New Delhi: Change in environmental conditions around the world due to human activities could negatively impact the health of millions of people, lead to decline in nutrient-rich crops and expand zinc deficiency, according to a set of studies released by US-based Harvard T.H. Chan School of Public Health on Thursday.

The changes could lead to deficiency of Vitamin A, Zinc and Folate in millions of people, especially in south Asia, including India, and lead to nearly 1.42 million deaths every year due to non-communicable diseases like heart diseases and cancer.

One of the studies on pollinators said that the decreasing numbers of food pollinators such as bees—falling in part due to pesticide use and destruction of habitats—could lead to a decline in nutrient-rich crops that have been linked with staving off disease. The second study on zinc revealed that the increasing levels of atmospheric carbon dioxide (CO2) could lead to lower levels of zinc in food which could greatly expand zinc deficiency in humans.

The studies said that the complete loss of animal pollinators globally would make 71 million people suffer from vitamin A deficiency and 173 million from folate deficiency and would lead to about 1.42 million additional deaths every year from non-communicable diseases and malnutrition-related diseases—a 2.7% increase in total yearly deaths.

According to the researchers, the most vulnerable would be people in eastern Europe and central, eastern, and southeast Asia, where the risk of non-communicable diseases is high, and intake of fruits, vegetables, nuts, and seeds is highly dependent on pollinators.

The study also said that carbon dioxide emissions could expose 132-80 million people to the new risk of zinc deficiency by 2050. Zinc is a key nutrient for maternal and child health, and its deficiency could cause increased risk of premature delivery, reduced growth and weight gain in young children and decreased immune function.

“Those most likely to be affected are from Africa and South Asia, including nearly 48 million people in India alone, the populations already burdened with the world’s highest levels of zinc deficiency, and reliant on crops for most of their dietary zinc," the study said.

“All of human civilization has taken place during a very stable set of biophysical conditions, but we are now changing those conditions at a rate that’s never been seen before," said Samuel Myers, a senior research scientist at the Harvard T.H. Chan School’s Department of Environmental Health, and senior author of the pollinator study and lead author of the zinc study.

“Whether we’re talking about land use, deforestation, degradation of global fisheries, disruption of the climate system, biodiversity loss, appropriation of fresh water, changes to aquatic systems—all of the changes are profound and they’re accelerating, and they represent a significant challenge to global health," he added.

For the pollinators study, the researchers looked at people’s dietary intake data for 224 types of food in 156 countries around the globe to quantify total per capita intake of vitamin A, folate, fruits, vegetables, and nuts and seeds under various pollinator decline scenarios. They estimated the potential health impacts of declines in pollinators, mostly bees and other insects.

Pollinators play a key role in roughly 35% of global food production and are directly responsible for up to 40% of the world’s supply of micronutrients such as vitamin A and folate, which are vital for children and pregnant women.

The study on pollinators also found that most of the estimated pollinator-related disease burden had to do with locally produced crops, and not imported ones.

“This means that most countries can benefit greatly by managing their own pollinator population, protecting both their public health as well as crop yields," said lead author of the pollinator study Matthew Smith, who is also from the Harvard T.H. Chan School of Public Health.

For those at highest risk for zinc deficiency, the researchers suggested possible interventions like zinc supplementation, fortification of staple foods with additional zinc, the application of zinc-containing fertilizers to crops, or the development of bio-fortified strains of crops such as rice and wheat.