维生素(总)--.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,维生素,Vitamins,1,维生素（,Vitamin,）,一词的来源,:,1911,年,Funk,从米糠中分离出一种可治疗,多发性神经炎的结晶维持生命的胺类,（,amine,）。,1912,年,Funk,提出了抗脚气病、抗坏血病、,抗癞皮病、抗佝偻病的四种物质，称其为,“生命胺（,Vitamine,）”。,1920,年定名为维生素（,Vitamin,）。,2,概 述,3,一、概念,二、维生素的命名与分类,三、维生素的特点,四、维生素缺乏,内容概览,4,一、概念,维生素是维持机体正常代谢和生理功能所必需的一类微量的低分子有机化合物。,5,共同特点：,（,1,）均以维生素本体，或可被机体利用的前体的,形式（维生素原）存在于天然食物中。,（,2,）大多数维生素在机体不能合成或合成量不足，必须由食物供给。,（,3,）非机体结构成分，不提供能量。,（,4,）人体需要量很少，但在调节物质代谢的过程中起着十分重要的作用。,（,5,）大多数水溶性维生素以辅酶或辅基的形式参与酶的功能。,6,二、维生素的命名与分类,命名：,按发现的历史顺序命名，如维生素,A,、维生素,B,1,、维生素,B,2,、维生素,C,、维生素,D,、维生素,E,等。,按其特有的生理功能、或治疗作用命名，如抗干眼病因子（维生素,A,）、抗癞皮病因子（烟酸）、抗坏血酸（维生素,C,）。,按其化学结构命名，如视黄醇、硫胺素、核黄素、钴胺素等等。,7,维生素,B,1,（硫胺素,抗脚气病维生素）,维生素,B,2,（核黄素）,维生素,PP,（尼克酸,抗癞皮病维生素）,维生素,B,6,（吡哆醇、吡哆醛、吡哆胺）,维生素,B,3,（泛酸）,维生素,M,（叶酸）,维生素,B,12,（钴胺素,抗恶性贫血病,维生素）,维生素,H,（生物素）,维生素,C,（抗坏血酸,抗坏血病维生素）,维生素,脂溶性,水溶性,维生素,A,（视黄醇,抗干眼病维生素）,维生素,D,（钙化醇,抗佝偻病维生素）,维生素,E,（生育酚）,维生素,K,（叶绿醌,凝血维生素）,B,族维生素,分类：,8,三、两类维生素的特点,脂溶性维生素 水溶性维生素,化学组成,C,、,H,、,O C,、,H,、,O,、,N,、,S,、,Co,溶解性,脂溶性 水溶性,蓄积与排泄,排泄效率低 排泄效率高,易于蓄积 不易蓄积,毒性,易于中毒 不易中毒,缺乏症,出现缓慢 很快出现,9,四、维生素缺乏,1.,原因,摄入量不足,吸收利用降低,需要量增加,长期滥用抗菌素,10,2.,缺乏过程,:,组织中维生素贮存量下降,生化指标异常、生理功能降低,组织病理改变、临床症状,死亡,11,3.,缺乏程度,:,临床缺乏,:,亚临床缺乏,:,边缘性缺乏（,marginal deficiency,）,:,12,Definition of Vitamin,As each vitamin was discovered during the first half of the 1900s,two characteristics clearly emerged to define a compound as a vitamin,as follows:,It must be a vital,organic,dietary substance that is not a carbohydrate,fat,protein,or material and is necessary in only very small amounts to perform a specific metabolic function or prevent an associated deficiency disease.,It cannot be manufactured by the body in sufficient quantities to sustain life;therefore it must be supplied by the diet.,13,维生素,A,（,Vitamin A,）,14,唐代 孙思邈,千金方,动物肝脏治疗眼病和夜盲症。,1913,年正式发表维生素,A,活性成分的学术报告，命名为脂溶性物质,A,，后更名为维生素,A,。,20,世纪,20,年代 维生素,A,与干眼病、组织细胞分化、生长发育、抗感染能力之间的因果关系。,20,世纪,30,年代 明确了维生素,A,的化学结构。,1940,年 人工合成的维生素,A,问世。,1987,年 发现了维生素,A,核内受体。,15,一、概念、理化性质,二、吸收与代谢,三、生理功能,四、维生素,A,缺乏的表现,五、维生素,A,营养状况的鉴定,六、推荐摄入量及食物来源,七、维生素,A,中毒,16,一、概念、理化性质,是指含有,-,白芷酮环的不饱和一元醇,并,具有视黄醇生物活性的一大类物质。