gene expression, and the pattern of lipid mediator production. Cell involved in the inflammatory response are typically rich in the n-6 fatty acid arachidonic acid, but the contents of arachidonic acid and of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can be altered through oral administration of EPA and DHA. Eicosanoids produced from arachidonic acid have roles in inflammation. EPA also gives rise to eicosanoids and these often have differing properties from those of arachidonic acid-derived eicosanoids. EPA and DHA give rise to newly discovered resolvins which are anti-inflammatory and inflammation resolving. Increased membrane content of EPA and DHA (and decreased arachidonic acid content) results in a changed pattern of production of eicosanoids and resolvins. Changing the fatty acid composition of cells involved in the inflammatory response also affects production of peptide mediators of inflammation (adhesion molecules, cytokines etc.). Thus, the fatty acid composition of cells involved in the inflammatory response influences their function; the contents of arachidonic acid, EPA and DHA appear to be especially important. The anti-inflammatory effects of marine n-3 PUFAs suggest that they may be useful as therapeutic agents in disorders with an inflammatory component.
leukocyte; neutrophil; macrophage; monocyte; eicosanoid; cytokine; interleukin; fish oil
Consumption of ω-3 fatty acids from fish oil, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), decreases risk for heart failure and attenuates pathologic cardiac remodeling in response to pressure overload. Dietary supplementation with EPA+DHA may also impact cardiac mitochondrial function and energetics through alteration of membrane phospholipids. We assessed the role of EPA+DHA supplementation on left ventricular (LV) function, cardiac mitochondrial membrane phospholipid composition, respiration, and sensitivity to mitochondrial permeability transition pore (MPTP) opening in normal and infarcted myocardium. Rats were subjected to sham surgery or myocardial infarction by coronary artery ligation (n=10–14), and fed a standard diet, or supplemented with EPA+DHA (2.3% of energy intake) for 12 weeks. EPA+DHA altered fatty acid composition of total mitochondrial phospholipids and cardiolipin by reducing arachidonic acid content and increasing DHA incorporation. EPA+DHA significantly increased calcium uptake capacity in both subsarcolemmal and intrafibrillar mitochondria from sham rats. This treatment effect persisted with the addition of cyclosporin A, and was not accompanied by changes in mitochondrial respiration or coupling, or cyclophilin D protein expression. Myocardial infarction resulted in heart failure as evidenced by LV dilation and contractile dysfunction. Infarcted LV myocardium had decreased mitochondrial protein yield and activity of mitochondrial marker enzymes, however respiratory function of isolated mitochondria was normal. EPA+DHA had no effect on LV function, mitochondrial respiration, or MPTP opening in rats with heart failure. In conclusion, dietary supplementation with EPA+DHA altered mitochondrial membrane phospholipid fatty acid composition in normal and infarcted hearts, but delayed MPTP opening only in normal hearts.
eicosapentaenoic acid; docosahexaenoic acid; myocardial infarction; mitochondrial permeability transition pore
Two strains of obligately barophilic bacteria were isolated from a sample of the world’s deepest sediment, which was obtained by the unmanned deep-sea submersible Kaiko in the Mariana Trench, Challenger Deep, at a depth of 10,898 m. From the results of phylogenetic analysis based on 16S rRNA gene sequences, DNA-DNA relatedness study, and analysis of fatty acid composition, the first strain (DB21MT-2) appears to be most highly similar to Shewanella benthica and close relatives, and the second strain (DB21MT-5) appears to be closely related to the genus Moritella. The optimal pressure conditions for growth of these isolates were 70 MPa for strain DB21MT-2 and 80 MPa for strain DB21MT-5, and no growth was detected at pressures of less than 50 MPa with either strain. This is the first evidence of the existence of an extreme-barophile bacterium of the genus Moritella isolated from the deep-sea environment.
