|Spinach in flower|
It is an annual plant (rarely biennial) growing as tall as 30 cm (1 ft). Spinach may survive over winter in temperate regions. The leaves are alternate, simple, ovate to triangular, and very variable in size from about 2–30 cm (1–12 in) long and 1–15 cm (0.4–5.9 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 (0.1–0.2 in) in diameter, maturing into a small, hard, dry, lumpy fruit cluster 5–10 mm (0.2–0.4 in) across containing several seeds.
Common spinach, S. oleracea, was long considered to be in the family Chenopodiaceae, but in 2003, that family was merged into the family Amaranthaceae in the order Caryophyllales. Within the family Amaranthaceae sensu lato, Spinach belongs to subfamily Chenopodioideae.
The English word "spinach" dates to the late 14th century, and is from espinache (Fr. épinard), of uncertain origin. The traditional view derives it from Old Provençal espinarc, which perhaps is via Catalan espinac, from Andalusian Arabic اسبيناخ asbīnākh, from Arabic السبانخ al-sabānikh, from Persian اسپاناخ aspānākh, meaning purportedly 'green hand', but the multiplicity of forms makes the theory doubtful.
Spinach is thought to have originated in ancient Persia (modern Iran and neighboring countries). It is not known by whom, or when, spinach was introduced to India, but the plant was subsequently introduced to ancient China, where it was known as "Persian vegetable" (bōsī cài; 波斯菜; present:菠菜). The earliest available record of the spinach plant was recorded in Chinese, stating it was introduced into China via Nepal (probably in 647 AD).
In AD 827, the Saracens introduced spinach to Sicily. The first written evidence of spinach in the Mediterranean was recorded in three 10th-century works: the 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 Spain by the latter part of the 12th century, where it was called raʼīs al-buqūl, 'the chieftain of leafy greens'. Spinach was also the subject of a special treatise in the 11th century by Ibn Ḥajjāj.
Spinach first appeared in England and France in the 14th century, probably via Spain, and it gained quick popularity because it appeared in early spring, when other vegetables were scarce and when Lenten dietary restrictions discouraged consumption of other foods. Spinach is mentioned in the first known English cookbook, the Forme of Cury (1390), where it is referred to as 'spinnedge' and/or 'spynoches'. Smooth-seeded spinach was described in 1552.
|Nutritional value per 100 g (3.5 oz)|
|Energy||97 kJ (23 kcal)|
|Dietary fiber||2.2 g|
|Vitamin A equiv.||
|Vitamin A||9377 IU|
|Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database
Raw spinach is 91% water, 4% carbohydrates, 3% protein, and contains negligible fat (table). In a 100 g (3.5 oz) serving providing only 23 calories, spinach has a high nutritional value, especially when fresh, frozen, steamed, or quickly boiled. It is a rich source (20% or more of the Daily Value, DV) of vitamin A, vitamin C, vitamin K, magnesium, manganese, iron and folate (table). Spinach is a good source (10-19% of DV) of the B vitamins riboflavin and vitamin B6, vitamin E, calcium, potassium, and dietary fiber.
Spinach, along with other green, leafy vegetables, contains an appreciable amount of iron attaining 21% of the Daily Value in a 100 g (3.5 oz) amount of raw spinach (table). For example, the United States Department of Agriculture states that a 100 g (3.5 oz) serving of cooked spinach contains 3.57 mg of iron, whereas a 100 g (3.5 oz) ground hamburger patty contains 2.49 mg. However, spinach contains iron absorption-inhibiting substances, including high levels of oxalate, which can bind to the iron to form ferrous oxalate and render much of the iron in spinach unusable by the body. In addition to preventing absorption and use, high levels of oxalates remove iron from the body.
A long-lasting persistent myth is that spinach contains significantly more iron than other green vegetables. The source behind the myth was a study from the 1930s which misplaced a decimal point and thus made it appear as if spinach contained ten times as much iron as it really did.
Spinach also has a moderate calcium content which can be affected by oxalates, decreasing its absorption. The calcium in spinach is among the least bioavailable of food calcium sources. By way of comparison, the human body can absorb about half of the calcium present in broccoli, yet only around 5% of the calcium in spinach.
Types of spinach
A distinction can be made between older varieties of spinach and more modern ones. Older varieties tend to bolt too early in warm conditions. Newer varieties tend to grow more rapidly, but have less of an inclination to run up to seed. The older varieties have narrower leaves and tend to have a stronger and more bitter taste. Most newer varieties have broader leaves and round seeds.
The three basic types of spinach are:
- 'Savoy' has dark green, crinkly and curly leaves. It is the type sold in fresh bunches in most supermarkets in the United States. One heirloom variety of savoy is 'Bloomsdale', which is somewhat resistant to bolting. Other common heirloom varieties are 'Merlo Nero' (a mild variety from Italy) and 'Viroflay' (a very large spinach with great yields).
- Flat- or smooth-leaf spinach has broad, smooth leaves that are easier to clean than 'Savoy'. This type is often grown for canned and frozen spinach, as well as soups, baby foods, and processed foods. 'Giant Noble' is an example variety.
- Semi-savoy is a hybrid variety with slightly crinkled leaves. It has the same texture as 'Savoy', but it is not as difficult to clean. It is grown for both fresh market and processing. 'Tyee Hybrid' is a common semi-savoy.
Production, marketing, and storage
|Source: UN Food & Agriculture Organization, Statistics Division (FAOSTAT)|
The Environmental Working Group reported spinach is one of the dozen most heavily pesticide-contaminated produce products. Depending on the soil and location where the spinach is grown, spinach may be high in cadmium contamination.
