Wild edible yams from Madagascar: New insights into nutritional composition support their use for food security and conservation

Yams (Dioscorea species) are an important food resource in Madagascar, where both cultivated winged yam (D. alata) and wild edible yams are consumed. However, there is limited knowledge on the nutrient composition of wild edible yams in Madagascar, and on how they compare with the cultivated winged yam. Therefore, in this study, nine wild edible yam species, one with two subspecies from Madagascar (D. bako, D. buckleyana, D. irodensis, D. maciba, D. orangeana, D. pteropoda, D. sambiranensis subsp. bardotiae and subsp. sambiranensis, D. seriflora and Dioscorea species Ovy valiha), were analysed for their nutrient composition, compared with cultivated D. alata. They include 6/6 of the most favoured wild edible yam species in Madagascar. We present new nutrient composition data (protein, carbohydrate/starch, energy, lipid, {beta}-carotene, minerals) for these nine wild edible yam species and show that they contain comparable levels of lipids and starch to D. alata, but none are better sources of protein than D. alata. We show that D. irodensis contains a significantly higher {beta}-carotene content when compared to all other edible yams analysed, and that D. buckleyana, D. irodensis and D. sambiranensis subsp. bardotiae have a higher calcium content than cultivated D. alata, while all nine wild edible yam species analysed contain a higher iron content, compared to cultivated D. alata. The nutrient composition data presented could provide new incentives to conserve wild edible yams and inform on strategies to select Disocorea species for sustainable cultivation and use, providing opportunities to enhance future food security in Madagascar.