Corn (and other seeds) have a lot of anti-nutrients - this is one reason people have gravitated to refined grains. The anti-nutrients are deactivated when the seed is boiled in an alkali - the process is called Nixtamalization [0]. Native Americans boiled their corn in wood ash. Lime [1] is now used for this purpose.
It's said the European explorers took Corn back to Europe, but didn't realize the wisdom of boiling corn in wood ash. Corn has a good amount of Vitamin B-3, but eating a diet of non-nixtamalized corn causes Pellegra [2] (Vitamin B-3 deficiency), due to the niacin not being available on account of it being locked up in the starch. (I think the Slate Star Codex blog talked about this phenomenon. Similarly, Cassava (yuca) root was taken from South America to Africa, but they didn't share how important it is to remove the cyanide in the outer shell and stem in the center...)
Making your own tortillas is very easy. I follow the directions on Bob's Masa [4] package: corn, salt, water, wait, spoon onto plastic wrap, fold plastic wrap, crush into tortilla-like shape, apply to hot plate.
I have ambition to use the lime I purchased at the mexican grocer to make my own masa, but I haven't gotten past watching videos on Youtube. I need some corn... Maybe I should grow corn this summer. I might have enough time to get some seeds in the ground. :)
[0] https://en.wikipedia.org/wiki/Nixtamalization
[1] https://en.wikipedia.org/wiki/Lime_(material)
[2] https://en.wikipedia.org/wiki/Pellagra#Epidemiology
[3] https://en.wikipedia.org/wiki/Cassava#Potential_toxicity
[4] https://www.bobsredmill.com/organic-golden-masa-harina-flour...