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1.
Lipase-catalyzed incorporation of n−3 PUFA into palm oil 总被引:4,自引:0,他引:4
Two immobilized lipases, IM60 from Rhizomucor miehei and QLM from Alcaligenes sp., were used as biocatalysts for the modification of the FA composition of palm oil by incorporating n−3 PUFA. Acidolysis
and interesterification reactions were conducted with hexane as organic solvent, and the products were analyzed by using GLC.
After a 24-h incubation in hexane, there was an average incorporation of 20.8% EPA and 15.6% DHA into palm oil, respectively,
while the percentages of palmitic and oleic acids in palm oil decreased by 28.8 and 11.8%, respectively. Higher EPA and DHA
incorporation was obtained when EPAX (fish oil concentrate high in n−3 PUFA) was used in the ethyl ester form (interesterification
reaction) than in the free acid form (acidolysis) in the presence of Lipozyme (IM60 lipase. Lipase QLM was found to discriminate
against EPA, and it showed slightly better catalytic activity for DHA in the free acid form than in the ethyl ester form.
Generally, as the mole ratio of the acyl donor to TAG increased, the percentage incorporation of EPA and DHA increased; however,
reactions catalyzed by Lipozyme IM60 did not show increases in the incorporation beyond a TAG/EPAX mole ratio of 3. When limitations
due to mass transfer were not a factor, an increase in the reactant amount also gave an increase in the percentage incorporation
of the n−3 PUFA. Palm oil containing EPA and DHA was successfully produced and may be beneficial in certain food and nutritional
applications. 相似文献
2.
Sufficient availability of both n-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFA) is required for optimal structural
and functional development in infancy. The question has been raised as to whether infant formulae would benefit from enrichment
with 20 and 22 carbon fatty acids. To address this issue, we determined the effect of fish oil and phospholipid (LCPUFA) sources
on the fatty acid composition of brain cortical areas and nonneural tissues of newborn piglets fed artificially for 2 wk.
They were fed sow milk, a control formula, or the formula enriched with n-3 fatty acids from a low-20:5n-3 fish oil added
at a high or a low concentration, or the formula enriched with n-3 and n-6 fatty acids from either egg yolk- or pig brain-phospholipids.
Both the fish oil- and the phospholipid-enriched formula produced significantly higher plasma phospholipid 22:6n-3 concentrations
than did the control formula. The 22:6n-3 levels in the brain, hepatic, and intestinal phospholipids were significantly correlated
with plasma values, whereas cardiac 22:6n-3 content appeared to follow a saturable dose-response. Feeding sow milk resulted
in a much higher 20:4n-6 content in nonneural tissues than did feeding formula. Supplementation with egg phospholipid increased
the 20:4n-6 content in the heart, red blood cells, plasma, and intestine in comparison to the control formula, while pig brain
phospholipids exerted this effect in the heart only. The addition of 4.5% fish oil in the formula was associated with a decline
in 20:4n-6 in the cortex, cerebellum, heart, liver, and plasma phospholipids, whereas using this source at 1.5% limited the
decline to the cerebellum, liver, and plasma. Whatever the dietary treatment, the phosphatidylethanolamine 20:4n-6 level was
10–20% higher in the brain temporal lobe than in the parietal, frontal, and occipital lobes in the temporal lobe by administering
the formula enriched with egg or brain phospholipids.
In conclusion, feeding egg phospholipids to neonatal pigs increased both the 22:6n-3 content in the brain and the 20:4n-6
content in the temporal lobe cortex. This source also increased the 22:6n-3 levels in nonneural tissues with only minor alterations
of 20:4n-6. These data support the notion that infant formulae should be supplemented with both 22:6n-3 and 20:4n-6 rather
than with 22:6n-3 alone. 相似文献
3.
