Allergy symptoms are many and vary with the individual. I go by cause and effect – if you find that the leg cramps happen when you eat fortified yeast and not when you don’t, then it seems pretty likely to be an allergy symptom.

I cannot take Wheat Germ because of this allergy. It took me 27 years
to find out what was causing my leg cramps. I know others who seem to have the same problem and would like to know if it is an allergy or side effect of yeast in foods.

I’ve not done a detailed study of this. I can’t eat most bread because I’m gluten-intolerant, but I have been able to eat yeast lately.
Flat-breads (unleavened) are worth checking out. pumpernickel is a dense rye-based bread which I think is yeast-free. Sprouted grain breads may be yeast free.
Sourdough may be OK.

These are some starting points. Check ingredients! If you discover some definitively yeast-free breads, please leave a comment and share your findings.