维生素a的作用?

2025-02-25 06:18:45
推荐回答(5个)
回答1:

http://baike.baidu.com/view/6447.htm
维生素A:有维护皮肤细胞功能的作用,可使皮肤柔软细嫩,有防皱去皱功效。维生素A主要作用是保持皮肤、骨骼、牙齿、毛发健康生长,还能促 进视力和生殖机能良好的发展。要摄取维生素A,除全乳制品、动物肝脏、肾脏、蛋、鱼肝油之外,多食用色泽鲜艳的蔬菜和深绿色疏菜,例如芹 菜、南瓜、萝卜等疏果皆含有丰富的维生素A,其中胡萝卜更是佼佼者,多吃不但令粗糙皮肤恢复正常,也能治夜盲症和降低血压。缺乏维生素A,可使上皮细胞的功能减退,导致皮肤弹性下降,干燥,粗糙,失去光泽。维生素A含量丰富的食物有动物肝脏、奶油、黄油、胡萝卜、白薯、绿叶蔬菜、栗子、蕃茄等。

回答2:

维生素A:有维护皮肤细胞功能的作用,可使皮肤柔软细嫩,有防皱去皱功效。维生素A主要作用是保持皮肤、骨骼、牙齿、毛发健康生长,还能促 进视力和生殖机能良好的发展。要摄取维生素A,除全乳制品、动物肝脏、肾脏、蛋、鱼肝油之外,多食用色泽鲜艳的蔬菜和深绿色疏菜,例如芹 菜、南瓜、萝卜等疏果皆含有丰富的维生素A,其中胡萝卜更是佼佼者,多吃不但令粗糙皮肤恢复正常,也能治夜盲症和降低血压。缺乏维生素A,可使上皮细胞的功能减退,导致皮肤弹性下降,干燥,粗糙,失去光泽。维生素A含量丰富的食物有动物肝脏、奶油、黄油、胡萝卜、白薯、绿叶蔬菜、栗子、蕃茄等。

回答3:

1、视觉功能

维生素A经典的或最早被认识的功能是在视觉细胞内参与维持暗视感光物质循环。视网膜上的杆状细胞含有的视紫红质,是由11-顺式视黄醛与视蛋白结合而成,其对暗光敏感。

2、维持皮肤粘膜完整性

维生素A是调节糖蛋白合成的一种辅酶,对上皮细胞的细胞膜起稳定作用,维持上皮细胞的形态完整和功能健全。

3、细胞核激素样作用

维生素A通过细胞核内类视黄酸受体,调节和控制细胞核内信使RNA的激活与表达。

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扩展资料

1、胡萝卜中的胡萝卜素能在体内转化成维生素A,只要在氧化酶的作用下就可以转换,而我们人类的肝里就有这种氧化酶。胡萝卜对眼部肌肤也有很好的针对性滋润帮助,因此,胡萝卜也是黑眼圈患者摆脱熊猫眼的绝佳食物。

2、红皮黄心番薯,含有丰富的胡萝卜素,其经人体吸收后转化为维生素A,具有滋润肌肤的功效。除此之外,番薯还具有祛除体内肺胃热,生津止渴,调和身体体液,以补中和血,从而使人的皮肤恢复健康的红润的肤色。

3、西红柿中含有丰富胡萝卜素,可以在体内转化为维A。具有清热止渴,养阴凉血的功效,能够帮助平抚肌肤皱纹,使皮肤恢复细嫩光滑,因此,皮肤干燥起皱的人可多吃西红柿,恢复肌肤光彩美丽。

参考资料:/baike.baidu.com/item/%E7%BB%B4%E7%94%9F%E7%B4%A0A/192716?fr=aladdin#5"target="_blank"title="只支持选中一个链接时生效">百度百科-维生素A

回答4:

〖药名〗维生素A(Vitamin
A,Retinol)
〖其它名称〗维生素甲,视黄醇
〖适应证〗有促进生长,维持上皮组织(如皮肤、结膜、角膜等)正常机能的作用,增强视网膜的感光力,参与体内的许多氧化过程(尤其是不饱和脂肪酸的氧化)。维生素A缺乏时生长停止,骨骼成长不良,生殖功能衰退,皮肤粗糙、干燥,发生干燥性眼炎及夜盲症。本品口服极易吸收。用于补充营养,以及治疗夜盲症、角膜软化症。
〖慎用证〗①授乳妇女慎用(有部分维生素A分泌于乳汁中);②肾功能减退者慎用。
〖药物相互作用〗氢氧化铝、矿物油、硫糖铝、新霉素、考来烯胺均能干扰本品吸收。
〖剂型〗胶丸剂
〖用法用量〗口服。成人预防用量每次5000国际单位,每日1次;儿童预防用量每日1500~2500国际单位。
〖用药观察〗①食物中脂肪、蛋白质与体内的胆盐和维生素E对维生素A吸收有密切关系,缺乏上述物质则吸收降低;②长期大剂量服用可引起维生素A过多症,甚至发生急、慢性中毒(以6个月至3岁的婴儿发病率最高)。急性中毒常表现为异常激动、头晕、嗜睡、复视、呕吐、腹泻、唇和掌脱皮等;慢性中毒表现为食欲不振、皮肤发痒、毛发干枯、脱发、口唇皲裂、易激动、骨痛、易骨折、颅内压增高等,一般停药1~2周后可消失;③成人1次用药超过100万国际单位,或小儿1次用药超过30万国际单位,可发生急性中毒症状;不论成人或小儿如连续每日用药10万国际单位超过6个月,均可致慢性中毒。一旦中毒应立即停止服药;④孕妇的用量每日不超过6000国际单位

回答5:

治疗或预防口腔疾病,如口腔炎症,口臭

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