Elvevoll EO Barstad H Breimo ES Brox J Eilertsen KE Lund T Olsen JO Osterud B 《Lipids》2006,41(12):1109-1114
This work was undertaken to study the impact of the source of n−3 FA on their incorporation in serum, on blood lipid composition,
and on cellular activation. A clinical trial comprising 71 volunteers, divided into five groups, was performed. Three groups
were given 400 g smoked salmon (n=14), cooked salmon (n=15), or cooked cod (n=13) per week for 8 wk. A fourth group was given 15 mL/d of cod liver oil (CLO) (n=15), and a fifth group served as control (n=14) without supplementation. The serum content of EPA and DHA before and after intervention revealed a higher rise in EPA
and DHA in the cooked salmon group (129% rise in EPA and 45% rise in DHA) as compared with CLO (106 and 25%, respectively)
despite an intake of EPA and DHA in the CLO group of 3.0 g/d compared with 1.2 g/d in the cooked salmon group. No significant
changes were observed in blood lipids, fibrinogen, fibrinolysis, or lipopolysaccharide (LPS)-induced tissue factor (TF) activity,
tumor necrosis factor-α (TNFα), interleukin-8 (IL-8), leukotriene B4 (LTB4), and thromboxane B2 (TxB2) in whole blood. EPA and DHA were negatively correlated with LPS-induced TNFα, IL-8, LTB4, TxB2, and TF in whole blood. In conclusion, fish consumption is more effective in increasing serum EPA and DHA than supplementing
the diet with fish oil. Since the n−3 FA are predominantly in TAG in fish as well as CLO, it is suggested that the larger
uptake from fish than CLO is due to differences in physiochemical structure of the lipids. 相似文献
4.
Maternal fish oil supplementation in lactation: Effect on visual acuity and n−3 fatty acid content of infant erythrocytes 总被引:5,自引:0,他引:5
Lauritzen L Jørgensen MH Mikkelsen TB Skovgaard lM Straarup EM Olsen SF Høy CE Michaelsen KF 《Lipids》2004,39(3):195-206
Studies on formula-fed infants indicate a beneficial effect of dietary DHA on visual acuity. Cross-sectional studies have
shown an association between breast-milk DHA levels and visual acuity in breast-fed infants. The objective in this study was
to evaluate the biochemical and functional effects of fish oil (FO) supplements in lactating mothers. In this double-blinded
randomized trial, Danish mothers with habitual fish intake below the 50th percentile of the Danish National Birth Cohort were
randomized to microencapsulated FO [1.3 g/d long-chain n−3 FA (n−3 LCPUFA)] or olive oil (OO). The intervention started within
a week after delivery and lasted 4 mon. Mothers with habitual high fish intake and their infants were included as a reference
group. Ninety-seven infants completed the trial (44 OO-group, 53 FO-group) and 47 reference infants were followed up. The
primary outcome measures were: DHA content of milk samples (0, 2, and 4 mon postnatal) and of infant red blood cell (RBC)
membranes (4 mon postnatal), and infant visual acuity (measured by swept visual evoked potential at 2 and 4 mon of age). FO
supplementation gave rise to a threefold increase in the DHA content of the 4-mon milk samples (P<0.001). DHA in infant RBC reflected milk contents (r=0.564, P<0.001) and was increased by almost 50% (P<0.001). Infant visual acuity was not significantly different in the randomized groups but was positively associated at 4
mon with infant RBC-DHA (P=0.004, multiple regression). We concluded that maternal FO supplementation during lactation did not enhance visual acuity
of the infants who completed the intervention. However, the results showed that infants with higher RBC levels of n−3 LCPUFA
had a better visual acuity at 4 mon of age, suggesting that n−3 LCPUFA may influence visual maturation. 相似文献
5.
The aim of this research was to investigate the effect of fish oil supplementation, in the third trimester of pregnancy and
early lactation period of healthy pregnant Danish women. Forty-four pregnant women were randomly allocated to fish oil supplementation
(1.3 g EPA and 0.9 g DHA per day) from week 30 of gestation (FO-group) or to a control regimen (olive oil or no oil; controls).
The FO-group was randomly subdivided into women stopping fish oil supplementation at delivery [FO(pregn)], and women continuing
supplementation for an, additional 30 d [FO(pregn/lact)]. Thirty-six women agreed to collect milk samples at days 4, 16, and
30 postpartum. The FA composition of the milk samples was determined by GLC. At days 4, 16, and 30 in lactation, FO(pregn/lact)
women (n=12) had, respectively 2.3 (P=0.001), 4.1 (P=0.001), and 3.3 (P=0.001) times higher mean contents of LCPUFA(n−3) in their breast milk compared with controls (n=13), and 1.7 (P=0.005), 2.8 (P=0.001), and 2.8 (P=0.001), times higher LCPUFA(n−3) contents, respectively, at these days compared with FO(pregn) women (n=11). The latter group did not differ significantly from controls with regard to LCPUFA(n−3) content in the breast milk. Similar
results were obtained when analyzing separately for effects on the milk content of DHA. Dietary supplementation with 2.7 g
LCPUFA(n−3) per day from week 30 of gestation and onward more than tripled the LCPUFA(n−3) content in early breast milk; supplementation
limited to pregnancy only was much less effective. 相似文献
6.
Recent studies have demonstrated that long-chain n−3 PUFA (LCn-3PUFA) are beneficial in reducing the risk of cardiac arrhythmias.
This study was conducted to determine the extent of incorporation of LCn-3PUFA into human atrium following supplementation
with a fish oil concentrate high in LCn-3PUFA. Volunteers preparing for coronary bypass surgery were randomized either to
the treatment group (n=8), receiving 6 g/d of fish oil concentrate (4.4 g of LCn-3PUFA), or the placebo group (n=9), receiving 6 g/d of olive oil for a minimum period of 6 wk. Blood samples were collected prior to commencement of treatment,
and preoperatively before bypass surgery. Atrial biopsies were obtained during surgery. The plasma and atrium samples were
analyzed by GC following trans-methylation to determine FA profile. Post-supplementation, the treatment group had significantly
higher plasma levels of 20∶5n−3, 22∶5n−3, and 22∶6n−3 than the placebo group. Analysis of the atrium total lipids revealed
a significant increase in the proportion of 20∶5n−3 following fish oil supplementation. There was no significant difference
in the concentration of 22∶5n−3 and 22∶6n−3 in the atrium total lipids; however, an upward trend was observed in subjects
receiving fish oil supplementation. In the phospholipid fraction of the atrium, both 20∶5n−3 and 22∶6n−3 increased, whereas
20∶4n−6 levels decreased. This study demonstrates for the first time that short-term supplementation with fish oil concentrate
results in significant incorporation of LNc-3PUFA with a concomitant depletion of the eicosanoid substrate (20∶4n−6) in the
human atrium. 相似文献
7.
We evaluated the utilization of α-linolenic acid (18∶3n−3) in growing rats consuming a diet deficient in n−6 PUFA. After 90
d, whole-body 18∶3n−3 accumulation was 55% lower, total n−3 PUFA accumulation was 21% lower, and 18∶3n−3 disappearance was
14% higher in n−6 PUFA-deficient rats. Part of the reduction of whole-body 18∶3n−3 in n−6 PUFA-deficient rats was due to the
25% increase in net conversion of 18∶3n−3 to long-chain n−3 PUFA. Despite adequate 18∶3n−3 intake, n−6 PUFA deficiency decreased
the accumulation of 18∶3n−3 and total n−3 PUFA. 相似文献
8.
Menhanden oil was purified by column chromatography to remove minor components. The effect of α-tocopherol (α TOH) (50–500
ppm) on the rate of formation of hydroperoxides in the original menahaden oil and in the purified menhaden triacylglycerol
(TAG) fraction was studied at 30°C in the dark. An increase in the initial rate of formation of hydroper-oxides was observed
at αTOH concentrations above 100 ppm in both substrates. The original menhaden oil oxidized more rapidly than the purified
menhaden, TAG at all antioxidant levels tested, and the presence of minor components in the menhaden oil was found to contribute
only to a limited extent to the peroxidizing effect of αTOH. The αTOH did not display any prooxidant activity at either of
the concentrations tested when the control oil was the purified menhaden TAG. Addition of ascorbyl palmitate eliminated the
initial peroxidizing effect of αTOH, and this emphasizes the participation of the α-toco-pheroxyl radical in the reactions
causing an accumulation of hydroperoxides at high concentrations of αTOH.
