B Vitamin Content of Rice Declines with Rising Co2

A new study quantifies the global impact of declines in a single nutrient in a single crop, and hints at wider impacts.

Photograph by Barcin/iStock

Rising levels of atmospheric COdon’t just warm the planet, they lower the levels of beneficial vitamins and other nutrients in grains and edible plants. New research has shown that rice grown at carbon dioxide levels that could be reached as soon as 2050 are expected to suffer a one-sixth to nearly one-third loss of their B vitamin content. A study conducted at the Harvard T.H. Chan School of Public Health (HSPH) now quantifies the health impact of that change.

Globally, rice is humanity’s most important staple food, and for half a billion people, the crop provides more than 50 percent of their daily calories. That poses a serious potential problem: a prior study published by principal research scientist Samuel Myers and colleagues at HSPH found that when atmospheric COreaches 550 parts per million (up from its current 410+ ppm), the reduced protein content of the rice will lead to protein deficiency in an additional 148 million people.That work also documented declines in the iron and zinc content of rice, wheat, barley, legumes, maize and potatoes—all of them important staple foods.

The latest study, published in GeoHealth, focuses on the impact of rising COon the B vitamins folate, riboflavin, and thiamin. Maternal deficiencies in folate can lead to neural-tube defects in unborn children, as well as weakness and loss of appetite in adults; thiamin deficiency causes beriberi; and low levels of riboflavin can cause skin lesions and nervous disorders, including migraines. Using a framework that allows them to estimate the impact of these changes on the global burden of disease, the researchers estimate that an additional 132 million people would suffer folate deficiency based on their consumption of rice alone, 67 million additional people will become deficient in thiamin, and 40 million more people will become deficient in riboflavin.

Those numbers almost certainly understate the impact. As Myers and his coauthor, HSPH research associate Matthew R. Smith, write: “Because elevated COconcentrations are likely to reduce B vitamins in other crops beyond rice, our findings likely represent an underestimate of the impact of anthropogenic COemissions on sufficiency of B vitamin intake.” And their new study does not attempt to quantify the global burden of disease that may be triggered by deficiencies in other nutrients that decline with rising CO2. As they put it, “CO2-induced nutritional declines could produce a major headwind on progress toward alleviating malnutrition, and deserves attention and concerted action.”

Read more articles by Jonathan Shaw

You might also like

In Sermon, Garber Urges Harvard Community to ‘Defend and Protect’ Institutions

Harvard’s president uses traditional Memorial Church address to encourage divergent views.

How Do Single-Celled Organisms Learn and Remember

A Harvard neuroscientist’s quest to model memory in single-celled organisms

A New Narrative of Civil Rights

Political philosopher Brandon Terry’s vision of racial progress

Most popular

What Trump Means for John Roberts’s Legacy

Executive power is on the docket at the Supreme Court.

Three Harvardians Win Macarthur Fellowships

A mathematician, a political scientist, and an astrophysicist are honored with “genius” grants for their work.

This Harvard Scientist Is Changing the Future of Genetic Diseases

David Liu has pioneered breakthroughs in gene editing, creating new therapies that may lead to cures.

Explore More From Current Issue

James Muller in white lab coat leaning on railing in hospital hallway.

Free Speech, the Bomb-and Donald Trump

A Harvard cardiologist on the unlikely alliances that shaped a global movement to prevent nuclear war

Student walking under bright stage lights shaped like smartphones displaying social media apps.

Two Years of Doxxing at Harvard

What happens when students are publicly named and shamed for their views?

David McCord in suit reading a book at cluttered wooden desk in office filled with framed art and shelves.

The Pump Celebrates Its 85th Birthday

Giving Harvard traditions their due