Spinach

Spinach (Spinacia oleracea) is considered to be one of the healthiest foods with several nutrients present in low calories. It is a cool-season green leafy vegetable and its primary season is from early spring in March to May, and then again in the fall from September to October. Even though, its growth is confined to cool season, the Fresh spinach is available throughout the year. Spinach does not grow well in hot, humid climates, so, farmers in the warm regions harvest spinach plants in large quantities through irrigation systems.

The plant has simple, oval or triangular shaped leaves, varying in size with larger leaves at the base and small leaves on the top of the flowering stem. The flavor of the crop will be ruined by the heat. So, Spinach needs consistent moisture.  Spinach leaves should be handled gently as they are easily prone to bruising.

Spinach first appeared in England and France in the 14th century. In England, it was referred as "the Spanish vegetable” for several years. Its origin is assumed to ancient Persia and in china it is still called "Persian Greens". Spinach cultivation spread to Nepal, and then to China by the seventh century. It was introduced   to Spain around the 11th century by Moors. In English cookbook, the Forme of Cury (1390), it is referred to as 'spinnedge' and/or 'spynoches. As written in the book ” A Modern Herbal”, during the First World War, spinach juice was mixed with wine and given to French soldiers who were weakened by heavy blood loss to restore their strength.

Spinach has long been thought of as a rich source of iron and in 1950s, children were forced to eat it by their parents. They thought that it would make their children fit and strong. A simple mathematical error done by a food analyst while calculating the iron content of the spinach, is the cause for the popular misconception that it has large amounts of iron. A decimal point put in the wrong place by him, led many people to believe that spinach contained large amounts of iron. The cartoon character, Popeye who swallowed tins of this leafy vegetable for instant energy to his muscles, also influenced the more consumption of this leafy vegetable.

Types

Savoy spinach, flat spinach, and semi-savoy spinach are the three types of spinach. Savoy is the most commonly found type and it has curlier leaves than other types and it has a mild taste. Flat spinach or smooth leaf spinach is usually grown for preserved purposes. Semi-savoy spinach is hybrid and less commonly used type.

Nutrients

According to the United States Department of Agriculture (USDA), a 100-gram serving of spinach has 28.1 micrograms of vitamin C, 34 percent of the daily recommendation.
Contrary to the popular belief, spinach is not a good source of iron, although it’s green leaves contain several other valuable nutrients.  This leafy vegetable has low fat and cholesterol, but it is rich in water-soluble vitamins, fat-soluble vitamins, minerals, and a wide variety of phytonutrients.
Raw spinach contains 91% water, 4% carbohydrates, 3% protein, and negligible amounts of fat. It is a rich source of vitamins A, C, E and K, thiamine, vitamin B6, folate, calcium, iron, magnesium, phosphorus, potassium, copper, and manganese.

Health benefits

Spinach is a good source of potassium and it is important element in regulating blood pressure. By reducing the effects of sodium in the body, it controls blood pressure. It keeps the blood glucose level in control in people with diabetes. The antioxidant alpha-lipoic acid of spinach, lowers blood glucose levels, increases insulin sensitivity, and prevents oxidative stress-induced changes in diabetic patients.
Alpha-lipoic acid also decreases peripheral neuropathy and autonomic neuropathy in       diabetics.
High fibre content and water of spinach help to prevent constipation
Beta-carotene of spinach lowers the risk of asthma.
Chlorophyll of spinach blocks the carcinogenic effects generated when grilling foods at a high temperature.
Consumption of carotene rich spinach, reduces the risk of age related macular degeneration which is a common cause of blindness among the elderly people.
The folate of spinach helps to prevent spina bifida in pregnant women.
The antioxidant effects of lutein, a carotenoid pigment, protects against many types of cancer.
It improves bone health and reduces anaemia.
Vitamin A of Spinach, helps in the growth of hair and all tissues of the skin. It helps in the production of sebum which keeps the hair moisturized.
Vitamin C is essential for the synthesis and maintenance of collagen, which provides structure to skin and hair.
Adequate intake of spinach prevents hair loss caused due to iron deficiency.

Drawbacks

Spinach has high levels of oxalic acid. High levels of oxalates limit the absorption of iron and calcium, and only a fraction can be used by the body. This will result in increasing their presence in the urine, which is fatal.
Eating spinach along with vitamin C supplements also increases oxalate levels which may result in the formation of kidney and bladder stones.
Spinach also contains high levels of nitrate which are converted into carcinogenic nitrosamines in the gut. So, spinach can be eaten in moderation and it should not be eaten in large amounts over a long period.
Avoid or reduce the intake of spinach while taking blood thinners because of its high levels of vitamin K that helps in blood clotting.
Avoid the consumption of spinach if suffering from kidney problems because of its high potassium content. In such persons Kidneys cannot remove potassium from blood and it may be fatal.

Storage of Spinach

Fresh spinach can be kept in the refrigerator for ten to fourteen days.
The best temperature to store spinach is (5-10) °C.
Fresh spinach loses much of its nutritional value and becomes dry within a few days without proper storage.
Refrigeration slows this effect down and the leaves stay fresh for prolonged periods of time, usually up to eight days.
However the spinach may lose most of its folate and carotenoid content in the process of refrigeration. So for longer storage, it is bleached and frozen, cooked and frozen, or canned. In this way storage in the freezer can be done for up to eight months.
Cool air and relatively high humidity will cause discolouration of spinach leaves, resulting in a ‘warty’ appearance which is less prevalent on the lower leaf surface and on older leaves.

“Purchase only such spinach, whose leaves are with a vibrant, deep green colour. Do not use any leaves that are wilted or that have wet, brown spots. Spinach attracts and holds bacteria easily, so wash it well before using. It is always best to buy organically grown spinach to avoid pesticides.
Never wash spinach before storing it in the refrigerator because the leaves will wilt quickly when exposed to water.”