Greater vegetable diversity needed for healthier diets and climate-resilient agriculture

In a study published in the Proceedings of the National Academy of Sciences (PNAS), the researchers show how a wider diversity of vegetables could help improve diets and strengthen agriculture against climate change. They use the term vegetable biodiversity to describe the full range of vegetable species, traditional varieties and their wild relatives.

The findings come as people worldwide consume nearly 40% fewer vegetables than recommended by the World Health Organization. Global production remains insufficient to meet recommended intake, and low vegetable consumption is among the five leading dietary risk factors contributing to the global burden of disease. More than one in three people cannot afford a healthy diet, highlighting the need to make vegetables more affordable and accessible.

The researchers argue that simply producing more of today’s most common vegetables will not be enough. Many traditional and underused vegetables are rich in vitamins and minerals, well adapted to local conditions and valued in local food cultures. Their diverse varieties and wild relatives also contain traits that can help breeders develop vegetables better able to withstand heat, drought, pests and diseases.

“Growing more vegetables alone is not enough. We also need to grow a greater diversity of vegetable species,” says Professor Eric Schranz, Professor of Biosystematics at Wageningen University & Research. “Much of the vegetable biodiversity we need can still be found in traditional varieties and their wild relatives. We urgently need to safeguard this diversity and connect conservation with breeding, use by farmers and healthier diets as the climate changes.”

The researchers identify more than 1,480 edible vegetable species worldwide, though the true number is likely even higher. Many are poorly researched and underused despite their importance in local diets and farming systems. 

The study draws on information about commonly consumed and underutilized species, displayed on the World Food Map. The World Food Map is an interactive resource that documents the diversity and distribution of edible species worldwide. Co-authors Dr Anna Herforth, Visiting Associate Professor at Wageningen University & Research, and Dr Chris Vogliano, a Wageningen postdoctoral researcher, are leading its development.

Among this wide diversity, the study highlights spider plant in Africa, bitter gourd in Asia, slippery cabbage in the Pacific, and the edible leaves of pumpkin, sweet potato and cowpea. Many are rich in vitamins and minerals, adapted to challenging growing conditions and valued in local food cultures. Yet they receive only a tiny fraction of the research, breeding and conservation efforts devoted to globally traded vegetables and staple grains.

By showing which vegetables are most relevant to different regions and climate challenges, the study can help researchers, practitioners and policymakers identify priorities for conservation, breeding and wider use. But many of these resources are already disappearing. Studies have documented substantial declines in the range of traditional vegetable varieties grown over the past century, while almost one-quarter of assessed wild relatives of major vegetable crops are threatened with extinction.

“Vegetables are, of course, one of the most important parts of a healthy diet,” says study co-author Dr Herforth. “But people tend to drop vegetables if they are too expensive or inaccessible. We need to tap into greater biodiversity so that everyone can access the food they need, and retain rich cultural culinary traditions.”

The researchers argue that conserving vegetable biodiversity is not enough on its own. Protecting seeds in genebanks such as the Centre for Genetic Resources, the Netherlands (CGN), helps safeguard them against permanent loss. But sustainably improving nutrition also depends on ensuring that diverse vegetables continue to be improved by plant breeders, grown by farmers, sold in markets and eaten by consumers. Conservation and use must therefore go hand in hand.

The researchers outline four priorities for governments, funders and researchers:

• Secure vegetable biodiversity for the future by rescuing, conserving and restoring traditional vegetable varieties and their wild relatives.
• Use vegetable biodiversity to develop improved varieties by expanding research, breeding and access to diverse genetic resources.
• Promote vegetable biodiversity to diversify diets by increasing the production, availability and consumption of a wider range of vegetables.
• Embed vegetable biodiversity in policy by integrating it into agriculture, health, education, climate and biodiversity strategies.

Taken together, these priorities would shift vegetable biodiversity from an overlooked resource to a central part of efforts to improve diets, strengthen climate resilience and develop the vegetables needed now and in the future.

Read the scientific paper.

Reversing vegetable biodiversity loss to diversify diets brought together researchers from/representing World Vegetable Center, the Crop Trust, the International Potato Center (CIP), Centre for Pacific Crops and Trees (Pacific Community), Wageningen University & Research, the International Center for Tropical Agriculture (CIAT), Food Security Leadership Council, New York Botanical Garden, and the CGIAR Genebank Accelerator.