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脂类脂类 Lipids单毓娟单毓娟(Dr.&Associated Prof.)第一章第一章 营养学根营养学根底底yujuan72163 (B703)In the fall of 1995 when 28-year-old skater Sergei Grinkov,a two-time Olympic gold medalist,collapsed and died of a fatal heart attack while training in Lake Placid,New York.戈尔蒂耶娃格林科夫戈尔蒂耶娃格林科夫一、脂类概述一、脂类概述Introduction of LipidsMain contentsIntroduction of LipidLipids in Nutrition ScienceClassification of triglycerides-3 and-6 fatty acids Fat digestion and absorptionFunctions of fatDisadvantages of fatsNutritional assessment of dietary fatDietary reference intakes(DRIs)of fatAn autopsy revealed that his coronary arteries were as severely clogged as those of a 70-year-old with established heart disease.Normal artery containing little cholesterol-rich plaque.Artery that is partially blocked with plaque,which can lead to a heart attack.Cholesterol-rich4High fat dietHeart disease?Lipid-Friend or foe?What causes a heart attack?Although some people think of dietary fat as something to be avoided,a certain amount of fat is absolutely essential for good health.So what suggestions do you give when people eat foods abundant in fat?Can you talk about something related with lipid or fat?Foods rich in fats?Lipids are found in all sorts of living things.二二、营养学上的脂类、营养学上的脂类Lipids in Nutrition Science什么是脂类？什么是脂类？Lipid:A diverse group of organic substances that are insoluble in water;lipid include triglycerides,phospholipids,and sterols.脂类：脂类：是由多种是由多种有机有机物质构成的一类物质物质构成的一类物质的总称，的总称，它们一般不溶于水，脂类包括甘它们一般不溶于水，脂类包括甘油三酯、磷脂和固醇。油三酯、磷脂和固醇。Definition of lipidz Organic:to describe foods that are grown without the use of non-natural fertilizers or chemicals.z Organic:These nutrients contain the element carbon.两种不同的含义两种不同的含义-Organic95%triglycerides Phospholipids(磷脂磷脂)sterols(固醇固醇)(甘油三酯甘油三酯)Composition of Lipids 甘油三酯的分子结构甘油三酯的分子结构Molecular structure of triglycerides CH2CH2OOC COOC COOC COOCH2CH2OOCH2CH2OOR1R1R3R3R2R21Glycerol3 Fatty acids(甘油甘油)(脂肪酸脂肪酸)Triglycerides is a molecule consisting of three fatty acids attached to a three-carbon glycerol backbone.Most of the fat we eat(95%)is in the form of triglycerides,the same way by which most of the fat in our body is stored.甘油三酯既是食物中脂肪的主要存在形式，甘油三酯既是食物中脂肪的主要存在形式，也是机体内脂肪的主要贮存形式也是机体内脂肪的主要贮存形式磷磷脂脂Phospholipids:A type of lipid in which a fatty acid is combined with another compound that contains phosphate;unlike other lipids,phospholipids are soluble in water.GlycerolFatty acidFatty acidPhosphatePhospholipidCell membrane甘油甘油脂肪酸脂肪酸磷脂主要贮存在脑、神经和肝脏中；磷脂主要贮存在脑、神经和肝脏中；磷脂是构成细胞膜的主要成分；磷脂是构成细胞膜的主要成分；磷脂的磷脂的主要功能主要功能有：提供能量；具有极性和非有：提供能量；具有极性和非极性双重特性，有助于物质转运；作为乳化剂，极性双重特性，有助于物质转运；作为乳化剂，有利于脂溶性物质的吸收、转运及代谢；转运有利于脂溶性物质的吸收、转运及代谢；转运血液中的脂类物质，防治胆固醇在血中的沉积；血液中的脂类物质，防治胆固醇在血中的沉积；促进和改善神经系统功能。促进和改善神经系统功能。