- Rice is consumed by more than half of the world's population
- However, this food item also contains arsenic – which can fortunately be removed
- A particular method not only removes the arsenic, but also preserves a lot of the nutrients
Rice is a worldwide essential. In fact, more than half of the world’s population depends on it as a staple food, according to a 2019 study published in Nature.
However, rice also naturally contains arsenic – a toxic substance – from the soil, and while there is a simple way to reduce the quantity, it lowers the level of nutrients in the process.
Arsenic is classified as a Group 1 carcinogen by the International Agency for Research on Cancer, and the World Health Organization (WHO) identifies exposure to arsenic as a major public health concern.
The carcinogen is water-soluble, which means it accumulates in rice, and exposure to it affects almost every organ in the body and can cause skin lesions, cancer, diabetes and lung disease.
On the bright side
Previous research from the University of Sheffield in the UK found half of the rice consumed in the UK exceeded European Commission regulations for levels of arsenic in rice meant for the consumption for infants or young children.
On the bright side, though, researchers from the University of Sheffield’s Institute for Sustainable Food investigated four different rice-cooking methods in order to determine which offered the best way of reducing arsenic while preserving nutrients.
All four methods involved cooking rice via the absorption method (as the rice cooks, it absorbs all the cooking water) using either unwashed rice, washed rice, pre-soaked rice, or parboiled rice.
According to their findings, the parboiling with absorption method (PBA) removed the largest amount of arsenic from the rice, while preserving nutrients like phosphorus, potassium, magnesium, zinc, and manganese.
The study was published in Science of The Total Environment.
"With our new method we are able to significantly reduce the arsenic exposure while reducing the loss of key nutrients," lead author and soil scientist Manoj Menon from the University of Sheffield said in a university statement.
This method, the researchers note, removes over 50% of the naturally occurring arsenic in brown rice, and 74% in white rice, while maintaining micronutrients.
To do this at home, you can do the following, the researchers advise:
- Bring water to the boil (four cups of fresh water for every cup of raw rice).
- Add your rice and boil for another five minutes.
- Discard the water (which has now removed much of the arsenic in the rice).
- Add more fresh water (two cups for each cup of rice).
- Finally, cover the rice with a lid, and cook on low to medium heat until the water has been absorbed.
Experiment should be repeated, but a good first step
"We highly recommend this method while preparing rice for infants and children as they are highly vulnerable to arsenic exposure risks," Menon said.
The researchers say the PBA method also uses less water, energy and cooking time than other cooking methods that can remove the arsenic.
They also encourage additional investigation into using this method in different environments, using different kinds of regional rice types, as well as different levels of water quality – although their experiment is a good first step.
Image: Getty/krisanapong detraphiphat