Beneficial n-3 polyunsaturated fatty acid levels and n6:n3 ratios after 4-week EPA + DHA supplementation associated with reduced CRP: A pilot study in healthy young adults

Chronic systemic inflammation is associated with many conditions of aging such as atherosclerosis. Lowering high n-6:n-3 polyunsaturated fatty acid (PUFA) ratios are commonly found in Western diets aids in preventing inflammatory-related diseases. However, it is not clear whether dietary interventions designed to alter n-6:n-3 PUFA ratios can reduce systemic inflammation in younger adults. Studies that evaluate PUFA intake often use subjective data from food frequency questionnaires or food records rather than more precise physiological measures of PUFAs (e.g. plasma levels). Therefore, the purpose of this pilot study that analyzed data from the experimental parent study of younger adults (n = 18), was to determine whether plasma PUFA levels were associated with levels of C-reactive protein (CRP), an inflammatory marker, and if supplementation with n-3 PUFAs was correlated with rising n-3 PUFA concentrations in plasma and decreasing n-6:n-3 ratios. In the parent study, participants received daily either placebo or n-3 PUFA softgels (1.6 g eicosapentaenoic acid [EPA] and 1.2 g docosahexaenoic acid [DHA]). EPA and DHA are the biologically active components in fish oil. Measures included blood for PUFA quantification at baseline and four weeks later, when blister wounds were created and wound fluid and saliva were collected. The saliva samples were used to measure CRP in the present study. We report that CRP was significantly and negatively correlated with total n-3 PUFAs (tau-β = ?0.373, p = 0.031) and positively correlated with n-6:n-3 ratios (tau-β = 0.320, p = 0.063). Those consuming EPA + DHA supplements had significantly higher concentrations of total n-3 PUFAs and significantly lower n-6:n-3 ratios (p The present study has shown that beneficial levels of n-3 PUFAs and n-6:n3 ratios were achieved with 4-weeks of EPA + DHA supplementation and were associated with reduced CRP in young adults. EPA + DHA supplementation for some young adults may help prevent inflammatory conditions later in life.

Effect of ω-3 Polyunsaturated Fatty Acid on Toll-like Receptors in Patients with Severe Multiple Trauma

This study examined the effects of ω-3 polyunsaturated fatty acid（ω-3PUFA） on the expression of toll-like receptor 2（TLR2）,toll-like receptor 4（TLR4） and some related inflammatory factors in peripheral blood mononuclear cells（PBMCs） of patients with early-stage severe multiple trauma.Thirty-two patients who were admitted to the Department of Traumatic Surgery,Tongji Hospital（Wuhan,China） between May 2010 and November 2010,and diagnosed as having severe multiple trauma with a injury severity score（ISS） no less than 16,were enrolled in the study and divided into two groups at random（n=16 in each）：ω-3PUFA group and control group in which routine parenteral nutrition supplemented with ω-3PUFA or not was administered to the patients in two groups for consecutive 7 days.Peripheral blood from these patients was collected within 2 h of admission（day 0）,and 1,3,5 and 7 days after the nutritional support.PBMCs were isolated and used for detection of the mRNA and protein expression of TLR2 and TLR4 by using real-time PCR and flow cytometry respectively,the levels of NF-κB by quantum dots-based immunofluorescence assay,the levels of TNF-α,IL-2,IL-6 and COX-2 by ELISA,respectively.The results showed that the mRNA and protein expression of TLR2 and TLR4 in PBMCs was significantly lower in ω-3PUFA group than in control group 5 and 7 days after nutrition support（both P0.05）.The levels of TNF-α,IL-2,IL-6 and COX-2 were found to be substantially decreased in PBMCs in ω-3PUFA group as compared with control group at 5th and 7th day（P0.05 for all）.It was concluded that ω-3PUFA can remarkably decrease the expression of TLR2,TLR4 and some related inflammatory factors in NF-κB signaling pathway in PBMCs of patients with severe multiple trauma,which suggests that ω-3PUFA may suppress the excessive inflammatory response meditated by the TLRs/NF-κB signaling pathway.