zA type of lipid found in foods and the body that has a ring structure;these multiple-ring structure is quite different from that of triglycerides.Sterol ring structure固醇固醇Sterols环状结构环状结构SterolszSterols are found in both plant and animal foods and are produced in the body.zPlants contain some sterols,but they are not very well absorbed and appear to block the absorption of dietary cholesterol.CholesterolzCholesterol is only found in the fatty part of animal products such as butter,eggs,whole milk,meats and poultry胆胆固固醇醇只只存存在于在于动物性食品中物性食品中.zWe dont need to consume cholesterol in our diet because our body continually synthesizes it,mostly in the liver and intestines 机体能机体能够合成胆固醇合成胆固醇.zToo much consumption is harmful。胆胆固固醇醇摄入入过多多对人体有害人体有害Cholesterol胆固醇胆固醇 zCholesterol is part of every cell membrane,where it works in conjunction with fatty acids to help maintain cell membrane integrity 保保持持细细胞胞膜膜的的完完整整性性.zCholesterol is particularly plentiful in the neural cells that make up our brain,spinal cord,and nerves 神神经经细细胞胞中中含含量量丰丰富富，参参与脑、脊髓和神经等的形成与脑、脊髓和神经等的形成.Cholesterol is the essential for lifezThe body also uses cholesterol to synthesize several important sterol compounds including sex hormones(estrogen,androgen,and progesterone),adrenal hormones,and vitamin D是是合合成成多多种种物物质的的原原料料：性性激激素素(雌雌激激素素、雄雄激激素素和黄体激素，和黄体激素，肾上腺激素和上腺激素和维生素生素D.zPhytosterols(植植物物固固醇醇，也也称称植植物物甾甾醇醇 are found in plant foods such as cererols,soybeans.And recent studies indicated that they have multiple and beneficial functions for human health.Phytosterols-good futureAnti-inflammation,regulating blood lipid,blood sugar,anti-cancer抗炎症、抗炎症、调节血脂、血糖、抗癌等作用调节血脂、血糖、抗癌等作用 To understand why someone want more/less of some fats than others we need to know more about their properties and how they work in our body.分类基础分类基础Basis of classification碳链长度碳链长度Chain length 碳链饱和度碳链饱和度Saturation level空间结构空间结构Spatial shape三三、甘油三酯的分类甘油三酯的分类Classification of TriglyceridesClassification by chain lengthShort-chain triglycerides(SCT)Long-chain triglycerides(LCT)6 Carbons12 Carbons Medium-chain triglycerides(MCT)8-12 Carbons中链脂肪中链脂肪长链脂肪长链脂肪important短链脂肪短链脂肪What information can we get based on this classification？Fatty acid chain length is important because it determines the methods of fat digestion and absorption and affects how fats function within the body.For example,short-and medium-chain fatty acids are digested and transported more quickly than long-chain fatty acids.食物中主要是以中链和长链脂肪为主。食物中主要是以中链和长链脂肪为主。Foods:椰子油椰子油(coconut oil)(coconut oil)和棕榈油和棕榈油(palm(palm oil)oil)Advantages:New advanced developments of MCT123消化快消化快(Fast digestion)吸收快吸收快(Fast absorption)易氧化分解易氧化分解(Easy oxygenolysis)Application:减肥和提高耐力减肥和提高耐力(Control weight,Improve endurance)按饱和度分类按饱和度分类Classification by saturation level饱和脂肪酸饱和脂肪酸Saturated fatty acid 多不饱和脂肪酸多不饱和脂肪酸Polyunsaturated fatty acidNo double bondMore than one double bond单不饱和脂肪酸单不饱和脂肪酸Monounsaturated fatty acid One double bondcoconut oil(椰子油椰子油)butterCream(奶酪奶酪)whole milk beefolive oil(橄榄油橄榄油)Peanut oil(花生油花生油)olive oilcottonseed oilcorn oil(玉米油玉米油)safflower oils(红花油红花油)Saturated fatty acids are saturated with hydrogen,meaning they have no carbons bonded together with a double bond.