Linolenic acid and folate in wild-growing African dark leafy vegetables (morogo)

Abstract

Transition from a low-fat vegetable-rich rural diet to a high-fat Westernised diet is considered a factor in the escalating occurrence of vascular-related diseases and type 2 diabetes in urban black South Africans. Consumption of morogo is a distinguishing feature of rural African diets. To determine fatty acid profiles and folate contents of three widely consumed, wild-growing, African dark green leafy vegetables (morogo). GC–MS was applied for analysis of fatty acid composition and a validated microbiological assay conducted to determine folic acid contents of wild-growing morogo sampled from deep rural villages in three different geographical regions of South Africa. Measured fatty acids ranged from 1610·2 to 2941·6 mg/100 g dry mass, with PUFA concentrations 1·4 to 2·8 times those of SFA. Calculated from the relative percentages of linoleic acid (18:2n-6) and linolenic acid (18:3n-3), the ratio of 18:2n-6 to 18:3n-3 PUFA was 1·0:3·4 to 1·0:8·9. The only MUFA was palmitoleic acid (16:1), measured at 34·7 (sd 0·3) to 79·0 (sd 9·3) mg/100 g dry mass, and the predominant SFA was palmitic acid (16:0), measured at 420·6 (sd 83·3) to 662·0 (sd 21·2) mg/100 g dry mass. Folic acid concentration varied from 72 to 217 μg/100 g fresh sample. Morogo is low-fat food item high in folate and with 18:3n-3 in excess of 18:2n-6, the proposed anti-inflammatory effects of which may lower risks of vascular-related chronic diseases and type 2 diabetes