First, a little background: Arsenic is an element found in soil, water, and air. It is odorless and tasteless and exists in both organic and inorganic forms. The World Health Organization considers arsenic exposure a “major public health concern.”

Inorganic arsenic is a known carcinogen. Regular exposure can increase the risk of bladder, lung, and skin cancer. It can also affect the gastrointestinal tract and increase risk of heart disease and diabetes.¹

Inorganic arsenic exposure happens mainly through drinking groundwater with high levels of arsenic, eating food prepared with this kind of water, and eating food crops irrigated with high-arsenic water. Inorganic arsenic can be introduced into the environment through pesticides and fertilizer.

Rice is grown under flooded conditions and will absorb arsenic from both the soil and the water. For people with celiac diseases, arsenic is a concern because many gluten-free products contain rice. Studies have looked at the amounts of arsenic in rice, rice-based products, and rice-based baby foods and found some to be relatively high.² Children with celiac disease are especially vulnerable to high levels of arsenic in the gluten-free foods marketed towards them.³

Brown rice has, on average, 80% more inorganic arsenic than white rice of the same type. Why? Arsenic is concentrated in the bran (outer layer) and germ (very inner layer) of a rice grain. White rice is made by polishing off the bran and removing the germ. Unfortunately, this process also removes the fiber and many of the vitamins and minerals. Brown rice flour also has higher levels of inorganic arsenic than white rice flour. Researchers Munera-Picazo and team have observed that some rice samples studied were below the threshold for arsenic content, proving that rice with low levels of arsenic is available in the market. They recommend that rice, in particular brown rice, only be used to prepare products for celiac consumers if it can be proven to contain low inorganic arsenic content.²

There is no federal limit for arsenic in rice and rice products. The Environmental Protection Agency adopted a lower standard for arsenic in drinking water of 10ppb (parts per billion to replace the previous standard of 50ppb.⁴ However, there is no federal limit for arsenic in rice and rice products.

It is important to consider that not all arsenic in food is inorganic. Also, depending on our body’s capacity to absorb nutrients, we may not necessarily absorb all of the inorganic arsenic we consume. In addition, very preliminary research shows that certain processing steps might reduce the arsenic content of rice used as an ingredient in gluten-free products - more research is needed here.² Regardless, experts recommend we take steps to reduce our exposure to arsenic.

What steps can I take to reduce arsenic in my gluten-free diet?⁵

1. Find out how much arsenic is in your tap water by contacting your local water treatment facility. Call the manufacturing company of bottled water for information on their products.
2. You do not need to cut rice out of your diet completely but it’s a good idea to reduce the amount of rice and rice products you eat.
3. Soak and rinse rice before cooking. Use a ratio of 6 cups water to 1 cup rice to cook the rice; drain the rice after it has finished cooking to remove about 50% of the arsenic.
4. Eat rice with lower levels of arsenic. White basmati rice from California, India, and Pakistan has half the inorganic arsenic as most other types of rice. Sushi rice grown in the United States is also low in arsenic. All types of rice (except sushi and quick cooking) from Arkansas, Louisiana, or Texas have the highest levels of arsenic. Keep in mind that brown rice contains more inorganic arsenic than white rice.
5. Eat a wide variety of gluten-free grains. Experiment with amaranth, millet, buckwheat, teff, sorghum and/or quinoa. Rotate them into your diet – do not select just one to replace rice. These alternative grains will offer you many important vitamins, minerals, and fiber which are important for a healthy gluten-free diet. They are more nutritious than rice, as well. Be sure they are labeled gluten-free to avoid cross contamination with gluten containing grains during harvest, transport, and production.
6. Check the labels of processed foods you eat – crackers, bread, cake mixes, snack foods, etc., to see if they contain rice, rice flour, rice syrup, or rice bran. Ingredients are listed in descending order of weight in the ingredients list. Look for products that contain fewer rice-based ingredients and more of the gluten-free grains listed above.

Going Forward:
Researchers continue to examine this potential for increased arsenic and other heavy metal exposure in adults and children on the gluten-free diet.^2,3,6 A study by Punshon found higher arsenic, mercury, and lead and lower levels of beneficial minerals (selenium, iron, copper and zinc) in rice and rice products versus wheat or non-rice GF grains.⁷ For a helpful summary of this article, which also offers more details on brown rice, please read Gluten-Free Watchdog’s article Arsenic and Mercury in Rice: New Research from Dartmouth College⁸

Subscribers to Gluten-Free Watchdog can review third-party testing results for arsenic in rice and rice-based foods. Researchers, such as Tracy Punshon of Dartmouth’s Trace Element Analysis Core, will continue to explore to what extent this exposure may present a long-term health risk to our gluten-free population.

References

1. Dartmouth Toxic Metals Superfund Research Program. Arsenic and your health. https://www.dartmouth.edu/~arsenicandyou/health/health-effects.html.
2. Munera-Picazo S, Burló F, Carbonell-Barrachina ÁA. Arsenic speciation in rice-based food for adults with celiac disease. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2014;31(8):1358-1366.
3. Munera-Picazo S, Ramírez-Gandolfo A, Burló F, Carbonell-Barrachina AA. Inorganic and total arsenic contents in rice-based foods for children with celiac disease. J Food Sci. 2014;79(1):T122-128.
4. S. Environmental Protection Agency. Drinking Water Requirements for States and Public Water Systems. https://www.epa.gov/dwreginfo/chemical-contaminant-rules.
5. Dartmouth Toxic Metals Superfund Research Program. Arsenic in rice and rice products. https://www.dartmouth.edu/~arsenicandyou/food/rice.html.
6. Raehsler SL, Choung RS, Marietta EV, Murray JA. Accumulation of Heavy Metals in People on a Gluten-Free Diet. Clin Gastroenterol Hepatol. 2018;16(2):244-251. doi:10.1016/j.cgh.2017.01.034
7. Punshon T, Jackson BP. Essential micronutrient and toxic trace element concentrations in gluten containing and gluten-free foods. Food Chem. 2018;252:258-264.
8. Gluten-Free Watchdog. Arsenic and Mercury in Rice: New Research from Dartmouth College. https://www.glutenfreewatchdog.org/news/arsenic-and-mercury-in-rice-new-research-from-dartmouth-college/.

Reviewed October 4, 2022.