无双无双键键Monounsaturated fatty acids contain two carbons bound by one double bond.1个双键个双键Polyunsaturated fatty acid have more than one double bond linking carbon atoms.2个双键个双键DefinitionHow to feel this difference between saturated and unsaturated？Long-chain saturated fatty acids stack well together to make solid forms at room temperature.Mono-and poly-unsaturated fatty acids do not stack well together because they are bent.These fatty acid are liquid at room temperature.Differences between saturated and unsaturated fatty acidsTypes of fatty acid in our foods Foods can be identified by animal-and plant-foods.vAnimal fats provide approximately 40 to 60%of their energy from saturated fatsvWhile plant fats provide 80 to 90%of their energy from mono-and poly-unsaturated fats.Food%of total kcal from fatButter100Milk,Whole(3.3%)49Milk,skim(non-fat)5Beef,ground54Turkey,boneless26Salmon 33Egg,large62Olive oil 100Coconut oil100Safflower oil100Major sources of Dietary FatPure foods providing energy按空间构型分类按空间构型分类Classification by spatial shape顺式脂肪酸顺式脂肪酸Cis-fatty acid反式脂肪酸反式脂肪酸Trans-fatty acid氢原子在双键的一侧氢原子在双键的一侧氢原子在双键的两侧氢原子在双键的两侧Classified by shapesaturated fatMolecules of saturated fat are like straight toothpicks:they have no double carbon bonds and always form straight,rigid chains.As they have no kinks,these chains can pack together tightly.That is why saturated fats,such as the fat in meats,are solid at room temperature.In contrast,each double carbon bond of unsaturated fats gives them a kink along their length.This means that they are unable to pack together.Based on this,unsaturated fats can occur in either a cis or a trans shape.Cisthings are located on the same side or near each other;Transmeans a cross or an opposite.Classified by shapeunsaturated fatA cis-fatty acid has both hydrogen atoms located on the same side of the double bond.氢原子在双键的氢原子在双键的一侧一侧Trans fatty acid has the hydrogen atoms attached on opposite sides of the double carbon bond.氢氢原子在双键的两侧原子在双键的两侧自然界中存在的脂肪酸主要为自然界中存在的脂肪酸主要为 Cis-脂肪酸；脂肪酸；食物中也是如此。食物中也是如此。Do they both existed in nature and foods？反式脂肪酸与人体健康反式脂肪酸与人体健康v 不饱和脂肪酸的不饱和键能与氢结合变不饱和脂肪酸的不饱和键能与氢结合变成饱和键，随着饱和程度的增加，油类可成饱和键，随着饱和程度的增加，油类可由液态变为固态，这一过程称为由液态变为固态，这一过程称为氢化氢化。v 在氢化过程中，可能会产生反式脂肪酸。在氢化过程中，可能会产生反式脂肪酸。v 氢化的氢化的作用作用：提高脂肪的抗氧化作用；提高脂肪的抗氧化作用；改变食物的结构。改变食物的结构。反式脂肪酸与人体健康反式脂肪酸与人体健康v 反式脂肪酸不具有必需脂肪酸的生物活反式脂肪酸不具有必需脂肪酸的生物活性和对脂蛋白的作用；性和对脂蛋白的作用；v 流行病资料也显示膳食反式脂肪酸与心流行病资料也显示膳食反式脂肪酸与心脏病之间存在某些联系；脏病之间存在某些联系；v 反式脂肪酸的主要食物来源：人造奶油、反式脂肪酸的主要食物来源：人造奶油、蛋糕、蛋糕、饼干、饼干、油炸食品油炸食品、乳酪产品、花生、乳酪产品、花生酱等食品。酱等食品。近日，全球最大的快餐集团麦当劳公开成认，在近日，全球最大的快餐集团麦当劳公开成认，在每份麦当劳薯条中，反式脂肪酸含量从过去的每份麦当劳薯条中，反式脂肪酸含量从过去的6 6克增克增加到了加到了8 8克。在每份麦当劳炸薯条中，不利于身体健克。在每份麦当劳炸薯条中，不利于身体健康的反式脂肪酸含量比过去增加了康的反式脂肪酸含量比过去增加了1/31/3。反式脂肪酸与人体健康反式脂肪酸与人体健康In 2003 the U.S.FDA ruled that trans fatty acids,or trans fats,must be listed as a separate line item on Nutrition Facts labels for conventional foods and some dietary supplements.v尽量防止购置食物标签中标有：植物氢化尽量防止购置食物标签中标有：植物氢化油、人造黄奶油、人造植物黄奶油、人造黄奶油、人造植物黄奶油、人造脂肪、氢化油、起酥油等字样的油、人造脂肪、氢化油、起酥油等字样的食物。