nutrition vs vitamin

nutrition and vitamin both are nouns.

Word	Noun	Adjective	Verb	Adverb
nutrition	Yes	No	No	No
vitamin	Yes	No	No	No

As nouns, vitamin is a hyponym of nutrition; that is, vitamin is a word with a more specific, narrower meaning than nutrition:

nutrition: a source of materials to nourish the body
vitamin: any of a group of organic substances essential in small quantities to normal metabolism

nutrition (noun)	vitamin (noun)
the scientific study of food and drink (especially in humans)	any of a group of organic substances essential in small quantities to normal metabolism
a source of materials to nourish the body
(physiology) the organic process of nourishing or being nourished; the processes by which an organism assimilates food and uses it for growth and maintenance