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Vitamins are organic compounds necessary in small amounts in the diet for the normal growth and maintenance of life of animals, including man. They do not provide energy, nor do they construct or build any part of the body. They are needed for transforming foods into energy and body maintenance. There are thirteen or more of them, and if any is missing a deficiency disease becomes apparent. Vitamins are similar because they are made of the same elements usually carbon, hydrogen, oxygen, and sometimes nitrogen. They are different in that their elements are arranged differently, and each vitamin performs one or more specific functions in the body. Getting enough vitamins is essential to life, although the body has no nutritional use for excess vitamins. Many people, nevertheless, believe in being on the ' safe side' and thus take extra vitamins. However, a wellbalanced diet will usually meet all the body' s vitamin needs. |
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wéi shēng sù shì yǒu jī huà hé wù, yǐn shí zhōng bì xū hán yǒu shǎo liàng wéi shēng sù yǐ wéi chí dòng wù bāo kuò rén de shēng cún hé zhèng cháng shēng zhǎng. tā men bù tí gōng néng liàng, yě bù gòu chéng shēn tǐ de rèn hé yī bù fen, tā men de rèn wù shì bǎ shí wù zhuǎn biàn chéng néng liàng hé wéi chí shēn tǐ jiàn kāng. zhì shǎo yǒu 13 zhǒng wéi shēng sù, ruò quē qí zhōng yī zhǒng, quē fá zhèng jí bìng biàn míng xiǎn kě jiàn. gè zhǒng wéi shēng sù dōu hěn xiāng sì, yīn wèi tā men yóu tóng yàng de yuán sù gòu chéng, yì bān shì tàn qīng yǎng, yǒu shí hái yǒu dàn. tā men de bù tóng zhī chǔ zài yú měi zhǒng wéi shēng sù nèi bù de yuán sù pái liè bù tóng, bìng qiě měi zhǒng wéi shēng sù zài rén tǐ nèi dōu yǒu yī zhǒng huò duō zhǒng tè shū zuò yòng. suī rán wéi shēng sù duì rén tǐ bìng wú shén me yíng yǎng shàng de yòng chǔ, dàn xī shōu zú gòu de wéi shēng sù shì bì yào de. jǐn guǎn rú cǐ, yǒu xiē rén chū yú bǎo xiǎn de xiǎng fǎ, hái shì shè rù guò liàng de wéi shēng sù. bù guò, jūn héng de yǐn shí yì bān néng gòu wán quán mǎn zú shēn tǐ duì wéi shēng sù de xū qiú. |