The present randomized, placebo-controlled, double-blind, parallel-groups clinical trial examined the effects of fish oil and multivitamin supplementation on the incorporation of n-3 and n-6 fatty acids into red blood cells. Healthy adult humans (n = 160) were randomized to receive 6 g of fish oil, 6 g of fish oil plus a multivitamin, 3 g of fish oil plus a multivitamin or a placebo daily for 16 weeks. Treatment with 6 g of fish oil, with or without a daily multivitamin, led to higher eicosapentaenoic acid (EPA) composition at endpoint. Docosahexaenoic acid (DHA) composition was unchanged following treatment. The long chain LC n-3 PUFA index was only higher, compared to placebo, in the group receiving the combination of 6 g of fish oil and the multivitamin. Analysis by gender revealed that all treatments increased EPA incorporation in females while, in males, EPA was only significantly increased by the 6 g fish oil multivitamin combination. There was considerable individual variability in the red blood cell incorporation of EPA and DHA at endpoint. Gender contributed to a large proportion of this variability with females generally showing higher LC n-3 PUFA composition at endpoint. In conclusion, the incorporation of LC n-3 PUFA into red blood cells was influenced by dosage, the concurrent intake of vitamin/minerals and gender.
fish oils; multivitamins; n-3; randomized; controlled trial (RCT); fatty acid; diet
This study was conducted to quantitatively determine the fatty acid contents of 20 species of marine fish and four species of shellfish from Straits of Malacca. Most samples contained fairly high amounts of polyunsaturated fatty acids (PUFAs), especially alpha-linolenic acid (ALA, C18:3 n3), eicosapentaenoic acid (EPA, C20:5 n3), and docosahexaenoic acid (DHA, C22:6 n3). Longtail shad, yellowstripe scad, and moonfish contained significantly higher (P < 0.05) amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), respectively. Meanwhile, fringescale sardinella, malabar red snapper, black pomfret, Japanese threadfin bream, giant seaperch, and sixbar grouper showed considerably high content (537.2–944.1 mg/100g wet sample) of desirable omega-3 fatty acids. The polyunsaturated-fatty-acids/saturated-fatty-acids (P/S) ratios for most samples were higher than that of Menhaden oil (P/S = 0.58), a recommended PUFA supplement which may help to lower blood pressure. Yellowstripe scad (highest DHA, ω − 3/ω − 6 = 6.4, P/S = 1.7), moonfish (highest ALA, ω − 3/ω − 6 = 1.9, P/S = 1.0), and longtail shad (highest EPA, ω − 3/ω − 6 = 0.8, P/S = 0.4) were the samples with an outstandingly desirable overall composition of fatty acids. Overall, the marine fish and shellfish from the area contained good composition of fatty acids which offer health benefits and may be used for nutraceutical purposes in the future.
Thraustochytrids, marine protists known to accumulate polyunsaturated fatty acids (PUFAs) in lipid droplets, are considered an alternative to fish oils as a source of PUFAs. The major fatty acids produced in thraustochytrids are palmitic acid (C16:0), n − 6 docosapentaenoic acid (DPA) (C22:5n − 6), and docosahexaenoic acid (DHA) (C22:6n − 3), with eicosapentaenoic acid (EPA) (C20:5n − 3) and arachidonic acid (AA) (C20:4n − 6) as minor constituents. We attempted here to alter the fatty acid composition of thraustochytrids through the expression of a fatty acid Δ5 desaturase gene driven by the thraustochytrid ubiquitin promoter. The gene was functionally expressed in Aurantiochytrium limacinum mh0186, increasing the amount of EPA converted from eicosatetraenoic acid (ETA) (C20:4n − 3) by the Δ5 desaturase. The levels of EPA and AA were also increased by 4.6- and 13.2-fold in the transgenic thraustochytrids compared to levels in the mock transfectants when ETA and dihomo-γ-linolenic acid (DGLA) (C20:3n − 6) were added to the culture at 0.1 mM. Interestingly, the amount of EPA in the transgenic thraustochytrids increased in proportion to the amount of ETA added to the culture up to 0.4 mM. The rates of conversion and accumulation of EPA were much higher in the thraustochytrids than in baker's yeasts when the desaturase gene was expressed with the respective promoters. This report describes for the first time the finding that an increase of EPA could be accomplished by introducing the Δ5 desaturase gene into thraustochytrids and indicates that molecular breeding of thraustochytrids is a promising strategy for generating beneficial PUFAs.
