Adherence to a Mediterranean diet and plasma fatty acids: data from the Bordeaux sample of the Three-City study

Higher adherence to a Mediterranean diet (MeDi) and n-3 PUFA may both contribute to decreased dementia risk, but the association between MeDi adherence and lipid status is unclear. The aim of the present study was to analyse the relationship between plasma fatty acids and MeDi adherence in French elderly community dwellers. The study population (mean age 75·9 years) consisted of 1050 subjects from Bordeaux (France) included in the Three-City cohort. Adherence to the MeDi (scored as 0-9) was computed from a FFQ and 24?h recall. The proportion of each plasma fatty acid was determined. Cross-sectional analysis of the association between plasma fatty acids and MeDi adherence was performed by multi-linear regression. After adjusting for age, sex, energy intake, physical activity, smoking status, BMI, plasma TAG and apoE-?4 genotype, plasma palmitoleic acid was significantly inversely associated with MeDi adherence, whereas plasma DHA, the EPA+DHA index and total n-3 PUFA were positively associated with MeDi adherence. The n-6:n-3 PUFA, arachidonic acid (AA):EPA, AA:DHA and AA:(EPA+DHA) ratios were significantly inversely associated with MeDi adherence. Plasma EPA was positively associated with MeDi adherence only in apoE-?4 non-carriers. There was no association between MeDi adherence and SFA and total MUFA. The present results suggest that the protective effect of the MeDi on cognitive functions might be mediated by higher plasma DHA and lower n-6:n-3 PUFA ratios.     

Seasonal Variations in Fatty Acid Composition and the N-6/N-3 Fatty Acid Ratio of Pikeperch (Sander LUCIOPERCA) Muscle Lipids

Total lipid, fatty acid composition and the N-6/N-3 fatty acid ratios of muscle of pikeperch (Sander lucioperca) was determined once every two months. The ratio of unsaturated fatty acids (UFA) was higher than half of the total fatty acid content, and the monounsaturated fatty acid (MUFA) was higher than the polyunsaturated fatty acid (PUFA) ratio. The n-3 fatty acids were present in excess of the n-6 fatty acids. Eicosapentaenoic (EPA), docosahexaenoic (DHA), and arachidonic (AA) acids were the most abundant PUFA. The fatty acid composition and n-6/n-3 fatty acids ratio in the muscle of pikeperch are significantly influenced by spawning and the season. Relative proportions of PUFA (especially n-3 fatty acids) diminished significantly with the maturation of gonads. The ratio of n-6/n-3 fatty acids was less than one except during the reproduction period. This result suggests that meat quality of pikeperch is very good except during the spawning period with respect to the n-6/n-3 fatty acids ratio.     

Reduction in n-3 PUFA levels and EPA/AA ratio in serum after desert travels in China

OBJECTIVES: The effects of 3 months of desert travel in China on serum fatty acids and tocopherol were studied. METHODS: In project staff members (6 males, 3 females, aged 19-27 years), serum levels of fatty acids and alpha-tocopherol were analyzed before and after travel by gas liquid chromatography and high-performance liquid chromatography, respectively. RESULTS: Comparison of the levels before and after the trip showed no differences in serum total cholesterol, triglycerides, total protein or alpha-tocopherol. There were no changes in the levels of total fatty acids, while the percentage of polyunsaturated fatty acids increased (p < 0.05). Levels of n-3 PUFA lowered from 166 micrograms/ml to 103 micrograms/ml, and those of n-6 PUFA had increased from 988 micrograms/ml to 1140 micrograms/ml after the trip (p < 0.01 and p < 0.001, respectively). No change was observed in the serum levels of alpha-linolenic acid (C18:3n-3), but lowering of the levels of eicosapentaenoic acid (EPA, C20:5n-3) from 41.4 micrograms/ml to 16.3 micrograms/ml and docosahexaenoic acid (DHA, C22:6n-3) from 107.8 micrograms/ml to 71.7 micrograms/ml was found after the trip (p < 0.05 and p < 0.01, respectively). Serum levels of linoleic acid (LA, C18:2n-6) increased from 832 micrograms/ml to 598 micrograms/ml (p < 0.001), and arachidonic acid (AA, C20:4n-6) tended to increase. The ratios of n-3/n-6 PUFA and EPA/AA decreased from 0.171 to 0.091 and from 0.258 to 0.096 after the trip, respectively (p < 0.01 for both). CONCLUSIONS: Our findings indicated that 3 months of desert travel increased the serum levels of n-6 PUFA and LA and reduced the serum levels of n-3 PUFA and EPA and the ratios of n-3/n-6 PUFA and EPA/AA, possibly due to a relative essential fatty acid deficiency.     

不同水产品消费地区孕妇脂肪酸摄入量调查

目的分析我国不同水产品消费地区孕妇脂肪酸摄入状况。方法应用食物频率法分别在淡水产品消费量较高的江苏省句容市、海产品消费量较高的山东省即墨市以及水产品消费量很低的河南省辉县市,对180名22~35岁孕妇进行妊娠中、晚期膳食调查,分析脂肪酸摄入状况。结果句容、即墨、辉县孕妇膳食中饱和脂肪酸(SFA),单不饱和脂肪酸(MUFA),多不饱和脂肪酸(PUFA)的比例分别为1:2.50:1.05、1:1.44:1.31、1:1.48:1.24。n-6PUFA/n-3PUFA分别为5.51、17.62、13.85。辉县孕妇膳食中SFA和n-6PUFA摄入量最高;句容孕妇膳食中MUFA和n-3PUFA摄入量最高;即墨孕妇膳食中二十碳五烯酸(EPA,20:5n-3)和二十二碳六烯酸(DHA,22:6n-3)摄入量最高。句容和辉县孕妇膳食中的花生四烯酸(AA,20:4n-6)摄入量均高于即墨。三地孕妇膳食中EPA和DHA均主要来自水产品;AA主要来自畜禽肉类和蛋类;亚麻酸(ALA,18:3n-3)和亚油酸(LA,18:2n-6)主要来自食用油、畜禽肉类、坚果和主食及糕点类。结论三地区SFA、MUFA、PUFA的摄入比例合理。即墨、辉县孕妇膳食中n-6/n-3PUFA比例偏高;即墨市孕妇膳食中DHA和EPA摄入量高于其它两地,但仍明显低于推荐量。建议增加孕妇膳食n-3PUFA,特别是DHA和EPA的摄入量。     

Inhibition of tumour necrosis factor-alpha and interleukin 6 production by mononuclear cells following dietary fish-oil supplementation in healthy men and response to antioxidant co-supplementation

Increased dietary consumption of the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (20 : 5n-3; EPA) and docosahexaenoic acid (22 : 6n-6; DHA) is associated with their incorporation into circulating phospholipid and increased production of lipid peroxide metabolites. The relationship between peripheral blood mononuclear cell (PBMC) function, n-3 PUFA intake and antioxidant co-supplementation is poorly defined. We therefore investigated tumour necrosis factor (TNF)-alpha and interleukin (IL) 6 production by PBMC and phospholipid fatty acid composition in plasma and erythrocytes of healthy male subjects (n 16) receiving supplemental intakes of 0.3, 1.0 and 2.0 g EPA+DHA/d, as consecutive 4-week courses. All subjects were randomised in a double-blind manner to receive a concurrent antioxidant supplement (200 microg Se, 3 mg Mn, 30 mg D-alpha-tocopheryl succinate, 90 mg ascorbic acid, 450 microg vitamin A (beta-carotene and retinol)) or placebo. There was a positive dose-dependent relationship between dietary n-3 PUFA intake and EPA and DHA incorporation into plasma phosphatidylcholine and erythrocyte phosphatidylethanolamine, with a tendency towards a plateau at higher levels of intake. Production of TNF-alpha and IL-6 by PBMC decreased with increasing n-3 PUFA intake but tended towards a 'U-shaped' dose response. Both responses appeared to be augmented by antioxidant co-supplementation at intermediate supplementary n-3 PUFA intakes. Thus, increased dietary n-3 PUFA consumption resulted in defined but contrasting patterns of modulation of phospholipid fatty acid composition and PBMC function, which were further influenced by antioxidant intake.     

