Overview:

Food security is still a significant challenge in developing and emerging countries, and sustainable foods are currently in demand. This systematic review explores the potential of Neglected and Underutilized Species (NUS) following a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework as resilient food sources to address food security, particularly in developing and poor countries. The study aims to highlight the nutritional, medicinal, economic, and environmental benefits of NUS, emphasizing their role in achieving the Sustainable Development Goal (SDG) of "Zero Hunger" by 2030. The review synthesizes data from 134 articles published between 2000 and 2022, focusing on the diversity, geographical distribution, and potential of NUS to contribute to sustainable food systems. The species diversity revealed that most documented NUS are studied or researched from Asia’s developing and poor countries, followed by Africa. NUS are exposed to hindrances as they are poorly highlighted in the mainstream ground of Sustainable Development Goals. Hence, key strategies must be undertaken to develop their utilization and integration into current agricultural practice. Thus, NUS can widen the prospect of becoming a future resilient food.

Key Findings:

1. Nutritional Value and Dietary Potential of Traditional Crops: NUS provide essential macronutrients (proteins, carbohydrates, fats) and micronutrients (vitamins A, B, C, calcium, zinc, iron). These crops improve dietary diversity, particularly for vulnerable groups such as children under five, adolescents, and women of reproductive age. Traditional leafy vegetables (Amaranthus graecizans, Solanum nigrum, Portulaca oleracea) in Africa contain high levels of iron, calcium, and vitamin A, supporting maternal and child nutrition. Tuber crops like Dioscorea spp. (yams) and Vigna subterranea (Bambara groundnut) offer high-energy, protein-rich alternatives to staple grains.

2. Environmental effects of traditional crops vs. staple crops: NUS are typically low-input crops, requiring fewer synthetic fertilizers and pesticides, reducing environmental degradation. They enhance soil health through nitrogen fixation (Vigna spp., Bambara groundnut), reducing the need for chemical fertilizers. Many NUS are drought-resistant and thrive in degraded soils, making them viable alternatives in arid and semi-arid regions. Unlike monoculture-dependent staples, NUS promote biodiversity conservation and ecosystem stability.

3. Barriers to consumer adoption: Some NUS crops are considered "famine food," leading to stigma and reduced acceptance. Many traditional crops require longer preparation times, making them less convenient for modern consumers. Poor commercialization and limited market access prevent NUS from reaching urban consumers.

4. Role of traditional crops in climate resilience: NUS are naturally adapted to extreme weather conditions, including drought, heat stress, and poor soil fertility. They serve as an essential food source in humanitarian and emergency aid settings, ensuring food availability during crises. Species such as Chenopodium quinoa (quinoa) and Lablab purpureus (hyacinth bean) are being promoted for their climate-resilient properties.

5. Challenges for farmers in increasing production: Farmers struggle to access high-yielding and improved NUS varieties (lack of quality seeds). Limited processing infrastructure and post-harvest losses hinder commercialization. Women, who play a central role in NUS cultivation, often lack access to financial resources and land (inequality gender).

6. Institutional and policy leverage points for strengthening traditional crops: Most national agricultural policies prioritize staple crops, marginalizing NUS. Policies integrating NUS into school feeding programs and government procurement can boost demand. Strengthening NUS market access through farmer cooperatives and fair-trade initiatives. Encouraging investment in NUS-based food products to enhance consumer appeal. Training programs for farmers on best practices in NUS production and value addition. Successful programs in West Africa have integrated NUS into climate-smart agricultural policies.

7. Ongoing Initiatives Supporting Traditional Crops

Peru’s Quinoa Expansion Program: Government policies have promoted quinoa as a climate-resilient crop, enhancing both domestic consumption and export markets.

West Africa’s Community Seed Banks: Local initiatives in Burkina Faso and Niger focus on preserving indigenous seeds and improving farmer access.

School Feeding Programs in Kenya and Ethiopia: Incorporating nutrient-rich NUS into school meals to improve child nutrition and support local farmers.

The majority of documented NUS are found in Asia (49.84%) and Africa (30.88%), with limited representation in Europe, North America, and Australia.

Recommendations:

• Conservation Strategies: Implement in-situ and ex-situ conservation methods to preserve genetic diversity. Promote breeding programs and gene pool utilization to enhance the resilience and productivity of NUS.

• Commercial Production: Encourage large-scale cultivation of NUS to improve dietary diversity, economic opportunities, and environmental sustainability. Develop market infrastructure and value chains to support small-scale producers.

• Research and development: Invest in research to explore the nutritional, medicinal, and environmental benefits of NUS. Focus on domestication, ecotype selection, and the development of sustainable agricultural practices.

• Policy implications: Develop policies that support the integration of NUS into national food systems. Provide incentives and subsidies for farmers to cultivate NUS and improve seed delivery systems.

• Nutrition education: Raise public awareness about the nutritional benefits of NUS. Promote the inclusion of NUS in school feeding programs and public health initiatives to improve dietary diversity, especially among vulnerable groups.

• Institutions and Policies: Governments and international organizations should create policies that incentivize the cultivation of NUS through subsidies, grants, and research funding. For example, the promotion of quinoa in Peru has transformed it from a neglected crop to a global superfood.