Nutrient content of eight African leafy vegetables and their potential contribution to dietary reference intakes

Abstract

Nutrient content and potential contribution of one average portion towards nutritional requirements (recommended dietary allowance; RDA) of eight African leafy vegetables (ALVs) was determined. Compared to dark-green leafy vegetables (DGLVs) as sub-group, calcium and magnesium content were similar or considerably higher, vitamin C content was considerably lower, while pigweed had higher potassium content and spider flower similar folate content. All ALVs, except Chinese cabbage, had higher iron content. Black nightshade, pigweed, cowpea and spider flower leaves had higher β-carotene content than DGLVs. For children, pigweed and cowpea leaves emerged as good sources of vitamin A (>75% RDA), followed by spider flower, black nightshade, tsamma melon, Jew's mallow and pumpkin leaves (50–75% RDA). For iron, pumpkin leaves provided 50–75% RDA. Black nightshade, tsamma melon, pigweed and cowpea leaves contributed 25–50% RDA, with Jew's mallow, spider flower and Chinese cabbage providing <25% RDA. The ALVs were not a good source of zinc. Most ALVs were nutritionally similar to DGLVs. For most nutrients Chinese cabbage had considerably lower values than the other ALVs. Most of the ALVs can considerably contribute to requirements of vitamin A and, to a lesser extent, iron, both critical nutrients for developing countries.