I do not believe this is the only quotation I will have about this topic, but it is one of the first. I do encourage you to look up the context and see that she is, indeed, talking about spicy food.
Christian Temperance and Bible Hygiene P. 46
Spices at first irritate the tender coating of the stomach, but finally destroy the natural sensitiveness of this delicate membrane. The blood becomes fevered, the animal propensities are aroused, while the moral and intellectual powers are weakened, and become servants to the baser passions. The mother should study to set a simple yet nutritious diet before her family.
For what it’s worth, my parents didn’t really follow this. The reason I can’t tolerate spicy food is because it fills my mouth with nothing but pain. I can not even taste spicy food, because it just hurts so bad. I do not know why this is the case. My body’s just weird I guess.