,分类,已形成的维生素,A,（,preformed vitamin A,）,维生素,A,原,（,provitamins A),视黄醇（,retinol,）,视黄醛（,retinal,）,视黄酸（,retinoic acid,）,胡罗卜素,胡罗卜素（,-carotene,）,胡罗卜素,17,已形成的维生素,A,（,preformed vitamin A,）,:,动物体内具有视黄醇生物活性的维生素,A,。,维生素,A,原（,provitamin A,）：,有色植物中（黄、绿、红色）含有类胡罗卜素。在体内可以转化为维生素,A,的类胡罗卜素为,维生素,A,原,。,18,理化性质,:,对热、酸、碱比较稳定，一般烹调和罐头加工,不易破坏。,空气中易氧化破坏。,紫外线照射可使其丧失活性。,油脂酸败时，可使其严重破坏。,食物中含有磷脂、维生素,E,、维生素,C,、其它,抗氧化剂时较为稳定。,19,二、吸收与代谢,1.,维生素,A,的吸收：,视黄基酯,酯键水解,（小肠）,吸收入肠粘膜,再次酯化,视黄基酯,掺入,乳糜微粒,淋巴,血液,肾脏（少量）,肝脏贮存（,90,）,20,视黄醇,RBP,TTR,维生素,A,在血液中的转运形式：,视黄醇,RBP,TTR,视黄醇,RBP,靶器官,21,维生素,A,的转化,:,视黄醇,视黄醛,视黄酸,氧化,还原,氧化,视黄酰,葡萄糖苷酸,排出体外,22,2.,维生素,A,原的吸收,胡萝卜素,15,，,15-,加氧酶,小肠粘膜,2,分子视黄醛,视黄醇,视黄醇酯,酯化,乳糜微粒,掺入,淋巴,血液,肝、肾,还原,23,1.,构成视觉细胞中的感光物质,三、生理功能,24,视色素：,视紫红质,11-,顺式视黄醛,全反式视黄醛,(,感受弱光,),视紫红质,视蛋白,暗处,弱光照,25,维持上皮组织结构的完整性,促进生长、发育、繁殖,抗癌作用,维持机体正常的免疫功能,6.,参与细胞表面糖蛋白的合成：,细胞连接、受体识别、细胞黏附与聚集,7.,抗氧化作用,26,维生素,A,缺乏病目前仍是不发达国家中威胁人类健康，尤其是儿童的主要疾病之一。据统计，不发达国家中每年约有,25,万至,50,万儿童,因罹患维生素,A,缺乏而导致,失明,，这些失明儿童中约,2/3,在数月后继发感染性疾病而死亡。,目前，我国人群中维生素,A,缺乏病的发生率已明显下降，但在边远农村地区仍有群体流行，儿童中,亚临床状态缺乏,现象还相当普遍。,四、维生素,A,缺乏的表现,27,1.,暗适应能力下降,夜盲症,干眼病,:,泪腺分泌减少。结膜、角膜上皮组织干燥、变性，结膜出现皱褶、混浊；角膜水肿、软化、溃疡、糜烂、穿孔等。儿童：,毕脱氏斑（,bitot spots,）。,28,皮肤,:,四肢伸侧、背部、肩部上皮过度角化：皮肤干燥、增生、异常粗糙、脱屑、毛囊过度角化，可出现鸡皮样丘疹，鱼鳞皮。,4.,头发：,干燥、稀疏脱落,5.,粘膜上皮不健全：,易患呼吸道感染,6,.,血红蛋白合成障碍,免疫功能低下,儿童生长发育迟缓,29,30,31,32,33,34,35,五、维生素,A,营养状况的鉴定,血清维生素,A,水平的测定,2.,相对剂量反应实验（,RDR,）,3.,血浆视黄醇结合蛋白,4.,暗适应能力,5.,眼结膜印迹细胞学法,6.,眼部症状：角膜干燥、,毕脱氏斑,等，,36,维生素,A,的推荐摄入量,(,gRE),年龄,RNI,男 女,18,800 700,50,800 700,孕早期,800,孕中期,900,孕末期,900,乳母,1200,六、推荐摄入量及食物来源,UL,3000,2400,37,视黄醇当量（,retinol equivalents,RE,）,膳食中全部具有视黄醇活性物质（包括已形成的维生素,A,和维生素,A,原）的总称,38,膳食中总视黄醇当量（,gRE,）,=,视黄醇（,g,）,+,0.167,-,胡罗卜,（,g,）,+0.084,其他维生素,A,原,（,g,）,1gRE,=,1g,视黄醇,=,6.0 g-,胡罗卜素,1IU,维生素,A,=,0.3g,视黄醇,39,食物来源,动物性食品：,动物肝脏 鱼肝油,鱼卵 蛋黄 奶,植物性食品：,深色蔬菜和水果：,菠菜 油菜 青椒 胡罗卜,红心红薯 芒果 杏 柿子,40,食物 含量（,VA,gRE,/100g,）,猪肝,4972,牛肝,20220,羊肝,20972,鸡肝,10414,鸡蛋黄,438,全蛋,310,鸭蛋黄,1980,鸭蛋,261,牛乳,24,羊乳,84,食 物 含量（胡萝卜素，,g,/100g,）,胡萝卜,4010,菠 菜,2920,韭 菜,1410,西红柿,550,辣 椒,340,西兰花,7210,生菜,1790,荷兰豆,480,油菜,620,芒果,8050,桔子,1660,维生素,A,的主要食物来源,41,七、维生素中毒,急性中毒（成人大于,RNI 100,倍，儿童大于,RNI 20,倍）,恶心、呕吐、头痛、眩晕、视觉模糊、囟门突起、嗜睡等，极大剂量可致命。,慢性中毒（大于,RNI 10,倍）,头痛、食欲降低、脱发、肝脾肿大、骨关节病；皮疹、脱屑、脱皮并伴有色素沉着等。,胎儿畸形,42,Vitamin A is the name of a group of fat-soluble retinoids,including retinol,retinal,retinoic acid,and,retinyl esters,(,视黄酯）,.Vitamin A is involved in immune function,vision,reproduction,and cellular communication.,Vitamin A is critical for vision as an essential component of,rhodopsin,（视紫红质）,and it supports the normal differentiation and functioning of the conjunctival membranes and cornea.,43,Vitamin A also supports cell growth and differentiation,playing a critical role in the normal formation and maintenance of the heart,lungs,kidneys,and other organs.,44,维生素,D,（,Vitamin D,）,45,一、理化性质及来源,二、吸收与转化,三、生理功能,四、缺乏症与过多症,五、营养水平鉴定,六、推荐摄入量,46,紫外线照射,VD,2,:,植物中的麦角固醇,VD,2,（麦角钙化醇）,VD,3,:,人体内胆固醇 脱氢胆固醇,VD,3,（胆钙化醇）,一、理化性质、来源,两种形式：,VD,2,（麦角钙化醇）,VD,3,（胆钙化醇）,紫外线照射,47,来源,机体自身合成,:,(200IU 400IU/,日,),食物中摄入,:,蛋黄、肝脏、鱼肝油、鱼卵、奶油,(,1IU=0.025,g,),48,维生素,D,的吸收,:,7,脱氢胆固醇,光照,V,D,3,膳食中,V,D,3,吸收,小肠,淋巴系统,血 液,肝 脏,（皮肤）,二、吸收与转化,49,维生素,D,的转化,VD,3,肝 脏,25-(OH)-D,3,（,1,）,（,2,）,25-(OH)-D,3,肾,25-,（,OH,）,-D,3,-1-,羟化酶,25-,（,OH,）,-D,3,-24-,羟化酶,1,25-(OH),2,-D,3,24,25-(OH),2,-D,3,（,3,）,+,DBP,靶器官（小肠、肾、骨）,24,25-(OH),2,-D,3,1,25-(OH),2,-D,3,与受体结合，发挥生物学效应,25-,羟化酶,50,三、维生素,D,的生理功能,1.,促进小肠对钙的吸收,1,25-(OH),2,-D,3,与肠粘膜上皮细胞中的特异性受体结合，激活基因转录，促进肠粘膜细胞合成,钙结合蛋白（,CaBP,）,51,CaBP,前体,CaBP,CaBP,Ca,复合体,1,25-(OH),2,-D,3,Ca,浓集器,Ca,转入细胞浆,依赖钙的,ATP,酶,52,促进肾小管对钙、磷的重吸收,通过,VDR,对骨骼的作用,1,25-(OH),2,-D,3,1,25-(OH),2,-D,3,：刺激成骨细胞,（钙盐从血中沉积入骨）,破骨细胞前体,破骨细胞 骨吸收,（钙盐从骨骼中释放入血）,骨盐沉着,53,4.,通过,VD,内分泌系统调节血钙水平,1,25-(OH),2,-D,3,甲状旁腺激素,降钙素,5.,参与机体多种功能的调节,54,骨吸收,（钙盐从骨骼中释放入血）,（钙盐从血中沉积入骨）,骨盐沉着,血钙降低,甲状旁腺激素,1,，,25-,（,OH,）,2,-D,3,血钙恢复正常,骨吸收,血钙过高,甲状旁腺激素,降钙素,血钙恢复正常,尿中钙磷排出,55,四、缺乏症与过多症,维生素,D,缺乏,佝偻病,(rickets),：,矿化障碍,骨质软化症,(osteomalacia),：,矿化障碍,骨质疏松症,(osteoporosis),：,骨基质和矿物质等比例减少,手足痉挛：,血钙降低,56,五、营养水平鉴定,25,（,OH,）,D3,57,维生素,D,的推荐摄入量（,RNI,）,18,5,50,10,孕早期,5,孕中期,10,孕末期,10,乳母,10,年龄,RNI(,g),六、推荐摄入量,58,Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent,hypocalcemic tetany,（,低血钙性抽搐,).,It is also needed for bone growth and bone remodeling by,osteoblasts(,成骨细胞,）,and,osteoclasts,（,破骨细胞,）,.Without sufficient vitamin D,bones can become thin,brittle,or misshapen.,Vitamin D sufficiency prevents rickets in children and osteomalacia