I first covered the issue of arsenic and rice in 2009 at the urging of a concerned consumer. That initial article can be accessed at http://www.glutenfreedietitian.com/newsletter/gluten-free-diet-arsenic-and-rice/. The present article could not have been written without the helpful and generous email correspondence from arsenic researchers at Dartmouth College.
Arsenic is a naturally occurring element that is found in both organic (carbon-containing) and inorganic (non-carbon-containing) forms. It may be present in soil, water, and air. Inorganic arsenic is a known carcinogen and ingestion may cause an increased risk of certain cancers. Ingestion of inorganic arsenic can also affect the skin and gastrointestinal tract.
Arsenic and the World Health Organization
The World Health Organization (WHO) calls arsenic exposure “a major public health concern.” According to the WHO, inorganic arsenic is very toxic while organic arsenic is less harmful. “Human exposure to elevated levels of inorganic arsenic occurs mainly through the consumption of groundwater containing naturally high levels of inorganic arsenic, food prepared with this water and food crops irrigated with high-arsenic water sources.” Public health measures are called for to decrease exposure to arsenic. While at one time the WHO had a provisional tolerable weekly intake of inorganic arsenic, this provisional intake has been withdrawn and a new tolerable weekly intake has not been set.
Arsenic and Water
The Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) have limits on the amount of total arsenic that may be found in drinking water and bottled water, respectively. This amount is 0.01 mg of arsenic per liter or 10 micrograms per liter (10 ppb). Keep in mind though that just because drinking water is allowed to contain 10 ppb arsenic does not mean that it does.
Based on allowed amounts, two liters (approximately 8 cups) of water should contain a maximum of 20 micrograms of total arsenic (arsenic in drinking water is inorganic).
Arsenic and Food
According to the European Food Safety Authority, several foods may contain inorganic arsenic and contribute to an individual’s exposure, including rice and rice-based products. Rice is an issue because it is grown under flooded conditions. This practice leads to the high mobilization of soil arsenic into the rice plant. That rice is a source of inorganic arsenic is particularly concerning to the gluten-free community especially among those who have a largely rice-based diet.
The EPA has set a Reference Dose for chronic oral exposure to inorganic arsenic of 0.0003 mg per kg of body weight per day. The EPA defines the Reference Dose as, “an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious noncancer effects during a lifetime.”
What this Means
Using the EPA equation (mg/kg/d) and myself as an example, the math is as follows: Divide weight in pounds by 2.2 (132 /2.2= 60). Then Multiply 60 kg by 0.0003 (60 x 0.0003=0.018). My inorganic arsenic intake from food and water should be limited to 0.018 mg (or 18 micrograms) per day.
Arsenic Test Results
The FDA has not yet set limits for the amount of inorganic arsenic in food. However, the agency is actively investigating the arsenic content of rice and recently released results of analytical testing on rice and rice products. They provided a summary of their findings to date.
The 49 samples of non basmati rice assessed by the FDA had an average inorganic arsenic level of 6.7 micrograms per serving (45 grams/1 cup cooked).
The 52 samples of basmati rice assessed by the FDA had an average inorganic arsenic level of 3.5 micrograms per serving (45 grams dry/1 cup cooked).
The 32 samples of rice cereal assessed by the FDA had an average inorganic arsenic level of 3.5 micrograms per serving (30 grams dry/1 cup).
The 32 samples of rice cakes assessed by the FDA had an average inorganic arsenic level of 5.4 micrograms per serving (30 grams dry/2 rice cakes).
The 28 samples of rice beverages assessed by the FDA had an average inorganic arsenic level of 3.8 micrograms per serving (1 cup).
Steps Concerned Consumers Can Take:
1. Find out how much arsenic is in your tap, well, or bottled water. Knowing this amount will give you some idea of the amount of rice and rice-based products you can eat and still fall within the EPA’s reference dose for inorganic arsenic. For information on tap water, you can call your local water department. If you use well water, you will have to test it for arsenic yourself. If you drink bottled water, you can call the company. Test results on bottled water conducted by the Natural Resources Defense Council are available at: http://www.nrdc.org/water/drinking/bw/appa.asp. Testing was done several years ago.
