(Nigeria Natural Medicine Development Agency)
Cyperus esculentus (Fam: Cyperaceae), commonly known as earth almond, tiger nut or yellow nutsedge, is a marble-sized tuber which grows underground, like potatoes. It is known in Nigeria as aya in Hausa language, ofio in Yoruba and akiausa in Ibo. Though there are three varieties (black, brown and yellow), only two – yellow and brown – are readily available in the market.
This tuber is rich in starch, fat, sugar, and protein, minerals (iron, phosphorus, potassium, Zinc and calcium), and vitamins E and C. It was found to contain saturated and unsaturated fatty acids, phytosterols, the amino acid arginine, antinutrients such as phytates, oxalates, saponins and tannins, and enzymes such as catalases, lipases and amylases.
Tiger nut can be eaten raw, roasted, dried, baked or be made into a refreshing beverage called tiger nut milk. They are generally soaked in water before they can be eaten, thus making them much softer and giving them a better texture. They are a popular snack in West Africa that can also be used as toppings for a variety of dishes, such as breakfast cereal, smoothies, salads and yogurts. They may be ground and used in bread or other baked goods.
Pharmacological actions and medicinal uses
Milk derived from tiger nut is a healthy option for those who cannot drink cow’s milk due to lactose intolerance. It has been reported to be a “health” food, since its consumption can help prevent urinary tract infection, heart disease and thrombosis; as well as helping to activate blood circulation and reduce the risk of colon cancer.
In ayurvedic medicine, tiger nuts are used in the treatment of flatulence, diarrhoea, dysentery, debility and indigestion. Tiger nuts are also said to act as a mild appetite suppressant because they contain resistant starch, a type of starch which resists digestion. This helps keep us feeling fuller for longer, and also reduces the amount of calories we absorb from the food.
“Resistant starch is also a prebiotic, which helps our bodies to naturally develop probiotic (friendly) bacteria ensuring a strong immune system”, a report says. Tiger nuts reportedly have anti-diabetic, weight-losing and anti-sickling properties. Because of its high content of the antioxidant, vitamin E, it helps slow down the ageing of the body cells, favours the elasticity of the skin and reduces skin wrinkles.
Research has indicated that Cyperus esculentus may play an important role in enhancement of fertility. Research findings revealed that methanolic extract of Cyperus esculentus significantly increased serum estrogen level as the dose concentration of extract increased, but did not significantly increase follicle stimulating hormone, luteinizing hormone and prolactin levels. Nigerian researchers have demonstrated how extracts of tiger nuts significantly increased gonadotropins, testosterone, and sperm parameters in a dose-dependent fashion. Men in Nigeria have used tiger nuts for generations to treat erectile dysfunction, increase sperm count and boost libido. They’re used as aphrodisiacs in Ayurvedic medicine.
Eating too many tiger nuts at a time can cause abdominal pain, bloating, flatulence, diarrhea or constipation. Tiger nuts contaminated with aflaxtoxins can cause side effects like liver damage, liver cancer, and fetal growth restriction during pregnancy.
Tiger nut is useful in the food industry for baking, the production of jam, beer and fermented products, such as yogurt; as a flavouring agent in ice cream; and in the preparation of kunnu (a local beverage in Nigeria). The tubers can be useful in the pharmaceutical industry; the cosmetic industry – in making starch extracts and oil for soap. It is also a potential oil crop for the production of biodiesel.
According to the Director General of Raw Materials Research and Development Council (RMRDC), Prof. Peter Onwualu, tiger nut and walnut can fetch Nigeria N100 billion annually and create direct and indirect employment for over 5,000 people.