膳食多不饱和脂肪酸与乳腺癌的发生

乳腺癌是引起妇女死亡的常见肿瘤之一，同时也是与膳食、营养因素，尤其是膳食脂肪关系最为密切的一类肿瘤。新近的多项研究显示，n-3多不饱和脂肪酸(n-3PUFA）和n-6 PUFA对肿瘤发生的作用相反，前者抑癌，而后者促癌。本文拟对膳食多不饱和脂肪酸与肿瘤，尤其与乳腺癌发病的关系作一综述。     

021膳食多不饱和脂肪酸与乳腺癌的发生

乳腺癌是引起妇女死亡的常见肿瘤之一,同时也是与膳食、营养因素,尤其是膳食脂肪关系最为密切的一类肿瘤.新近的多项研究显示,n-3多不饱和脂肪酸(n-3 PUFA)和n-6 PUFA对肿瘤发生的作用相反,前者抑癌,而后者促癌.本文拟对膳食多不饱和脂肪酸与肿瘤,尤其与乳腺癌发病的关系作一综述.     

073 n-3脂肪酸对肿瘤细胞凋亡的影响及作用机制

n-3脂肪酸(n-3 PUFA)是一类重要的多不饱和脂肪酸,与人体多种生理过程密切相关.目前研究发现它们可能具有一定的抗肿瘤效应,而经多种途径调控肿瘤细胞凋亡是其发挥作用的重要机制之一.本文从分子生物学角度就n-3 PUFA对肿瘤细胞凋亡的影响及作用机制作一综述.     

不同n-6/n-3 PUFA构成比对大鼠脂联素表达的影响及与CDK5/PPARγ关系

目的研究在膳食脂肪产热比26.52%时,不同n-6/n-3多不饱和脂肪酸(polyunsaturated fatty acids,PUFA构成比对大鼠脂联素表达的影响及CDK5/PPARγ介导的机制。方法 50只雄性Wistar大鼠按体质量(body weight, bw)随机分成对照组及4个实验组。对照组喂基础饲料,实验组分别将饲料中n-6/n-3PUFA构成比调配为1:1、5:1、10:1和20:1,测定干预前血清脂联素含量。膳食干预12w,记录体质量变化,计算食物利用率及能量转化效率,测定睾周、肾周脂肪组织重量、肾周脂肪组织脂联素表达、血清脂联素含量、肾周脂肪组织PPARγ、CDK5及p-PPARγ(Ser273)的表达。结果当n-6/n-3 PUFA构成比高于5:1,大鼠能量转化效率升高、体质量增加并伴有肾周脂肪蓄积。n-6/n-3 PUFA构成比为1:1、5:1膳食大鼠血清脂联素含量和PPARγ表达增加,CDK5、p-PPARγ蛋白降低;构成比为20:1膳食降低大鼠脂肪组织脂联素、PPARγ和CDK5蛋白的表达,且不能改变p-PPARγ蛋白表达。结论在正常的膳食脂肪供给情况下,与较高的n-6/n-3 PUFA构成比(20:1)相比,n-6/n-3 PUFA构成比为5:1可能通过升高PPARγ表达以及降低p-PPARγ(Ser273)从而提高脂联素表达。[营养学报,2020,42(2):157-161]     

083 n-3多不饱和脂肪酸与免疫系统关系的研究进展

随着过去数十年脂肪酸摄入模式的改变和免疫性疾病发生的明显增加，n-3多不饱和脂肪酸（n-3 PUFA）的摄入与免疫系统关系的研究日益受到重视。目前普遍认为n-3 PUFA及其代谢产物均可通过直接或间接的途径对免疫系统发挥作用，继而抑制免疫系统作用的发挥和炎症反应的发展。但近年来也有报道指出n-3 PUFA在特定情况下也可促进免疫细胞发挥其功能。本文根据相关文献资料，对该领域研究进展予以介绍。     

