Comparative analysis of nutrients in frequently consumed Indigenous African vegetables: implications for geriatric nutrition

Abstract

The promotion and consumption of African Indigenous Vegetables (AIVs) offers potential to improve diet quality and reduce the burden of non-communicable diseases among older persons. However, limited information exists on the minerals, vitamins and phytochemicals that contribute to these benefits. This study assessed the nutritional composition of three genotypes of each of four commonly consumed AIVs in Uganda: Solanum aethiopicum Shum (E16, E15, and E11), Solanum aethiopicum Gilo (G4, G9, and G6), Amaranthus sp. (Var. 008, Var. 025, and Var. 007), and Vigna unguiculata L. Walp (UCU Cow 1, Aseremoya, and Acc23). The vegetables were analysed for minerals (Fe, Zn, Ca, Mg, K), dietary fibre, phytochemicals (anthocyanins, tannins, catechins, polyphenols, chlorogenic acid, gallic acid, ferulic acid, flavonoids), and vitamins (α-tocopherol and β-carotene) using standard procedures and means were separated using One-Way ANOVA. Significant differences (p<0.05) were observed across AIVs. S. aethiopicum Shum E16 exhibited the highest mineral levels, while V. unguiculata genotypes showed the lowest Mg, Fe, and K content. Iron was highest in S. aethiopicum Gilo G4 (8.83mg/100g). Leafy vegetables contained greater quantities of phytochemicals, dietary fibre, β-carotene, and α-tocopherol than fruit vegetables. Principal component analysis segregated genotypes based on nutrient profiles: phytochemicals and fibre strongly influenced V. unguiculata clustering, minerals influenced Solanum spp, and tocopherol and gallic acid distinguished Amaranthus genotypes. These findings highlight distinct nutritional advantages across AIV species. V. unguiculata exhibited particularly high phytochemical and vitamin content, suggesting its value as a nutrient-dense component of diets aimed at supporting healthy ageing.