The cardiovascular benefits of marine-derived omega-3 fatty acids are supported by epidemiologic and clinical studies. Both healthy patients and those with confirmed coronary heart disease are advised by the American Heart Association to consume omega-3 fatty acids either through dietary fatty fish or fish oil products. We present two case reports of patients with dyslipidemia who were switched from an omega-3 dietary supplement or a prescription omega-3 drug containing eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) to a new prescription EPA-only drug, icosapent ethyl (IPE). Products containing a combination of EPA and DHA, including dietary supplements and prescription products, are more likely to increase low-density lipoprotein cholesterol (LDL-C) levels compared with pure EPA-only products. The lipid profiles of these two patients were improved with IPE treatment, illustrating the potentially favorable effects of IPE compared with other products containing both EPA and DHA.
omega-3 fatty acids; fish oil; eicosapentaenoic acid; docosahexaenoic acid; lipids; icosapent ethyl
Long chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are considered essential omega-3 fatty acids in human nutrition. In marine microalgae EPA and/or DHA are allegedly involved in the regulation of membrane fluidity and thylakoid membrane functioning. The cellular content of EPA and DHA may therefore be enhanced at low temperature and irradiance conditions. As a result, polar and cold temperate marine microalgal species might potentially be suitable candidates for commercial EPA and DHA production, given their adaptation to low temperature and irradiance habitats.
In the present study we investigated inter- and intraspecific EPA and DHA variability in five polar and (cold) temperate microalgae. Intraspecific EPA and DHA content did not vary significantly in an Antarctic (Chaetoceros brevis) and a temperate (Thalassiosira weissflogii) centric diatom after acclimation to a range of irradiance levels at two temperatures. Interspecific variability was investigated for two Antarctic (Chaetoceros brevis and Pyramimonas sp. (Prasinophyceae)) and three cold-temperate species (Thalassiosira weissflogii, Emiliania huxleyi (Prymnesiophyceae) and Fibrocapsa japonica (Raphidophyceae)) during exponential growth. Interspecific variability was shown to be much more important than intraspecific variability. Highest relative and absolute levels of DHA were measured in the prymnesiophyte E. huxleyi and the prasinophyte Pyramimonas sp., while levels of EPA were high in the raphidophyte F. japonica and the diatoms C. brevis and T. weissflogii. Yet, no significant differences in LC-PUFA content were found between polar and cold-temperate species. Also, EPA and DHA production rates varied strongly between species. Highest EPA production rate (174 μg L-1 day-1) was found in the Antarctic diatom Chaetoceros brevis, while DHA production was highest in the cold-temperate prymnesiophyte Emiliania huxleyi (164 μg L-1 day-1). We show that, following careful species selection, effective mass cultivation of marine microalgae for EPA and DHA production may be possible under low temperature and irradiance conditions.
Eicosapentaenoic acid; Docosahexaenoic acid; Thalassiosira weissflogii; Chaetoceros brevis; Fibrocapsa japonica; Emiliania huxleyi; Pyramimonas sp.
We investigated the fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. One- and two-year-old fish were cultured in floating net cages and sampled randomly for analysis. Moisture, protein, lipid and ash contents were determined by methods of Association of Analytical Chemist (AOAC) International. Fatty acid profile was determined by gas chromatography. Crude protein, fat, moisture and ash contents showed no significant differences between the two age groups. The contents of total polyunsaturated fatty acids and docosahexaenoic acid (DHA) were significantly higher and eicosapentaenoic acid (EPA) content was significantly lower in the two-year-old large yellow croaker than in the one-year-old (P<0.05). No significant differences were observed in the contents of total saturated fatty acids and monounsaturated fatty acids, or the ratio of n-3/n-6 fatty acids among the large yellow croakers of the two age groups. We conclude that large yellow croakers are good food sources of EPA and DHA.
Fatty acid; Large yellow croaker; Age
We investigated the lipid composition of vegetative cells of Stigmatella aurantiaca. Four phospholipids were isolated and identified: phosphatidylethanolamine as the main component, phosphatidylglycerol, lysophosphatidylethanolamine in an exceptionally large amount (17%), and phosphatidylinositol (18 to 25%), rare in procaryotic cells. This composition did not change significantly during growth. The fatty acids of total lipids were found to be rather similar to those of other strains of myxobacteria; the main fatty acids found were unsaturated and branched. We noted a different fatty acid pattern for each phospholipid. The presence of unusual alkyl ether linkages, established by chemical hydrolysis and infrared spectroscopy, was unexpected in these bacteria. Diacyl ester, dialkyl ether, and monoacyl-monoalkyl structures were shown in phosphatidylethanolamine and phosphatidylglycerol. Lysophosphatidylethanolamine was essentially a monoacyl form, whereas phosphatidylinositol was a unique dialkyl ether phospholipid.