体内ω-6 PUFAs与ω-3 PUFAs比例是影响ω-3 PUFAs发挥健康效应的重要因素

ω-3多不饱和脂肪酸(PUFAs)是人类重要的结构营养素和功能营养素,大量基础实验与人群研究已阐明其降脂、抗炎、防治心脑血管疾病、改善肿瘤微环境等作用。然而,随着ω-3 PUFAs人群干预试验的逐渐增多,部分研究并未发现该类显著效应。这种结果的不一致性阻碍了ω-3 PUFAs在更多医学指南中的应用,也限制了ω-3 PUFAs在临床诊疗和慢病管理中的推广。ω-6 PUFAs是另一类重要的多不饱和脂肪酸,但随着膳食结构的变迁,全球普遍存在ω-6 PUFAs摄入超标和ω-3 PUFAs摄入不足,进而导致体内ω-6与ω-3比例显著上升的问题。ω-6 PUFAs在体内与ω-3 PUFAs存在细胞膜结构占位竞争及代谢竞争的关系,高ω-6/ω-3比例可能会阻碍ω-3 PUFAs发挥其健康效应,并与众多慢病的发生、发展密切相关。本综述通过分析ω-3和ω-6 PUFAs在体内的交互作用及ω-6/ω-3比例对ω-3 PUFAs的影响,提出体内ω-6/ω-3比例是影响ω-3 PUFAs效应发挥的重要因素。同时,本文指出以往部分ω-3 PUFAs研究忽视了ω-6/ω-3比例这一重要指标,在研究终点时仍未恢复平衡的ω-6/ω-3比例可能是导致研究结果不一致的关键原因,提示尽快规范ω-3 PUFAs研究标准、将ω-6/ω-3比例纳入质控监测指标将有助于客观揭示ω-3 PUFAs的健康效应,并最终推动ω-3 PUFAs在慢病管理中的标准化应用。

Transgenic Pigs Carrying a Synthesized Fatty Acid Desaturase Gene Yield High Level of ω-3 PUFAs

Polyunsaturated fatty acids （PUFAs） are essential for normal growth in mammals, especially the ω-3 PUFAs, which play important roles in preventing several life-threatening diseases, such as coronary heart disease and diabetes. In this study, we aimed to investigate whether the sFat-1 gene from Caenorhabditis briggsae could be functionally expressed in transgenic pigs, and whether the transgenic could synthesize high quality ω-3 PUFAs endogenously. In this study, a gene construct consisting of CMV promoter and 1.9 kb cDNA of ω-3 fatty acid desaturase gene （sFat-1） from C. briggsae was injected into the male pronucleus of pig embryos by microinjection. The piglets were screened for the transgene by PCR, Southern blot and reverse transcription-PCR analysis. Pigs that give positive results were mated with wild-type pigs to produce the next generation and the transmission of transgene was examined by PCR analysis. Fatty acids compositions of various tissues in the transgenic pigs were then analyzed by gas chromatograph. A total of 878 embryos were transferred into 42 recipients, among which 29 successfully got pregnant and gave birth to a total of 162 piglets, and 8 of them were identified to be transgenic. Fatty acid compositions in the transgenic pigs were altered, and the levels of ω-6：ω-3 ratios were decreased from 14.53 in the control to 2.62 in Fat-1 transgenic pigs. A number of primary sFat-1-transgenic pigs were bred in this study, which lays the foundation for cultivation of new varieties of transgenic pigs.

膳食中高n-6/n-3多不饱和脂肪酸比值对小鼠精子浓度及活度的影响

目的近年来男性精子数量、质量呈下降趋势。文中研究小鼠膳食中高n-6/n-3多不饱和脂肪酸比值对其精子浓度及活度的影响。方法健康的B6小鼠20只,随机数表法分成对照组(基础饲料)和实验组(基础饲料+10%花生四烯酸),每组10只。喂食8周后,取各组小鼠附睾尾检测小鼠精子浓度及活度的变化,观察小鼠附睾组织显微结构的改变。结果实验组小鼠血清中α-亚麻酸、二十碳五烯酸、二十二碳六烯酸、二十二碳五烯酸、亚油酸含量均较对照组明显下降(P<0.01),而花生四烯酸和n-6/n-3 PUFAs明显升高(P<0.01)。实验组精子浓度(7×106个/mL)较对照组(80×106个/mL)显著下降,实验组精子活度(27%)较对照组(86%)显著下降,差异有统计学意义(P<0.01)。附睾组织管腔中精子数目明显减少。结论膳食中高n-6/n-3多不饱和脂肪酸比值对精子数量、质量具有显著损伤作用。

