Dave Babcock has written an excellent article on the debate over whether high fructose corn syrup is natural:
So, let's say I was making you dinner, and in preparing one of the ingredients was "fixed to a column by the use of a synthetic fixing agent, glutaraldehyde." Even if I told you that I washed off all the "unreacted glutaraldehyde," would you be willing to call the dinner I made you "natural?"
If you wouldn't, don't eat with the decision makers from the FDA.
More on natural claims is here: USDA Reopens Comments on Use of "Natural" and here: Health Canada Guidance on Food-like Natural.