Maternal Factors Associated with Levels of Fatty Acids,Specifically n-3 PUFA during Pregnancy: ECLIPSES Study

An optimal fatty acid (FA) profile during pregnancy, especially docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), is essential for the health of the mother and child. Our aim was to identify the socioeconomic and maternal lifestyle factors associated with serum FA concentration in pregnant women. A longitudinal study was conducted on 479 pregnant women, who were assessed during the first (T1) and third (T3) trimesters of pregnancy. Data on maternal characteristics, food consumption, and lifestyle were collected. Serum FA concentrations were analysed by a gas chromatography–mass spectrometry combination. The multiple linear regression showed that high educational level and older age were significantly associated with higher EPA and DHA concentrations and lower values of n-6/n-3 and arachidonic acid (AA)/EPA in T1 and/or T3. Regarding diet—fish and seafood consumption increased EPA concentration and reduced n-6/n-3 and AA/EPA values in both trimesters, whereas its consumption increased DHA concentration only in T1. Smoking was associated with lower DHA concentration in T1 and higher values of n-6/n-3 ratio in both trimester. Overweight and obesity were associated with higher values of n-6/n-3 ratio and AA/EPA ratio in T1. A statistically non-significant association was observed with saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). In conclusion, high educational levels, older age, fish, seafood consumption, and/or non-smoking, are factors that influence better omega-3 polyunsaturated fatty acid (n-3 PUFA) profile in both trimesters of pregnancy. Further research is needed to go in-depth into these findings and their health consequences.     

Maternal fat intake during pregnancy and wheeze and eczema in Japanese infants: the Kyushu Okinawa Maternal and Child Health Study

PurposeThis cohort study examined the relationship between maternal intake of individual fatty acids, meat, and fish during pregnancy and the risk of wheeze and eczema in children aged 23–29 months because epidemiologic evidence on this topic is inconclusive.MethodsSubjects were 1354 Japanese mother-child pairs. Data on maternal intake during pregnancy were assessed with a validated diet history questionnaire. Data on symptoms of wheeze and eczema were based on criteria of the International Study of Asthma and Allergies in Childhood.ResultsSignificant inverse exposure-response relationships were observed between maternal intake of eicosapentaenoic acid (EPA) and EPA plus docosahexaenoic acid (DHA) during pregnancy and infantile wheeze although the adjusted odds ratios between extreme quartiles fell just short of the significance level. No such inverse relationships were detected for infantile eczema. Maternal intake of total fat, saturated fatty acids, monounsaturated fatty acids, total n-3 polyunsaturated fatty acids (PUFA), α-linolenic acid, DHA, total n-6 PUFA, linoleic acid, arachidonic acid, cholesterol, fish, and meat and the ratio of n-3 to n-6 PUFA consumption were not significantly related to infantile wheeze or eczema.ConclusionsHigher maternal intake of EPA and EPA plus DHA during pregnancy may reduce the risk of infantile wheeze.     

