Spinach is an edible flowering plant placed in the family Amaranthaceae. It’s scientifically called Spinacia oleracea. It is an annual plant reaching a length of 30 cm. The plant is rarely biennial. In the temperate regions the plant could even survive in the winter months. The leaves are alternate, simple, and ovate to triangular-based. They may be 2-30 cm long and 1-15cm wide. The larger leaves are found in the bottom of the plant while little leaves are present around the flowering area. The flowers are inconspicuous, yellow-green and 3-4 millimeters in diameter. They mature into a small, hard, dry, lumpy fruit bunch which measures 5-10 mm.
The term spinach comes from an Arabic word. Spinach is of considerable importance from nutritional point of view. It’s rich in antioxidants especially when fresh, steamed or quickly boiled. It’s a potent source of vitamin A, vitamin C, vitamin E, vitamin K, magnesium, manganese, folate, betaine, iron, vitamin B2, calcium, potassium, vitamin B6, folic acid, copper, protein, phosphorus, zinc, niacin, selenium and omega-3 fatty acids. A present study has indicated that spinach also contains opioid peptides called rubiscolins. Polyglutamyl folate is a very important component of cells and spinach is a rich source of folic acid. Boiling the spinach leaves reduces folate content but microwaving does not impact the folate content.
Spinach along with other green leafy vegetables is regarded as a fantastic source of iron. According to an estimate of United States Department of Agriculture 180 grams of boiled spinach comprises 6.43 mg of iron, whereas one 170 g ground hamburger patty contains at most 4.42 mg. The bioavailability of iron is dependent upon its absorption which is affected by a number of factors. Iron enters body in two forms either heme or non-heme iron. All the iron present in vegetables, grains and three-fifth of the animal foods comprises non-heme iron. The iron is consumed unless and until consumed by a supply of vitamin C. spinach comprises iron absorption inhibiting factors along with high levels of oxalate which forms ferrous oxalate upon binding with iron. This form is unstable and can’t be absorbed in body.
Spinach also has high calcium content. Calcium in spinach is bioavailable of calcium sources. There are three types of spinach available commercially. These are savoy, semi-savoy and smooth or flat leaf spinach. Savoy spinach has dark green, crinky and curled leaves. It is marketed in new bunches. They are resistant to bolting. The smooth or flat leaf spinach bears smooth leaves and it is not hard to clean this variety as compared to savoy variety. This is very popularly used in soups, processed foods and baby foods. Semi-savoy is a hybrid variety with slightly crinkled leaves. It has the exact same texture like that of the savoy spinach and is easier to be cleaned out. It’s developed for fresh and processed foods. Spinach is sold in loose, bunched, prepackaged bags, canned or frozen forms. Fresh spinach loses much of its nutritional value after being stores in refrigerator for few days. Much of the folate and carotenoid content of spinach becomes lost upon storage. The cartoon character Popeye the Sailor Man is depicted as having a strong affinity for spinach, becoming physically stronger after consuming it.