August 31: Day of the walnut

It is the day of the walnut, in the French Revolutionary calendar. Here are 10 things you might not know about walnuts:

1. The word walnut is of Germanic and Old English origin, and means "foreign nut".
2. The two most common major species of walnuts are the Persian or English walnut and the black walnut. The English walnut (Juglans regia) originated in Persia, and the black walnut (Juglans nigra) is native to eastern North America.
3. China is the world's largest producer of walnuts, but the USA is the largest exporter.
4. The Walnut Whip is Nestle Rowntree's oldest current brand, having been launched in 1910 by Duncan's of Edinburgh. The company uses over a million walnuts a week making them, and they claim someone in the UK eats one every two seconds.
5. A 100 gram serving of Walnuts contains 15.2 grams of protein, 65.2 grams of fat, 6.7 grams of dietary fibre, 654 calories and several dietary minerals, particularly manganese and B vitamins.
6. Walnut oil is used as a food ingredient, particularly in salad dressings. It has a low smoke point, which limits its use for frying.
7. Walnut is the main ingredient of Fesenjan, a khoresh (stew) in Iranian cuisine.
8. Walnuts have other uses besides eating them. They have been used to make inks and dyes. Leonardo da Vinci and Rembrandt used walnut ink. Walnut dyes were used in classical Rome and in medieval Europe for dyeing hair. The shells were at one time ground up and used by the US Army as a non-abrasive cleaner for aviation parts, until a walnut grit clogging up a helicopter's oil port caused a fatal crash in 1982.
9. In China, large, symmetrical walnuts are so highly prized that they are used as investments and can be worth thousands of dollars.
10. In Bach Flower Remedies, walnut is used to protect against the effects of change. It is recommended for transitions in life, such as birth, teething, starting school, puberty and marriage. It is said to help people break links with the past and move forward more easily.