Fiddleheads are the curled, edible shoots of the ostrich fern and are considered a seasonal delicacy in many parts of Canada. Every year, thousands of Canadians get food poisoning. Fiddleheads can cause food poisoning if they have not been stored, prepared or cooked properly. Fiddlehead ferns are high in antioxidants and essential fatty acids, which are often found in so-called "superfoods." They can be especially good for people who don't eat fish, which are also high in essential fatty acids.