不同n-6/n-3脂肪酸构成对小鼠心血管疾病危险因素的影响

目的研究不同脂肪酸构成对小鼠血脂代谢、炎症和氧化应激及内皮细胞功能的影响。方法雄性KM小鼠随机分为5组,分别喂饲正常对照饲料、猪油高脂饲料和n-6/n-3多不饱和脂肪酸(PUFA)比值为1∶1、5∶1、20∶1的高脂饲料5周,比较各组小鼠血清中甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、白介素-6(IL-6)、丙二醛(MDA)、超敏C反应蛋白(hsCRP)、肿瘤坏死因子(TNF-α)、脂质过氧化物(LPO)、8-异前列腺素F2α(8-isoPGF2α)、氧化型低密度脂蛋白(ox-LDL)、游离脂肪酸(FFA)、选择素(ES)和血管性血友病因子(v WF)的含量变化。结果猪油组LDL-C和非高密度脂蛋白胆固醇(non-HDL-C)水平显著高于其他各组(P0.05)。n-6/n-3 PUFA 1∶1组和5∶1组血清TG、TC水平显著低于猪油组(P0.05)。20∶1组血清FFA水平显著高于1∶1组和5∶1组(P0.05)。1∶1组和5∶1组血清炎症因子和氧化应激指标及ES水平均显著低于猪油组和20∶1组(P0.05)。5∶1组血清v WF水平显著低于猪油组和20∶1组(P0.05)。结论与猪油和高n-6/n-3 PUFA比值高脂饲料相比较,低n-6/n-3PUFA比值高脂饲料可改善小鼠脂代谢、炎症与氧化应激和内皮细胞功能。     

高n-3多不饱和脂肪酸鱼油饮食对小鼠肠道菌群的影响

目的探讨高n-3多不饱和脂肪酸(n-3 PUFAs)鱼油饮食的摄入对于肠道菌群的影响。方法选取成年C57BL/6小鼠,随机分成正常对照低脂组和高n-3多不饱和脂肪酸鱼油饮食两组,进行为期4w的低脂(low fat diet,LFD)和鱼油饮食(fish oil diet,FO)。并于第4w末收集粪便,提取基因组DNA,使用Miseq高通量测序技术分析其菌群结构特征。结果 FO组和LFD组小鼠肠道内菌群差异明显。FO组菌群多样性较LFD组降低,同时Bacteroidetes(拟杆菌门)明显下降,出现了新的优势菌群Akkermansia菌属。结论高n-3多不饱和脂肪酸鱼油饮食的摄入明显改变了小鼠肠道菌群结构,而这有可能是n-3PUFA在体内调控机体免疫功能的机制之一。     

n-3多不饱和脂肪酸在肿瘤防治中的意义

n-3脂肪酸属必需脂肪酸,包括α-亚麻酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA).大量研究证实,n-3脂肪酸能抑制多种肿瘤细胞生长,预防肿瘤的发生.作者就 n-3脂肪酸防治肿瘤的作用、机制及应用作一综述.     

基于2019年全球疾病负担研究数据分析1990-2019年我国居民脂肪酸摄入情况的年龄和年份变化趋势

目的 深入分析1990-2019年我国居民近三十年的膳食脂肪酸摄入情况的年龄和年份变化特征，为进行合理的膳食指导提供基础资料。方法 利用2019年全球疾病负担研究中的关于n-3多不饱和脂肪酸（PUFA）、PUFA和反式脂肪酸（TFAS）我国居民1990-2019年的摄入数据的估计值，采用Joinpoint回归模型分析摄入情况随年龄和年份的变化趋势特征。结果 近30年，我国居民n-3 PUFA、PUFA摄入情况均未达标。n-3 PUFA的摄入量和PUFA摄入能量占比总体呈现上升趋势，其中，n-3 PUFA摄入量增加速度随着年份推移而增加，45～74岁组在2008-2019年间摄入量增加速度较其他年龄段要快；PUFA在1996-2009年左右上升速度较快且50～84岁年龄组较其他年龄组更快，1990-1996年和2009-2019年左右上升速度较慢。TFAS摄入能量占比总体呈现下降趋势，2001-2009年左右下降速度较快且35岁及以上相对其他年龄组下降更快。结论 除n-3 PUFA外，近10年PUFA和TFAS摄入情况向好的趋势减慢。建议继续加大营养健康教育的宣传力度，促进居民n-3 P...     