n-6/n-3多不饱和脂肪酸不同比例对乳腺癌细胞脂代谢调控基因的影响

目的探讨不同n-6/n-3多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）构成对乳腺癌细胞脂代谢调控基因及MAPK活性的影响.方法选用MCF-7（ER＋）和MDA-MB-231（ER-）乳腺癌细胞为实验对象,用不同n-6/n-3 PUFA构成（1～10）处理细胞后,MTT法观察细胞增殖能力,RT-PCR分析细胞脂代谢关键性调控基因（COX-2、5-LOX、PPARβ和PPARγ）表达变化,Western blot检测细胞MAPK蛋白磷酸化水平.结果 MCF-7细胞不表达COX-2基因.与对照组相比,单纯n-6和10：1 n-6/n-3 PUFA能明显促进这两种乳腺癌细胞增殖,诱导细胞COX-2、5-LOX、PPARβ和PPARγmRNA表达上调,并促进细胞MAPK磷酸化（P＜0.01）;与之相反的是,单纯n-3和1：1 n-6/n-3 PUFA显著抑制细胞生长,下调细胞COX-2、5-LOX、PPARβ和PPARγ mRNA表达,并抑制细胞MAPK磷酸化（P＜0.01）;但5：1 n-6/n-3 PUFA效果不明显.结论 n-6/n-3 PUFA不同比例对MCF-7和MDA-MB-231乳腺癌细胞脂代谢调控基因及信号转导的影响是不同的.在n-6/n-3比值为1～10范围内,单纯n-3和1：1 n-6/n-3能明显抑制脂代谢基因表达及信号转导,发挥显著抗乳腺癌细胞增殖效应.

N-6/N-3多不饱和脂肪酸不同比例对乳腺癌细胞缝隙连接细胞通讯的影响

目的观察n-6／n-3多不饱和脂肪酸（polyunsaturated fatty acid，PUFA）不同比例对乳腺癌细胞缝隙连接细胞通讯的影响。方法n-6／n-3PUFA不同比例（1～10）处理MCF-7（ER^＋）和MDA-MB-231（ER^-）乳腺癌细胞，采用免疫细胞化学观察细胞核Ki-67表达，Western blot检测细胞膜和细胞质缝隙连接蛋白Cx26、Cx43表达，划痕负载染料迁移法分析细胞缝隙连接通讯功能。结果免疫组化结果显示，单纯n-6和10：1n-6／n-3 PUFA增强两种乳腺癌细胞Ki-67表达（P〈0．05），5：1 n-6／n-3 PUFA虽无明显变化，但单纯n-3和1：1n-6／n-3 PUFA抑制细胞Ki-67表达（P〈0．01）。免疫印迹发现，单纯n-3和1：1n-6／n-3 PUFA能明显上调MCF-7细胞膜和细胞质的Cx26、Cx43蛋白表达，单纯n-6 PUFA却下调两种蛋白表达；在MDA-MB-231细胞，n-6／n-3 PUFA不同比例对膜和细胞质的Cx43蛋白表达与MCF-7细胞具有相同趋势，但对Cx26蛋白则无明显作用。用划痕负载染料迁移法却发现，n-6／n-3 PUFA不同比例对细胞缝隙连接通讯功能均无明显影响。结论单纯n-3和1：1n-6／n-3PUFA对MCF-7和MDA-MB-231乳腺癌细胞增殖活性的抑制作用，可能是Cx26和Cx43蛋白通过独立于缝隙连接细胞通讯功能的调节所致。

n-6／n-3多不饱和脂肪酸不同比例对乳腺癌细胞胰岛素样生长因子受体表达的影响

目的探讨n-6／n-3多不饱和脂肪酸（polyunsaturated fatty acid，PUFA）不同比例对乳腺癌细胞株MCF-7（ER^＋）及MDA-MB-231（ER^-）胰岛素样生长因子受体一1（insulin—like growth factor receptor-1，IGF-1R）表达的影响。方法用不同比例的n-6／n．3PUFA（1～10）处理细胞，MTF法检测细胞增殖能力变化；RT—PCR检测细胞IGF-1RmRNA表达变化；Westem blot检测IGF-1R蛋白在细胞膜的表达变化。结果单纯n-6PUFA和10：1n-6／n-3 PUFA能够明显促进MCF-7细胞和MDA—MB-231细胞增殖，诱导细胞IGF-1 RmRNA及蛋白表达上调（P〈0．01）；单纯n-3PUFA和1：1n-6／n-3PUFA则显著抑制细胞增殖，并降低细胞IGF-1RmRNA及蛋白表达水平（P〈0．01）；但5：1n-6／n-3PUFA效果不明显（P〉0．05）。结论不同n-6／n-3PUFA构成能差异性调节乳腺癌细胞IGF-1R表达，其中单纯n-3PUFA和1：1n-6／n-3PUFA能明显降低其表达并抑制乳腺癌细胞增殖。