代谢综合征患者血清三酰甘油多不饱和脂肪酸谱与内脏脂肪的关系

目的 探讨血清三酰甘油中的n-6与n-3必需多不饱和脂肪酸（PUFA）各组分及其比例与代谢综合征患者核磁共振测量的腹腔内脏脂肪面积（MRI-IAF）的关系.方法 比较在体检中新发现的代谢综合征和健康人群的代谢和体脂指标的差异,探讨代谢综合征患者血清三酰甘油脂肪酸谱各组分与MRI-IAF等体脂参数的相关性,并且以相关的血清脂肪酸谱组分为被筛选变量,逐步回归分析以上变量对MRI-IAF、腰围和体质指数（BMI）的影响.结果 代谢综合征组的各项体脂及代谢指标均较对照组差,其中MRI-IAF差距较大[（108.3±13.3）cm2 vs.（63.0±7.1）cm2,t=18.28,P＜0.05）],代谢综合征组血清三酰甘油的n-6/n-3 PUFA比值高于对照组（10.1±3.3vs.7.2±2.1,t=8.564,P＜0.05）,而C18∶3 n-3[（1.4±0.4）％vs.（1.7±0.6）％,t=-3.295]、C20∶5 n-3[（0.2±0.2）％vs.（0.6±0.6）％,t=-3.611]、C22∶6n-3[（0.9±0.5）％vs.（1.2±0.6）％,t=-2.920]及n-3PUFA低于对照组[（2.5±0.6）％vs.（3.7±1.2）％,t=-7.034]（P均＜0.05）,所有n-6 PUFA及C22∶5 n-3的差异无统计学意义;n-6/n-3 PUFA、n-3 PUFA、二十二碳六烯酸和二十碳五烯酸均与MRI-IAF （r=-0.377～0.565,P=0.024）相关,n-6/n-3 PUFA还与腰围（r=0.400,P=0.016）和BMI相关（r=0.357,P=0.033）,而n-6 PUFA与各体脂参数不相关;逐步回归分析提示n-6/n-3PUFA比值与MRI-IAF、腰围、BMI的相关性较强（校正的R2=0.102～0.299,P=0.033）.结论 血清三酰甘油n-6/n-3 PUFA比值和n-3 PUFA与代谢综合征患者MRI-IAF等体脂参数相关,补充膳食n-3 PUFA的同时可能还需要考虑避免n-6 PUFA的过量摄入.     

Long-chain n-3 polyunsaturated fatty acid dietary recommendations are moderately efficient in optimizing their status in healthy middle-aged subjects with low fish consumption: a cross-over study

Several dietary recommendations have been made for marine n-3 polyunsaturated fatty acid (PUFA) intake; however, the effectiveness of these fatty acids has not been thoroughly examined. The aim of this study was to investigate whether public-aimed dietary recommendations for long-chain n-3 PUFA from oily fish or fish oil supplements are efficient in optimizing their status in red blood cells (RBCs) and platelets of healthy middle-aged subjects with low customary fish consumption. In a randomized, cross-over trial conducted over an 8-week period and separated by a 6-month washout period, 33 participants received an oily fish (salmon), providing 274 mg eicosapentaenoic acid (EPA) + 671 mg docosahexaenoic acid (DHA) per day, or a commercial fish oil supplement, providing 396 mg EPA + 250 mg DHA per day. Blood samples were collected before and after each intervention period, and RBCs and platelets were used for analysis of fatty acids. After 8 weeks, there were significant increases in EPA and DHA content in RBCs and platelets with both salmon and fish oil capsules. The increase in EPA in both RBCs and platelets was higher with capsules, whereas the increase in DHA in both RBCs and platelets was higher with salmon. In spite of the quantitative and qualitative differences between n-3 fatty acid profiles in salmon and the fish oil supplement, the overall incorporation of these fatty acids into RBCs and platelets did not differ in our short-term study (P > .05). The sum of EPA + DHA significantly increased in both compartments following dietary recommendations for oily fish and fish oil supplements intake in middle-aged healthy subjects with low baseline long-chain n-3 PUFA status, although targeted values with optimal cardioprotective effect of more than 8% were not achieved.     

Comparison of n-3 polyunsaturated fatty acid contents of wild and cultured Australian abalone

The fatty acid contents of wild and cultured Australian adult blacklip abalone, Haliotis rubra, were analysed by gas liquid chromatography. Wild abalone contained significantly higher levels of total n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (20:5n-3), docosapentaenoic acid (22:5n-3) and alpha-linolenic acid (18:3n-3) than cultured abalone (P<0.05). The predominant n-3 PUFA was docosapentaenoic acid in wild abalone, while in cultured abalone a high level of eicosapentaenoic acid was found. The concentration of docosahexaenoic acid (22:6n-3) was low in both wild and cultured abalone, and cultured abalone had a significantly higher percentage composition of this fatty acid than wild abalone (P<0.01). Significantly higher levels of arachidonic acid (20:4n-6), 22:2n-6, 22:4n-6 and total n-6 PUFA were also found in wild abalone than in cultured animals (P<0.05). The ratio of n-3 PUFA to n-6 PUFA was the same in wild and cultured abalone. Manipulation of nutrient sources of cultured abalone may influence their lipid composition. Consumption of either wild or cultured abalone will contribute to dietary n-3 PUFA intake, with benefits to human health.     