in adults.Together with calcium,vitamin D also helps protect older adults from osteoporosis.,59,Vitamin D has other roles in the body,including modulation of cell growth,neuromuscular and immune function,and reduction of inflammation.Many genes encoding proteins that regulate cell proliferation,differentiation,and apoptosis are modulated in part by vitamin D.Many cells have vitamin D receptors,and some convert 25(OH)D to 1,25(OH)2D.,60,维生素,E,（,Vitamin E,）,61,一、分类及理化性质,二、吸收与代谢,三、生理功能,四、维生素,E,的缺乏与过多,五、维生素,E,营养水平的鉴定,六、适宜摄入量及食物来源,62,生育酚（,tocopherols,）,生育三烯酚（,tocotrienols),-T,100,-T,2550,-T,1035,-T,-TT,30,-TT,-TT,-TT,63,细胞,维生素,E,体内的代谢途径,维生素,E,粪排泄,60,80%,CM,VE,肝脏,V,E,代谢产物,VLDL,VE,LDL,VE,HDL,VE,尿,代谢产物,64,生理功能,1.,抗氧化作用,-,生 育 酚,脱氢抗坏血酸,2GSH NADP,-,生育酚自由基,抗坏血酸,GSSG NADPH,自由基,65,不饱和脂肪酸,（生物膜上）,CH=CH,CH,CH,2,CH,CH,2,H,2,O,O,OH,OH,|,|,H,2,O,O,VE,Se,2GSH GSSG,GPX,GPX,：,谷胱甘肽过氧化物酶,过氧化物,（有毒）,（羟基化合物）,66,2.,促进蛋白质的更新、合成,3.,预防和延缓衰老,4.,与动物的生殖功能和精子生成有关,5.,调节血小板的粘附和聚集作用,67,维生素,E,营养状况的评价,状况 血清维生素,E,（,mol/L,）红细胞,H,2,O,2,溶血试验（）,缺乏,20,偏低,12,17 10,20,正常,17 10,68,膳食中总,-TE,（,mg,）,RRR-,生育酚,0.5,-,生育酚,0.1,-,生育酚,0.3,-,生育三烯酚,0.74,dl-,生育酚,维生素,E,适宜摄入量：,14mg,-TE,69,Antioxidants protect cells from the damaging effects of,free radicals,（,自由基,）,which are molecules that contain an,unshared electron,（,未共价电子,）,.,Free radicals damage cells and might contribute to the development of cardiovascular disease and cancer.Unshared electrons are highly energetic and react rapidly with oxygen to form,reactive oxygen species,(,ROS,，活性氧自由基,).,70,The body forms ROS endogenously when it converts food to energy,and antioxidants might protect cells from the damaging effects of ROS.,The body is also exposed to free radicals from environmental exposures,such as cigarette smoke,air pollution,and ultraviolet radiation from the sun.ROS are part of signaling mechanisms among cells.,71,Vitamin E is a fat-soluble antioxidant that stops the production of ROS formed when fat undergoes oxidation.Scientists are investigating whether,by limiting free-radical production and possibly through other mechanisms,vitamin E might help prevent or delay the chronic diseases