Nutritional and health benefits of wild and cultivated yam (Dioscorea spp.) species consumed in eastern Democratic Republic of Congo

Yam (Dioscorea spp.) is a tuber-producing crop and an important staple in the tropics and subtropics, valued for its nutritional, health and sociocultural relevance. However, there is limited awareness of its nutritional and health benefits among local communities in eastern Democratic Republic of Congo (DRC), prompting its underutilization. This study aimed to (a) document the diversity of cultivated and semi-domesticated yam species in eastern DRC; (b) explore indigenous knowledge on their nutritional and health benefits; and (c) assess the nutrient composition and antioxidant activity of major yam species consumed in the region. Data collection involved ethno-botanical surveys, plant specimen collections, interviews with 123 community members, and physicochemical profiling using standard analytical methods. Ten yam species were documented in eastern DRC, including two domesticated species, with distribution patterns shaped by biophysical conditions and cultural factors. Species richness was higher in highland forest zones compared to lowland savannas. Local communities use yam to treat more than 15 health conditions, including stomach pains, food intoxications, skin wounds and infections, reproductive abnormalities, immune system deficiency, respiratory challenges, diabetics, etc. Physicochemical composition analysis revealed interspecific variations potentially contributing to their nutritional and therapeutic relevance by local communities. Notably, Dioscorea dumetorum tubers exhibited the highest protein content (8.7 g/100 g) and potassium concentration (240.2 mg/100 g), D. praehensilis was rich in carbohydrates (80.9 g/100 g), and D. bulbifera had highest calcium concentration (40.1 mg/100 g), underscoring the yam nutritional significance in the local diet. All yam species encompassed saponins, terpenoids, and alkaloids, though D. praehensilis and purple D. alata had the highest antioxidant activity that exceeded 90% inhibition level. These findings provide valuable insights on yam diversity and their potential to sustain nutritious healthy diets in eastern DRC.