The Great Rice Debate
Following alarming reports from the United States about the discovery of high arsenic levels in rice sold in the US market, experts from the International Rice Research Institute (IRRI) in the Philippines have reassured consumers that rice is safe to eat.
In a statement released to SciDev.Net, IRRI said that "that there is no evidence to show that people should stop eating rice grown in Asia because of concerns about arsenic." But it stopped short of denying claims that arsenic was present in rice.
The preliminary results of a study of 200 rice samples, published by the US Food and Drug Administration (FDA) last week (19 September), showed that sampled rice contained average levels of 3.5 to 6.7 micrograms of inorganic arsenic per average serving.
Separately, Consumer Reports — a marketplace standards nongovernmental organisation that earlier pressured the FDA to define standards for arsenic in apple juice — announced on 18 September that it had found arsenic levels in rice of up to 8.7 micrograms per average serving.
It is difficult to tell at what point arsenic levels in rice become dangerous, as, while there is an official standard for water, there is none for food.
Currently China is the only country to have set arsenic limits on food, said Joy Duldulao, a senior researcher at PhilRice (the Philippine Rice Research Institute).
The FDA plans to assess legal standards for arsenic levels in rice at the end of the year, once they have analysed 2,300 rice samples.
Safety levels vary according to how much rice an individual consumes, Duldulao added. However, citing data from the UN Food and Agriculture Organization, she said the tolerable weekly intake is only 15 micrograms of inorganic arsenic per kilogram of body weight.
Consumer Reports warned that eating rice high in arsenic just once a day can drive arsenic levels in the human body up by 44 per cent, while two meals could boost levels to 70 per cent.
Arsenic is a naturally occurring substance found in water, air and soil. However, in high quantities it is also a potent poison linked to bladder and kidney cancer. It is absorbed by all plants, although concentrations are higher in leafy vegetables, apples and rice.
Rice is believed to have higher arsenic levels than other plants because it is grown in flooded soils, thus optimising conditions for the absorption of arsenic.
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Bowl of rice image via Shutterstock.