Dietary polyunsaturated fatty acids (PUFA), in particular the long chain marine fatty acids docosahexaenoic (DHA) and eicosapentaenoic (EPA), are linked to many health benefits in humans and in animal models. Little is known of the molecular response to DHA and EPA of the small intestine, and the potential contribution of this organ to the beneficial effects of these fatty acids. Here, we assessed gene expression changes induced by DHA and EPA in the wildtype C57BL/6J murine small intestine using whole genome microarrays and functionally characterized the most prominent biological process.
The main biological process affected based on gene expression analysis was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR, and -in a second animal experiment- intestinal fatty acid oxidation measurements confirmed significant gene expression differences and showed in a dose-dependent manner significant changes at biological functional level. Furthermore, no major changes in the expression of lipid metabolism genes were observed in the colon.
We show that marine n-3 fatty acids regulate small intestinal gene expression and increase fatty acid oxidation. Since this organ contributes significantly to whole organism energy use, this effect on the small intestine may well contribute to the beneficial physiological effects of marine PUFAs under conditions that will normally lead to development of obesity, insulin resistance and diabetes.
Although it is believed that fish ω-3 fatty acids may decrease breast cancer risk, epidemiological evidence has been inconclusive. This study examined the association between fish and fish ω-3 fatty acids intake with the risk of breast cancer in a case-control study of Korean women.
We recruited 358 incident breast cancer patients and 360 controls with no history of malignant neoplasm from the National Cancer Center Hospital between July 2007 and April 2008. The study participants were given a 103-item food intake frequency questionnaire to determine their dietary consumption of fish (fatty and lean fish) and ω-3 fatty acids derived from fish (eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)).
Using a multivariate logistic regression model, high intake of fatty fish was associated with a reduced risk for breast cancer in both pre- and postmenopausal women (OR [95% CI] for highest vs. lowest intake quartiles, p for trend: 0.19 [0.08 to 0.45], p < 0.001 for premenopausal women, 0.27 [0.11 to 0.66], p = 0.005 for postmenopausal women). Similarly, reductions in breast cancer risk were observed among postmenopausal subjects who consumed more than 0.101 g of EPA (OR [95% CI]: 0.38 [0.15 to 0.96]) and 0.213 g of DHA (OR [95% CI]: 0.32 [0.13 to 0.82]) from fish per day compared to the reference group who consumed less than 0.014 g of EPA and 0.037 g of DHA per day. Among premenopausal women, there was a significant reduction in breast cancer risk for the highest intake quartiles of ω-3 fatty acids (ORs [95% CI]: 0.46 [0.22 to 0.96]), compared to the reference group who consumed the lowest quartile of intake.
These results suggest that high consumption of fatty fish is associated with a reduced risk for breast cancer, and that the intake of ω-3 fatty acids from fish is inversely associated with postmenopausal breast cancer risk.
Marine polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with improvement in the Metabolic Syndrome (MS). The aim of this study is to evaluate how three fish-oil diets with different eicosapentaenoic acid/docosahexaenoic acid ratios (EPA/DHA ratio) affect the histology of liver, kidney, adipose tissue and aorta in a preliminary morphological study. This work uses an animal model of metabolic syndrome in comparison with healthy animals in order to provide information about the best EPA:DHA ratio to prevent or to improve metabolic syndrome symptoms.
35 Wistar rats, as a control, and 35 spontaneously hypertensive obese rats (SHROB) were fed for 13 weeks with 3 different suplemmentation of fish oil containing EPA and DHA ratios (1:1, 2:1 and 1:2, respectively). All samples were stained with haematoxylin/eosin stain, except aorta samples, which were stained also with Verhoeff and van Gieson’s stain. A histological study was carried out to evaluate changes. These changes were statistically analyzed using SPSS IBM 19 software. The quantitative data were expressed by mean ± SD and were compared among groups and treatments using ANOVA with post-hoc tests for parametric data and the U-Mann–Whitney for non-parametric data. Qualitative data were expressed in frequencies, and compared with contingency tables using χ2 statistics.