饲粮n-6/n-3多不饱和脂肪酸比例对鹅肌肉脂肪酸组成的影响

本文旨在探讨饲粮n-6/n-3多不饱和脂肪酸(PUFA)比例对扬州鹅肌肉脂肪酸组成的影响。试验选取160只健康、体重接近的21日龄扬州鹅,随机分成4组,分别饲喂n-6/n-3 PU-FA比例为12∶1、9∶1、6∶1及3∶1的饲粮,于70日龄时取胸肌和腿肌,进行脂肪酸组成的测定。结果表明:1)在胸肌中,亚油酸的含量9∶1组显著高于3∶1组(P<0.05),而与其他各组之间无显著差异(P>0.05);α-亚麻酸的含量3∶1组显著高于6∶1和9∶1组(P<0.05),极显著高于12∶1组(P<0.01)。2)在腿肌中,亚油酸的含量12∶1和6∶1组均显著高于3∶1组(P<0.05),而与9∶1组无显著差异(P>0.05);α-亚麻酸的含量3∶1组显著高于6∶1组(P<0.05),极显著高于12∶1和9∶1组(P<0.01)。综上所述,鹅肌肉中n-6/n-3 PUFA比例随饲粮中该比例的下降而下降,并以3∶1组最低,但除12∶1组的腿肌n-6/n-3 PUFA比例较高外,其他各组比例均在世界卫生组织推荐的适于人体健康的(6∶1)～(10∶1)的比例范围内。

Cytochrome P450 monooxygenase-mediated eicosanoid pathway:A potential mechanistic linkage between dietary fatty acid consumption and colon cancer risk

Human consumption of linoleic acid(LA,18:2ω-6,abundant in vegetable oils)is very high.Animal experiments showed that excessive LA intake increased azoxymethane-induced colon tumorigenesis,however,the impact of excessive LA on colon cancer in human is not conclusive,making it difficult to make dietary recommendations for optimal intake of LA.Understanding the molecular mechanisms of LA on colon tumorigenesis could help to clarify its health effect,and facilitate development of mechanismbased strategies for preventing colon cancer.Recent studies show that the previously unappreciated cytochrome P450 monooxygenase-mediated eicosanoid pathway is upregulated in colon cancer and plays critical roles in its pathogenesis,and could contribute to the effects of dietary LA,as well asω-3 fatty acids,on colon tumorigenesis.In this review,we will discuss recent studies about the roles of cytochrome P450 monooxygenases in fatty acid metabolism and its roles in colonic inflammation and colon cancer,and how this information could help us to clarify the health impacts of dietary fatty acids.

日粮中添加亚麻籽油提高鸡肉中n-3PUFA含量的研究

选择216只21日龄罗斯308商品代肉用母雏,随机分为3组,每组6个重复,每个重复12只鸡。第1组为对照组,在玉米-豆粕型基础日粮上添加5%混合油,处理组分别在基础日粮中添加3%亚麻籽油(2组)和5%亚麻籽油(3组),试验期3周,旨在研究在日粮中添加不同水平的亚麻籽油对鸡肉中n-3PUFA含量和肉鸡生产性能影响。试验结果表明:与对照组相比,3%、5%亚麻籽油组肌肉组织中n-3C18:3、n-3C20:5和n-3PUFA含量显著提高(P<0.05),n-6/n-3比值显著降低(P<0.05),n-3C22:6水平则变化不大(P>0.05)。5%亚麻籽油组n-3PUFA总量显著高于3%亚麻籽油组(P<0.05),n-6/n-3比值低于3%亚麻籽油组(P>0.05)。n-3C18:3在胸肌和腿肌中的沉积量显著高于肝脏(P<0.05),n-3C20:5、n-3C22:6在胸肌和腿肌中的沉积量显著低于肝脏(P<0.05)。添加3%、5%亚麻籽油对肉鸡生产性能无显著性影响(P>0.05)。以上结果表明,肉鸡饲粮中使用亚麻籽油,可生产出n-3PUFA含量较高,n-6/n-3值较低,对人类健康有益的功能性鸡肉产品。

ω-3PUFAs Prevent MK-801-induced Cognitive Impairment in Schizophrenic Rats via the CREB/BDNF/TrkB Pathway

