Pollinator decline is a hidden health crisis, from remote Nepali villages to global diets

Jumla district, in western Nepal, can be reached by land only one way: the Karnali highway, often described as one of the most dangerous roads in the world, which cuts through the Himalayas to link the district's terraced valleys with the rest of the country. The 120,000 people who live there are close to self-sufficient, eating and selling what they grow. Food insecurity and malnutrition are constant companions.

Local beekeepers have noticed something wrong. Hives are languishing and honey production is falling, and they estimate that about half their bees have disappeared over the past decade. Thomas Timberlake, an ecologist at the University of York, says the beekeepers saw the bees as valuable for honey but did not fully realise they were also essential to producing their crops.

Timberlake and colleagues set out to measure that dependence, in a study published last month in Nature. Across 10 remote Jumla villages, they tracked people's diets, crop yields and farming income for a year, alongside how pollinators interacted with the crops. That included the slow work of counting pollen grains on the bodies of bees. Pollinators turned out to be directly responsible for more than 20% of residents' intake of vitamin A, vitamin E and folate, and for 44% of their farming income. It is the first study of its kind to offer direct evidence linking pollinators to human health. Timberlake notes that the villages are geographically isolated, with poor trade links and little money, so if local fruit and vegetable yields fall, people cannot simply buy imported food instead. They would just stop eating those foods.

The work builds on a decade of effort to pin down what pollinators do for nutrition. A 2015 modelling study in the Lancet found that a complete collapse of the world's pollinators would cause an extra 1.4 million deaths a year from malnutrition-related disease. Sam Myers, director of the Johns Hopkins Institute for Planetary Health and a co-author, wanted to move past the hypothetical and ask what penalty we already pay for having too few pollinators.

The threat is real. About three-quarters of agricultural crops rely on pollinator services, and bees do more of that work than any other group. Forests, grasslands and wildflower meadows have been converted to industrial agriculture and development, leaving bees and butterflies without food or nesting sites. Pesticides, especially neonicotinoids, which interfere with bees' nervous systems, add to the toll, as do the climate crisis and invasive species. When IPBES, the intergovernmental biodiversity science body, last assessed pollinators in 2016, it estimated that more than 40% of bee species may be threatened globally, though many lacked adequate data. Simon Potts of the University of Reading, who co-chaired that assessment, says the big picture is unchanged: where data exist, most groups of wild pollinators are declining, and the best data come from North America and Europe. In 2025, the IUCN red list found at least 172 bee species in Europe at risk of disappearing.

Potts draws a distinction between wild and managed bees. About half the world's crops are pollinated by bees, often honeybees, kept in hives and treated much like livestock. Those managed populations have held fairly steady while wild species have fallen. Even so, 2022 research in Environmental Health Perspectives found that 3% to 5% of global vegetable, fruit and nut production is lost to inadequate pollination. That study, led by Myers, concluded that managed honeybees have not compensated for wild losses or kept pace with growth in pollinator-dependent crops. Myers and colleagues linked the shortfall to an additional 500,000 deaths a year, using data from hundreds of farms, yield figures, diet-related health risks and a model of the global food trade.

Those deaths are not concentrated among the poorest. Myers says most were in eastern Europe and former Soviet republics, where sedentary lifestyles and diets heavy in red meat make heart disease, stroke and diabetes more common, and where fruit, vegetables, nuts and seeds offer protection. If pollinators are lost, he says, those foods will become more expensive, and middle-class families may be unable to afford the most protective ones. A Science Advances modelling study points to the tropics as most vulnerable to pollination shortfalls: sub-Saharan Africa, northern South America and south-east Asia, with large projected losses for cocoa in Africa, mango in India and watermelon in China.

The picture extends beyond food. About 80% of the world's population relies on herbal medicine for primary healthcare, according to a 2022 study, and ecologists estimate about 28,000 medicinal plants, including echinacea and chamomile, are insect-pollinated. Lucas Garibaldi, who directs an agroecology and rural development institute in Argentina, adds that pollinators also sustain green spaces that benefit mental health. He cautions that firm links are hard to draw: four years ago he found only two peer-reviewed modelling studies on the subject, human health has many causes, and it is difficult to isolate food from particular pollinators.

In Nepal, where crop monocultures and new pesticides are eroding pollinator habitat, NGOs are working with the government on a national pollinator strategy. Timberlake's research suggests that planting wildflowers, providing nesting sites and cutting pesticide use could raise farmer income by up to 30% and lift 9% of the population out of nutrient deficiency.