A yam is a starchy vegetable.
There are about 600 species of yams found around the world, most of them in the tropics.
Yams are native to warmer regions of both hemispheres.
They are grown in Africa, Asia, Latin America, the Caribbean and Oceania.
In certain tropical cultures, notably of West Africa and New Guinea, the yam is the primary agricultural commodity and the focal point of elaborate ritual.
People started to cultivate yams, rather than digging up wild ones, as long as 10,000 years ago in both Africa and Asia.
Yams are perennial herbaceous vines cultivated for the consumption of their starchy tubers.
The leaves have many veins that extend from the top of the heart-shape throughout the surface of the leaf and has long stems that are attached to the vines of the plant.
The flowers are generally small and individually inconspicuous, though collectively showy.
They have a cylindrical shape starchy tubers with blackish or brown, bark-like skin and white, purple, or reddish flesh.
Yam tubers vary in size from that of a small potato to over 60 kg (130 lb).
Yam tubers can grow up to 15 m (49 ft) in length and 7.6 to 15.2 cm (3.0 to 6.0 in) high. The tuber may grow into the soil up to 1.5 meters (4.9 ft) deep.
They vary in taste from sweet to bitter to tasteless. Yams are consumed as cooked starchy vegetables. They are often boiled and then mashed into a sticky paste or dough, but they may also be fried, roasted, or baked in the manner of potatoes.
There are 118 calories in 100 grams (3.5 ounces) of yam.
Yams are one of the highest vegetable sources of carbohydrate and energy (kilojoules). They are a good source of B vitamins (B1, B2, B3, B5, B6, B9), Vitamin C, Vitamin A, Vitamin E, Vitamin K, manganese, iron, potassium and dietary fiber.
The health benefits of yams include heals skin diseases, cures respiratory problems and aids digestion, improves bowel habits, increases nutrient absorption of the body, supports and protects the female endocrine system, acts as a cancer deterrent and improve cognitive capacity helps to increase the production of red blood cells in the body.
Yam is available all year round, unlike other, unreliable, seasonal crops. These characteristics make yam a preferred food and a culturally important food security crop in some sub-Saharan African countries.
The name “yam” appears to derive from Portuguese inhame or Canarian (Spain) ñame, which derived from West African languages during trade. The main derivations borrow from verbs meaning “to eat”.