Spinach is sold loose, bunched, packaged fresh in bags, canned, or frozen. Fresh spinach loses much of its nutritional value with storage of more than a few days. While refrigeration slows this effect to about eight days, spinach will lose most of its folate and carotenoid content, so for longer storage, it is blanched and frozen, cooked and frozen, or canned. Storage in the freezer can be for up to eight months.
Spinach is packaged in air, or in nitrogen gas to extend shelf life. Some packaged spinach is exposed to radiation to kill any harmful bacteria that may be on the leaves. The Food and Drug Administration approves of irradiation of spinach leaves up to 4.0 kilograys; however, using radiation to sanitize spinach is of concern because it may deplete the leaves of their nutritional value. Researchers at the Agricultural Research Service experimentally tested the concentrations of vitamins C, E, K, B9, and four carotenoids in packaged spinach following irradiation. They found with increasing level of irradiation, four nutrients showed little or no change. Those nutrients include vitamins B9, E, K, and the carotenoid neoxanthin. This study showed the irradiation of packaged spinach to have little or no change to the nutritional value of the crop, and the health benefits of irradiating packed spinach to reduce harmful bacteria seem to outweigh the loss of nutrients.
In popular culture
- Douglas Harper, Online Etymological Dictionary s.v. spinach. Accessed 03/07/2010,
- "spinach". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public library membership required.)
- Boswell, Victor R. (August 1949). "Garden Peas and Spinach from the Middle East". Reprint of "Our Vegetable Travelers". National Geographic Magazine. 96 (2). Archived from the original on March 23, 2010. Retrieved March 7, 2010.
- Rolland, Jacques L.; Sherman, Carol (2006). The Food Encyclopedia. Toronto: Robert Rose. pp. 335–338. ISBN 9780778801504.
- Ibn al-ʻAwwām, Yaḥyá ibn Muḥammad. "23.8". Kitāb al-Filāḥah. Retrieved July 30, 2014.
- 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.
- Rolland, Jacques; Sherma, Carol (2006). Spinach. The Food Encyclopedia: Over 8,000 Ingredients, Tools, Techniques and People. Toronto: Robert Rose. Archived from the original on July 24, 2011. Retrieved March 7, 2010.
- Spinach, The George Mateljan Foundation
- Margaret Grieve; Maud Grieve (1 June 1971). A modern herbal: the medicinal, culinary, cosmetic and economic properties, cultivation and folk-lore of herbs, grasses, fungi, shrubs, & trees with all their modern scientific uses. Courier Dover Publications. pp. 761–. ISBN 978-0-486-22799-3. Retrieved 13 August 2010.
- "Raw spinach per 100 g, Full Report from the USDA National Nutrient Database". US Department of Agriculture, National Nutrient Database for Standard Reference Release 27. 2014. Retrieved 1 February 2015.
- Noonan SC, Savage GP (1999). "Oxalate content of foods and its effect on humans" (PDF). Asia Pac J Clin Nutr. 8 (1): 64–74. doi:10.1046/j.1440-6047.1999.00038.x. PMID 24393738.
- Williams, Sue Rodwell; Long, Sara (1997). Nutrition and diet therapy. p. 229. ISBN 978-0-8151-9273-2.
- Rekdal, Ole Bjørn (2014-08-01). "Academic urban legends". Social Studies of Science. 44 (4): 638–654. doi:10.1177/0306312714535679. ISSN 0306-3127. PMC . PMID 25272616.
- Insel, Paul M.; Turner, R. Elaine; Ross, Don (2003). Nutrition. p. 474. ISBN 978-0-7637-0765-1. Retrieved 2009-04-15.
- Heaney, Robert Proulx (2006). Calcium in human health. p. 135. ISBN 978-1-59259-961-5. Retrieved 2009-04-15.
- Whitney E, Rady Rolfes S (Jan 1, 2010). Understanding Nutrition. Cengage Learning. ISBN 0538734655.
- "Crops/Regions/World List for Production Quantity of Spinach in 2014". UN Food & Agriculture Organization. 2016. Retrieved 14 December 2016.
- "Highlights of the Dirty Dozen™ for 2016". Environmental Working Group. 2016. Retrieved 14 December 2016.
- "ToxGuide for cadmium" (PDF). Atlanta, GA: Agency for Toxic Substances and Disease Registry, US Department of Health and Human Services. October 2012.
- "Storage Time And Temperature Effects Nutrients In Spinach". Retrieved 2008-07-05.
- Bliss RM (27 May 2010). "Nutrient Retention of Safer Salads Explored". US Department of Agriculture.
- Gabbatt, Adam (8 December 2009). "E.C. Segar, Popeye's creator, celebrated with a Google doodle". The Guardian. Retrieved 5 May 2010.
- D. Maue; S. Walia; S. Sahore; M. Parkash; S. K. Walia; S. K. Walia (2005). "Prevalence of Multiple Antibiotic Resistant Bacteria in Ready-to-Eat Bagged Salads". American Society for Microbiology meeting. June 5–9. pp. Atlanta. Abstract
- Rogers, Jo. What Food is That?: and how healthy is it?. The Rocks, Sydney, NSW: Lansdowne Publishing Pty Ltd, 1990. ISBN 1-86302-823-4.
- Cardwell, Glenn. Spinach is a Good Source of What?. The Skeptic. Volume 25, No 2, Winter 2005. Pp 31–33. ISSN 0726-9897
- Blazey, Clive. The Australian Vegetable Garden: What's new is old. Sydney, NSW: New Holland Publishers, 1999. ISBN 1-86436-538-2
- Stanton, Rosemary. Complete Book of Food and Nutrition. Australia, Simon & Schuster, Revised Edition, 1995. ISBN 0-7318-0538-0
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