I am actually the one that found the information on truvia. I then posted the letter here for Dr. O and everyone else and he shared it in his newsletter. The best thing you can do with any products you have a question about is to email or call the company. I prefer email, then I have it in writing to refer to later. You just never know what is in something until you write the company. Truvia says nothing about being derived from corn it talks about erythritol being found in pears and grapes on their website but says nothing about corn. (I thought that was very misleading, because it is NOT from pears and grapes) Most companies are very responsive and answer all of your questions.(Including the truvia company) In this case I asked them what their erythritol was made from because I know it is usually made from corn.
I don't think I have ever had a company not answer me. I always asked if there are any grains in any of the ingredients in their product and I make sure I tell them that corn is an ingredient I can not have. (some people think corn is a vegetable) It seems like corn is hidden in everything.