食物。v每周应食用两次鱼，以利于每周应食用两次鱼，以利于-3-3 脂肪酸的脂肪酸的摄入，从而减少其危害。摄入，从而减少其危害。如何减少反式脂肪酸的危害？如何减少反式脂肪酸的危害？-3 脂肪酸脂肪酸四四、-3和和-6脂肪酸脂肪酸CCCCCCCHHHHHHHHHHHHHHCHHHCOOH-3脂肪酸脂肪酸 DHA（22：6）EPA（20：5）-亚麻酸亚麻酸-6脂肪酸脂肪酸花生四烯酸花生四烯酸亚油酸亚油酸必需脂肪酸必需脂肪酸(essential fatty acid，EFA)：是：是指人体不可缺少而自身又不能合成，必须通过指人体不可缺少而自身又不能合成，必须通过食物供给的脂肪酸。食物供给的脂肪酸。Definition:EFA are indispensable and must be consumed in the diet because they can not be made by our bodies.亚油酸亚油酸(Linoleic acid,LA)和和-亚麻酸亚麻酸(-linolenic acid，ALA)是人体必需的两种脂肪酸。是人体必需的两种脂肪酸。必需脂肪酸必需脂肪酸Essential Fatty Acid必需脂肪酸的功能必需脂肪酸的功能Function of EFA是磷脂的重要组成成分是磷脂的重要组成成分 与精子形成有关与精子形成有关是合成前列腺素的前体是合成前列腺素的前体 有利于组织修复有利于组织修复与胆固醇的代谢有关与胆固醇的代谢有关 缺缺乏乏生长缓慢生长缓慢生殖障碍生殖障碍皮肤损伤皮肤损伤(皮疹等皮疹等)其他心血管疾病等其他心血管疾病等-3脂肪酸脂肪酸EPA and DHA are derived from ALA.Alpha-linolenic acid(ALA)降低甘油三酯的作用降低甘油三酯的作用 阻碍甘油三酯掺入到肝的阻碍甘油三酯掺入到肝的VLDLVLDL颗粒中，分泌到血液颗粒中，分泌到血液循环中的甘油三酯减少；降血压作用循环中的甘油三酯减少；降血压作用 。抗炎症作用抗炎症作用抗癌作用抗癌作用脑和视网膜发育上的重要物质脑和视网膜发育上的重要物质-3脂肪酸的生物学功能脂肪酸的生物学功能-6脂肪酸脂肪酸亚油酸亚油酸(LA)花生四烯酸花生四烯酸AA)AA)v降低胆固醇的作用降低胆固醇的作用 v具有促进生长、发育及妊娠的作用具有促进生长、发育及妊娠的作用 v是一些特殊脂类如磷脂的组成成分，维持是一些特殊脂类如磷脂的组成成分，维持组织膜结构的完整性和最正确的不饱和水平。组织膜结构的完整性和最正确的不饱和水平。-6-6脂肪酸的生物学功能脂肪酸的生物学功能-3和和-6脂肪酸的食物来源脂肪酸的食物来源-3脂肪酸脂肪酸:主要存在于鱼油主要存在于鱼油(Fish oil)和鱼类产和鱼类产品品(fish products)。-6脂肪酸脂肪酸:主要存在于植物油中主要存在于植物油中,如葵花油如葵花油(sunflower oil)、红花油红花油(safflower)、玉米油、玉米油(corn oil)、豆油、豆油(soy oil)和和 花生油花生油(peanut oil)。-3和和-6脂肪酸的比例脂肪酸的比例人类最早食用的根本都是野生植物和散养动物，人类最早食用的根本都是野生植物和散养动物，食物中的食物中的-3-3和和-6-6有着严格比例有着严格比例,根本保持平根本保持平衡。衡。工业化时代，人类大量食用加工和养殖产品，使工业化时代，人类大量食用加工和养殖产品，使得体内所含得体内所含-6-6越来越多，比例严重失调。越来越多，比例严重失调。据估计，目前美国等兴旺国家里，人体内的据估计，目前美国等兴旺国家里，人体内的-6-6和和-3-3比例可能到达比例可能到达3030：1 1，甚至达，甚至达5050：1 1。北京儿童医院与瑞典皇家医院在河北石家庄地区北京儿童医院与瑞典皇家医院在河北石家庄地区的调查，该地区妇女的调查，该地区妇女-6-6和和-3-3的比例在的比例在2626：1 1-3-3脂肪酸有脂肪酸有益的生物学功益的生物学功能能过多过多-6-6脂肪酸有脂肪酸有害的生物学功能害的生物学功能Because fats are not soluble in water,they cannot enter our blood stream easily from the digestive tract.Thus,fats must be digested,absorbed,and transported within the body differently from other water-soluble nutrients.五、脂肪的消化、吸收五、脂肪的消化、吸收Fat digestion and absorptionMouth:Salivary glands in the mouth produce an enzyme,lingual lipase,that digests some triglycerides.Salivary enzymes have a limited role in the breakdown of fats.Fat digestion-in mouthPartially digestMoisture and chewFat digestion-in StomachzFat arrives intact at the stomach where it is mixed and broken into droplets.zGastric lipase digests some triglycerides.zBecause they are not soluble in water,these fat droplets typically float on top of the watery digestive juices in the stomach until they are passed into the small intestine.zAs fat enters the small intestine from the stomach,the gallbladder contracts and releases bile,which acting much like soap,breaking down the fat into smaller and smaller droplets.zAt the same time,lipid-digesting enzymes produced in the pancreas travel into the small intestine.Two organs assisting fat digestionDo you remember the structure of triglycerides？Once bile has broken the fat into small droplets,these pancreatic enzymes take over,breaking the fatty acids away from their glycerol backbones(Real breakdown).Each triglyceride molecule is broken down into two free fatty acids and one monoglyceride(one fatty acid was left).In this case,a glycerol molecule with one fatty acid still attached.Fat digestion in the small intestineThe process of fat digestionSalivary glands produce enzyme to digest a few fats.Fat is mixed and broken into droplets.Gastric lipase digest some fats.Gallbladder releases bile into the small intestineBile breaks fats into smaller droplets;Lipid-digesting enzyme break fats into monoglycerides and 2 fatty acids.Lipid-digesting enzymes entered into small intestineThe majority of fat absorption occurs in the mucosal lining of the small intestine with the help of a micelle.A micelle is a spherical(round)compound that can trap the free fatty acids and the monoglycerides and transport them to the mucosal cells for absorption.Fat absorption-primarily in the small intestine 博博 士士 学学 位位 论论 文文 Because fats do not mix with water,most fats cannot be transported freely in the bloodstream.How does the absorbed fat get into the blood stream?To solve this problem,the fatty acids are reformulated back into triglycerides and then packaged into lipoprotein before being released into the bloodstream.Why lipoprotein can be absorbed into the bloodstream?Structure of a lipoprotein Lipoprotein is a spherical compound in which the fat clusters in the center and phospholipids and proteins form the outside of the sphere.Chylomicron乳乳糜糜微微粒粒 is a specific lipoprotein produced in the mucosal cell of the intestine to transport dietary fat out of the intestine tract into the blood.Chylomicron is a fat carrier in the small intestine.Have you remembered?I mentioned that the short-and medium-chain fatty acids are digested more quickly than long-chain fatty acids?Why?When short and medium-chain fatty acids are digested and transported to the mucosal cell of the small intestine,they do not have to be reformed into triglycerides and incorporated into chylomicrons.Instead,they can travel in the bloodstream bound to either a transport protein or a phospholipid.It should be mentioned that two following lipoprotein served as transporter in different wayLow density lipoproteinLDL：less triglycerides，more cholesterolsHigh density lipoproteinHDL):carry cholesterol back to liver for breaking downTransport of fat in the bodyObviously.How does our body deal with fat absorbed？There are three primary fates of the fatabsorbed.zIt can immediately be taken up and used as a source of energy for the cells.zIt can be used to make lipid-containing compounds(some examples?)in the body.zIt can be stored in the muscle or adipose tissue as a triglyceride for later use.