Vitamins or Supplements ?

I was at the Chemist today looking for some Evening Primrose Oil capsules, they had vitamins and supplements. I asked the assistant what the difference was but she didn't seem to know. Am I being a bit thick.? Could anyone enlighten me please?

 

A dietary supplement is intended to supply nutrients, (vitamins, minerals, fatty acids or amino acids) that are missing or not consumed in sufficient quantity in a person's diet. This category may also include herbal supplements which claim to treat or prevent certain diseases or conditions.

cheers,
John

 

Thanks JB