Hazelnuts are the seeds of Corylus avellana, a species originating in Asia Minor that is now widespread in all temperate climate areas of the world. In Italy, the main regions where they are cultivated are Piedmont, Latium, Campania and Sicily, but the main producer of hazelnuts worldwide is Turkey.
There are at least 11 species belonging to the genus Corylus, they can reach heights of between 3 and 8 metres and flower in early spring, before the leaves develop. The fruits can be eaten raw, roasted or reduced to a paste.

Hazelnuts are mainly used as a food source of protein, minerals, vitamin E and unsaturated fatty acids, especially alpha-linolenic acid. However, there are currently no data available to establish a recommended dosage; however, it should be noted that 100 g of hazelnuts provide approximately 15 mg of vitamin E.