Arsenic in rice: Part I—Test results 11/12
(This article is adapted from the November 2012 Consumer Reports magazine.)
Part I—Test results | Part II—How to cut your risk | Part III—Tracing the sources of arsenic
Organic rice baby cereal, rice breakfast cereals, brown rice, white rice—new tests by Consumer Reports have found that those and other types of rice products on grocery shelves contain arsenic, many at worrisome levels.
Arsenic not only is a potent human carcinogen but also can set up children for other health problems in later life.
Following its January 2012 investigation, "Arsenic in Your Juice," which found arsenic in apple and grape juices, Consumer Reports tested more than 200 samples of a host of rice products. They included iconic labels and store brands, organic products and conventional ones; some were aimed at the booming gluten-free market.
See the chart summarizing test results for arsenic in rice or rice products.
Arsenic can cause cancer in humans
Though rice isn’t the only dietary source of arsenic—some vegetables, fruits, and even water can harbor it—the Environmental Protection Agency assumes there is actually no “safe” level of exposure to inorganic arsenic. (See Part III: Tracing the sources of arsenic.)
Yet no federal limit exists for arsenic in most foods. There is a limit for drinking water-- 10 parts per billion (ppb). But keep in mind that level is twice the 5 ppb that the EPA originally proposed and that New Jersey actually established.
Using the 5-ppb New Jersey standard in the study, Consumer Reports found that a single serving of some rices could give an average adult almost one and a half times the inorganic arsenic he or she would get from a whole day’s consumption of water, about 1 liter.
Testers also discovered that some infant rice cereals, which are often a baby’s first solid food, had levels of inorganic arsenic at least five times more than has been found in alternatives such as oatmeal. Given the findings, Consumer Reports suggests limiting the consumption of rice products. (See Part II on how to cut your risks.)
Brand information and trends
The study was a snapshot of the market, with many products purchased in the New York metropolitan area and online, to gauge the extent of arsenic’s presence in everyday foods. It can’t be used for overall conclusions about specific brands. Still, there were important trends:
• White rice grown in Arkansas, Louisiana, Missouri, and Texas, which account for 76 percent of domestic rice, generally had higher levels of total arsenic and inorganic arsenic in the tests than rice samples from elsewhere.What industry and government say
• Within any single brand of rice tested, the average total and inorganic arsenic levels were always higher for brown rice than for white.
• People who ate rice had arsenic levels that were 44 percent greater than those who had not, according to the analysis of federal health data. And certain ethnic groups were more highly affected, including Mexicans, other Hispanics, and a broad category that includes Asians.
• Reducing arsenic in food is feasible. Consumer Reports examined the efforts of two food companies, including Nature's One, trying to tackle the problem and learned about methods being used to try to reduce arsenic in products.
• Based on these findings, Consumer Reports experts are asking the Food and Drug Administration to set limits for arsenic in rice products and fruit juices as a starting point.
Rice producers argue that concerns about dietary exposure to arsenic in rice are overblown. “There is no documented evidence of actual adverse health effects from exposure to arsenic in U.S.-grown rice,” says Anne Banville, a vice president at the USA Rice Federation, a trade association representing the $34 billion rice industry. “And we believe the health benefits of rice must be properly weighed against the risks of arsenic exposure, which we believe are minimal.”
But scientists warn of complacency. “We already know that high concentrations of arsenic in drinking water result in the highest known toxic substance disease risks from any environmental exposure,” says Allan Smith, M.D., Ph.D., a professor of epidemiology at the University of California, Berkeley. “So we should not be arguing to wait for years until we have results of epidemiologic studies at lower arsenic intake, such as from rice consumption, to take action.” His studies of arsenic in public water in Chile and Argentina helped show that it causes lung and bladder cancer and other diseases.
Such long-term studies that track health effects of exposure to arsenic in rice have only recently begun in the U.S. Researchers at the Dartmouth Children’s Environmental Health and Disease Prevention Research Center in late 2011 published a small but informative study that indicated consuming slightly more than a half-cup of cooked rice per day resulted in a significant increase in urinary arsenic levels, comparable to the effects of drinking a liter of water containing the federal maximum of 10 ppb arsenic. The authors say their results suggest “many people in the U.S. may be exposed to potentially harmful levels of arsenic through rice consumption.”
The USA Rice Federation says it is working with the FDA and the EPA as they examine and assess arsenic levels in food and has supplied rice samples to those agencies for research. It also says some of its member companies may be doing their own testing. One rice company has shared details of how it is taking matters into its own hands. Grant Lundberg, CEO of Lundberg Family Farms in Richvale, Calif., which sells rice and rice products, says the company is testing more than 200 samples of the many varieties of rice in its supply chain and plans to share the results with FDA scientists.
“We’re committed to providing safe food, to really listening to our consumers, and dealing with this problem very openly because doing the research needed to assess what the risks really are is the only way to go,” Lundberg says.
What the tests revealed
Consumer Reports tested 223 samples of various rice products that were bought mostly in April and May, many from stores in the New York metropolitan area and online retailers. The samples covered a variety of rice-containing food categories, including infant cereals, hot cereals, ready-to-eat cereals, rice cakes, and rice crackers. Tests included products often used by people on gluten-free or other special diets, including rice pasta, rice flour, and rice drinks.
At least three samples of each of the foods and beverages were tested for total arsenic. Testers measured specific levels of inorganic arsenic. And they checked for two forms of organic arsenic, called DMA and MMA.