This study was to determine the protective effect of ω-3 polyunsaturated fatty acids（ω-3PUFAs） on MK-801-induced cognitive impairment in schizophrenia（SZ） rats and the underlying mechanism. A rat model of schizophrenia was induced by MK-801. The cognitive function of rats was assessed using a Morris water maze. The number of hippocampal neurons was measured by Nissl staining. The expression of CREB, p-CREB, BDNF, TrkB, p-TrkB, AKT, p-AKT, ERK, and p-ERK in the hippocampus of rats was detected by Western blotting. The results showed that ω-3PUFAs attenuated MK-801-induced cognitive impairment and hippocampal neurons loss, reversed the injury of the CREB/BDNF/TrkB pathway induced by MK-801, and antagonized MK-801-induced down-regulation of p-AKT and p-ERK in the hippocampus of rats. In conclusion, ω-3PUFAs enhances the CREB/BDNF/TrkB pathway by activating ERK and AKT, thereby increasing the synaptic plasticity and decreasing neuron loss, and antagonizing MK-801-induced cognitive impairment in schizophrenic rats.

Relationship between high dietary fat intake and Parkinson’s disease risk: a meta-analysis

OBJECTIVE: To assess whether dietary fat intake influences Parkinson’s disease risk. DATA SOURCES: We systematically surveyed the Embase and PubMed databases, reviewing manuscripts published prior to October 2018. The following terms were used:(“Paralysis agitans” OR “Parkinson disease” OR “Parkinson” OR “Parkinson’s” OR “Parkinson’s disease”) AND (“fat” OR “dietary fat” OR “dietary fat intake”). DATA SELECTION: Included studies were those with both dietary fat intake and Parkinson’s disease risk as exposure factors. The Newcastle-Ottawa Scale was adapted to investigate the quality of included studies. Stata V12.0 software was used for statistical analysis. OUTCOME MEASURES: The primary outcomes included the relationship between high total energy intake, high total fat intake, and Parkinson’s disease risk. The secondary outcomes included the relationship between different kinds of fatty acids and Parkinson’s disease risk. RESULTS: Nine articles met the inclusion criteria and were incorporated into this meta-analysis. Four studies scored 7 and the other five studies scored 9 on the Newcastle-Ottawa Scale, meaning that all studies were of high quality. Meta-analysis results showed that high total energy intake was associated with an increased risk of Parkinson’s disease (P = 0.000, odds ratio (OR)= 1.49, 95% confidence interval (CI): 1.26–1.75);in contrast, high total fat intake was not associated with Parkinson’s disease risk (P = 0.123, OR = 1.07, 95% CI: 0.91–1.25). Subgroup analysis revealed that polyunsaturated fatty acid intake (P = 0.010, OR = 1.03, 95% CI: 0.88–1.20) reduced the risk of Parkinson’s disease, while arachidonic acid (P = 0.026, OR = 1.15, 95% CI: 0.97–1.37) and cholesterol (P = 0.002, OR = 1.09, 95% CI: 0.92–1.29) both increased the risk of Parkinson’s disease. Subgroup analysis also demonstrated that, although the results were not significant, consumption of n-3 polyunsaturated fatty acids (P = 0.071, OR = 0.88, 95% CI: 0.73–1.05),α-linolenic acid (P = 0.06, OR = 0.86, 95% CI: 0.72–1.02), and the n-3 to n-6 ratio (P = 0.458, OR = 0.89, 95% CI: 0.75–1.06) were all linked with a trend toward reduced Parkinson’s disease risk. Monounsaturated fatty acid (P = 0.450, OR = 1.06, 95% CI: 0.91–1.23), n-6 polyunsaturated fatty acids (P = 0.100, OR = 1.15, 95% CI: 0.96–1.36) and linoleic acid (P = 0.053, OR = 1.11, 95% CI: 0.94–1.32) intakes were associated with a non-significant trend toward higher PD risk. Saturated fatty acid (P = 0.619, OR = 1.01, 95% CI: 0.87–1.18) intake was not associated with Parkinson’s disease. CONCLUSION: Dietary fat intake affects Parkinson’s disease risk, although this depends on the fatty acid subtype. Higher intake of polyunsaturated fatty acids may reduce the risk of Parkinson’s disease, while higher cholesterol and arachidonic acid intakes may elevate Parkinson’s disease risk. However, further studies and evidence are needed to validate any link between dietary fat intake and Parkinson’s disease.

