Walnuts (Juglans regia) are also called English walnuts or common walnuts. Walnuts survived the ice ages of the Tertiary period in Asia (for example in Syria) and have been eaten for at least 9000 years.
From Wikipedia: “Juglans regia, Persian walnut, English walnut, or especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himalayas and southwest China. The largest forests are in Kyrgyzstan, where trees occur in extensive, nearly pure walnut forests at 1,000–2,000 m (3000 to 7000 ft) altitude —notably at Arslanbob in Jalal-Abad Province. It is widely cultivated across Europe.”
“Walnuts are used in a variety of dishes from cakes to walnut ice cream. In addition to whole nuts, shelled walnuts and walnut oil are sold, as well as nuts for decoration for desserts. Walnuts are also used in Waldorf salad, tortelloni, skordalia, kozunak, lobio, nunt, and tschurtschchela.
Another possibility is to use walnuts taken from the harvest of immature green nuts in June. Preserves can be made from these that have a high vitamin C content (candied, also called black nuts) or a walnut liqueur (nussgeist, nussschnaps). In Italy, they are used to make a special liqueur called Nocino. In Serbia, Croatia, and Bosnia and Herzegovina, the green nuts are used to make a liqueur called Orahovac.”
“Walnuts contain 42 to 62.5 percent fat, 11 to 16 percent protein, and 15 to 23 percent carbohydrates, depending on whether they are fresh or dried. Walnuts are the nuts that have the highest content of linolenic acid (7490 mg/100 g), an omega-3 fatty acid that is healthy for the heart. They are rich in tocopherols, a group of four different forms of vitamin E. They are also a good source of zinc, an element that is important for the liver and hair, as well as potassium, magnesium, phosphorus, sulfur, iron, calcium, pantothenic acid, and vitamins A, B1, B2, B3, and C. A 100 g serving contains 2783 kJ.
In a study on Mediterranean diets, it was found that walnuts can help protect against type 2 diabetes. Recent studies have shown that a serving of nine walnuts and one teaspoon of walnut oil a day can protect the body against high blood pressure in stressful situations. In combination with linseed oil, walnuts can also help to improve the health of blood vessels. In addition, walnuts have been shown to counteract cardiovascular disease and help inhibit prostate cancer.*”
Note (italics): * = Translation from a German Wikipedia entry