Eating just three spoonfuls of brown rice every week could raise your risk of brain damage and cancer, a report suggests.
Researchers at Healthy Babies, Bright Futures — a pressure group for infant health — tested more than 200 samples of rice bought from popular grocers like Trader Joe’s, Whole Foods and Safeway.
Each was tested for inorganic arsenic, a more toxic form of the element linked to a higher risk of neurodevelopmental delay, cancer and heart problems.
All rice types tested — brown, white, basmati, sushi and jasmine — were found to contain the toxic substance, but levels were highest in brown rice on average.
An uncooked brown rice brand sold by major grocer Smart and Final was found to have the highest levels of inorganic arsenic at 201 micrograms per kilogram.
The findings suggest that for the average adult, eating just two-and-a-half tablespoons per day would lead someone to exceed their maximum safe levels set by the Environmental Protection Agency (EPA).
The USA Rice Federation, which represents rice growers, noted that arsenic in food was ‘alarming’ but argued there was no public safety issue.
This is likely because cooking rice in water removes up to 66 percent of the arsenic they contain, while washing them two to four times in tap water can remove up to 84 percent of arsenic present.
Researchers are raising concerns over the toxic heavy metal levels in rice (stock image)
The above shows the proportion of rice samples in the report that exceeded the FDA’s safety threshold for inorganic arsenic in children’s cereal (about 100 micrograms per kilogram)
Nearly all the samples were found to contain three other heavy metals linked to neurodevelopmental delay — lead, cadmium and mercury — but at much lower levels.
The EPA has set a recommended limit of exposure to inorganic arsenic at 0.06 micrograms per kilogram of bodyweight, or 4.8micrograms per day for the average US adult who weighs 176lbs (80kg).
For comparison, the uncooked brown rice contained 201 micrograms of inorganic arsenic per kilogram — more than 40 times higher than the recommended daily limit.
It means that to stay within the safe limit, an adult could eat no more than 23.9 grams of this rice per day — roughly three tablespoons of uncooked rice.
The EPA’s limit was set based on studies that showed the minimum safe level to avoid heart disease or diabetes.
Inorganic arsenic can contribute to the development of heart disease via causing inflammation within the heart and blood vessels, studies suggest. Research has also indicated that it raises the risk of suffering from cancer, with the EPA considering the element a ‘human carcinogen’.
Inorganic arsenic differs from organic arsenic because it is more likely to be absorbed into cells, where it can cause damage.
About three-quarters of the arsenic found in the rice products were inorganic, though levels varied depending on the product.
Overall across all brands tested, the researchers found that uncooked rice contained about 85 micrograms of arsenic per kilogram.
The researchers also tested 66 samples of rice alternatives, such as couscous, quinoa and faro, finding the levels of heavy metals in these were 69 percent lower on average.
All the rice samples tested in the research were uncooked, with the team noting that cooking rice in water would reduce heavy metal levels.
This is because up to 66 percent of arsenic leaches out of the grains when they are cooked in boiling water and the water is drained away, according to a 2019 study.
An additional 13 to 84 percent of arsenic can be removed from rice by washing it before cooking.
The above shows the levels of heavy metals in different types of rice, including arsenic. The worst offender was brown rice
Overall, researchers found that rice contained three times more heavy metals than others
The report’s authors recommend cooking rice in a pot with six to ten cups of water per cup of rice, to remove the most arsenic.
The USA Rice Federation said: ‘We know that arsenic in food is alarming for many consumers and that you may have questions,’ a spokesperson said.
‘And while we do not agree that there is a public health safety issue as a result of trace amounts of arsenic in rice, we will continue to work with the FDA to ensure the US rice supply meets any threshold established.’
For the report, researchers purchased more than 200 rice containers from 20 major metro areas across the US — including New York, Los Angeles and Washington DC.
Overall, brown rice contained the most arsenic with an average of 130 micrograms per kilogram.
The second highest levels were detected in Arborio, or risotto, rice from Italy, which contained about 100 micrograms of arsenic.
White rice had the third highest level, at just below 100 micrograms per kilogram, followed by Jasmine rice from Thailand, at about 80 micrograms.
Indian basmati rice and sushi rice grown in California had the lowest levels of the rice tested on average at about 60 micrograms.
Roughly three-quarters of the arsenic detected in all the rice brands was inorganic, the report suggests.
As part of the research, the organization also tested 66 samples of nine alternative grains like quinoa, faro and barley.
These were found to contain 33 micrograms per kilogram of arsenic on average, well below the levels in the average rice.
Results also showed they contained 69 percent less heavy metal contamination than rice, on average, making them safer substitutes.
The researchers indicated these foods could be better to eat, but noted they were also much more expensive.
Researchers have also raised concerns over microplastics in rice
As a compromise, they suggested people should try to eat rice with lower levels of arsenic — such as California-grown, Thai jasmine and Indian basmati rice.
The highest levels of arsenic were detected in brown and white rice grown in Southeast US or labeled simply as ‘USA’ and in Arborio rice from Italy.
A saffron-seasoned rice was also found to contain lead levels up to 32 times higher than the average for other samples.
Rice is one of the most popular grains in the US, consumed by more than 257.7million people with the country eating 4.9million metric tons per year — equivalent to about 15 Empire State buildings.
But it tends to contain more heavy metals because it is grown in water-logged paddies, where it can easily absorb them from its surroundings.
Arsenic is a naturally occurring element found in the Earth’s crust, that can exist in both organic and inorganic forms. Scientists are more concerned about inorganic arsenic because this is more readily absorbed into cells, where it can cause damage.
It can be released into the environment through mining and smelting metals, or via pesticides, burning coal and incinerating waste.