associated with free radicals.,72,维生素,C,（抗坏血酸）（,Ascorbic acid,）,73,一、化学结构和性质,二、吸收、转运及代谢,三、生理功能,四、缺乏与过量,五、机体营养水平的鉴定,六、推荐摄入量与食物来源,74,75,化学结构和性质,L-,抗坏血酸 脱氢抗坏血酸 二酮古洛糖酸,2H,+2H,+H,2,O,（还原型抗坏血酸）（氧化型抗坏血酸）（无生理功能）,76,Vc,的生理功能,77,（,1,）促进胶原蛋白的合成，维持细胞间质的完整性,脯氨酸 羟脯氨酸,赖氨酸 羟赖氨酸,羟化酶,羟化酶,Vc,胶原蛋白,1.,参与羟化反应,保证血管基底膜的完整性,促进伤口愈合,保证骨、牙的形成,78,（,2,）,促进神经递质的合成,通过对芳香族氨基酸代谢的作用，来维持精神和神经系统的正常状态。,苯丙氨酸 酪氨酸 多巴 多巴胺,去甲肾上腺素,色氨酸,5-,羟色氨酸,5-,羟色胺,羟化,羟化,羟化,羟化,79,（,3,）促进类固醇的羟化,促进胆固醇的代谢,胆固醇 胆酸,羟化,Vc,（,4,）促进有机药物或毒物的羟化解毒,80,2.,还原作用,（,1,）促进抗体的合成,胱氨酸 半胱氨酸,还原,Vc,半胱氨酸,半胱氨酸,-S-S-,抗体,81,（,2,）对造血功能的影响,促进铁的吸收 促进四氢叶酸的形成,Fe Fe,吸收,叶酸 四氢叶酸,（活性形式）,Vc,82,还原型,Vc GSSG,不饱和脂肪酸,氧化型,Vc,G,SH,脂质过氧化物,解毒,（,3,）维持巯基酶的活性，清除自由基,83,维生素,C,缺乏症,坏血病（,Scurvy,）,1.,出血症状,2.,骨骼、牙齿,3.,皮肤,4.,精神方面,维生素,C,过多：,四、,Vc,的缺乏症与过多,84,85,86,87,88,89,营养水平鉴定,1.,血浆中,Vc,的含量,2.,白细胞中,Vc,的含量,3.,尿负荷试验,4.,尿中还原型抗坏血酸肌酐（,mg/g),90,中国营养学会,2000,年制定的维生素,C,的推荐摄入量（,RNI,）,年龄,RNI(,mg),18,100,50,100,孕早期,100,孕中期,130,孕末期,130,乳母,130,91,维生素,C,的食物来源,含量较高,：,菜花、西兰花、苦瓜、油菜、圆白菜、,茼蒿、,草莓、橘子、荔枝、,红果、柚子、,含量中等,：,土豆、大白菜、柿子、红薯、韭菜,含量低,：,苹果、梨、香蕉等,含量很高,：,鲜枣、酸枣、猕猴桃、柿子椒、沙棘,92,Vitamin C is required for the biosynthesis of collagen,L-carnitine,and certain neurotransmitters;vitamin C is also involved in protein metabolism.,Collagen is an essential component of connective tissue,which plays a vital role in wound healing.,Vitamin C is also an important physiological antioxidant and has been shown to regenerate other antioxidants within the body,including alpha-tocopherol(vitamin E).,93,Ongoing research is examining whether vitamin C,by limiting the damaging effects of free radicals through its antioxidant activity,might help prevent or delay the development of certain cancers,cardiovascular disease,and other diseases in which oxidative stress plays a causal role.,94,In addition to its biosynthetic and antioxidant functions,vitamin C plays an important role in immune function and improves the absorption of nonheme iron,the form of iron present in plant-based foods.Insufficient vitamin C intake causes scurvy,which is characterized by fatigue or lassitude,widespread connective tissue weakness,and capillary