The Effects of Dietary Fatty Acid Pattern on Layer's Performance and Egg Quality

The feeding trial was conducted to determine the effects of flaxseed on layer＇s performance and egg quality, and the effects of the dietary ratio of ω-6 fatty acid to ω-3 fatty acid on fatty acid deposition in yolk using flaxseed as resource of ω-3 fatty acid and sunflower seed as resource of ω-6 fatty acid. 192 20-wk-old Newroman commercial hens were randomly divided into 4 treatment groups with 6 replicates containing 8 birds. The rations corresponding with the four treatments were formulated with 4% flaxseed ＋ 9% sunflower seed, 8% flaxseed ＋ 18% sunflower seed, 15% flaxseed, and soybean meal, respectively. Sunflower seed was unshelled and flaxseed was whole. Ratios of ω-6 fatty acid to ω-3 fatty acid in 4 dietary treatments were 5.67, 5.21, 1.07, and 11.83, respectively. It can be concluded that long-term feeding 15% flaxseed had no significant （P〉 0.05） influence on egg production, egg weight, eggshell quality, yolk weight, and percentage of yolk weight. Dietary ratio of ω-6 fatty acid to ω-3 fatty acid had impact on the 0-3 fatty acid levels in yolk, nevertheless yolk fatty acid profiles were different from those of dietary fatty acid compositions.

ω-6/ω-3多不饱和脂肪酸比值对不同肿瘤发病风险的系统综述和Meta分析

目的系统评价ω-6/ω-3多不饱和脂肪酸(omega-6/omega-3 polyunsaturated fatty acids)比值与不同肿瘤发病风险的关系。方法系统检索9个数据库(Pubmed、Embase、Web of Science、Cochrane Library、Medline、知网、维普、万方、生物医学文献数据库)截至2024年1月31日有关ω-6/ω-3 PUFAs比值与肿瘤发病风险关系的研究,利用纽卡斯尔-渥太华量表(Newcastle-Ottawa Scale,NOS)对最终纳入的文献进行质量评价,R4.3.3软件进行Meta分析。结果共纳入27篇ω-6/ω-3PUFAs比值对不同肿瘤发病率影响的研究,其中队列研究7项,病例对照研究20项。共纳入研究对象197401例,病例组和暴露组81950例,对照组和非暴露组115451例。Meta分析结果显示:ω-6/ω-3PUFAs比值与不同肿瘤发病风险关联无统计学意义(OR=1.03,95%CI:0.98~1.09,P=0.18)。亚组分析显示,较高的ω-6/ω-3PUFAs比值会增加乳腺癌的发病风险(OR=1.05,95%CI:1.01~1.10,P=0.01),而与前列腺癌(OR=1.26,95%CI:0.67~2.38,P=0.47),结直肠癌(OR=0.99,95%CI:0.89~1.10,P=0.85)的发病风险关联无统计学意义。在非欧美地区,较高的ω-6/ω-3PUFAs比值会显著增加不同肿瘤发病的风险(OR=1.24,95%CI:1.01~1.51,P=0.04),而在欧美地区则没有统计学意义(OR=1.02,95%CI:0.97~1.07,P=0.46),在评估暴露指标与不同肿瘤发病风险的关系中,饮食摄入(OR=1.04,95%CI:0.98~1.09,P=0.17)和基于血液(红细胞、血清、血浆)测定的ω-6/ω-3PUFAs比值(OR=1.00,95%CI:0.92~1.09,P=0.96),均无统计学意义的关联。针对乳腺癌的亚组分析显示,在欧美地区,较高的ω-6/ω-3PUFAs比值会增加乳腺癌的发病风险(OR=1.05,95%CI:1.01~1.11,P=0.03),但在非欧美地区则无统计学意义(OR=1.05,95%CI:0.97~1.14,P=0.22)。较高的饮食摄入ω-6/ω-3PUFAs比值会增加乳腺癌的发病风险(OR=1.05,95%CI:1.01~1.10,P=0.02),而血液中(红细胞、血清、血浆)ω-6/ω-3PUFAs比值对乳腺癌发病的风险关联却没有统计学意义(OR=1.07,95%CI:0.93~1.23,P=0.37)。结论ω-6/ω-3PUFAs比值与不同肿瘤发病风险的影响尚无明确结论,但较高的ω-6/ω-3PUFAs比值会增加乳腺癌的发病风险,尤其是在欧美地区。而在非欧美地区,较高的ω-6/ω-3PUFAs比值会显著增加不同肿瘤发病的风险。此外,较高的饮食摄入ω-6/ω-3PUFAs比值也会增加乳腺癌的发病风险。上述观点有待通过更多前瞻性干预实验加以实证确认。