EPA:DHA 1:1 treatment tended to improve the density and the wrinkling of elastic layers in SHROB rats. Only Wistar rats fed with EPA:DHA 1:1 treatment did not show mast cells in adipose tissue and has less kidney atrophy. In both strains EPA:DHA 1:1 treatment improved inflammation related parameters in liver and kidney.
EPA:DHA 1:1 treatment was the most beneficial treatment since improved many histological parameters in both groups of rats.
Metabolic syndrome; Omega-3-polyunsaturated fatty acids; EPA/DHA ratio; Histology; SHROB rats; Fish oils
The long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have human health benefits. Alternatives to fish as sources of EPA and DHA are needed. Oil from the micro-algae Nannochloropsis oculata contains a significant amount of EPA conjugated to phospholipids and glycolipids and no DHA. Krill oil contains EPA and DHA conjugated to phospholipids. We compare the appearance of fatty acids in blood plasma of healthy humans after consuming a high fat meal followed by either algal oil or krill oil.
Ten healthy males aged 18-45 years consumed a standard high fat (55 g) breakfast followed by either algal oil (providing 1.5 g EPA and no DHA) or krill oil (providing 1.02 g EPA and 0.54 g DHA). All participants consumed both oils in random order and separated by 7 days. Blood samples were collected before the breakfast and at several time points up to 10 hours after taking the oils. Fatty acid concentrations (μg/ml) in plasma were determined by gas chromatography.
Fatty acids derived mainly from the breakfast appeared rapidly in plasma, peaking about 3 hours after consuming the breakfast, and in a pattern that reflected their content in the breakfast. There were time-dependent increases in the concentrations of both EPA and DHA with both algal oil (P < 0.001 for EPA; P = 0.027 for DHA) and krill oil (P < 0.001 for both EPA and DHA). The concentration of EPA was higher with algal oil than with krill oil at several time points. DHA concentration did not differ between oils at any time point. The maximum concentration of EPA was higher with algal oil (P = 0.010) and both the area under the concentration curve (AUC) and the incremental AUC for EPA were greater with algal oil (P = 0.020 and 0.006). There was no difference between oils in the AUC or the incremental AUC for DHA.
This study in healthy young men given a single dose of oil indicates that the polar-lipid rich oil from the algae Nannochloropis oculata is a good source of EPA in humans.
Omega-3; Eicosapentaenoic acid; Docosahexaenoic acid; Algal oil; Krill oil; Polar lipids; Glycolipids; Phospholipids
The American Heart Association’s Strategic Impact Goal Through 2020 and Beyond recommends ≥ two 3.5-oz fish servings per week (preferably oily fish) partly to increase intake of omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We examined the intake of total fish, fish high in omega-3 fatty acids, α-linolenic acid, EPA, and DHA in U.S. adults (19 + years) using data from the National Health and Nutrition Examination Survey, 2003–2008.
Usual intakes from foods alone and from foods plus dietary supplements were determined using the methods from the National Cancer Institute.
Mean usual intake of total fish and fish high in omega-3 fatty acids was 0.61 ± 0.03 and 0.15 ± 0.03 oz/day, 0.43 and 0.07 respectively. Total fish and fish high in omega-3 fatty acids median intake was 0.43 and 0.07 oz/day, respectively. Intake from foods alone for ALA, EPA and DHA was 1.5 ± 0.01 g/d, 23 ± 7 mg/d and 63 ± 2 mg/d, respectively. ALA, EPA and DHA from food only median intakes were 1.4 g/d, 18 mg/d and 50 mg/d, respectively. Intake of ALA, EPA and DHA from foods and dietary supplements was 1.6 ± 0.04 g/d, 41 ± 4 mg/d and 72 ± 4 mg/d, respectively. While intakes of fish high in omega-3 fatty acids were higher in older adults (0.13 ± 0.01 oz/d for those 19–50 yrs and 0.19 ± 0.02 oz/d for those 51+ year; p < 0.01) and in males as compared to females (0.18 ± 0.02 vs 0.13 ± 0.01 oz/d, respectively; p < 0.05), few consumed recommended levels. Males also had higher (p < 0.05) intake of EPA and DHA from foods and dietary supplements relative to females (44 ± 6 vs 39 ± 4 and 90 ± 7 vs 59 ± 4 mg/d, respectively) and older adults had higher intakes of EPA, but not DHA compared to younger adults (EPA: 34 ± 3 vs 58 ± 9, p < 0.05; DHA: 68 ± 4 vs 81 ± 6, p < 0.05).
