Even those of us who can eat grains don't get much from it in the way of nutrition because of the anti-nutrients that are in all seeds. It needs to be prepared in certain ways to neutralize the anti-nutrients, and commercially, it is NOT. I have only recently, in the past couple of years, been going through the trouble to make it a habit to lacto-ferment my wheat, but I still buy my sandwich bread and corn products. Corn needs to be soaked in lime water. I bought the Mrs. Wage's pickling lime last year, but it is still unopened!
And I am pretty hardcore in my food prep, so I understand how most people can be depleted. If even I am depleted with all my efforts....sheesh!
Liver is a great source of B's. I, like many people, can't get past the yuk factor. But if I could, I would only eat VERY properly raised liver, grass-fed and pharmaceutical-free, and organic. No chemicals on the grass, either.
So I take supplements!

It is easier! You might also consider a good multi, too. Especially with your absorption issues.