Corn vs Wheat

What is worse in dry cat foods:

Ground corn

Corn gluten meal

Wheat flour

Wheat gluten

I know they are all not great, but I know that my cat doesn't digest peas well which eliminates many natural brands.

This is my personal opinion. So, please keep that in mind, but based off of my experience working with hundreds of rescue cats in no kill shelters, working as a vet tech and owning cats, I would say corn of any type seems to cause more allergies and put excessive weight on the animal faster.

Ground corn is a filler, Corn Gluten meal is used as a protein.
Wheat is easier on the tummy IMHO. By far the least allergenic of the two.
It also depends on the order they are on the food - the higher on the ingredient list, the higher the percentage. Ideally, you want the most meat as possible on the first 6 ingredients..... You might have chicken on the first ingredient, then corn gluten meal as the second, then corn as third..... well... chicken is almost 80% water...... Right there you can see that your food is mostly made of corn and grains, not a good thing for cats.
Anyways, hope this helps some -
But yes, in between the two, I would go with wheat, and keep it low in the list :nod:

I would take corn gluten or wheat gluten over plain corn or wheat, as the gluten is more or less purified protein whereas the corn meal itself would be high in carbs a bit higher than wheat at least.  

Corn and wheat are both common allergens, but that's just statistics.  Your cat may be allergic to just one and not the other, or neither and be fine on both.   But because vegetable proteins are incomplete, I consider them an inferior source to meat protein.    Keep them low on the ingredient list, and it doesn't bother me.