As omega-3 fatty acids are deemed important from authoritative bodies, supplementation in addition to food sources may need to be considered to help U.S. adults meet recommendations.
NHANES; Usual intake; Fish; Omega-3 fatty acids; EPA; DHA; Cardiovascular
The long chain omega-3 fatty acids (n-3 fatty acids) that derive from fish (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) are associated with a reduced risk of cardiovascular and other chronic disease. However, studying associations between EPA and DHA intake and disease rigorously requires a valid biomarker of dietary intake, and measuring tissue fatty acid levels directly is expensive and time consuming.
Because the nitrogen stable isotope ratio (15N/14N, expressed as δ15N) is elevated in fish, we investigated whether δ15N can provide a valid, alternative biomarker for EPA and DHA intake.
We examined the relationship between red blood cell (RBC) δ15N and RBC EPA and DHA in a community-based sample of 496 Yup'ik Eskimos with widely varying intake of n-3 fatty acids. We also assessed the correlation between δ15N and EPA and DHA dietary intake, based on a 24-hour dietary recall and a 3-day food record completed by a subset of 221 participants.
RBC δ15N was strongly correlated with RBC EPA and DHA (r = 0.83 and 0.75 respectively). These correlations differed only modestly by sex and age class. RBC δ15N also correlated with dietary EPA and DHA intake (r = 0.47 and 0.46, respectively), and did not differ by sex and age.
These results strongly support the validity of RBC δ15N as a biomarker of EPA and DHA intake. Because analysis of RBC δ15N is rapid and inexpensive, it could facilitate wide scale assessment of EPA and DHA intake for clinical and epidemiological studies.
Increasing demand for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) containing fish oils is putting pressure on fish species and numbers. Fisheries provide fish for human consumption, supplement production and fish feeds and are currently supplying fish at a maximum historical rate, suggesting mass-scale fishing is no longer sustainable. However, the health properties of EPA and DHA long-chain (LC) omega-3 polyunsaturated fatty acids (PUFA) demonstrate the necessity for these oils in our diets. EPA and DHA from fish oils show favourable effects in inflammatory bowel disease, some cancers and cardiovascular complications. The high prevalence of these diseases worldwide indicates the requirement for alternative sources of LC-PUFA. Strategies have included plant-based fish diets, although this may compromise the health benefits associated with fish oils. Alternatively, stearidonic acid, the product of α-linolenic acid desaturation, may act as an EPA-enhancing fatty acid. Additionally, algae oils may be a promising omega-3 PUFA source for the future. Algae are beneficial for multiple industries, offering a source of biodiesel and livestock feeds. However, further research is required to develop efficient and sustainable LC-PUFA production from algae. This paper summarises the recent research for developing prospective substitutes for omega-3 PUFA and the current limitations that are faced.
eicosapentaenoic acid (EPA); docosahexaenoic acid (DHA); omega-3; inflammation; dietary fatty acids; fish oils; stearidonic acid; algae
Epidemiological studies suggest that high fish intake is associated with a decreased risk of colorectal cancer which has been linked to the high content of the n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acids (EPA) and docosahexaenoic acid (DHA) in some fish. The aim of the study was to compare the modulation of gene expression in LT97 colon adenoma cells in response to EPA and DHA treatment. Therefore, we used custom-designed cDNA arrays containing probes for 306 genes related to stress response, apoptosis and carcinogenesis and hybridised them with cDNA from LT97 cells which were treated for 10 or 24 h with 50 μM EPA or DHA. There was a marked influence of n-3 PUFA on the expression of several gene types, such as detoxification, cell cycle control, signaling pathways, apoptosis and inflammation. DHA and EPA generally modulated different sets of genes, although a few common effects were noted. In our approach, we used preneoplastic adenoma cells which are a relevant model for target cells of chemoprevention. If verified with real time PCR, these results identify genes and targets for chemoprevention of colon cancer.
cDNA array; n-3 polyunsaturated fatty acids; Colon cancer; Gene expression