A review of health benefits of selected South African indigenous fruits and vegetables

Abstract

Recent studies have indicated that South African diets from conventional food sources frequently lack balanced nutrition which has led to poor health and wellbeing of local communities. Therefore, the purpose of this review was to establish potential health benefits of indigenous fruits and vegetables to address risks of nutritional deficiencies, chronic diseases, and pathogenic infections. Google Scholar, ScienceDirect, and ResearchGate databases were used to find relevant articles from which to identify promising indigenous fruit trees and vegetables. Most fruits (Adonsonia digitata, Vangueria infausta, Parinari. curatellifolia, Strychnos species, Sclerocarya birrea, etc.) and vegetables (Solanum nigrum, Momordica foetida, Vigna subterranean, Amaranthus species, Bidens pilosa, Abelmoschus esculentus, Cucurbita species, etc.) had high concentration levels of dietary fibres, vitamins (A, B1, B2, B3, B9, C, E), and minerals (Zinc, copper, manganese, magnesium, and selenium). Some of the indigenous crops had higher concentration levels of vitamins (A, C), iron, and calcium than those of commercialised fruits or vegetables. As such, those indigenous crops could easily meet or exceed recommended daily allowances of various nutrients. The same indigenous crops also had an array of secondary metabolites such as polyphenols (phenolic acids, flavonoids, tannins, coumarins), polysaccharides, alkaloids, saponins, anthraquinones, coumarins, carotenoids, glycosides, quercetin, kaempferol, phytic acids, and linoleic acids. Dietary fibres, nutrients, and secondary metabolites exhibited antioxidant, anti-inflammatory, immunomodulatory, and antimicrobial properties, which could play a critical role in the prevention and treatment of nutrient deficiencies, chronic diseases, and pathogenic infections. The therapeutic potential of nutrients and secondary metabolites may necessitate those food plants to be classified as nutraceuticals or functional foods. Since results were mostly based on in vitro and animal-based in vivo studies, clinical tests should be undertaken to establish efficacy and safety of dietary fibres, phytonutrients, and secondary metabolites based on optimal human dosages.