不同n-6/n-3多不饱和脂肪酸构成比对高脂饲料喂养大鼠脂联素和糖脂代谢及抗氧化能力的影响

目的探讨高脂饲料喂养条件下,不同n-6/n-3多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)构成比对大鼠脂联素和糖脂代谢及抗氧化能力的影响。方法50只雄性Wistar大鼠按体重随机分为5组:1个普通饲料组(脂肪供能比17%,n-6/n-3PUFA=5∶1)和4个高脂饲料组(脂肪供能比均为42%,n-6/n-3 PUFA构成比分别为1∶1、5∶1、10∶1、20∶1)。喂养12周后检测大鼠血糖和血脂(0、4、8和12周)、血清抗氧化指标(0和12周)以及睾周脂肪组织脂联素mRNA、蛋白表达和血清脂联素水平(12周)。结果大鼠各指标初始值组间差异均无统计学意义(P>0.05)。12周时,n-6/n-3PUFA 10∶1、20∶1组血糖显著高于对照组(P<0.05),4个高脂组血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)显著高于对照组(P<0.01),其中20∶1组TG显著高于其余3组(P<0.01);4个高脂组谷胱甘肽过氧化物酶和超氧化物歧化酶含量显著低于对照组(P<0.05),其中20∶1组下降最明显,丙二醛含量显著高于对照组(P<0.05),其中10∶1组上升最明显;20∶1组脂联素mRNA表达显著低于对照组、1∶1组和5∶1组(P<0.05),5∶1组脂联素蛋白表达水平显著高于其余高脂组(P<0.05),而20∶1组表达水平最低(P<0.05)。结论较低的n-6/n-3 PUFA构成比(1∶1和5∶1),有助于改善高脂饲料条件下大鼠糖脂代谢及抗氧化能力,提高脂联素表达。

日粮中脂肪酸对羊牛猪肉中长链多不饱和脂肪酸和共轭亚油酸的影响

随着消费者健康意识的提高,越来越多的研究关注提高家养动物肉产品中多不饱和脂肪酸（PUFA）含量,尤其是n-3长链脂肪酸和共轭亚油酸（CLA）在羊、牛、猪肉肌内脂中的含量.研究结果表明通过添加鱼油或鱼粉能提高动物肉中n-3长链脂肪酸含量.富含亚麻油酸（LNA）的日粮能提高肉中LNA、二十碳五烯酸（EPA）和二十二碳五烯酸（DPA）水平,但大部分对肌肉中二十二碳六烯酸（DHA）水平没有影响.然而,在日粮中添加鱼油或鱼粉大部分能提高动物肌肉中DHA含量.大部分研究中提高n-3脂肪酸含量的同时n-6脂肪酸含量下降,这主要归因于试验组日粮中n-6脂肪酸降低.这样刚好可以使肉中两者比例更合理,但对多不饱和脂肪酸与饱和脂肪酸比例没什么影响. 饲喂反刍动物富含n-3脂肪酸日粮（亚麻籽或加草料）、鱼油或富含LA的浓缩料可提高肌肉中c9t11CLA含量.牛肉、羊肉中c9t11CLA在总脂中含量介于0.2～1.0 g/100 g,不随营养因素提高到更高.相对应的,在单胃动物日粮中添加混合CLA油则显著提高CLA含量.

孕期膳食脂肪酸与新生儿出生结局关系的研究

目的 探讨孕期膳食脂肪酸与新生儿出生状况的关系。方法 招募早孕妇女,采用即时性图像法调查孕中、晚期膳食状况,计算食物摄入量,以及能量、宏量营养素和脂肪酸摄入量;采集新生儿体质量、身长和BMI等体格生长指标,分析孕期膳食脂肪酸摄入与新生儿体格生长之间的关联。结果 在有效纳入的516名孕妇中,孕中期和孕晚期膳食多不饱和脂肪酸（PUFA）平均摄入量以及占总脂肪酸比例分别为15.09g/d、23.93%和17.18g/d、24.7%,其中n-6和n-3 PUFA摄入量在孕中期为14.23 g/d和3.45 g/d,孕晚期为16.08 g/d和3.81 g/d,差异均有统计学意义（P〈0.05）。孕中期n-6/n-3 PUFA比值为4.11,孕晚期4.28,差异无统计学意义（P〉0.05）。二十二碳六烯酸（DHA）摄入量在孕中期为64.43 mg/d,孕晚期75.12 mg/d,差异有统计学意义（P〈0.05）。亚油酸（LA）和α-亚麻酸（ALA）两种必需脂肪酸占能量的百分比在孕中期分别为5.95%和1.42%,孕晚期为6.20%和1.45%,差异无统计学意义（P〉0.05）。孕中期n-3和n-6 PUFA摄入量、n-6/n-3比值均与新生儿BMI呈正相关（r=0.142~0.189,P〈0.05）,孕晚期只有n-3 PUFA和DHA摄入量与新生儿出生体质量呈正相关（r=0.206,0.193,P〈0.05）,n-6/n-3比值与新生儿BMI未表现出相关性（r=-0.018,P〉0.05）。结论 孕中期膳食n-6和n-3摄入与新生儿BMI相关。