广州成人膳食n-6/n-3脂肪酸比值与心血管疾病危险因素的关系

目的分析广州40～65岁居民膳食n-6/n-3脂肪酸比值与心血管疾病危险因素的关系。方法 40～65岁广州市民1133人,采用定量食物频数问卷调查对象的每日摄入食物种类和数量,计算能量和营养素摄入量,检测其红细胞膜脂肪酸构成、血脂及颈动脉内中膜厚度(IMT),分析n-6/n-3比值大小高Q3,中Q2,低Q1与血压、血脂和IMT的关系。结果 995人资料完整纳入分析。对象日均膳食总能量摄入为9.10±2.09MJ、脂肪供能比为(34.3±7.9)%。膳食n-6/n-3脂肪酸比值为(29.74±22.71):1,红细胞膜n-6/n-3脂肪酸比值为(2.7±1.0):1,膳食SFA:MUFA:PUFA为1:1.5:1。膳食n-3脂肪酸摄入量与红细胞膜n-3构成比、膳食n-6/n-3比值与红细胞膜n-6/n-3比值均呈显著正相关关系。膳食n-6/n-3比值最高组Q3(>31.16)对象的收缩压、TC和IMT水平显著高于最低组Q1(<17.40);红细胞膜n-6/n-3比值最高组Q3(>3.04)和中间组Q2(2.18～3.03)对象的收缩压、舒张压、TC、LDL-C及IMT水平均显著高于最低组Q1(≤2.17)。结论广州市40～65岁居民膳食n-6/n-3脂肪酸比值约为30:1;该比值小于17.40:1时,有较低的血压,总胆固醇及IMT水平。     

不同n-3/n-6多不饱和脂肪酸构成比膳食对大鼠一磷酸腺苷活化蛋白激酶表达的影响

目的研究不同n-3/n-6配比脂肪酸对大鼠磷酸腺苷酸活化蛋白激酶(AMP-activated protein kinase,AMPK)蛋白及活性表达的影响。方法58只SD大鼠适应性喂养7d后,尾静脉取血。根据血清总胆固醇水平随机分为:空白(基础饲料);高脂(高脂饲料);高脂1:1(高脂饲料+n-3/n-6=1:1配方油);高脂1:5(高脂饲料+n3/n6=1:5配方油);低脂1:1(脱脂基础饲料+n-3/n-6=1:1配方油);低脂1:5(脱脂基础饲料+n3/n6=1:5配方油)6组,喂养45d,观察大鼠摄食与体重增长。于实验前1d,15d,30d,45d分别各取血测血清总胆固醇水平,于D45处死动物。Western blotting分别分析肝和下丘脑组织中AMPK-α总蛋白及其活性表达。结果添加PUFA的4个比例组血清TC、体重与高脂组相比,显著降低,且低脂2个比例组和高脂1:1组均与高脂1:5组相比有显著差异。添加PUFA的4个比例组均与高脂组相比,大鼠下丘脑AMPK-α总蛋白表达水平明显降低,肝AMPK-α蛋白表达水平均比高脂组明显升高。结论PUFA改善血脂可能是通过增加肝AMPK表达,抑制下丘脑AMPK表达,增加肝脂肪酸氧化和抑制食欲,影响血脂代谢。     

不同年龄阶段小鼠脑聚集二十二碳六烯酸及脂肪酸去饱和酶的变化

【目的】 探讨生命早期不同年龄阶段脑摄取、聚集二十二碳六烯酸(DHA)(C22:6n-3)及相关去饱和酶的变化。 【方法】 使用6~8周龄清洁级C57BL/6J雌性小鼠,分别给予n-3 多不饱和脂肪酸(n-3 PUFAs)缺乏饲料和含n-3 PUFAs饲料喂养6周,然后雌雄合笼交配繁殖,新生仔鼠分别于生后7、21 d和42 d时取血、脑和肝脏。采用甲酯化-气相色谱分析对血浆、脑和肝脏中脂肪酸谱进行分析;采用荧光定量PCR方法对脑和肝脏中脂肪酸去饱和酶1(FADS1)和脂肪酸去饱和酶2(FADS2)基因mRNA表达进行检测。 【结果】 对不同年龄小鼠组织脂肪酸的比较发现,脑中DHA和总n-3 PUFAs含量在两种不同饲料组均随年龄增加而升高;而肝中的含量则随年龄增加而降低。与n-3 PUFAs缺乏组相比,饲料中添加n-3 PUFAs可使仔鼠生后7、21 d和42 d时脑和肝脏中DHA和总n-3 PUFAs含量均显著升高;升高的程度在脑组织中随年龄增加而降低,而在肝脏组织中则不随年龄变化。对不同年龄段FADS表达的比较发现,FADS1和FADS2 mRNA在脑组织中的表达量于42 d时显著高于7 d和21 d,而在肝组织中的表达量于各年龄段之间无显著性差异。与n-3 PUFAs缺乏组相比,饲料中添加n-3 PUFAs可使仔鼠生后7 d和21 d时脑组织FADS1和FADS2表达水平显著降低,而42 d时的表达无变化;肝组织中这两种酶mRNA水平在7 d和21 d时无变化,42 d时FADS1显著降低。 【结论】 发育期脑对DHA的聚集需求随着年龄增大而逐渐减少;FADS在脑中的表达水平随年龄增大而升高。同时,饲料n-3 PUFAs缺乏状态对脑聚集DHA以及FADS的影响在年龄小时更明显。     

