Nutritional value of leafy vegetables of sub-Saharan Africa and their potential contribution to human health: A review

This paper reviews the literature on African leafy vegetables (ALVs) consumed in sub-Saharan Africa. The aim is to evaluate the nutritional value of these plant species and their potential impact on the nutritional status of the people living in sub-Saharan Africa. Processing and the presence of antinutritional factors are taken into consideration as they adversely affect the nutritional content of the ALVs. The role of dietary fiber and other important components found in ALVs is also discussed due to their importance in the prevention of chronic and lifestyle diseases. Many of the ALVs are good sources of micronutrients, especially Manihot esculenta which contains 1970 μg retinol equivalents/100 g edible portion and 311 mg/100 g of vitamin C, as well as Chenopodium album with up to 6 mg/100 g iron, 18.5 mg/100 g zinc, 226 mg/100 g calcium and up to 211 mg/100 g magnesium. These vegetables may help to meet daily requirements of these and other essential nutrients, especially in individuals with marginal nutritional status. Furthermore, ALVs such as Arachis hypogea and Bidens pilosa are good sources of dietary fibre, while Nasturtium aquatica, Urtic dioica and Xanthosoma mafaffa are excellent free radical scavengers. In many instances ALVs have levels of these components that are higher than those of exotic vegetables such as spinach and cabbage. Factors such as storage, cooking methods and drying influence the micronutrient, antioxidant and antinutritional factor content of these vegetables. The consumption, cultivation and possibly the commercialization of these ALVs should therefore be promoted.