Definition of vitamin in US English:



  • 1Any of a group of organic compounds which are essential for normal growth and nutrition and are required in small quantities in the diet because they cannot be synthesized by the body.

    • ‘The vitamin can decrease cholesterol and boost circulation - but large doses can cause a red rash.’
    • ‘Evidence indicates that a lack of basic nutrients including vitamins in the diet can cause heart disease or make it worse.’
    • ‘Studies have shown that deficiency in essential vitamins can lead to antisocial behaviour.’
    • ‘The dandelion is very nutritious, containing more vitamins and minerals than most vegetables.’
    • ‘Jackie believes that we all need to do is watch the vitamin and mineral levels in our diet.’
    • ‘Our bodies actually only need tiny amounts of vitamins and minerals.’
    • ‘Most vitamin and mineral supplements stay in your body and continue to work for two to three days.’
    • ‘The decline is not consistent with all nutrients and vitamins, but it is clear that our food is not what it once was.’
    • ‘Not so long ago, most people would not have had an ideal regular intake of vitamin C, a vitamin the human body cannot synthesize.’
    • ‘This is due to a lack of thiamine, a vitamin that is essential for the mechanisms by which energy is released from foodstuffs.’
    • ‘They will be fed, once a week, a diet of chicken and meat laced with the vitamins and nutrients they need.’
    • ‘We never thought in terms of nutritional value or vitamins in those days.’
    • ‘Can your body derive all of the vitamins and minerals that it needs from food, and is it really necessary to take a supplement?’
    • ‘Other genes, to make the plant synthesise essential amino acids and vitamins, can also be added.’
    • ‘Young bodies grow quickly and they need all the vitamins and minerals they can get.’
    • ‘Drop in and they will advise you on your vitamin requirements for the coming winter.’
    • ‘It is a time characterised by a lack of vitamins in the human body after a hard winter.’
    • ‘Eating nutritious foods rich in vitamins and minerals is just another way to improve your health.’
    • ‘She also said that it could be stress related or maybe even a vitamin deficiency that the tests don't show up.’
    • ‘We include protein for growth and essential minerals and vitamins in raw foods, salads and fruits.’
    1. 1.1North American A pill containing a specified amount of a particular vitamin or vitamins, taken as a dietary supplement.
      ‘I woke up this morning and took a vitamin’


Early 20th century: from Latin vita ‘life’ + amine, because vitamins were originally thought to contain an amino acid.