Bread-Bakers v100.n059.16

I find that 1 1/2 tablespoons of nonfat dry milk powder improves the results
(better rise and texture) when I bake whole wheat bread in my bread machine.
Can you help me understand what the mechanism is?  Because of health issues,
I'm trying to avoid milk products.  Are there non-dairy alternatives?

Thanks,
Heather Reseck
Carnation, WA