If you've dropped gluten from your diet – proteins found in wheat, rye and barley – chances are your pantry is home to a box of brown rice, a package of rice crackers and perhaps a loaf of bread made from rice flour.
Yet, according to research from the University of Illinois in Chicago, eating a gluten-free diet that's based on rice products could be exposing you to higher levels of arsenic, a compound linked to adverse health effects.
What is arsenic?
Arsenic is an element that's present in water, air and soil. It comes from natural sources as well as industrial pollution and the use of arsenic-containing pesticides.
There are two forms of arsenic: organic and inorganic. Exposure to inorganic arsenic has been more closely tied to adverse health effects. (In this case, "organic" is a chemical term and does not refer to growing or production methods.)
Both forms of arsenic are found in low levels in many foods, including grains, fruits and vegetables, fruit juices and meat, since the chemical is absorbed through soil and water. Rice accumulates arsenic far more readily than other plants because it's grown in standing water.
The health risks of long-term exposure to low levels of inorganic arsenic are unclear, but exposure to high levels has been shown to contribute to skin lesions, nerve problems, kidney impairment, cardiovascular disease, diabetes and cancer risk.
The health risks of high-level arsenic exposure have been most dramatically seen where people have been exposed to contaminated drinking water.
Gluten-free and arsenic exposure
The University of Illinois study, published online in the journal Epidemiology, analyzed data from 7,471 participants who completed the U.S. National Health and Nutrition Examination Survey (NHANES) between 2009 and 2014. (NHANES surveys and physical examinations are designed to assess the health and nutritional status of adults and kids in the U.S.)
People who reported eating a gluten-free diet had almost double the concentration of inorganic arsenic in their urine compared with those who didn't follow a gluten-free diet.
Keep in mind, the study looked at measurements made at one point in time; it found a correlation between gluten-free eating and urinary arsenic, which doesn't prove causation.
It also relied on self-reported data regarding gluten-free diets, which can be prone to error.
The researchers didn't ask which foods people ate, so they can only speculate that rice and rice-based gluten-free products contributed to higher arsenic urinary levels. Even if rice was the culprit, it's not known if such arsenic concentrations would have health implications.
Previous concerns about rice
It's not the first time that concerns have been raised about the level of arsenic in rice and rice-based foods.
In 2012, Consumer Reports released the results of an analysis of more than 60 rice products (e.g., white and brown rice, baby cereal, breakfast cereal, rice crackers, rice pasta, rice milk, rice syrup). Arsenic was detected in almost all products.
"Worrisome" levels were found in some products prompting the non-profit organization to recommend that consumers moderate consumption of rice-based foods.
In November, 2014, Consumer Reports released a new analysis that also included U.S. FDA data of 656 products. Compared with 2012 data, products tested had just as much inorganic arsenic and some foods, such as rice cereal and rice pasta, contained even more.
The analysis also found that arsenic content depended on the type of rice and where it was grown. White basmati rice grown in California, India and Pakistan, and sushi rice from the U.S. had, on average, half the inorganic arsenic content than most other types of rice.
Brown rice harboured 80 per cent more arsenic than white rice of the same type. Arsenic is more abundant in the outer layers of whole grains, which are stripped away during refining.
In April, 2016, the FDA released a scientific review of arsenic content in rice and rice products available in the United States. Among all products, inorganic arsenic ranged from 1 parts per billion in infant cereal to 160 ppb in brown rice.
Almost half of infant rice cereal samples fell below 100 ppb, the European Union's upper limit for infant cereals. (There are no established arsenic limits for rice and rice-based foods in the United States or Canada.)
Based on its testing, the FDA proposed a limit of 100 ppb for inorganic arsenic in infant cereal. Research had found that exposure to inorganic arsenic in infants and pregnant women may impair a child's learning ability.
What is Health Canada doing?
A 2010-2011 Canadian Food Inspection Agency assessment found detectable levels of arsenic in most samples of rice and other products tested; yet, none posed a concern to human health, the agency stated.
The CFIA tested arsenic in rice and rice products again in 2015 and 2016; the results are currently being analyzed. This year, the agency is testing arsenic levels in various foods including grain-based products and frozen and ready-to-eat meals.
Tips to reduce arsenic intake
Rice is a nutritious food that delivers carbohydrate, B vitamins and minerals. And, if you choose brown rice, which I recommend, you'll get fibre and phytochemicals, too.
Rice shouldn't be the only grain you eat, though.
Both Health Canada and the U.S. FDA advise consuming a variety of grains to minimize exposure to inorganic arsenic from rice. Other iron-fortified cereals for infants include oat, barley and multigrain.
Cooking rice in lots of water (six parts water to one part rice) and draining off the excess water has been shown to reduce inorganic arsenic content by 40 to 60 per cent.
If you eat a gluten-free diet, include alternatives to cereals, crackers, breads and crackers made from rice/rice flour. The 2014 Consumer Reports analysis determined that amaranth, buckwheat, millet and whole grain corn (polenta) – all gluten-free – have negligible levels of arsenic.
Quinoa (gluten-free) and gluten-containing bulgur, barley and farro have low levels.
Brown-rice syrup, a refined sugar found in infant formula, energy bars, cereal bars and breakfast cereals, and rice milk are other sources of arsenic.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto