青岛市体检人群日常膳食脂肪摄入调查分析

目的探讨青岛居民日常膳食中脂肪的摄入量,分析膳食脂肪摄入构成。方法在青岛市市立医院2012年健康查体人群中随机抽取189例进行体格检查、病史调查、空腹血生化检查、膳食调查。通过简化的食物频率表进行现场调查问卷,询问每一个调查对象过去一年中各类食物的摄入频率和摄人量。结果青岛居民每日每人粮谷类食物的平均摄入量约200g,薯类食物约26g,畜禽肉及内脏约85g,海产品约73g,其中小黄鱼、海虾和蛤蜊的摄入量较其他海产品高;坚果类和油脂类平均摄入量分别约23g和40g,摄入量较高。脂肪约占摄入总能量的37％,其中比重最高的为油脂类,约占摄入脂肪的43％,其次为坚果类（约11％）,其他分别为畜禽肉类（约5％）,海产品（约1．8％）。饱和脂肪酸（SFA）：单不饱和脂肪酸（MUFA）：多不饱和脂肪酸（PUFA）的比值为1：1．5：1．49,比例不均衡,其中MUFA、PUFA占总脂肪酸比例较高,而ω-3PUFA摄入量较低,人均每天仅约为0．15g。结论青岛居民膳食中营养素摄入齐全,脂肪摄人偏高,脂肪酸比例失衡,这样的膳食结构不利于预防和控制血脂异常及心血管等疾病。     

应用食物频率法评价普米族膳食多不饱和脂肪酸摄入与高血压、血脂异常的关系

目的研究普米族膳食中多不饱和脂肪酸的摄入与高血压、血脂异常的关系。方法选择云南省怒江州兰坪白族普米族自治县18岁以上376例普米族居民为研究对象,采用问卷调查收集研究对象过去一年中各种食物的摄入频率及摄入量、现病史和家族史情况;测量研究对象血压;采集调查对象空腹血测定甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)。结果普米族居民的膳食脂肪摄入量较高,占RNI的198.5%;三大产能营养素的供能比失衡,但n-3PUFA、EPA、DHA的人均摄入量并不高。普米族居民高血压患病率为15.4%;血脂异常类型主要表现为低高密度脂蛋白血症,占54.8%,高胆固醇血症占8%,高甘油三酯血症占19.1%,TC或TG异常人群占25.0%。PUFAs与血脂异常、n-6PUFA与高血压呈负相关关系。结论普米族居民应减少油脂类及高脂肪食物的摄入,增加富含DHA、EPA类食物的摄入,以防止心血管疾病的发生与发展,降低血脂。     

膳食脂肪对高血压人群血脂水平的影响

目的 探讨改善膳食脂肪摄入情况对血脂的影响。方法 对营养健康教育前后高血压患者的膳食脂肪摄入情况及血脂水平进行测定分析。结果 基线调查表明人群膳食脂肪及胆固醇摄入量过高,脂肪供能比占总热能的30％以上;血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL－L）水平偏高。相关分析表明,体质指数（BMI）和饱和脂肪酸（SFA）与血清TC、TG、LDL－C呈正相关;高密度脂蛋白（HDL－C）／TC与BMI、SFA呈负相关,而与单不饱和脂肪酸（MUFA）呈正相关。进行社区营养干预后,干预组脂肪供能比小于总热能的30％,与对照组相比及自身干预前后比较差异均有显著性,胆固醇摄入量有下降趋势;干预组人群血脂TC、LDL－C水平显著降低。结论 研究结果提示减少膳食脂肪和胆固醇摄入量,适当增加单不饱和脂肪酸摄入对高血压人群降低血脂水平,控制血压是有效的。     

广州市555名40～65岁居民膳食现况调查

目的了解广州市555名40～65岁居民的膳食营养状况,为当地居民合理膳食提供科学依据。方法招募广州市民555名（男188名,女367名）,用食物模具量化的食物频数问卷（foodfrequencyquestionnaire,FFQ）和三日膳食回顾调查研究居民每日摄入食物种类和数量,与中国居民膳食营养素参考摄入量及膳食平衡宝塔相比,评价受调查者的营养素摄人状况。结果（1）膳食特点：以粮谷类（306．6±100．5）g／d为主要能量来源;畜禽肉（128．0±87．7）g／d和食用油（36．7±13．0）g／d摄人过量;奶类（108．8±115．4）g／d和豆制品（25．0±26．0）g／d摄入不足;蔬菜摄入量为（572．1±235．5）g／d;水果摄入量（186．3±132．9）g／d。（2）膳食能量为（2128．5±523．0）kcal／d,碳水化合物摄入量（285．6±75．1）g／d,供能比（54．5±7．4）％;蛋白质摄人量（83．1±28．1）g／d,供能比（15．7±3．2）％;脂肪摄入量（82．9±28．6）g／d,供能比（29．7±6．6）％,饱和脂肪酸（saturatedfattyacid,SFA）：单不饱和脂肪酸（monounsaturatedfattyacid,MUFA）：多不饱和脂肪酸（polyunsaturatedfattyacid,PUFA）为1：1．5：1,胆固醇摄人量（335．7±174．6）g/d。结论该人群的膳食需要改进的方面包括控制食用油摄人量在25g／d以内,通过增加禽肉和大豆类的摄人次数和数量以减少畜肉的摄入,最终达到减少胆固醇的摄人。     

膳食脂肪酸对人体脂蛋白代谢影响研究进展

血脂异常是诱发心血管疾病(CVD)的主要危险因素之一。膳食脂肪酸的组成可以调节脂肪及脂蛋白代谢,缓解血脂异常,从而有益于改善CVD。本文旨在介绍几种膳食脂肪酸对人体脂蛋白代谢影响的最新研究进展。血脂异常患者摄入高比例的n-3多不饱和脂肪酸(n-3PUFA)可以减少肝脏分泌富甘油三酯脂蛋白(TRL)促进TRL向低密度脂蛋白(LDL)的转化,同时n-3PUFA可以减少TRLapoB-48分泌。高比例的n-6PUFA摄入可通过加速极低密度脂蛋白胆固醇和甘油三酯的脂解作用来降低二者的浓度。在一项针对饱和脂肪酸的研究中,高sn-2位软脂酸膳食可以降低餐后血脂。降低中链甘油三酯(MCT)的比例不会明显改变TRL的代谢。将摄入的碳水化合物替换为单不饱和脂肪酸可增加TRL代谢率。反式脂肪酸会降低LDL分解同时提高高密度脂蛋白(HDL)分解。以n-3PUFA为代表的脂肪酸调节脂蛋白代谢可以作为一种调控血脂及预防潜在CVD的途径。本文同时将介绍载脂蛋白E(APOE)基因与n-3PUFA的相互作用。     

我国居民不饱和脂肪酸的膳食摄入与构成分析

目的 分析中国居民不饱和脂肪酸摄入量及膳食摄入来源。方法 采用气相色谱法测定膳食样品中脂肪酸含量,并结合各类膳食的消费量获取不同地区各类脂肪酸的实际摄入量。结果 中国居民单不饱和脂肪酸（MUFA）平均摄入量为29.25g/d(12.53%E,供能百分比)，主要来自于肉类（35.5%）和蔬菜类（32.0%），来自于其他食品类别的比例小于10%。多不饱和脂肪酸（PUFA）平均摄入量为22.48 g/d(9.72%E)，主要来自于蔬菜类（33.8%）、肉类（20.8%）、谷类（17.7%）和豆类（13.0%）。n-6PUFA平均摄入量为19.78 g/d(8.59%E)，其主要膳食来源与PUFA相似。n-3PUFA平均摄入量为2.70 g/d(1.19%E)，主要来自于蔬菜类（38.9%），肉类（15.9%）、豆类（12.7%）和谷类（12.1%）。二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）膳食平均摄入量为0.067 g/d(0.03%E)，主要来自于水产类（75.4%）和蛋类（19.8%）。结论 中国居民的不饱和脂肪酸摄入量充足，满足需求。其中，PUFA和n-3PUFA膳食摄入量符合...     

膳食多不饱和脂肪酸与女性内脏型肥胖的关系

目的分析女性内脏型肥胖与膳食多不饱和脂肪酸(PUFA)之间的相关性,为预防女性肥胖提供依据。方法选取2013年在天津市和平区健康体检中心进行健康体检的1 617名女性为调查对象,按照内脏脂肪面积(VFA)的大小,分为内脏脂肪正常组(VFA90 cm2,1 011例)和内脏脂肪肥胖组(VFA≥90 cm2,606例)。对体检者进行体格检查、实验室生化指标检查和膳食调查,并采用体脂仪测定VFA。应用SPSS 19.0软件及t检验和χ2检验进行统计学分析。应用协方差分析以及logistic回归分析女性VFA与PUFA之间的相关性。结果女性内脏脂肪肥胖组的年龄、体质指数(BMI)、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)以及空腹血糖(FPG)均高于内脏脂肪正常组,高密度脂蛋白胆固醇(HDL-C)显著低于内脏脂肪正常组,差异均有统计学意义(P0.01)。年龄、BMI、TG、TC、LDL-C和FPG与VFA呈正相关(r值分别为0.479、0.792、0.401、0.300、0.325和0.262,P0.01),HDL-C与VFA呈负相关(r=-0.210,P0.01)。随着VFA的升高,膳食n-3 PUFAs的摄入量逐渐减少,趋势性检验差异有统计学意义(P0.05)。采用步入法调整年龄、BMI、能量、膳食纤维、饱和脂肪酸、不饱和脂肪酸、体力活动和吸烟饮酒等混杂因素后,最高摄入水平的n-3 PUFAs(OR=0.67,95%CI:0.45~0.98)和n-6 PUFAs(OR=0.65,95%CI:0.44~0.97)是女性内脏型肥胖的保护性因素。未发现n-6/n-3比例与女性内脏型肥胖相关。结论在女性人群中膳食低n-3、n-6 PUFAs摄入水平容易导致体内内脏脂肪蓄积。     

郑州市城区居民食物摄入状况调查结果分析

目的 调查分析郑州市城区居民食物摄入状况,为合理膳食指导干预提供参考。方法 采用多阶段整群随机抽样方法,抽取郑州市城区24个社区,每个社区10～12户,对每户所有3岁及以上人群,采取3 d 24 h膳食回顾法和食物称重法进行调查分析。结果 2020年共调查267户738人,每标准人日谷薯类（595.4 g）和蛋类（51.4 g）食物摄入高于推荐量;奶及奶制品（56.7 g）、蔬菜类（203.2 g）、水产类（0 g）、大豆及坚果（5.3 g）、水果类（18.1 g）和食用油（21.5 g）摄入低于推荐量;畜禽肉类（70.6 g）和食用盐（5.4 g）摄入符合推荐量。各类食物中仅谷薯类和蛋类摄入量大于2012全国监测数据（Z = 20.65,P＜0.001;Z = 18.33,P＜0.001）。男性谷薯类和蔬菜类的摄入量大于女性（χ2 = 15.09,P＜0.001;χ2 = 4.43,P = 0.035）;女性奶及奶制品的摄入量多于男性（χ2 = 4.19,P = 0.041）;不同年龄性别居民食物摄入量波动较大。结论 郑州市城区居民膳食结构不太合理,奶及奶制品、蔬菜类、水产类、大豆及坚果和水果类摄入量不足,应不断进行膳食结构优化,做好居民合理膳食指导干预工作。     

广州中老年居民膳食n-3脂肪酸摄入水平与血脂关系的研究

目的分析广州居民膳食n-3脂肪酸摄入水平与血脂的关系。方法志愿者形式招募40～75岁广州市民,采用定量食物频数问卷调查研究对象每日食物摄入种类及数量,计算能量及营养素,特别是n-3脂肪酸含量。检测空腹血脂4项。将膳食n-3脂肪酸摄入量四分位分组分析其与血脂的相关关系。结果共招募3974名研究对象,其膳食总能量摄入量为(7.68±2.24)MJ/d、脂肪供能比为(33.1±7.8)%,饱和脂肪酸供能比为(8.3±2.2)%。膳食n-3脂肪酸摄入量为(1.29±1.02)g/d,其中α-亚麻酸(ALA)为(1.18±0.99)g/d[(0.58±0.42)%energy],二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)为(99.50±103.09)mg/d。校正年龄、性别、BMI、总能量、饱和脂肪酸及膳食n-6脂肪酸摄入量等混杂因素后,膳食ALA摄入量与空腹血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)呈剂量依赖的负相关关系(P<0.05),Q4(2.23g/d)的TC、HDL-C及LDL-C显著低于Q1(0.47g/d)(P<0.05);膳食EPA+DHA摄入量与TG及HDL-C也呈线性负相关关系(P﹤0.05),Q1(26.40 mg/d)的TG及HDL-C水平显著高于其他3组(P<0.05)。结论与ALA和EPA+DHA摄入量分别为0.47 g/d和26.40 mg/d相比,摄入量达到2.23 g/d和200.30 mg/d时有利于将血脂维持在较低水平。     

成都市某社区40～64岁人群膳食结构和营养素分析

目的了解中老年人膳食结构和营养素摄入情况,为有针对性的开展营养改善工作提供依据。方法选取成都市40～64岁居民571名,采用食物频率回顾问卷进行调查,了解其一般情况及过去1年食物摄入情况,分析各类食物摄入量及膳食能量、营养素摄入情况,并测量其身高体重。结果调查对象平均每日食物摄入量为：主食338.0g（谷类327.8g,薯类10.1g）,蔬菜471.3g,水果86.4g,豆类58.6g,奶类129.9g,畜肉102.7g,禽肉11.8g,水产品25.8g,食用油37.5g;食用油和豆类摄入量高于膳食指南推荐量,奶类、水果和水产品的摄入量低于推荐量;谷类、薯类、禽肉、水产品摄入量低于全国平均水平,蔬菜、豆类、坚果和畜肉类高于全国平均水平;膳食中脂肪、胆固醇、烟酸、维生素E、钠、磷、铁、铜和锰摄入量高于推荐量,钙摄入量低于推荐量。结论中年居民膳食结构和营养素摄入与膳食指南推荐量有差异,营养过剩与营养不良并存。     

Long-chain n-3-to-n-6 polyunsaturated fatty acid ratios in breast adipose tissue from women with and without breast cancer

Animal studies suggest that dietary polyunsaturated fatty acids (PUFAs) of the n-6 class, found in corn and safflower oils, may be precursors of intermediates involved in the development of mammary tumors, whereas long-chain (LC) n-3 PUFAs, found in fish oil, can inhibit these effects. This case-control study was designed to examine the relationship between the PUFA composition of breast adipose tissue and the risk of breast cancer. Using fatty acid levels in breast adipose tissue as a biomarker of past qualitative dietary intake of fatty acids, we examined the hypothesis that breast cancer risk is negatively associated with specific LC n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid) and positively associated with n-6 PUFAs (linoleic acid and arachidonic acid). Breast adipose tissue was collected from 73 breast cancer patients and 74 controls with macromastia. The fatty acid levels were determined by gas-liquid chromatography. A logistic regression model was used to obtain odds ratio estimates while adjusting for age. The age-adjusted n-6 PUFA (linoleic acid and arachidonic acid) content was significantly higher in cases than in controls (P = 0.02). There was a trend in the age-adjusted data suggesting that, at a given level of n-6 PUFA, LC n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid) may have a protective effect (P = 0.06). A similar inverse relationship was observed with LC n-3-to-n-6 ratio when the data were adjusted for age (P = 0.09). We conclude that total n-6 PUFAs may be contributing to the high risk of breast cancer in the United States and that LC n-3 PUFAs, derived from fish oils, may have a protective effect.     

Increasing trends in dietary total fat and fatty acid intake among Korean children: using the 2007–2017 national data

BACKGROUND/OBJECTIVESThe prevalence of obesity has been increasing in Korean children. As an unhealthy diet is known as one of the major determinants of childhood obesity, assessing and monitoring dietary fat intake of children is needed.SUBJECTS/METHODSThis analysis included 9,998 children aged 3–11 yrs from the 2007–2017 Korea National Health and Nutrition Examination Surveys. Dietary data were obtained from a single 24-h dietary recall. Intakes of total fat and fatty acids, including saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), n-3 fatty acid (n-3 FA), and n-6 fatty acid (n-6 FA) were evaluated as the absolute amount (g) and proportion of energy from each fatty acid (% of energy). The total fat and SFA intake were also assessed according to compliance with dietary guidelines. Linear trends in the dietary fats intake across the survey period were tested using multiple regression models.RESULTSTotal fat intake significantly increased from 38.5 g (20.3% of energy) to 43.4 g (23.3% of energy) from 2007 to 2017. This increase was mainly accounted for the increases in intakes of SFA (7.2% to 8.4% of energy) and MUFA (6.2% to 7.5% of energy). PUFA intake increased from 4.4 to 4.7% of energy during the 11-yrs period: from 0.57 to 0.63% of energy for n-3 FA and from 3.8 to 4.1% of energy for n-6 FA. The proportions of children who consumed amounts exceeding the dietary guidelines for total fat and SFA significantly increased from 2007 to 2017, with increases from 9.8% to 17.4% for total fat and from 36.9% to 50.9% for SFA.CONCLUSIONSProminent increasing trends in the consumption of total fat and SFA but tiny change in n-3 FA intake were observed in Korean children. The healthy intake of dietary fats should be emphasized in this population.     

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.     

Dietary Lipids in Early Development and Intestinal Inflammatory Disease

Inflammatory bowel diseases are life-long reoccurring inflammatory disorders of the gastrointestinal tract and have been increasing in incidence in recent decades, notably in the pediatric population. Although genetic predisposition remains an important factor, this increased incidence most likely reflects an environmental change. One potential contributor to this is the change in dietary fat intake, with dietary intake of n-6 polyunsaturated fatty acids (PUFAs) following a similar temporal pattern to the change in inflammatory bowel disease incidence. Dietary n-6 PUFAs comprise a major, modifiable, environmental factor known to promote a heightened inflammatory response through a number of pathways, including their role as precursors for synthesis of eicosanoids and their inhibitory effect on the synthesis of the n-3 PUFAs eicosapentanoic acid and do-cosahexanoic acid. The increase in n-6PUFA intake affects individuals of all ages, with fetal PUFA accretion and infant dietary PUFA intake from breast milk reflecting maternal dietary intake. A high level of n-6 PUFA in milk results in increased n-6 PUFA in colonicphospholipids and an exaggerated inflammatory response to chemically induced colitis. Conversely, during development, a diet low in n-6 PUFAs and high in n-3 PUFAs increases colonic n-3 fatty acids, attenuates the inflammatory response, and lowers colonic damage. High dietary n-6 PUFA intake may be an important environmental modifier that contributes to inflammatory bowel diseases.     

Position of the American Dietetic Association and Dietitians of Canada: dietary fatty acids

It is the position of the American Dietetic Association (ADA) and Dietitians of Canada (DC) that dietary fat for the adult population should provide 20% to 35% of energy and emphasize a reduction in saturated fatty acids and trans-fatty acids and an increase in n-3 polyunsaturated fatty acids. ADA and DC recommend a food-based approach for achieving these fatty acid recommendations; that is, a dietary pattern high in fruits and vegetables, whole grains, legumes, nuts and seeds, lean protein (ie, lean meats, poultry, and low-fat dairy products), fish (especially fatty fish high in n-3 fatty acids), and use of nonhydrogenated margarines and oils. Implicit to these recommendations for dietary fatty acids is that unsaturated fatty acids are the predominant fat source in the diet. These fatty acid recommendations are made in the context of a diet consistent with energy needs (ie, to promote a healthful body weight). ADA and DC recognize that scientific knowledge about the effects of dietary fats on human health is incomplete and take a prudent approach in recommending a reduction in those fatty acids that increase risk of disease, while promoting intake of those fatty acids that benefit health. Registered dietitians play a pivotal role in translating dietary recommendations for fat and fatty acids into healthful dietary patterns for different population groups.     