Though inorganic arsenic is considered the most toxic, concerns have been raised about potential health risks posed by those two organic forms, which the International Agency for Research on Cancer has labeled “possibly carcinogenic to humans.” Testers found DMA in the 32 rices tested, which include choices from the south central states and elsewhere, including California, India, and Thailand.
Mixed results for brown rice
In brands for which both a white and a brown rice were tested, the average total and inorganic arsenic levels were higher in the brown rice than in the white rice of the same brand in all cases.
Among all tested rice, the highest levels of inorganic arsenic per serving were found in some samples of Martin Long Grain Brown rice, followed by Della Basmati Brown, Carolina Whole Grain Brown, Jazzmen Louisiana Aromatic Brown, and Whole Foods’ 365 Everyday Value Long Grain Brown. But testers also found samples of brown rice from Martin and others with inorganic arsenic levels lower than that in some white rice.
Though brown rice has nutritional advantages over white rice, it is not surprising that it might have higher levels of arsenic, which concentrates in the outer layers of a grain. The process of polishing rice to produce white rice removes those surface layers, slightly reducing the total arsenic and inorganic arsenic in the grain.
In brown rice, only the hull is removed. Arsenic concentrations found in the bran that is removed during the milling process to produce white rice can be 10 to 20 times higher than levels found in bulk rice grain.
We also tested for lead and cadmium, other metals that can taint food. The levels we found were generally low overall. Based on our recommended limits for rice products, even the few samples with elevated lead and cadmium should not contribute significantly to dietary exposure.
Cereals cause concern
Worrisome arsenic levels were detected in infant cereals, typically consumed between 4 and 12 months of age.
Among the four infant cereals tested, we found varying levels of arsenic, even in the same brand. Gerber SmartNourish Organic Brown Rice cereal had one sample with the highest level of total arsenic in the category at 329 ppb, and another sample had the lowest total level in this category at 97.7 ppb. It had 0.8 to 1.3 micrograms of inorganic arsenic per serving.
Earth’s Best Organic Whole Grain Rice cereal had total arsenic levels ranging from 149 ppb to 274 ppb, but higher levels of inorganic arsenic per serving, from 1.7 to 2.7 micrograms.
Ready-to-eat cereals, which are popular with adults as well as children, also gave cause for concern. For instance, Barbara’s Brown Rice Crisps had inorganic arsenic levels that ranged from 5.9 to 6.7 micrograms per serving. Kellogg’s Rice Krispies, at 2.3 to 2.7 micrograms, had the lowest levels for the category in the tests.
Higher arsenic levels in people who eat rice
If rice truly is an important source of arsenic exposure, then people who eat rice should have greater arsenic levels in their body, on average, than people who do not. To find out, testers analyzed data collected annually by the National Center for Health Statistics for the National Health and Nutrition Examination Survey (NHANES). The survey contains information on the health and nutrition of a nationally representative sample of the U.S. population, based on interviews and physical exams, which may include blood and urine tests.
The data analysis was led by Richard Stahlhut, M.D., M.P.H., an environmental health researcher at the University of Rochester, who is experienced in NHANES analysis, and Ana Navas-Acien, M.D., Ph.D., a physician-epidemiologist with expertise in arsenic research at Johns Hopkins University’s Bloomberg School of Public Health.
Working with Consumer Reports statisticians, they reviewed NHANES data from 2003 through 2010 from participants age 6 or older whose urine was tested for arsenic and who had reported what they’d had to eat or drink from midnight to midnight the day before their examination. A urine test is the best measure of recent arsenic exposure because most of it is excreted in urine within a few days after ingestion.
Because seafood contains a form of organic arsenic called arsenobetaine, generally considered nontoxic to humans, researchers then excluded from their analysis anyone who reported eating seafood during the 24-hour period and those with detectable levels of arsenobetaine in their urine. The remaining participants therefore were more likely to have had exposure to inorganic arsenic, which poses the greatest potential health risks.
The resulting analysis of 3,633 study participants found that on average, people who reported eating one rice food item had total urinary arsenic levels 44 percent greater than those who had not, and people who reported consuming two or more rice products had levels 70 percent higher than those who had no rice.
“Despite our taking into account other common sources of arsenic, and no matter which way we sliced the data, we see a very strong association between rice consumption and arsenic exposure,” says Stahlhut, who along with Navas-Acien led a similar analysis of NHANES data for the January 2012 Consumer Reports article on arsenic in juice. That analysis found that study participants who reported drinking apple or grape juice had total urinary arsenic levels that were on average nearly 20 percent higher than those who didn’t. Consumers Union, the advocacy arm of Consumer Reports, urged the FDA to set a 3 ppb limit for total arsenic in apple and grape juice.
“These findings show that rice is an important source of arsenic exposure for the U.S. population,” says Navas-Acien. The associations were even stronger for rice, compared with juice, and are consistent with the relatively high levels of arsenic, including inorganic arsenic, measured in rice samples, she says. She says the results underscore the need for monitoring arsenic in food and establishing safety standards. A new study of NHANES data from Dartmouth researchers also shows that rice consumption can contribute to increased urinary arsenic levels in children.
Arsenic in rice: Part II--How to cut your risk; Part III--Tracing the sources of arsenic. 11/12
Download this PDF with complete details of the test results.
New study finds arsenic in infant formula, cereal bars. 2/12
Consumer Reports discloses additional data from its arsenic tests. 12/11
Part I—Test results | Part II—How to cut your risk | Part III—Tracing the sources of arsenic