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Human activity could cause crops to become less nutritious

A recent investigation has found that human-caused carbon dioxide emissions are responsible for the degradation of staple crops such as rice and wheat, which are becoming less nutritious. Over the next three decades, 175 million people could become zinc deficient and 122 million people could become protein deficient as a direct result of human activities.

In addition, more than one billion women and children are at risk of losing a large amount of their dietary iron intake, increasing the threat of anemia and other diseases.

Study lead author Sam Myers is the principal research scientist at Harvard T. H. Chan School of Public Health.

“Our research makes it clear that decisions we are making every day – how we heat our homes, what we eat, how we move around, what we choose to purchase–are making our food less nutritious and imperiling the health of other populations and future generations,” said Myers.

Currently, there are more than two billion members of the global population that are deficient in one or more nutrients. The majority of our key nutrients come from plants, including 63 percent of dietary protein, 81 percent of iron, and 68 percent of zinc.

It has been shown in previous research that higher levels of atmospheric CO2 lead to crop yields that are less nutritious, with concentrations of iron and protein that are up to 17 percent lower when crops are exposed to CO2 concentrations of 550 parts per million (ppm) during growth.

For the current study, the team set out to develop the most accurate analysis of the global health burden that could be caused by CO2-related nutrient shifts in crops across 151 countries.

The study showed that by the middle of this century, when atmospheric CO2 concentrations are expected to reach around 550 ppm, roughly 175 million people could become deficient in zinc and 122 million people could become protein deficient. An additional 1.4 billion women and young children will be at risk of iron deficiency.

The researchers pointed out that billions of people that already live with nutritional deficiencies would experience worse conditions if crops became less nutritious.

“One thing this research illustrates is a core principle of the emerging field of planetary health,” said Myers. “We cannot disrupt most of the biophysical conditions to which we have adapted over millions of years without unanticipated impacts on our own health and wellbeing.”

The study is published in the journal Nature Climate Change.

By Chrissy Sexton, Staff Writer

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