Have you heard of nutritional yeast? 

It is a single-celled organism that is grown on molasses.  It has a ton of nutrition like folic acid, vitamin b, selenium, zinc and proteins.  It is also gluten-free, low fat, zero sugar and no preservatives.  I usually get my at Whole Foods in the bulk section but you can also order online at Amazon or maybe find it in the natural foods section of your grocery store. 

Since the nutritional yeast comes as a powder or flakes you can easily sprinkle it on your pizza.  There are a lot of other ways to use it too like kale chips, roasted vegetables, etc.

I think it is a great nutritional alternative to yeast and paleo friendly!