I can only find one study about not enough dirt causing autoimmune disease, and the study was done on mice. Are their any others?
I've done everything "right" (according to he health blogs), grew up playing in the dirt, kissed my pets, have caught wild viruses, had a whole foods diet, breastfed until one, very limited amount of processed foods and sugar etc and I still have autoimmune diseases and my immune system is shot to pieces.
I limit processed foods, eat as much fresh veg (especially dark green) as possible and take probiotics - but so far no luck for me. It may work for others though. It's always worth a try- especially if it is good for you.