Presented in part at the Annual Meeting of the American Oil Chemists’ Society in San Diego, April 25–28, 2000. 相似文献
9.
There are conflicting findings over the bioavailability of long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) from krill oil (KO) compared with fish oil (FO) in short- and long-term studies. The aim of this study was to compare the effects of KO versus FO on the enrichment of molecular species of plasma phospholipids in young women following a 30-day consumption of the n-3 oils. Eleven healthy women aged 18–45 years consumed seven capsules of KO per day (containing a total of 1.27 g n-3 PUFA) or five capsules of FO per day (total of 1.44 g n-3 PUFA) for 30 days in a randomized crossover study, separated by at least a 30-day washout period. Fasting blood samples were collected at day zero (baseline), day 15 and day 30 and analyzed by HPLC-MS/MS for molecular species of phospholipids. Supplementation increased n-3 PUFA in main phospholipids classes in both groups. After 30 days of supplementation, 35 out of 70 molecular species containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPAn-3) had a significantly greater concentration in KO group compared with the FO treated group. The majority (89%) of the differentiated molecular species were choline and ethanolamine ether-phospholipids. These data reveal that analysis of plasma phospholipids following 30 days of consumption of KO (a marine oil rich in phospholipids, including ether phospholipids) resulted in an enrichment of n-3 PUFA in molecular species of ether-phospholipids compared with FO (a triacylglycerol-rich marine oil). 相似文献
10.
The influence of grass-only diets either from rye-grass-dominated lowland pastures (400 m above sea level) or botanically
diverse alpine pastures (2000 m) on the FA profile of milk was investigated using three groups of six Brown Swiss cows each.
Two groups were fed grass-only on pasture (P) or freshly harvested in barn (B), both for two experimental periods in the lowlands
and, consecutively, two periods on the alp. Group C served as the control, receiving a silage-concentrate diet and permanently
staying in the lowlands. Effects of vegetation stage or pasture vs. barn feeding on milk fat composition were negligible.
Compared with the control, α-linoleic acid (18∶3n−3) consumption was elevated in groups P and B (79%, P<0.001) during the lowland periods but decreased on the alp to the level of C owing to feed intake depression and lower 18∶3n−3
concentration in the alpine forage. Average 18∶3n−3 contents of milk fat were higher in groups, P and B than in C by 33% (P<0.01) at low and by 96% (P<0.001) at high altitude, indicating that 18∶3n−3 levels in milk were to some extent independent of 18∶3n−3 consumption. The
cis-9,trans-11 CLA content in milk of grass-fed cows was higher compared with C but lower for the alpine vs. lowland periods whereas
the trans-11, cis-13 isomer further increased with altitude. Long-chain n−3 FA and phytanic acid increased while arachidonic acid decreased
with grass-only feeding, but none of them responded to altitude. Grass-only feeding increased milk α-tocopherol concentration
by 86 and 134% at low and high altitude (P<0.001), respectively. Changes in the ruminal ecosystem due to energy shortage or specific secondary plant metabolites are
discussed as possible causes for the high 18∶3n−3 concentrations in alpine milk. 相似文献
11.