Protective effect of dietary n-3 polyunsaturated fatty acids on myocardial resistance to ischemia-reperfusion injury in rats

Dietary n-3 polyunsaturated fatty acids (PUFA) reduce coronary heart disease (CHD) complications, such as chronic arrhythmia and sudden cardiac death. Improved myocardial resistance to ischemia-reperfusion injury results in smaller myocardial infarction, which is a major factor in the occurrence of CHD complications. We hypothesized that a specific dietary fatty acid profile (low in saturated and n-6 PUFA but high in plant and marine n-3 PUFA) may improve myocardial resistance to ischemia-reperfusion injury and reduce infarct size. To test this assumption, we used a well-defined rat model of myocardial infarction. Based on our results, in comparison to a diet that is high in either saturated or n-6 PUFA but poor in plant and marine n-3 PUFA, a diet that is low in saturated fats and n-6 PUFA but rich in plant and marine n-3 PUFA results in smaller myocardial infarct size (P < .01). The effects of the 3 diets were also examined by analyzing the fatty acid composition of plasma, erythrocyte cell membranes, and the phospholipids of myocardial mitochondria. The results show a great accumulation of n-3 PUFA and a parallel decrease in arachidonic acid, the main n-6 PUFA, in plasma, cell membranes, and cardiac mitochondria (P < .0001). We conclude that improved myocardial resistance to ischemia-reperfusion may be one of the critical factors explaining the protective effects of dietary n-3 PUFA against CHD complications in humans. In addition to increasing n-3 PUFA intake, an optimal dietary pattern aimed at reducing cardiovascular mortality should include a reduction of the intake of both saturated and n-6 PUFA.     

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.     

Maternal Supplementation with Cow’s Milk Naturally Enriched with PUFA Alters the Metabolism of Sows and the Fatty Acid Profile of the Offspring

The study aimed to evaluate the supplementation of gilts with cow’s milk naturally enriched with n-3 and n-6 polyunsaturated fatty acids (PUFA) on reproductive outcomes, and the serum biochemical and FA profile of swine females and their offspring. During 316 days, 30 gilts were distributed into three groups: (1) Control, fed a basal diet + milk from cows without oil; (2) n-3, fed a basal diet + milk from cows fed a diet enriched with linseed oil; (3) n-6, fed a basal diet + milk from cows fed a diet enriched with soybean oil. The gilts receiving the diets containing PUFA had higher serum urea and very-low-density lipoprotein levels and lower serum total protein and low-density lipoprotein levels compared to the Control group. Females supplemented with n-3 presented higher serum palmitic acid and γ-linolenic acid levels than those fed n-6. Piglets from the Control group were heavier at birth than those from females supplemented with enriched milk. The piglets from females receiving enriched milk had 140 g higher body weight from 1 to 21 days old compared to the Control group, and greater average daily weight gain from 7 to 14 days old. The serum eicosapentaenoic acid level of piglets fed n-3 was 69% higher than those fed n-6, which reduced the AA/EPA ratio. Gilts supplemented with PUFA-enriched cow’s milk showed changes in their serum palmitic and γ-linolenic acid levels, in addition to improved performance, EPA concentration and consequently reduced AA/EPA ratio in their piglets, demonstrating beneficial results for their progeny.     