Effect of fish oil enriched enteral diet on inflammatory bowel disease tissues in organ culture: Differential effects on ulcerative colitis and Crohn's disease

AIM： To investigate the influence of fish oil enriched enteral diet on intestinal tissues taken from Crohn＇s disease （CD）, ulcerative colitis （UC） and non-inflamed non-IBD control patients in vitro. METHODS： Colonoscopic biopsies from patients with active CD （n = 4）, active UC （n = 7）, and non-inflamed non-IBD control patients （n = 4） were incubated （three dilutions of 1：20, 1：10, and 1：5） with Waymouth＇s culture medium and enteral elemental diet （EO28, SHS, Liverpool, UK） modified in the fatty acid composition with fish oil （EF） in an organ culture system for 24 h. In each experimental set-up, incubation with Waymouth＇s medium alone as control was included. Tissue viability was assessed by adding bromodeoxyuridine （BrdU） to the culture fluid and immunohistochemically staining for BrdU uptake. Cytokine ratio of IL-1ra/IL-1β （low ratio indicative of inflammation） and production of those cytokines as a percentage of medium control were assayed in the culture supernatant. RESULTS： Incubation of CD-affected tissue with EF （1：20, 1：10, and 1：5） modestly and non-significantly increased IL-1ra/IL-1β ratio as compared with medium control （CD 39.1±16.1; 26.5±7.8, 47.1±16.8 vs control 13.0±2.2）, but incubation of UC-affected tissues increased IL-1ra/IL-1β ratio significantly in all three dilutions （UC 69.1±32.2, P〈0.05; 76.1±36.4, P = 0.05; 84.5±37.3, P〈0.02; vs control 10.2±3.7）. Incubation of non-inflamed non-IBD control tissue did not increase the IL-1ra/IL-1β ratio in any dilution compared to medium control （69.3±47.0, 54.1±30.6, 79.4±34.0 vs control 76.1±37.3）. Average percentage production of IL-1β indexed against medium control was significantly less in UC after EF incubation as compared with CD （UC 24.0±4.8 vs CD 51.8±8.1; P〈0.05）. Average percentage production of IL-tra was markedly higher in UC （135.9±3.4） than that in control patients （36.5±4.3） （p〈0.0001）. CONCLUSION： IBD tissues, after incubation with elemental diet modified in its fatty acid composition with fish oil, show an increase in IL-1ra/IL-1β cytokine ratio. This effect of ω-3 fatty acid modulation is significantly more marked in UC compared with CD and is accompanied by both a reduction of IL-1β and increase of IL-1ra. The positive direct anti-inflammatory effect of elemental diet with fish oil in tissue affected with UC suggests dietary treatment of UC may be possible.

新时期国民膳食脂质摄入推荐的几点建议

随着社会经济水平的快速提高,我国居民膳食结构发生了明显的改变。膳食脂质是膳食结构的重要组成部分,其推荐摄入量对改善居民膳食结构,实现新时期健康中国建设目标的都有着重要影响。对中国居民膳食脂质参考摄入量的修订提出几点建议。(1)我国18岁及以上居民的膳食脂肪供能比可接受范围上限(U-AMDR)是30%E,低于欧盟和北美国家的35%E。有学者建议提高我国成年人膳食脂肪供能比的U-AMDR,但仍缺乏足够的证据,暂不宜做修改。然而,考虑到老年人需要高能量和营养密度膳食的特点,应考虑提高老年人膳食脂肪的U-AMDR。(2)一些研究表明n-6/n-3多不饱和脂肪酸比值(n-6/n-3PUFA)与多种慢性非传染性疾病发生风险密切相关。我国居民膳食中n-6/n-3PUFA比值的平均值达到8.6,在某些人群中甚至更高。因此,建议将膳食中n-6/n-3PUFA比值的推荐值纳入新版膳食脂质参考摄入量推荐中。(3)尽管开展了大量研究,但膳食胆固醇摄入量与心血管疾病等多项慢性疾病发生结局之间的关系仍不明确。我国城市居民平均每日胆固醇摄入量为264.0mg,农村居民为168.8 mg,处于正常范围。基于目前的研究证据,仍无法针对一般成年人群制订膳食胆固醇摄入限量。对于心脑血管疾病等慢性疾病的患者,建议参考相应疾病指南中膳食胆固醇摄入量的推荐。