Flaxseed, echium, and canola oils contain α-linolenic acid (18∶3n−3, ALA) in a range of concentrations. To examine their effect
on elevating cardiac levels of long-chain n−3 FA, diets based on these n−3-containing vegetable oils were fed to rats for
4 wk. Sunflower oil, which contains little ALA, was a comparator. Despite canola oil having the lowest ALA content of the
three n−3-containing vegetable oils, it was the most potent for elevating DHA (22∶6n−3) levels in rat hearts and plasma. However,
the relative potencies of the dietary oils for elevation of EPA (20∶5n−3) in heart and plasma followed the same rank order
as their ALA content, i.e., flaxseed>echium>canola>sunflower oil. This paradox may be explained by lower ALA intake leading
to decreased competition for Δ6 desaturase activity between ALA and the 24∶5n−3 FA precursor to DHA formation. 相似文献
12.
Effect of dietary n−6 and n−3 polyunsaturated fatty acids on peroxidizability of lipoproteins in steers 总被引:3,自引:0,他引:3
The susceptibility of major plasma lipoproteins to lipoperoxidation was studied in relation to the FA composition of their
neutral and polar lipids in steers given PUFA-rich diets. Two trials used, respectively, 18 (“sunflower” experiment, S) or
24 (“linseed” experiment, L) crossbred Salers x Charolais steers. Each involved three dietary treatments over a 70-d period:
a control diet (CS or CL diets) consisting of hay and concentrate, or the same diet supplemented with oilseeds (4% diet dry
matter) fed either as seeds (SS or LS diets) or continuously infused into the duodenum (ISO or ILO diets). Compared with control
diets, ISO and ILO treatments tended to decrease the resistance time of LDL and HDL classes to peroxidation, mainly owing
to the enrichment of their polar and neutral lipids with PUFA. With diets SS and LS, sensitivity of major lipoprotein classes
(LDL, light and heavy HDL) was not affected because ruminal hydrogenation of dietary PUFA decreased their incorporation into
lipoparticles. ISO and ILO treatments induced a more important production of conjugated dienes and hydroperoxides generated
by peroxidation in the three lipoprotein classes due to the higher amounts of PUFA esterified in lipids of the core and the
hydrophilic envelope of particles. The production of malondialdehyde (MDA) increased in steers fed linseed supplements, indicating
that MDA production did not occur with linoleic acid provided by sunflower oil supplements. Thus, plasma peroxidation of PUFA
generates toxic products in steers fed diets supplemented with PUFA and can be deleterious for the health of the animal during
long-term treatment. 相似文献
13.
The test presented permits detection of as little as 5% of tea seed oil in 95% olive oil. Cottonseed oil or sesame oil interfere with the test. The interference of sesame oil can be overcome to a great extent through the modification recommended. Rancid olive oil interferes with the test. Heated oils may interfere. However, such oils are not likely to be present in olive oil sold for food purposes. 相似文献
14.
Dietary intake of fish vs. formulations leads to higher plasma concentrations of n−3 fatty acids 总被引:1,自引:0,他引:1
The n−3 fatty acids from fish appear to be more efficacious, in terms of cardioprotection, than equivalent amounts provided
as capsules. Volunteers were given, for 6 wk, either 100 g/d of salmon, providing 383 mg of EPA and 544 mg of DHA, esterified
in glycerol lipids, or 1 or 3 capsules of fish oil/d, providing 150 mg of EPA and 106 mg of DHA or 450 mg of EPA and 318 mg
of DHA, as ethyl esters. Further, we reevaluated data from a previous study carried out with the same design, i.e., with 3
and 6 capsules/d of fish oil, providing 1290 and 2580 mg/d EPA and 960 and 1920 mg/d DHA. Marked increments in plasma EPA
and DHA concentrations (μg/mg total lipid) and percentages of total fatty acids were recorded at the end of treatment with
either n−3 capsules or salmon. Net increments of EPA and DHA in plasma lipids were linearly and significantly correlated with
the dose after capsule administration. Further, increments in plasma EPA and DHA concentration after salmon intake were significantly
higher than after administration of capsules. The same increments would be obtained with at least two- and ninefold higher
doses of EPA and DHA, respectively, if administered with capsules rather than salmon. We provide experimental evidence that
n−3 fatty acids from fish are more effectively incorporated into plasma lipids than when administered as capsules and that
increments in plasma concentrations of EPA and DHA given as capsules are linearly correlated with their intakes. 相似文献
15.