The Pattern of Fatty Acids Displaced by EPA and DHA Following 12 Months Supplementation Varies between Blood Cell and Plasma Fractions

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are increased in plasma lipids and blood cell membranes in response to supplementation. Whilst arachidonic acid (AA) is correspondingly decreased, the effect on other fatty acids (FA) is less well described and there may be site-specific differences. In response to 12 months EPA + DHA supplementation in doses equivalent to 0–4 portions of oily fish/week (1 portion: 3.27 g EPA+DHA) multinomial regression analysis was used to identify important FA changes for plasma phosphatidylcholine (PC), cholesteryl ester (CE) and triglyceride (TAG) and for blood mononuclear cells (MNC), red blood cells (RBC) and platelets (PLAT). Dose-dependent increases in EPA + DHA were matched by decreases in several n-6 polyunsaturated fatty acids (PUFA) in PC, CE, RBC and PLAT, but were predominantly compensated for by oleic acid in TAG. Changes were observed for all FA classes in MNC. Consequently the n-6:n-3 PUFA ratio was reduced in a dose-dependent manner in all pools after 12 months (37%–64% of placebo in the four portions group). We conclude that the profile of the FA decreased in exchange for the increase in EPA + DHA following supplementation differs by FA pool with implications for understanding the impact of n-3 PUFA on blood lipid and blood cell biology.     

Mechanisms of action of (n-3) fatty acids

(n-3) PUFA are a family of biologically active fatty acids. The simplest member of this family, α-linolenic acid, can be converted to the more biologically active very long-chain (n-3) PUFA EPA and DHA; this process occurs by a series of desaturation and elongation reactions, with stearidonic acid being an intermediate in the pathway. Biological activity of α-linolenic and stearidonic acids most likely relates to their conversion to EPA. The very long-chain (n-3) PUFA have a range of physiological roles that relate to optimal cell membrane structure and optimal cell function and responses. Thus, (n-3) PUFA play a key role in preventing, and perhaps treating, many conditions of poor health and well-being. The multiple actions of (n-3) PUFA appear to involve multiple mechanisms that connect the cell membrane, the cytosol, and the nucleus. For some actions, (n-3) PUFA appear to act via receptors or sensors, so regulating signaling processes that influence patterns of gene expression. Some effects of (n-3) PUFA seem to involve changes in cell membrane fatty acid composition. Changing membrane composition can in turn affect membrane order, formation of lipid rafts, intracellular signaling processes, gene expression, and the production of both lipid and peptide mediators. Under typical Western dietary conditions, human cells tend to have a fairly high content of the (n-6) fatty acid arachidonic acid. Increased oral intake of EPA and DHA modifies the content of arachidonic acid as well as of EPA and DHA. Arachidonic acid is the substrate for eicosanoids involved in physiology and pathophysiology. The eicosanoids produced from EPA frequently have properties that are different from those that are produced from arachidonic acid. EPA and DHA are also substrates for production of resolvins and protectins, which seem to be biologically extremely potent. Increasing the contents of EPA and DHA in membranes modifies the pattern of production of these different lipid mediators.     

