Cinnamon is a spice obtained from the inner bark of several tree species from the genus Cinnamomum. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, breakfast cereals, snackfoods, tea and traditional foods. The aroma and flavour of cinnamon derive from its essential oil and principal component, cinnamaldehyde, as well as numerous other constituents, including eugenol.
Cinnamon has been known from remote antiquity. It was imported to Egypt as early as 2000 BC, but those who reported that it had come from China had confused it with cinnamon cassia, a related species. Cinnamon was so highly prized among ancient nations that it was regarded as a gift fit for monarchs and even for a deity; a fine inscription records the gift of cinnamon and cassia to the temple of Apollo at Miletus. Its source was kept mysterious in the Mediterranean world for centuries by those in the spice trade to protect their monopoly as suppliers. Cinnamomum verum, which translates as 'true cinnamon', is native to India, Sri Lanka, Bangladesh, and Myanmar. Cinnamomum cassia (cassia) is native to China. Related species, all harvested and sold in the modern era as cinnamon, are native to Vietnam, Indonesia and other southeast Asian countries with warm climates.
According to Pliny the Elder, a Roman pound (327 grams (11.5 oz)) of cassia, cinnamon, or serichatum cost up to 1500 denarii, the wage of fifty months' labour. Diocletian's Edict on Maximum Prices from 301 AD gives a price of 125 denarii for a pound of cassia, while an agricultural labourer earned 25 denarii per day. Cinnamon was too expensive to be commonly used on funeral pyres in Rome, but the Emperor Nero is said to have burned a year's worth of the city's supply at the funeral for his wife Poppaea Sabina in AD 65.
Indonesian rafts transported cinnamon directly from the Moluccas to East Africa (see also Rhapta), where local traders then carried it north to Alexandria in Egypt. Venetian traders from Italy held a monopoly on the spice trade in Europe, distributing cinnamon from Alexandria. The disruption of this trade by the rise of other Mediterranean powers, such as the Mamluk sultans and the Ottoman Empire, was one of many factors that led Europeans to search more widely for other routes to Asia.
Cinnamon is an evergreen tree characterized by oval-shaped leaves, thick bark, and a berry fruit. When harvesting the spice, the bark and leaves are the primary parts of the plant used. Cinnamon is cultivated by growing the tree for two years, then coppicing it, i.e., cutting the stems at ground level. The following year, about a dozen new shoots form from the roots, replacing those that were cut. A number of pests such as Colletotrichum gloeosporioides, Diplodia spp., and Phytophthora cinnamomi (stripe canker) can affect the growing plants.
The barks of the species are easily distinguished when whole, both in macroscopic and microscopic characteristics. Ceylon cinnamon sticks (quills) have many thin layers and can easily be made into powder using a coffee or spice grinder, whereas cassia sticks are much harder. Indonesian cinnamon is often sold in neat quills made up of one thick layer, capable of damaging a spice or coffee grinder. Saigon cinnamon (C. loureiroi) and Chinese cinnamon (C. cassia) are always sold as broken pieces of thick bark, as the bark is not supple enough to be rolled into quills.
Ground cinnamon is composed of around 11% water, 81% carbohydrates (including 53% dietary fiber), 4% protein, and 1% fat (table). In a 100 gram reference amount, ground cinnamon is a rich source of calcium (100% of the Daily Value, DV), iron (64% DV), and vitamin K (30% DV).
Reviews of clinical trials reported lowering of fasting plasma glucose and inconsistent effects on hemoglobin A1C (HbA1c, an indicator of chronically elevated plasma glucose). Four of the reviews reported a decrease in fasting plasma glucose, only two reported lower HbA1c, and one reported no change to either measure. The Cochrane review noted that trial durations were limited to 4 to 16 weeks, and that no trials reported on changes to quality of life, morbidity or mortality rate. The Cochrane authors' conclusion was: "There is insufficient evidence to support the use of cinnamon for type 1 or type 2 diabetes mellitus." Citing the Cochrane review, the U.S. National Center for Complementary and Integrative Health stated: "Studies done in people donít support using cinnamon for any health condition."