From [wikipedia][1] > A vitamin is an organic compound and a vital nutrient that an organism requires in limited amounts. An organic chemical compound (or related set of compounds) is called a vitamin when the organism cannot synthesize the compound in sufficient quantities, and it must be obtained through the diet; thus, the term "vitamin" is conditional upon the circumstances and the particular organism A vitamin is therefore not defined by its structure but by its availability. There is therefore no taste associated to vitamins in general. So, no we are not able to sense vitamins generally speaking just because there is no natural objective category of substances that one can call vitamin. --------- Note by the way, that the health effect of vitamins supplmentation (for most people) is debated. For example, you might want to have a look at the following two skeptics posts - [Do vitamins improve memory abilities?][2] - [Do vitamin supplements have any health benefits?][3] One of the most important scientist of the 20th century, [Linus Pauling][4] advocated for the health benefits of vitamin C. Due to his strong influence, the reputation of vitamin C quickly grew but his work remained controversial and there are still very little evidence that supplement of vitamin C does any good. [1]: https://en.wikipedia.org/wiki/Vitamin [2]: http://skeptics.stackexchange.com/questions/19593/do-vitamins-improve-memory-abilities [3]: http://skeptics.stackexchange.com/questions/20227/do-vitamin-supplements-have-any-health-benefits [4]: https://en.wikipedia.org/wiki/Linus_Pauling