Nutrients and health benefits of underutilized green leafy vegetables.

What is it about?

Despite their potential for achieving food security and for combating hidden hunger (micronutrient deficiency), dark green leafy vegetables are still underutilized in many parts of the world. In this review paper, the nutrient composition and health benefits and five underutilized Nigerian green leafy vegetables were investigated. The green leafy vegetables are Talinum triangulare, Amaranthus hybridus, Gnetum africanum, Pterocarpus mildbraedii and Telfairia occidentalis. Amaranthus hybridus is also known as African Spinach, Amaranth or bushgreen. Talinum triangulare is also known as water leaf or spinach. Gnetum africanum is also known as Eru, Okazi, Ukazi, Afang, or Okok; Pterocarpus mildbraedii is also known as white camp wood; Telfairia occidentlis is also known as fluted gourd and fluted pumpkin. Gnetum africanum (Eru) is mainly collected from the wild and could be propagated using the seeds. The leaves are difficult to chew and slightly bitter. It may be mixed with T. occidentalis and T. triangulare leaves to make delicious and health boosting soup in the Nigerian cuisine. Pterocarpus mildbraedii leaves may be collected from the wild and are sometimes domesticated. Telfairia occidentalis is mainly cultivated. Talinum traingluare and Amaranthus hybridus may be cultivated or found in the wild. Green leafy vegetables provide sensory appeal to foods and are “colours of good health” since they contribute micronutrients for metabolic reactions of the body and phytonutrients that are precursors for many metabolic reactions. Amaranthus hybridus is a rich source of β-carotene, iron, calcium, vitamin C and folic acid. A. hybridus is good for managing blood pressure, prevents heart diseases, lowers blood cholesterol, boosts the immune system, treats anaemia, and helps in weight reduction. Telfairia occidentalis leaf contains significant amounts of folic acid, calcium, zinc, potassium, cobalt, copper, iron, vitamins A, C, and K. T. occidentalis possesses hypolipidaemic, anti-hyperglycaemic, hepatoprotective, and antioxidant properties. It is used to manage anaemia, diabetes, gastrointestinal disorders and sustain flow of breast milk during lactation. Talinum triangulare is rich in carotenoids (lutein and zeaxanthin), low in calories and high in fibre. T. triangulare improves memory, perception, and cognitive abilities; sensitizes the neurons in the cerebrum; has anti-fungal; anti-bacterial; and anti-inflammatory properties. It also has strong antioxidant properties. Gnetum africanum is exceptionally rich in protein (20.12%), fibre, iron, flavone glycosides and stilbenes. It helps to keep the heart healthy, controls excess urination treats boils, wart and enlarged spleen and improves digestion. G. africanum possesses anti-inflammatory properties. Pterocarpus mildbraedii is rich in ascorbic acid and carotenoids. P.mildbraedii is used in traditional settings for the treatment of fever, headaches, convulsion, pains, and respiratory disorders. While G. africanum is exceptionally rich in protein, A hybridus had the highest essential amino acid composition when compared with the other five green leafy vegetables. Phenylalanine and arginine contents of all the GLVs were higher than the FAO standard values. A. hybridus had higher amounts of histidine, and leucine than the FAO standard. The leucine content of P. mildbraedii isoleucine and threonine contents of G. africanum and valine content of T. triangulare was higher than the FAO standard values. T. triangulare had higher amounts of valine than the FAO standard value while G. africanum had higher amounts of threonine than the FAO standard. A. hybridus had the highest essential amino acid composition while T. occidentalis had the least when compared with the FAO standard. Talinum triangulare, Gnetum africanum and Pterocarpus mildbraedii are also good sources of essential amino acids. Amaranthus hybridus, Pterocarpus mildbraedii and Telfairia occidentalis contain relatively high amounts of vitamins and minerals and are blood and immune system boosters. G. africanum and P. mildbraedii possess antimicrobial properties. The vitamin contents of these GLVs are reduced more than the minerals during processing. There was no loss of iron in A. hybridus because of storage and loss of iron in T. triangulare was relatively low. The intake of green leafy vegetables should be diversified for optimal health benefits

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Photo by Victor Birai on Unsplash

Photo by Victor Birai on Unsplash

Why is it important?

Green leafy vegetables can promote food security by providing micronutrients that prevent hidden hunger (micronutrient deficiencies). They also have a lot of health benefits. This paper highlight the nutrient composition and health benefits of five underutilized green leafy vegetables. Many researchers can use it as a basis for further research. Many consumers can also use it as a guide.

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