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 Researchers analyzed supplies of 224 types of food in 156 countries,
quantified the vitamins and nutrients in foods dependent on animal
pollinators, and then calculated what nutritional deficits people
could face if pollinators ceased to exist.
Globally, dietary changes forced by the extinction of pollinators
might increase deaths from non-communicable diseases and
malnutrition-related problems by about 1.4 million, or a 2.7 percent
gain in mortality, the researchers estimate.
“It is striking how important animal pollinators are for human
health globally,” said senior study author Samuel Myers, an
environmental health researcher at Harvard University.
While scientists can’t predict with certainty when, if at all,
pollinators might become extinct, Myers and colleagues note in a
paper in The Lancet that there’s ample evidence of declining
populations of certain types of pollinators in many parts of the
world.
Since 2006, U.S. managed honeybee colonies have seen yearly losses
of 30 percent, for example, and there’s been a 15 percent annual die
off in European colonies, the authors note. Over 30 years,
significant declines in wild pollinator populations have been
documented across North America, Asia and Europe, with several
species going extinct.
The causes aren’t clearly understood but there’s a growing consensus
in the scientific community that declining populations of insect
pollinators in particular may be happening due to pest infestations,
disease, rising pesticide use and loss of habitats, the study team
writes.
At least some of these changes may be slowed or halted by changes in
human activity, such as reductions in pesticide use, Myers told
Reuters Health.
During pollination, pollen from the stamen, or “male” part of a
flower, moves to the stigma, or “female” part, fertilizing it and
resulting in the production of fruits and seeds. Some plants can
reproduce using wind-blown pollen, while others need insects and
animals to transport the pollen.
Insects like bees, wasps, moths, butterflies, and beetles are the
most common pollinators, but other species such as birds and mammals
also transport pollen. Some common non-insect pollinators include
hummingbirds, fruit bats, flying foxes, possums, lemurs and geckos.
Assuming all of these pollinators disappeared, 71 million people in
low-income countries could become newly deficient in vitamin A, and
an additional 2.2 billion individuals already getting less than the
recommended amount of this nutrient would have further declines in
consumption, the researchers estimate. Vitamin A is essential for
good vision, a healthy immune system and cell growth.
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Under the same worst-case scenario, 173 million people would become
newly deficient in folate, while an additional 1.2 billion already
deficient would become more so. Folate is a type of B vitamin that’s
needed for cell growth, metabolism and to help prevent the risk of
some birth defects.
Total pollinator extinction could also reduce global supplies of
fruit by 23 percent, vegetables by 16 percent, and nuts and seeds by
22 percent, the researchers calculate.
Wealthier populations would be relatively insulated from food loss,
able to afford any price hikes that might accompany increasingly
scarce commodities, the researchers predict. Poorer people,
meanwhile, would have disproportionately malnourished diets.
The research was funded by the Bill and Melinda Gates Foundation and
the Winslow Foundation.
The authors caution that incomplete or inaccurate data on dietary
habits around the world, mainly based on government records of
average food consumption, might in turn throw off the accuracy of
the estimated impact of pollinators on food supplies and nutrient
availability.
Even so, as the first study to fully link global declines in animal
pollinators to human health, the findings lend new urgency to the
issue, Gretchen Daily, an environmental scientist at Stanford
University in California, argues in an editorial accompanying the
study.
“More and more evidence shows the tremendous health value of fresh
fruits, veggies, nuts and seeds, so declines in their availability
will likely have major health impacts well beyond what vitamin pills
could make up for,” Daily said by email.
SOURCE: http://bit.ly/1Dlp06q The Lancet, online July 15, 2015.
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