A Food-Based Intervention in a Military Dining Facility Improves Blood Fatty Acid Profile

Enhancing dietary omega-3 highly unsaturated fatty acids (n-3 HUFA) intake may confer neuroprotection, brain resiliency, improve wound healing and promote cardiovascular health. This study determined the efficacy of substituting a few common foods (chicken meat, chicken sausage, eggs, salad dressings, pasta sauces, cooking oil, mayonnaise, and peanut butter) lower in omega-6 polyunsaturated fatty acids (n-6 PUFA) and higher in n-3 HUFA in a dining facility on blood fatty acid profile. An eight-week prospective, between-subjects (n = 77), repeated measures, parallel-arm trial was conducted. Participants self-selected foods consumed from conventionally produced foods (control), or those lower n-6 PUFA and higher n-3 HUFA versions (intervention). Changes in blood omega-3 index, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), n-6 PUFA, lipid profile, and food satisfaction were main outcomes. Between-group differences over time were assessed using a linear mixed model to measure the effect of diet on blood serum fatty acids and inflammatory markers. The intervention group achieved a higher omega-3 index score (3.66 ± 0.71 vs. 2.95 ± 0.77; p < 0.05), lower total n-6 (10.1 ± 4.6 vs. 15.3 ± 6.7 µg/mL; p < 0.05), and higher serum concentration of EPA (5.0 ± 1.31 vs. 4.05 ± 1.56 µg/mL; p < 0.05) vs. controls. Satisfaction in intervention foods improved or remained consistent. Substitution of commonly eaten dining facility foods with like-items higher in DHA and EPA and lower in n-6 PUFA can favorably impact fatty acid status and the omega-3 index.     

Dietary flavonoids increase plasma very long-chain (n-3) fatty acids in rats

Flavonoids probably contribute to the health benefits associated with the consumption of fruit and vegetables. However, the mechanisms by which they exert their effects are not fully elucidated. PUFA of the (n-3) series also have health benefits. Epidemiological and clinical studies have suggested that wine flavonoids may interact with the metabolism of (n-3) PUFA and increase their blood and cell levels. The present studies in rats were designed to assess whether flavonoids actually increase plasma levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the main very long-chain (n-3) PUFA. Rats were fed a corn-derived anthocyanin (ACN)-rich (ACN-rich) or ACN-free diet with constant intakes of plant and marine (n-3) PUFA for 8 wk (Expt. 1). Plasma fatty acids were measured by GC. The ACN-rich diet contained ~0.24 ± 0.01 mg of ACN/g pellets. There were no significant differences between groups in the main saturated, monounsaturated, and (n-6) fatty acids. In contrast, plasma EPA and DHA were greater in the ACN-rich diet group than in the ACN-free diet group (P < 0.05). We obtained similar results in 2 subsequent experiments in which rats were administered palm oil (80 μL/d) and consumed the ACN-rich or ACN-free diet (Expt. 2) or were supplemented with fish oil (60 mg/d, providing 35 mg DHA and 12 mg EPA) and consumed the ACN-rich or ACN-free diet (Expt. 3). In both experiments, plasma EPA and DHA were significantly greater in the ACN-rich diet group. These studies demonstrate that the consumption of flavonoids increases plasma very long-chain (n-3) PUFA levels. These data confirm previous clinical and epidemiological studies and provide new insights into the health benefits of flavonoids.     

Persistent changes in the fatty acid composition of erythrocyte membranes after moderate intake of n-3 polyunsaturated fatty acids: study design implications.

To examine the incorporation of n-3 polyunsaturated fatty acids (PUFAs) into erythrocyte membranes during and after moderate n-3 PUFA intake, 12 healthy men were fed three diets for 6-wk periods in a 3 x 3 crossover design, supplying different amounts of eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3): a control diet, a fish diet (0.15 g EPA/d, 0.41 g DHA/d), and a fish + oil diet (5 g fish oil/d; 0.99 g EPA/d and 0.99 g DHA/d). A 6-wk washout period was allowed between diets. Between 6 and 12 wk after the fish + oil diet, erythrocyte EPA and DHA were still declining and it was only after 18 wk that erythrocyte EPA had returned to baseline whereas DHA had not. Investigators examining variables that are influenced by altered membrane fatty acid composition should be aware of these prolonged effects when designing studies. Protracted washout periods (greater than 18 wk) make the classic crossover design prohibitive and a parallel design becomes essential.     