膳食n-6/n-3脂肪酸比值对小鼠淋巴细胞脂肪酸构成和功能的影响

目的观察膳食n6n3脂肪酸比值对淋巴细胞脂肪酸构成及细胞功能的影响。方法BALBc小鼠随机分为5组n6n3比值分别为1(A组)、75(B组)、15(C组)、30(D组)和正常对照组,其中实验组S∶M∶P模拟中国居民膳食脂肪酸摄入的S∶M∶P为1∶15∶1,正常对照组为AIN93G配方的1∶15∶37。基础饲料采用AIN93G配方,脂肪酸构成以食用油脂调配。饲养12周。测定小鼠T淋巴细胞功能,脾淋巴细胞脂肪酸构成、PGE2水平。结果n6n3比值接近1时,小鼠T淋巴细胞增殖活性、CD4+、CD8+T细胞比例、培养上清IL2、PGE2水平显著降低;淋巴细胞C18∶2、C20∶4、n6PUFA含量显著减少;C22∶6、C16∶1、C18∶1、总MUFA含量明显高于其他实验组。淋巴细胞C22∶6含量与淋巴细胞增殖活性显著负相关;C20∶5含量与CD4+T淋巴细胞比例、IL2水平显著负相关;C16∶1含量与CD4+、CD8+T淋巴细胞比例显著负相关。结论小鼠脾淋巴细胞的脂肪酸构成受膳食脂肪酸构成的影响;n6n3比值为1组与比值为30的膳食组相比较,小鼠T淋巴细胞增殖活性受到抑制。     

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.     

代谢综合征患者甘油三酯水平与血清多不饱和脂肪酸的相关性

目的 研究代谢综合征（MS）患者血脂与血清多不饱和脂肪酸（PUFA）的相关性.方法 选取2011年6月至2012年6月绍兴市人民医院住院控制血糖的74例代谢综合征患者,以同期门诊体检的62例为正常对照,采用酶法测定血脂,高效气相色谱法测定血清磷脂脂肪酸谱组分,并计算血清PUFA百分含量.结果 MS组甘油三醋（TG）水平明显高于对照组[（2.0±0.8） mmol/L比（1.3±0.5）mmol/L,P=0.000].MS组n-3 PUFA百分含量（9.8％±2.2％比11.1％±2.4％,P =0.002）、n-6 PUFA百分含量（35.4％±6.7％比39.5％±7.8％,P=0.009）、总PUFA百分含量均明显低于对照组（45.2％±8.9％比50.6％±10.1％,P=0.000）.相关性分析显示TG浓度水平与n-3 PUFA、总PUFA百分含量呈负相关（r=-0.42,P=0.008;r=-0.23,P=0.013）.结论 MS患者n-3 PUFA、n-6 PUFA、PUFA明显低于健康对照,其血清TG水平与血清PUFA呈负相关.     

Lack of effect of dietary n-6:n-3 PUFA ratio on plasma lipids and markers of insulin responses in Indian Asians living in the UK

Summary Background Indian Asians living in Western Countries have an over 50 % increased risk of coronary heart disease (CHD) relative to their Caucasians counterparts. The atherogenic lipoprotein phenotype (ALP), which is more prevalent in this ethnic group, may in part explain the increased risk. A low dietary long chain n-3 fatty acid (LC n-3 PUFA) intake and a high dietary n-6 PUFA intake and n-6:n-3 PUFA ratio in Indian Asians have been proposed as contributors to the increased ALP incidence and CHD risk in this subgroup. Aim To examine the impact of dietary n-6:n-3 PUFA ratio on membrane fatty acid composition, blood lipid levels and markers of insulin sensitivity in Indian Asians living in the UK. Methods Twentynine males were assigned to either a moderate or high n-6:n-3 PUFA (9 or 16) diet for 6 weeks. Fasting blood samples were collected at baseline and 6 weeks for analysis of triglycerides, total-, LDL- and HDL-cholesterol, non-esterified fatty acids, glucose, insulin, markers of insulin sensitivity and C-reactive protein. Results Group mean saturated fatty acid, MUFA, n-6 PUFA and n-3 PUFA on the moderate and high n-6:n-3 PUFA diets were 26 g/d, 43 g/d, 15 g/d, 2 g/d and 25 g/d, 25 g/d, 28 g/d, 2 g/d respectively. A significantly lower total membrane n-3 PUFA and a trend towards lower EPA and DHA levels were observed following the high n-6:n-3 PUFA diet. However no significant effect of treatment on plasma lipids was evident. There was a trend towards a loss of insulin sensitivity on the high n-6:n- 3 PUFA diet, with the increase in fasting insulin (P = 0.04) and HOMA IR [(insulin x glucose)/ 22.5] (P = 0.02) reaching significance. Conclusion The results of the current study suggest that, within the context of a western diet, it is unlikely that dietary n-6:n-3 PUFA ratio has any major impact on the levels of LC n-3 PUFA in membrane phospholipids or have any major clinically relevant impact on insulin sensitivity and its associated dyslipidaemia. Source of support: This project was funded by the Food Standards Agency (FSA), UK.