- Nutritional value of rice grown under high levels of atmospheric
carbon dioxide found to be low with reduced vitamins and essential
- Rice is low cost staple food in several developing countries and
consuming rice having low nutritional value may result in malnutrition.
Increasing levels of atmospheric
carbon dioxide due to rising air pollution levels can reduce the nutritional
value of rice according to an international research team that studied rice samples
obtained from field experiments
undertaken by a professor in the University of Tokyo.
is not just a major source of calories, but also proteins and vitamins for many
people in developing countries and for poorer communities within developed
countries," said Professor Kazuhiko Kobayashi of the University of Tokyo,
co-author of the recent study and expert in effects of air pollution on
‘Levels of protein, iron, zinc and vitamins B1, B2, B5, and B9 low in rice grown under higher carbon dioxide concentrations.’
Details of Study
The team grew rice under
experimentally created high carbon dioxide concentrations and analyzed the samples for their nutritional content. The details of the study is
- The rice was cultivated at research sites in China and Japan
using an open-field method where the scientists built 17-meter-wide
(56-foot-wide) plastic pipe octagons raised about 30 centimeters (1 foot)
above the top of the crops in standard rice fields.
- A network of sensors and monitors estimated wind speed and direction
to find out how much carbon dioxide comes out of the pipes in order to increase the local carbon dioxide
concentration to the desired test level. The technique is termed as
Free-Air Carbon dioxide Enrichment (FACE)
first started using this technique in 1998, because we knew that plants raised
in a plastic or glass house do not grow the same as plants in normal, open
field conditions. This technique allows us to test the effects of higher carbon
dioxide concentrations on plants growing in the same conditions that farmers
really will grow them some decades later in this century," said Kobayashi.
- The pipes and tubes had to be raised above ground level to prevent
wildlife such as raccoons from chewing through the crops and disrupting the
- The scientists assessed a total of 18 different
varieties of rice for protein, iron, and zinc content. Nine varieties
of Chinese rice were tested for the vitamin B1, B2, B5, and B9 levels. The
medical terms for the vitamins are thiamine (B1), riboflavin (B2),
pantothenic acid (B5), and folate (B9).
- The levels of key minerals and vitamins were reduced in rice grown under high CO2 levels. Specifically, concentrations of
vitamins B1, B2, B5, and B9, iron, protein and zinc were reduced in rice
grown under high atmospheric CO2 levels that would be expected in the
second half of this century (approximately 568 to 590 parts per million).
- Interestingly not all varieties of rice demonstrated
the same degree of decline in nutritional quotient. Thus, future research
projects could focus on production of rice varieties that retain their
nutritional value despite increased carbon dioxide levels.
Thus, the findings of the
study suggest that rising CO2 levels in the atmosphere that would be expected
to occur in the next few decades could lower the nutritional value of rice and
put entire populations at risk of malnutrition
estimate that nearly six hundred million people in Bangladesh, Cambodia,
Indonesia, Myanmar, Lao People's Democratic Republic, Vietnam, and Madagascar
derive at least 50 percent of their daily calories and/or protein directly from
rice. This was also true in Japan during the 1960s, however, current Japanese
receive only about 20 percent of their daily energy requirements from rice.
Takeaway from Study
findings of the study underscore the
importance of initiating urgent measures to produce rice varieties that manage
to retain their nutritional value
despite exposure to high atmospheric
is especially important since rice is a low cost staple diet of several
populations in developing countries and are at risk of malnutrition if the
nutritional value of low-cost staple foods like rice goes down.
- Chris Mooney, "Rice, the staple food of billions, could become less nutritious because of climate change" (2018), journal Science Advances
- Carbon dioxide in Earth's atmosphere - (https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere)