It is an annual plant (rarely biennial), growing as tall as 30 cm (1 ft). Spinach may overwinter in temperate regions. The leaves are alternate, simple, ovate to triangular, and very variable in size: 2–30 cm (1–12 in) long and 1–15 cm (1⁄2–6 in) broad, with larger leaves at the base of the plant and small leaves higher on the flowering stem. The flowers are inconspicuous, yellow-green, 3–4 mm (1⁄8–5⁄32 in) in diameter, and mature into a small, hard, dry, lumpy fruit cluster 5–10 mm (1⁄4–3⁄8 in) across containing several seeds.
In 2022, world production of spinach was 33 million tonnes, with China alone accounting for 93% of the total.[1]
As opposed to most flowering plants used as vegetables, spinach is a dioecious plant, meaning different plants can have either female or male flowers.[a][7]
The flowers are small, green and wind pollinated.
Spinach male flowers
Spinach female flowers
Round seeds of the 'Monnopa' cultivar
Spiky seeds of the 'Erste Ernte' cultivar
History
Spinach is thought to have originated about 2,000 years ago in ancient Persia from which it was introduced to India and later to ancient China via Nepal in 647 CE as the "Persian vegetable".[8] In 827 CE, the Arabs introduced spinach to Sicily.[9] The first written evidence of spinach in the Mediterranean was recorded in three 10th-century works: a medical work by al-Rāzī (known as Rhazes in the West) and in two agricultural treatises, one by Ibn Waḥshīyah and the other by Qusṭus al-Rūmī. Spinach became a popular vegetable in the Arab Mediterranean and arrived in the Iberian Peninsula by the latter part of the 12th century, where Ibn al-ʻAwwām called it raʼīs al-buqūl, 'the chieftain of leafy greens'.[10] Spinach was also the subject of a special treatise in the 11th century by Ibn Ḥajjāj.[11][better source needed]
Spinach first appeared in England and France in the 14th century, probably via Iberia, and gained common use because it appeared in early spring when fresh local vegetables were not available.[8] Spinach is mentioned in the first known English cookbook, the Forme of Cury (1390), where it is referred to as 'spinnedge' and 'spynoches'.[8][12] During World War I, wine fortified with spinach juice was given to injured French soldiers with the intent to curtail their bleeding.[8][13]
Although spinach contains moderate amounts of iron and calcium, it also contains oxalates, which may inhibit absorption of calcium and iron in the stomach and small intestine. Cooked spinach has lower levels of oxalates, and its nutrients may be absorbed more completely.[16][17]
Cooking spinach significantly decreases its vitamin C concentration, as vitamin C is degraded by heating. Folate levels may also be decreased, as folate tends to leach into cooking liquid.[18]
Spinach is rich in nitrates and nitrites, which may exceed safe levels if spinach is over-consumed.[19]
In 2022, world production of spinach was 33 million tonnes, with China alone accounting for 93% of the total.[1]
Marketing and safety
Fresh spinach is sold loose, bunched, or packaged fresh in bags. Fresh spinach loses much of its nutritional value with storage of more than a few days.[21] Fresh spinach is packaged in air, or in nitrogen gas to extend shelf life. While refrigeration slows this effect to about eight days, fresh spinach loses most of its folate and carotenoid content over this period of time. For longer storage, it is canned, or blanched or cooked and frozen.[21]
Some packaged spinach is exposed to radiation to kill any harmful bacteria. The Food and Drug Administration approves of irradiation of spinach leaves up to 4.0 kilograys, having no or only a minor effect on nutrient content.[22]
Spinach may be high in cadmium contamination depending on the soil and location where the spinach is grown.[23]
Due to spinach's high content of vitamin K, individuals taking the anticoagulantwarfarin, which acts by inhibiting vitamin K, are instructed to minimize consumption of spinach (and other dark green leafy vegetables).[24]
The comics and cartoon character Popeye the Sailor Man is portrayed as gaining strength by consuming canned spinach.[27] The accompanying song lyric is: "I'm strong to the finich [sic], 'cuz I eats me spinach."[28] This is usually attributed to the iron content of spinach, but in a 1932 strip, Popeye states that "spinach is full of vitamin A" and that is what makes people strong and healthy.[29] As it happens, spinach is not a better source of dietary iron than many other vegetables. The false idea that spinach is an especially good source of dietary iron is an academic urban legend.[30]
^Birlouez, Éric (2020). "Une fabuleuse diversité, «L'épinard, légume de carème»" [A fabulous diversity, «Spinach, the lent vegetable»]. Petite et grande histoire des légumes [A small and great history of vegetables]. Carnets de sciences (in French) (1 ed.). Versailles/impr. en Suisse: Quæ. p. 52-54. ISBN978-2-7592-3196-6. Quæ
^Clifford A. Wright. Mediterranean Vegetables: A Cook's ABC of Vegetables and their Preparation in Spain, France, Italy, Greece, Turkey, the Middle East, and North Africa, with More than 200 Authentic Recipes for the Home Cook. (Boston: Harvard Common Press, 2001). pp. 300-301.
^National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). "Chapter 4: Potassium: Dietary Reference Intakes for Adequacy". In Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). pp. 120–121. doi:10.17226/25353. ISBN978-0-309-48834-1. PMID30844154. Retrieved 2024-12-05.
^"The Press: I Say It's Spinach". Time. October 22, 1951. Retrieved February 1, 2014. Many a New Yorkerism (e.g., Cartoonist Carl Rose's 'I say it's spinach, and I say the hell with it') has become a part of the language.
^Joe Schwarcz, Monkeys, Myths, and Molecules: Separating Fact from Fiction in the Science of Everyday Life, 2015, ISBN1770411917, p. 245; spinach actually contains beta-carotene, which the body converts to vitamin A