妊娠期糖尿病患者的膳食结构分析

目的分析常州地区妊娠期糖尿病孕妇（GDM）膳食摄入情况,为孕妇营养指导提供依据。方法以2010年1月至2012年12月在常州市妇幼保健院产科门诊确诊的GDM孕妇133例为调查组,孕周为24—28周,选取同期产检的、年龄相近、孕周相同的正常孕妇110例作为对照组,采用24小时回顾性膳食调查（3天）,比较两组孕妇膳食能量和膳食结构区别,特别是蛋白和脂肪结构。结果GDM组平均每日能量摄入、蛋白质、脂肪、碳水化合物三大营养素的摄入量明显升高。其中GDM组平均每日摄入的饱和脂肪酸量（15．73±7．75）g,高于对照组（12．53±4．44）g,差异具有统计学意义（t=-4．02,P〈0．01）：GDM组动物蛋白（59．08±19．58）g摄入量高于对照组（48．71±12．93）g,GDM组动物脂肪（40．02±14．37）g摄入量高于对照组（29．15±10．53）g,GDM组豆类蛋白构成比（7．16±6．29）％较对照组（12．83±7．42）％明显低,GDM组动物脂肪构成比（40．86±10．68）％高于对照组（36．68±9．91）％,GDM组植物脂肪构成比（59．13±10．68）％低于对照组（63．32±9．91）％。GDM组单不饱和脂肪酸供能比（12．65±3．23）％、多不饱和脂肪酸供能比（10．47±2．90）％,低于对照组（13．474-3．23）％和（11．95±3．21）％。以上各项差异均具有统计学意义（分别为P〈0．05和P〈0．01）。结论GDM孕妇孕期膳食结构的不合理性主要表现为动物性食物摄入增多、蛋白质中豆类蛋白构成比的减少、脂肪中动物脂肪的构成比增多、饱和脂肪酸摄入量增多和多不饱和脂肪酸供能比减少,     

What are the health effects of fat?

In order to answer the question which health benefits are to be expected from dietary fat, we have to differentiate between different kinds of fat with varying fatty acid composition. Saturated fatty acids are commonly judged to have a negative health impact as they lead to increased serum cholesterol levels and a higher risk of coronary heart disease. Therefore, all recommendations stress the importance to limit the intake of saturated fatty acids. Monounsaturated fatty acids, on the other hand, have a positive impact on the serum lipid profile, lead to decreased LDL-oxidation and favorably influence the metabolism of diabetics. However, it is essential that monounsaturated fatty acids be mainly supplied by plant oils like rape seed or olive oil and not by foods that are simultaneously rich in saturated fatty acids. Concerning polyunsaturated fatty acids, it is important to increase the supply of n-3 fatty acids (ratio of n-6:n-3: about 5:1) as there is substantial evidence for their protective effects. If the fatty acid composition of the diet is optimized, even a total dietary fat content of 35% of total energy intake can be adequate as long as there is enough physical activity and the diet is rich in plant-derived foods like vegetables, fruits, cereals, potatoes, beans and legumes.     

Differences in the intramolecular structure of structured oils do not affect pancreatic lipase activity in vitro or the absorption by rats of (n-3) fatty acids

The fatty acid composition and intramolecular structure of dietary triacylglycerols (TAGs) influence their absorption. We compared the in vitro pancreatic lipase activity and the lymphatic transport in rats of fish oil and 2 enzymatically interesterified oils containing 10:0 and (n-3) PUFAs of marine origin to investigate whether the positional distribution of fatty acids influenced the overall bioavailability of (n-3) PUFAs in the body. The structured oils had the (n-3) PUFA either mainly at the sn-1,3 position (LML, M = medium-chain fatty acid, L = long-chain fatty acid) or mainly at the sn-2 position (MLM). Oils were administered to lymph-cannulated rats and lymph was collected for 24 h. The fatty acid composition as well as the lipid class distribution of lymph samples was determined. In vitro pancreatic lipase activity was greater when fish oil was the substrate than when the structured oils were the substrates (P < 0.001 at 40 min). This was consistent with a greater 8-h recovery of total fatty acids from fish oil compared with the 2 structured oils (P < 0.05). The absorption profiles of MLM and LML in rats and their in vitro rates of lipase activity did not differ. This indicates that the absorption rate is highly influenced by the lipase activity, which in turn is affected by the fatty acid composition and intramolecular structure. The lipid class distribution in lymph collected from the 3 groups of rats did not differ. In conclusion, the intramolecular structure did not affect the overall absorption of (n-3) PUFAs.