fragility.,95,维生素,B,1,（硫胺素）,（,Thiamin,）,96,一、化学结构和性质,二、吸收、转运及代谢,三、生理功能,四、缺乏症,五、机体营养水平的鉴定,六、推荐摄入量与食物来源,97,98,脱羧酶,转酮醇酶,1.,构成多种酶的辅酶,99,三羧循环途径,糖代谢,葡萄糖 丙酮酸,脂肪代谢 脂肪酸 辅酶,A,氨基酸代谢 支链氨基酸,酮戊二酸,乙酰辅酶,A,+,CO,2,琥珀酰辅酶,A,+,CO,2,三羧循环,氧化脱羧,脱羧酶,丙酮酸,100,5,磷酸核糖,5,磷酸木酮糖,转酮醇酶,7,磷酸景天糖,3,磷酸甘油醛,磷酸戊糖途径,101,乙酰胆碱 胆碱乙酸,（神经传导递质）,维生素,B1,胆碱酯酶,2.,抑制胆碱酯酶的活性 促进胃肠蠕动,促进胃肠蠕动,102,维生素,B1,缺乏,脚气病（,beriberi,）,症状：,神经系统,心血管系统,全身性水肿,胃肠表现,分型：,干型脚气病,湿型脚气病,混合型脚气病,婴儿脚气病,103,104,105,106,机体营养水平的鉴定,1.,尿中硫胺素排出量,2.,红细胞转羟乙醛酶活性系数,（,erythrocyte transketolase activation coefficient,E-TKAC,）,ETK-AC,加入,TPP,后红细胞,转酮醇酶,活性 未加,TPP,时该酶活性,未加,TPP,时该酶活性,100,107,中国营养学会,2000,年制定的维生素,B,1,的推荐摄入量（,RNI,）,年龄,RNI(,mg),男 女,18,1.4 1.3,50,1.3,孕早期,1.5,孕中期,1.5,孕末期,1.5,乳母,1.8,108,食物来源,动物性食品,植物性食品 全谷 豆类 坚果,动物内脏（肾 肝 心）,瘦肉 蛋类,109,The basic function of thiamin as a coenzyme factor relates to the production of energy from glucose and the storage of energy as fat,making energy available to support normal growth.Thiamin is especially necessary for maintaining good function of three body systems discussed in the following,：,110,Gastrointestinal System,Lack of thiamin causes poor appetite,indigestion,constipation and poor stomach action from lack of muscle tone,as well as deficient gastric hydrochloric acid secretion.The cells of smooth muscles and secretory glands must have energy to do their work;thiamin is a necessary agent for producing that energy.,111,Nervous System,The central nervous system depends on glucose for energy.Without sufficient thiamin,this energy is not produced and the nerves cannot conduct their work.Alertness and reflex responses decrease;apathy,fatigue,and irritability result.If the thiamin deficit continues,nerve tissue damage causes nerve irritation,pain,prickly or deadening sensations,and,finally,paralysis.,112,Cardiovascular System,Without constant energy,the heart muscle weakens and heart failure results.Blood circulation becomes problematic when the muscles in vessel walls also weaken.Weakened vessels dilate,leading to fluid accumulation in the lower part of the