Lois,
Your best bet is to call the mfg and ask them about it. Not all MFS is GF. Nancy's right - it's more than likely from corn, but you don't know for sure. Companies like Kraft, ConAgra, UniLever will not hide gluten in MFS and "natural flavors". So you can be safe in knowing when you see those items on their labels, it does not contain gluten unless otherwise stated.
Keep readin' those labels and callin' those mfgs!!
Unilever Family Product List
ConAgra Family Product List
Kraft Family Product List