n−3 fatty acid enrichment of edible tissue of poultry: A review 总被引:1,自引:0,他引:1
There is clear evidence of the nutritional benefits of consuming long-chain n−3 PUFA, which are found predominantly in oily
fish. However, oily fish consumption, particularly in the United Kingdom, is declining, as is the consumption of all meats
with the exception of poultry, which has increased in consumption by 73% in the last 30 yr. This pattern, if less marked,
is reflected throughout Europe, and therefore one means of increasing long-chain n−3 PUFA consumption would be to increase
the long-chain n−3 PUFA content in the edible tissues of poultry. This review considers the feasibility of doing this, concentrating
particularly on chickens and turkeys. It begins by summarizing the benefits to human health of consuming greater quantities
of n−3 FA and the sources of n−3 PUFA in the human diet. The literature on altering the FA composition of poultry meat is
then reviewed, and the factors affecting the incorporation of n−3 PUFA into edible tissues of poultry are investigated. The
concentration of α-linolenic acid (ALA) in the edible tissues of poultry is readily increased by increasing the concentration
of ALA in the birds' diet (particularly meat with skin, and dark meat to a greater extent than white meat). The concentration
of EPA in both white and dark meat is also increased when the birds' diet is supplemented with EPA, although supplementing
the diet with the precursor (ALA) does not result in a noticeable increase in EPA content in the edible tissues. Although
supplementing the birds' diets with relatively high concentrations of DHA does result in an increased concentration of DHA
in the tissues, the relationship between dietary and tissue concentrations of DHA is much weaker than that observed with ALA
and EPA. The impact that altering the FA composition of edible poultry tissue may have on the organoleptic and storage qualities
of poultry products is also considered. 相似文献
16.
The intake of individual n−6 and n−3 PUFA has been estimated in 4,884 adult subjects (2,099 men and 2,785 women), volunteers
from the French SU.VI.MAX intervention trial. The food intakes of each subject were recorded in at least ten 24-h record questionnaires
completed over a period of 2.5 yr, allowing the estimation of the daily intake of energy; total fat; and linoleic, α-linolenic,
arachidonic, eicosapentaenoic (EPA), n−3 docosapentaenoic (DPA), and docosahexaenoic (DHA) acids. The mean total fat intake
corresponded to 94.1 g/d (36.3% of total energy intake) in men and 73.4 g/d (38.1% of energy) in women. The intake of linoleic
acid was 10.6 g/d in men and 8.1 g/d in women, representing 4.2% of energy intake; that of α-linolenic acid was 0.94 g/d in
men and 0.74 g/d in women, representing 0.37% of energy intake, with a mean linoleic/α-linolenic acid ratio of 11.3. The mean
intakes of long-chain PUFA were: arachidonic acid, 204 mg/d in men and 152 mg/d in women; EPA, 150 mg/d in men and 118 mg/d
in women; DPA, 75 mg/d in men and 56 mg/d in women; DHA, 273 mg/d in men and 226 mg/d in women; long-chain n−3 PUFA, 497 mg/d
in men and 400 mg/d in women. Ninety-five percent of the sample consumed less than 0.5% of energy as α-linolenic acid, which
is well below the current French recommendation for adults (0.8% of energy). In contrast, the mean intakes of long-chain n−6
and n−3 PUFA appear fairly high and fit the current French recommendations (total long-chain PUFA: 500 mg/d in men and 400
mg/d in women; DHA: 120 mg/d in men and 100 mg/d in women). The intakes of α-linolenic acid, and to a lesser extent of linoleic
acid, were highly correlated with that of lipids. Whereas the main source of linoleic acid was vegetable oils, all food types
contributed to α-linolenic acid intake, the main ones being animal products (meat, poultry, and dairy products). The main
source of EPA and DHA (and of total long-chain n−3 PUFA) was fish and seafood, but the major source of DPA was meat, poultry,
and eggs. Fish and seafood consumption showed very large interindividual variations, the low consumers being at risk of insufficient
n−3 PUFA intake. 相似文献
17.