Comparison of n-3 polyunsaturated fatty acid contents of wild and cultured Australian abalone

The fatty acid contents of wild and cultured Australian adult blacklip abalone, Haliotis rubra, were analysed by gas liquid chromatography. Wild abalone contained significantly higher levels of total n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (20:5n-3), docosapentaenoic acid (22:5n-3) and α-linolenic acid (18:3n-3) than cultured abalone (P<0.05). The predominant n-3 PUFA was docosapentaenoic acid in wild abalone, while in cultured abalone a high level of eicosapentaenoic acid was found. The concentration of docosahexaenoic acid (22:6n-3) was low in both wild and cultured abalone, and cultured abalone had a significantly higher percentage composition of this fatty acid than wild abalone (P<0.01). Significantly higher levels of arachidonic acid (20:4n-6), 22:2n-6, 22:4n-6 and total n-6 PUFA were also found in wild abalone than in cultured animals (P<0.05). The ratio of n-3 PUFA to n-6 PUFA was the same in wild and cultured abalone. Manipulation of nutrient sources of cultured abalone may influence their lipid composition. Consumption of either wild or cultured abalone will contribute to dietary n-3 PUFA intake, with benefits to human health.     

不同膳食脂肪酸对大鼠乳腺癌组织脂肪酸组成和脂代谢基因表达的影响

目的探讨不同膳食脂肪酸组成影响大鼠乳腺癌发生、发展的可能分子机制。方法用8种不同膳食脂肪酸组成(SFA、MUFA、n-6PUFA、n-3PUFA、1∶1n-6/n-3、5∶1n-6/n-3、10∶1n-6/n-3、1∶2∶1S/M/P其中n-6/n-31∶1)喂养SD雌性大鼠,并在大鼠乳腺癌模型的基础上,用气相色谱内标法观察大鼠乳腺组织脂肪酸组成改变,RT-PCR分析组织脂代谢调控基因(FAS、COX-2和5-LOX)的表达。结果在不同膳食脂肪酸构成中,只有1∶1n-6/n-3能有效抑制大鼠乳腺癌的发生。不同膳食脂肪酸构成可导致大鼠乳腺组织脂肪酸组成发生相应变化,且各组间的脂肪酸含量有显著差异。高乳腺癌诱发的SFA、MUFA、n-6PUFA、5∶1n-6/n-3、10∶1n-6/n-3和1∶2∶1S/M/P喂养组乳腺组织含有较多的C18∶1、C18∶2和C20∶4,而EPA和DHA含量极少。无或低乳腺癌诱发的n-3PUFA和1∶1n-6/n-3喂养组乳腺组织EPA和DHA明显增多,C20∶4含量显著减少。RT-PCR结果显示1∶1n-6/n-3低诱癌组较相应对喂组上调FAS、COX-2和5-LOXmRNA表达力度明显弱于其它高乳腺癌诱发组。结论不同膳食脂肪酸组成能明显改变大鼠乳腺组织脂肪酸组成,进而影响脂代谢基因FAS、COX-2和5-LOX表达,可能是大鼠乳腺癌发生的分子机制之一。     

Plant- and marine-derived n-3 polyunsaturated fatty acids have differential effects on fasting and postprandial blood lipid concentrations and on the susceptibility of LDL to oxidative modification in moderately hyperlipidemic subjects

BACKGROUND: Dietary alpha-linolenic acid (ALA) can be converted to long-chain n-3 polyunsaturated fatty acids (PUFAs) in humans and may reproduce some of the beneficial effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular disease risk factors. OBJECTIVE: This study aimed to compare the effects of increased dietary intakes of ALA and EPA+DHA on a range of atherogenic risk factors. DESIGN: This was a placebo-controlled, parallel study involving 150 moderately hyperlipidemic subjects randomly assigned to 1 of 5 interventions: 0.8 or 1.7 g EPA+DHA/d, 4.5 or 9.5 g ALA/d, or an n-6 PUFA control for 6 mo. Fatty acids were incorporated into 25 g of fat spread and 3 capsules to be consumed daily. RESULTS: The change in fasting or postprandial lipid, glucose, or insulin concentrations or in blood pressure was not significantly different after any of the n-3 PUFA interventions compared with the n-6 PUFA control. The mean (+/- SEM) change in fasting triacylglycerols after the 1.7-g/d EPA+DHA intervention (-7.7 +/- 4.99%) was significantly (P < 0.05) different from the change after the 9.5-g/d ALA intervention (10.9 +/- 4.5%). The ex vivo susceptibility of LDL to oxidation was higher after the 1.7-g/d EPA+DHA intervention than after the control and ALA interventions (P < 0.05). There was no significant change in plasma alpha-tocopherol concentrations or in whole plasma antioxidant status in any of the groups. CONCLUSION: At estimated biologically equivalent intakes, dietary ALA and EPA+DHA have different physiologic effects.     

