Do vitamins lose their qualities if...?

Question

Do vitamins lose their qualities if exposed to high temperature and what is the highest temperature in which they still preserve their quality? And do they lose their qualities if mixed with vinegar?

Answer 1

The temperature issue varies from vitamin to vitamin, they're very different chemically from each other. In general, many of them will decompose at high temperatures--i.e. boiling water or higher.

The answer is definitely no to the vinegar thing. Vinegar is a dilute solution of a weak acid (acetic acid), pH of approximately 5. Your stomach has concentrated hydrochloric acid in it, with a pH of 1-2. If the vitamins can survive your stomach, they can survive vinegar.