While it is suggested cornstarch shouldn't be consumed raw, it is perfectly safe to eat once cooked. Cornstarch is generally edible in small quantities and in some cases can be used to maintain blood sugar levels for those with Type 2 diabetes and hypoglycemia.
Pica, compulsively eating a substance that is not food, is frequently associated with such a mineral deficiency and often goes away when the deficiency is corrected. Here is another woman's experience: “I have been eating Argo Corn Starch on and off for about 15 years now.
Like Luffy, Zoro shows little interest or attraction to women.
No. Zoro hasn't shown Conqueror's Haki at any point in the series.