Martin Kontrík František Šimko Dagmar Galusková Martin Nosko Valéria Bizovská Michal Hičák Dušan Galusek Aydar Rakhmatullin Michal Korenko 《Journal of the European Ceramic Society》2018,38(4):1143-1151
TiB2 samples were exposed to molten KF?AlF3?Al2O3: 54.8-42.1-3.1 mol% salt, at 680 °C for 50, 100 and 200 h. The corroded samples of TiB2 were investigated by SEM-EDX, EBSD, XRD, FT-IR and MAS NMR analysis. Corrosion was noted to occur predominantly as pitting attacks on the surface of the investigated materials. An inter-crystal and trans-crystal corrosion were identified on the cross-sections of the samples. A perturbation of TiB bonds was detected (SEM-EDX and NMR analysis), at which a formation of orthorhombic TiO2 was also identified (EBSD analysis). The subsequent NMR, XRD and FT-IR analysis of the behaviour of TiB2 powder in molten KF?AlF3?Al2O3 supports the statement about the formation of orthorhombic TiO2 and mullite type of aluminium borates. 相似文献
18.
Fatty acids,the immune response,and autoimmunity: A question of n−6 essentiality and the balance between n−6 and n−3 总被引:8,自引:0,他引:8
Harbige LS 《Lipids》2003,38(4):323-341
The essentiality of n−6 polyunsaturated fatty acids (PUFA) is described in relation to a thymus/thymocyte accretion of arachidonic
acid (20∶4n−6, AA) in early development, and the high requirement of lymphoid and other cells of the immune system for AA
and linoleic acid (18∶2n−6, LA) for membrane phospholipids. Low n−6 PUFA intakes enhance whereas high intakes decrease certain
immune functions. Evidence from in vitro and in vivo studies for a role of AA metabolites in immune cell development and functions shows that they can limit or regulate cellular
immune reactions and can induce deviation toward a T helper (Th)2-like immune response. In contrast to the effects of the
oxidative metabolites of AA, the longer-chain n−6 PUFA produced by γ-linolenic acid (18∶3n−6, GLA) feeding decreases the Th2
cytokine and immunoglobulin (Ig)G1 antibody response. The n−6 PUFA, GLA, dihomo-γ-linolenic acid (20∶3n−6, DHLA) and AA, and
certain oxidative metabolites of AA can also induce T-regulatory cell activity, e.g., transforming growth factor (IGF)-β-producing
T cells; GLA feeding studies also demonstrate reduced proinflammatory interleukin (IL)-1 and tumor necrosis factor (TNF)-α
production. Low intakes of long-chain n−3 fatty acids (fish oils) enhance certain immune functions, whereas high intakes are
inhibitory on a wide range of functions, e.g., antigen presentation, adhesion molecule expression, Th1 and th2 responses,
proinflammatory cytokine and eicosanoid production, and they induce lymphocyte apoptosis. Vitamin E has a demonstrable critical
role in long-chain n−3 PUFA interactions with immune functions, often reversing the effects of fish oil. The effect of dietary
fatty acids on animal autoimmune disease models depends on both the autoimmune model and the amount and type of fatty acids
fed. Diets low in fat, essential fatty acid deficient (EFAD), or high in long-chain n−3 PUFA from fish oils increase survival
and reduce disease severity in spontaneous autoantibody-mediated disease, whereas high-fat LA-rich diets increase disease
severity. In experimentally induced T cell-mediated autoimmune disease, EFAD diets or diets supplemented with long-chain n−3
PUFA augment disease, whereas n−6 PUFA prevent or reduce the severity. In contrast, in both T cell- and antibody-mediated
autoimmune disease, the desaturated/elongated metabolites of LA are protective. PUFA of both the n−6 and n−3 families are
clinically useful in human autoimmune-inflammatory disorders, but the precise mechanisms by which these fatty acids exert
their clinical effects are not well understood. Finally, the view that all n−6 PUFA are proinflammatory requires revision,
in part, and their essential regulatory and developmental role in the immune system warrants appreciation. 相似文献
19.
Tomoji Igarashi Marit Aursand Yoshiaki Hirata Ingrid S. Gribbestad Shun Wada Michio Nonaka 《Journal of the American Oil Chemists' Society》2000,77(7):737-748
By using a 500 MHz proton nuclear magnetic resonance (1H NMR) spectrometer we have developed a quantitative method for determining the contents of docosahexaenoic acid (DHA) in fish oils (mg/g), the molar proportions (mol%) of DHA to all other fatty acids composing the fish oils, and the molar proportions of total n-3 fatty acids to all other non-n-3 fatty acids in the fish oils. After examining the suitability of ethylene glycol dimethyl ether (EGDM), methanol, and 1,4-dioxane as internal standards, experimental conditions were optimized by mainly using EGDM as an internal standard. By setting the pulse repetition time at 30 s, five times longer than the longest T 1 of the 1H NMR signals of fish oils, good reproductibility of data and analytical times less than 10 min were achieved. The use of the internal standard also allowed us to quantify DHA on a weight basis (mg/g). Verification of the method was carried out in an interlaboratory study between Japan and Norway on bonito, tuna, and salmon oils. The relative errors in the 1H NMR data between Japan and Norway were 0.57–5.29% for quantification of DHA, 0.7–2.09% for the molar proportion of DHA, and 0.1–1.41% for the molar proportion of total n-3 fatty acids. Good agreement was observed between the 1H NMR data and those obtained by gas chromatography (GC). The sample preparation before 1H NMR measurements required only two steps: sample weighing and preparation of an internal standard solution. Based on the high reproducibility, simplicity of the procedure, and clarity of principle, the proposed 1H NMR method was judged to be a promising alternative to the GC method in quantification of DHA and n-3 fatty acids in fish oils. 相似文献
20.
Artificially reared infant rats were used to determine the effects of long-chain polyunsaturated fatty acid (LCP-UFA) supplementation on blood and tissue concentrations of arachidonic acid (AA) and docosahexaenoic acid (DHA). Beginning at 7 d of age, infant rats were fed for 10 d with rat milk formulas supplemented with AA at 0,0.5 and 1.0%, or supplemented with DHA at 0,0.5 and 1.0% of total fatty acid. The supplementation of AA increased accretion of the fatty acid in tissue and blood phospholipids with a maximum increase of 9% in brain, 15% in liver, 25% in erythrocytes, and 43% in plasma above the values of unsupplemented infant rats. Rat milk formula containing 1.0% of AA had no added benefits over that containing 0.5% of AA. The supplementation of DHA increased phospholipid DHA by a maximum of 24% in brain, 87% in liver, 54% in erythrocytes, and 360% in plasma above the unsupplemented control. The increase in tissue and blood DHA was concentration-dependent on formula fatty acid. Brain phosphatidylcholine and phosphatidylethanolamine were similarly enriched with AA and DHA by supplementation of the corresponding fatty acids. In general the observed increase of AA was accompanied by a decrease in 16:0, 18:1n−9, and/or 18:2n−6, whereas the increased DHA was associated with a reduction of 18:1n−9, 18:2n−6, and/or 20:4n−6. Clearly, infant rats were more responsive to DHA than AA supplementation, suggesting a great potential of dietary manipulation to alter tissue DHA concentrations. However, the supplementation of DHA significantly decreased tissue and blood AA/DHA ratios (wt%/wt%), whereas there was little or no change in the ratio by AA supplementation. Although the physiological implications of the levels of AA and DHA, and AA/DHA ratios achieved under the present experimental conditions are not readily known, the findings suggest that artificial rearing could provide a suitable model to investigate LCPUFA requirements using various sources of AA and DHA in rats. 相似文献