The effect of feeding structured triacylglycerols enriched in eicosapentaenoic or docosahexaenoic acids on murine splenocyte fatty acid composition and leucocyte phagocytosis

The effects of altering the type of n-3 polyunsaturated fatty acid (PUFA) in the mouse diet on the ability of monocytes and neutrophils to perform phagocytosis were investigated. Male weanling mice were fed for 7 d on one of nine diets which contained 178 g lipid/kg and which differed in the type of n-3 PUFA and in the position of these in dietary triacylglycerol (TAG). The control diet contained 4.4 g alpha-linolenic acid/100 g total fatty acids. In the other diets, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) replaced a proportion (50 or 100 %) of the alpha-linolenic acid, and were in the sn-2 or the sn-1(3) position of dietary TAG. There were significant increases in the content of n-3 PUFA in spleen-cell phospholipids when EPA or DHA was fed. These increases were largely independent of the position of EPA or DHA in dietary TAG except when EPA was fed at the highest level, when the incorporation was greater when it was fed in the sn-2 than in the sn-1(3) position. There was no significant effect of dietary DHA on monocyte or neutrophil phagocytic activity. Dietary EPA dose-dependently decreased the number of monocytes and neutrophils performing phagocytosis. However, when EPA was fed in the sn-2 position, the ability of active monocytes or neutrophils to engulf bacteria was increased in a dose-dependent fashion. This did not occur when EPA was fed in the sn-1(3) position. Thus, there appears to be an influence of the position of EPA, but not of DHA, in dietary TAG on its incorporation into cell phospholipids and on the activity of phagocytic cells.     

Ethnic differences in early pregnancy maternal n-3 and n-6 fatty acid concentrations: an explorative analysis

Ethnicity-related differences in maternal n-3 and n-6 fatty acid status may be relevant to ethnic disparities in birth outcomes observed worldwide. The present study explored differences in early pregnancy n-3 and n-6 fatty acid composition of maternal plasma phospholipids between Dutch and ethnic minority pregnant women in Amsterdam, the Netherlands, with a focus on the major functional fatty acids EPA (20 : 5n-3), DHA (22 : 6n-3), dihomo-gamma-linolenic acid (DGLA; 20 : 3n-6) and arachidonic acid (AA; 20 : 4n-6). Data were derived from the Amsterdam Born Children and their Development (ABCD) cohort (inclusion January 2003 to March 2004). Compared with Dutch women (n 2443), Surinamese (n 286), Antillean (n 63), Turkish (n 167) and Moroccan (n 241) women had generally lower proportions of n-3 fatty acids (expressed as percentage of total fatty acids) but higher proportions of n-6 fatty acids (general linear model; P < 0.001). Ghanaian women (n 54) had higher proportions of EPA and DHA, but generally lower proportions of n-6 fatty acids (P < 0.001). Differences were most pronounced in Turkish and Ghanaian women, who, by means of a simple questionnaire, reported the lowest and highest fish consumption respectively. Adjustment for fish intake, however, hardly attenuated the differences in relative EPA, DHA, DGLA and AA concentrations between the various ethnic groups. Given the limitations of this observational study, further research into the ethnicity-related differences in maternal n-3 and n-6 fatty acid patterns is warranted, particularly to elucidate the explanatory role of fatty acid intake v. metabolic differences.