Vitamins are naturally occurring organic compounds that are essential for the proper functioning of the human body, and they were not "invented" by any one individual. The term "vitamin" was coined by Polish biochemist Casimir Funk in 1912. Funk used the word "vitamine" to describe a group of organic compounds that were vital for health, and he later isolated and identified thiamine (Vitamin B1).
The discovery of various vitamins was the result of research by numerous scientists over many years. Each vitamin has its own unique history and was identified by different researchers. For example, vitamin C (ascorbic acid) was identified by several scientists, including Albert Szent-Györgyi and Norman Haworth. Similarly, the B-complex vitamins were discovered by various scientists, as mentioned in a previous response.
Vitamins are essential for health, and understanding their roles and sources has been a collaborative effort in the field of nutrition and biochemistry.