legs.,113,维生素,B,2,（核黄素）,（,Riboflavin,）,114,一、化学结构和性质,二、吸收、转运及代谢,三、生理功能,四、缺乏的临床表现,五、机体营养水平的鉴定,六、推荐摄入量与食物来源,115,116,FMN,FAD,蛋白质,FMN,FAD,蛋白质,胃酸,小肠上端吸收,影响吸收的因素,促进因素：,胃酸、胆汁酸,摄入量高,动物性食物来源,抑制因素：,铜、锌、铁等二价金属离子,抗酸剂：氢氧化铁、氢氧化镁,酒精、咖啡,117,（,FAD,NAD,）,1.,参与体内的生物氧化与能量生成,葡萄糖,丙酮酸,乙酰辅酶,A,三羧循环,脂肪,脂肪酸,脂肪酰辅酶,A,乙酰辅酶,A,三羧循环,氨基酸,氨,+,酮酸,（,FMN,FAD,）,2H,-,氧化,H,（,NAD,FAD,）,2H,CO2,（,VB1,）,118,生物氧化：,物质在生物体内的氧化分解,地点：,线粒体内,生物氧化阶段：,糖,脂类,蛋白质,葡萄糖,脂肪酸 甘油,氨基酸,乙酰辅酶,A,分解,CO,2,CO,2,CO,2,H,H,H,递氢体统（电子传递系统）,ATP,O,2,H,2,O,FMN,、,FAD,、,NAD,、,NADP,呼吸链,119,GSSG GSH,（抗氧化作用）,2.FMN,FAD,作为辅酶参与色氨酸与维生素,B6,的代谢,3.FAD,作为谷胱甘肽还原酶的辅酶，参与体内的抗氧化防御系统。,通过细胞色素,P450,，参与药物代谢,谷胱甘肽还原酶,FAD,120,四、缺乏的临床表现,1.,口腔炎：口角炎、舌炎、唇炎,2.,皮炎,3.,眼,4.,长期缺乏，生长迟缓，轻中度缺铁性贫血,121,122,123,124,125,126,127,机体营养水平的鉴定,1.,红细胞中核黄素含量,2.,尿中核黄素排出量,3.,谷胱甘肽还原酶活性系数,（,glutathione reductase activation coefficient,GRAC,）,GRAC,=,加入,FAD,后红细胞或全血中,GR,活性,未加,FAD,时红细胞或全血中该酶活性,128,中国营养学会,2000,年制定的维生素,B2,的推荐摄入量（,RNI,）,年龄,RNI(,mg),男 女,18,1.4 1.2,50,1.4,孕早期,1.7,孕中期,1.7,孕末期,1.7,乳母,1.7,129,食物来源,动物性食品,植物性食品 豆类 绿叶蔬菜,动物内脏（肾 肝 心）,蛋类 奶类,130,Deficiency Disease,Signs of riboflavin deficiency include cracked lips and mouth corners;a swollen red tongue;eyes burning,itching,or tearing from extra blood vessels in the cornea;and a scaly greasy dermatitis(,脂溢性皮炎）,in skin folds.Because nutritional deficiencies are usually multiple,riboflavin deficiencies seldom occur alone.They are most likely to occur with deficiencies of other B vitamins and protein.,131,There is no specific deficiency disease comparable to beriberi.A rare deficiency condition of riboflavin has been given the general name aribofiavinosis,（核黄素缺乏症）,.Its symptoms relate to tissue inflammation and breakdown and poor wound healing;even minor injuries easily become aggravated and do not heal well.,132,维生素,PP,（烟酸，尼克酸）,（,Niacin,Nicotinic acid,）,133,一、化学结构和性质,二、吸收、转运及代谢,三、生理功能,四、缺乏的临床表现,五、毒性,六、机体营养水平的鉴定,七、推荐摄入量与食物来源,134,135,糖代谢,生理功能,1.,以辅酶,I,和辅酶,II,的形式做为脱氢酶的辅酶，,参与呼吸链的组成，参与生物氧化还原的全过程,有氧氧化：丙酮酸 乙酰辅酶,A,2H,CO2,（,FAD,）,（,VB1,）,NAD,无氧酵解：,丙酮酸 乳酸,NAD,磷酸戊糖途径：,6,磷酸葡萄糖,6,磷酸,葡萄糖内酯,NADP,136,NAD,，,NADP,（,FAD,FMN,）,蛋白质代谢,脂肪代谢,脂肪 脂肪酸 脂肪酰辅酶,A,乙酰辅酶,A,三羧循环,-,氧化,NAD,（,FAD,）,H,氨基酸 氨,+,酮酸,2H,137,以辅酶,I,的形式参与蛋白质的聚核糖基化作用，,与,DNA,的复制、修复和细胞分化有关。,做为葡萄糖耐量因子的组成成分，,具有增强胰岛素效能的作用。,大剂量的烟酸可降低血脂，扩张血管。,138,烟酸缺乏症：,癞皮病（,Pellagra,）,皮