A cob of hazel is roughly spherical, about 20 millimeters in diameter, with an outer fibrous husk surrounding a smooth shell. It is eatable and contains 62% fat, 17% protein, 7% sugar, vitamins and minerals. Its oil is used in confectionery (to produce e.g. halva), pharmaceutical industry, perfume production and paint industry.

The biggest advantage of hazelnuts is their high content of fatty acids, mostly unsaturated fatty acids. That is why people with an increased level of cholesterol should be encouraged to eat them.

Hazelnuts are a significant source of protein and vitamins. They contain C and B vitamins, as well as minerals: iron, zinc, potassium, phosphorus and copper. They are high caloric – 100g equals 700 calories; that is why they should be consumed with care by those who take care of not putting on weight.

On the contrary, hazelnuts should be eaten by people suffering from insomnia and nervous problems, children with anemia, patients who have undergone long-term therapies and are in the process of rehabilitation, and people of any age exhausted by mental work, as the high content of phosphorus restores functions of grey matter.