六、脂肪的功能六、脂肪的功能Functions of Fat1提供能量和贮存能量提供能量和贮存能量Provide and store energyFat provide 9 kilocalories(kcals)per gram.Fat is a primary source of energy.特点：不能给脑、神经细胞和红细胞提供能量特点：不能给脑、神经细胞和红细胞提供能量2保持体温正常保持体温正常Maintain body Maintain body temperaturetemperature How much energy for protein?34 维持细胞功能及保护机体维持细胞功能及保护机体 Help maintain cell function and Help maintain cell function and provide provide protection to the body protection to the body 5 提供必需脂肪酸提供必需脂肪酸 Provide essential fatty acidProvide essential fatty acid内分泌作用内分泌作用Endocrine secretion 瘦素瘦素Functions of Fat 更有效地利用碳水化合物和更有效地利用碳水化合物和节约蛋白蛋白质作用作用Utilize more effectively carbohydrates and protein sparing action 转运脂溶性维生素转运脂溶性维生素(transport of fat-soluble vitamins)改善食物的感官性状改善食物的感官性状(色香味型色香味型)(Contribute to the flavor and texture of foods)增加饱腹感增加饱腹感(Help us to feel satisfied)67Functions of Fat89Summary-Functions of FatWould you summary some keywords about functions of fat?EnergyBody temperatureFatty acidFat-soluble vitaminsCell function/ProtectionSecretionFlavor and textureSatietyLike many things,a little can be good,but a lot can be harmful.Too much fat,regardless of the type,can be damaging to our bodies.七、脂肪的不利影响七、脂肪的不利影响 Disadvantages of fats 1摄入过多脂肪将导致疾病摄入过多脂肪将导致疾病(Eating too much of certain fats can lead to disease)2脂肪限制了食物的保质期脂肪限制了食物的保质期(Fats limit the shelf life of foods)Diets high in SFA cardiovascular disease Diets too high in UFA StrokeDiets too high in fatWeight gain/Obesity八、脂肪的营养学评价八、脂肪的营养学评价脂肪的消化率脂肪的消化率Digestive rate)Digestive rate)必需脂肪酸的含量必需脂肪酸的含量(Quantity of EFA)(Quantity of EFA)所含各种脂肪酸的比例所含各种脂肪酸的比例(Ratio among the(Ratio among the various fatty acids)various fatty acids)脂溶性维生素的含量脂溶性维生素的含量(Quantities of fat-(Quantities of fat-soluble vitamins)soluble vitamins)EPA EPA 和和DHADHA的含量的含量(Quantities of DHA and(Quantities of DHA and EPA)EPA)适宜的数量和类型适宜的数量和类型Right amount&Right types九、脂肪的膳食参考摄入量九、脂肪的膳食参考摄入量Dietary reference intakes of fatadvantageDis-Fats中国营养学会中国营养学会(Chinese Nutrition Society):成人脂肪摄入量应占总能量摄入成人脂肪摄入量应占总能量摄入20%30%；一般认为一般认为EFA的摄入量应不少于总能量的的摄入量应不少于总能量的3%。建议建议-3与与-6脂肪酸摄入比为脂肪酸摄入比为1:46较适宜较适宜。中国居民膳食脂肪适宜摄入量中国居民膳食脂肪适宜摄入量AIs脂肪供能占总能量的百分比脂肪供能占总能量的百分比年龄年龄/岁岁脂肪脂肪%SFAMUFAPUFA-6/-3胆固醇胆固醇（mg）0 45 504:10.5 35 404:12 30 354 6:17 25 304 6:114 25 30108104 6:1成人成人20 301010104 6:1300老年老年20 306 8108 104:1300v人类膳食脂肪主要来源于动物的脂肪组织和肉人类膳食脂肪主要来源于动物的脂肪组织和肉类以及植物的种子。类以及植物的种子。v动物脂肪相对含饱和脂肪酸和单不饱和脂肪酸动物脂肪相对含饱和脂肪酸和单不饱和脂肪酸多，而多不饱和脂肪酸含量较少。多，而多不饱和脂肪酸含量较少。v植物油主要含不饱和脂肪酸。植物油主要含不饱和脂肪酸。v亚油酸亚油酸-6-6普遍存在于植物油中，亚麻酸普遍存在于植物油中，亚麻酸-3-3在豆油和紫苏籽油中较多，深海鱼贝在豆油和紫苏籽油中较多，深海鱼贝类食物相对含类食物相对含 EPA EPA 和和 DHA DHA较多。较多。脂肪的食物来源脂肪的食物来源Food ItemOmega-3 Fatty acid(g/serving)Salmon oil(fish oil)4.39Herring oil（青鱼油）（青鱼油）1.52Shrimp（河虾）（河虾）1.11Trout（鳟鱼）（鳟鱼）1.05Walnuts（核桃）（核桃）0.51Salmon0.5Crab（螃蟹）（螃蟹）0.34Omega-3 Fatty acid content of selected foodsSummary脂肪的分类脂肪的分类必需脂肪酸必需脂肪酸/-3/-3脂肪酸脂肪酸脂肪的功能脂肪的功能脂肪推荐的膳食供给量脂肪推荐的膳食供给量Thanks very much&Hope you enjoy it!
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