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As pollinators decline worldwide, look for a rise in nutritional disease and death in humans

This study says that it “provides the first global analysis of the contribution of pollination to human health through diet.”

A 10 percent loss in a certain pollinator is likely to produce a 10 percent loss in the crop dependent upon it, and therefore a 10 percent decline in nutrients available from that food.
REUTERS/ Dominic Ebenbichler

It’s often noted in discussions of threats to honeybees and other pollinators that perhaps 35 percent of foods in the human diet are directly dependent upon the services of insects, birds and bats that carry pollen from flower to flower.

Almost as often, you’ll see some representative examples listed – almonds, peaches, peppers, cucumbers, coffee – along with an invitation to imagine the boring blandness of a diet in which all this bountiful diversity is supplanted with corn, potatoes and wheat.

Now a new study published in the noted British medical journal The Lancet probes more deeply into the nutritional and health dimensions of such a dietary shift, and of course the consequences go far beyond matters of appetite and the pleasures of caffeine.

Looking at just two nutrients – vitamin A and folate, also known as folic acid and vitamin B9 – the researchers found that:

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[C]omplete loss of animal pollinators globally would push an additional 71 million people into vitamin A deficiency and 173 million more into folate deficiency, and would lead to about 1.42 million additional deaths per year from non-communicable diseases (NCDs) and malnutrition-related diseases — a 2.7% increase in total yearly deaths. A 50% loss of pollination would result in roughly half that impact, the researchers found.

Most of this burden of disease would result from reduced consumption of foods that protect against NCDs like heart disease, stroke, and certain cancers and, unlike the populations frequently impacted by environmental degradation, many of the most vulnerable populations reside in relatively developed countries. Researchers found that those most vulnerable would be in eastern Europe and in central, eastern, and Southeast Asia, where risks of NCDs are high and intake of fruits, vegetables, nuts, and seeds is highly dependent on pollinators.

That summary is taken from an announcement of the study by Harvard University’s T.C. Chan School of Public Health, which also quotes its senior author, Samuel Myers, in the observation that

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. 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.

First study of its kind

Other research has discussed in a general way the possible linkages between nutritional well-being and changes in diet driven by declines in pollinator-dependent food production, and at least one small (four nations) study has attempted to quantify impacts on vitamin A supplied by diet.

But this study claims that it “provides the first global analysis of the contribution of pollination to human health through diet, specifically examining our reliance on pollinator-dependent foods for controlling chronic and malnutrition-related disease.”

And if it was narrow in its focus on just two nutrients, it was broad in its statistical reach.

Databases of the UN Food and Agriculture Organization were the starting point, with 156 nations selected because reliable figures were available both for population and for food consumption by commodity. Additional databases allowed for computation of “nutrient densities” per capita.

Projecting the consequences for a 100 percent loss of pollinators wasn’t done because anyone considers that a likely scenario; it simply created a metric that could be used to calculate, working backwards, the impact of partial losses, since the relationships between pollinator contribution, commodity production and nutrient availability appear to be pretty much fixed.

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That is, a 10 percent loss in a certain pollinator is likely to produce a 10 percent loss in the crop dependent upon it, and therefore a 10 percent decline in nutrients available from that food.

It’s worth noting that the disease consequences of vitamin A and folate deficiency fall heavily on pregnant women and also on children, including blindness at birth, neurological disorders and other developmental problems that can persist for a lifetime.

Others, like heart disease, stroke and cancers of the lung and esophagus, can afflict anyone.

Conservative projections

It’s also important to say that the death and disease projections cited above can actually be taken as somewhat conservative, because the study excluded certain other variables that would likely make things worse:

  • The figures reflect occurrences of disease and death only among people who would become newly deficient in these vitamins as a result of food shortages; the impacts on people whose diets are already deficient, and would become more so, weren’t projected.
  • The modeling assumed that whatever foods were lost because of pollinator decline would be made up in volume, at least, by starchy, “staple” commodities. If that didn’t happen, which certainly seems possible, then death and disease from malnutrition – including the health problems associated specifically with vitamin A and folate deficiency – would rise further.
  • The modeling of outcomes used present-day populations only, without attempting to extend the impacts to the 2 billion to 3 billion additional humans who are projected to be eating on Earth by mid-century, roughly doubling food demand.

While the struggles of U.S. beekeepers with their managed colonies are the continued focus of most U.S. coverage of pollinator issues, this research team was motivated by a more global concern:

Since 2006, managed honey bee colonies in the USA have seen sustained and significant annual winter colony losses at around 30%,  while Europe has seen smaller but substantial losses (15%).

For non-managed wild pollinators, for which quantitative abundance data are more sparse, numerous studies have documented significant declines in their diversity and range over the past three decades throughout North America, Europe, and Asia, with many species going extinct. Additionally, bird and mammal pollinator species have also experienced increasing scarcity, extinction, and narrowing ranges globally over the past 25 years.

Despite recent investigations, the exact cause of these trends remains poorly understood, although a consensus is forming to attribute decreased insect pollination—the predominant type of animal pollination—to a combination of causes, including pest infestations, disease, increased use of pollinator-harming pesticides, and loss of habitat  and forage.

In other words, to causes we could actually do something about, if we elected to try.