Environmental context shapes the nutritional quality of Gnetum africanum Welw

Abstract

Gnetum africanum, a nutritionally significant leafy vegetable across Central and West Africa, is sourced from both natural forest ecosystems and managed home gardens. To understand the impact of the cultivation environment on the nutritional profile of G. africanum leaves, we conducted a comparative analysis of their proximate composition and micronutrient content, harvested from these contrasting environmental settings. Our quantitative analyses reveal divergent nutritional characteristics associated with the source ecosystem. Specifically, forest-derived leaves exhibited significantly higher levels of dry matter (92.43 ± 0.04%), total ash (8.65 ± 0.07%), crude fibre (9.68 ± 0.07%), and total carbohydrate (50.99 ± 0.02%) (mean ± SEM). Conversely, home garden samples showed higher moisture content (8.40 ± 0.03%), crude protein (24.42 ± 0.12%), total fat (3.82 ± 0.07%), and consequently, a higher energy value (329.16 ± 0.27 kcal/100 g). Furthermore, forest-sourced leaves were enriched in key minerals, notably calcium (392.07 ± 0.40 mg/100 g), sodium (101.53 ± 0.19 mg/100 g), and potassium (795.65 ± 0.25 mg/100 g). In contrast, home garden samples showed higher concentrations of iron (36.29 ± 0.18 mg/100 g) and vitamins, including vitamin A (658.45 ± 0.18 mg/100 g) and vitamin C (71.50 ± 1.36 mg/100 g). Our findings unveil the ecosystem-dependent nutritional quality of a key African leafy vegetable. Given the demonstrated nutritional advantages of forest-derived G. africanum samples, our results emphasise the critical importance of conserving natural forest habitats to safeguard the availability of nutrient-dense plant resources. Our study provides crucial insights for nutritional security and highlights the ecological underpinnings of food quality in non-domesticated food sources.