2. Change the source of and cooking method for rice. If you would like to continue eating rice, Dr. Andrew Meharg from the Institute of Biology and Environmental Sciences, University of Aberdeen, Aberdeen, UK and a world renowned expert on arsenic, offered the following advice when I interviewed him in 2009:
a. Source rice from low arsenic areas. California rice is lower in arsenic than South Central rice.
b. Use high water to rice volumes similar to when cooking pasta. Discard the water during cooking. This practice will remove a large portion of the inorganic arsenic.
3. Replace at least some of the rice you eat with other gluten-free grains. Dr. Meharg also recommends not having such a strong dependence on rice products and switching to using other grains if possible. Look closely at the rice-based products you are eating to see where you can make substitutions. Some suggestions include:
a. Instead of rice cakes try Real Foods Corn Thins http://cornthins.com/prodOriginal.aspx
b. Instead of rice pasta try Mrs. Leeper’s Corn Pasta http://www.mrsleepers.com/products.html, Ancient Harvest Quinoa Pasta made from corn and quinoa http://www.quinoa.net/145/163.html, or King Soba Buckwheat Noodles http://www.kingsoba.com/organic-noodles-buckwheat.php.
c. Instead of hot rice cereal try gluten-free oatmeal, Ruth’s Chia Goodness cereal http://www.ruthshempfoods.com/, Pocono Cream of Buckwheat http://thebirkettmills.com/shop/organic/pocono-cream-of-buckwheat, or teff hot cereal (see recipe below).
e. Instead of rice-based beverages try soy-based beverages.
f. Try recipes that substitute buckwheat, millet, quinoa, teff, and sorghum for rice.
My Personal Thoughts
I eat a lot of plain rice. It is one of the few foods that sit well in my stomach. When I look at the amount of inorganic arsenic allowed in water, there doesn’t seem to be much room for arsenic in food. However, as already mentioned, just because water is allowed to contain a certain amount of arsenic does not mean that all tap and bottled water contains maximum amounts. This is similar to the issue with gluten-free foods. While up to (but not including) 20 ppm gluten is allowed under the proposed FDA rule, the vast majority of foods tested through Gluten Free Watchdog are testing below 5 ppm. Having investigated the arsenic levels of my tap and bottled water, I will be decreasing but not giving up completely the rice in my diet.
Words of Wisdom
Over the past couple days I have been communicating with premier arsenic researchers at Dartmouth College. Brian Jackson, PhD, Director of the Trace Element Analysis Core Facility at Dartmouth, wrote the following to me in an email, “It’s important to consider that we are talking about effects of long term low level exposures and these limits are based on extrapolations from effects at higher levels of exposure assuming a worst case linear correlation. Also, not all arsenic in food is inorganic arsenic and not all inorganic arsenic will necessarily be adsorbed by the body. The limits are aimed at reducing population-level health effects and it’s hard to comprehend what that means on an individual basis. Added to that, there may be offsetting health benefits to a gluten free diet. Don’t get me wrong, I think we need much more product testing and limits to remove products that are high in inorganic arsenic; we need to push for more regulation but we don’t need to hit the panic button either.”
Teff Hot Cereal
(Originally published in The Gluten-Free Nutrition Guide by Tricia Thompson. McGraw-Hill; 2008)
If you like hot cereal, then you may want to give this nutritious recipe a try. Cooked teff grain has a nice nutty, chewy texture and a mild flavor.
¾ cup water
¼ cup uncooked teff grain
¼ cup raisins (or any other dried fruit)
1 tablespoon unsweetened dried coconut
1 tablespoon yogurt
1 tablespoon maple syrup
In a small saucepan bring water to a boil. Add teff and raisins. Cover and reduce heat to low (maintain a simmer). Cook until all the water is absorbed. Top with coconut, yogurt, and maple syrup.
Makes 1 serving
US Environmental Protection Agency. Arsenic Compounds. 2007. Available at: http://www.epa.gov/ttnatw01/hlthef/arsenic.html
US Environmental Protection Agency. Basic Information about Arsenic in Drinking Water. 2012. Available at: http://water.epa.gov/drink/contaminants/basicinformation/arsenic.cfm.
US Environmental Protection Agency. Inorganic Arsenic. 2007. Available at: http://www.epa.gov/teach/chem_summ/Arsenic_summary.pdf
US Geological Survey. Arsenic in Groundwater in the United States. 2011. Available at: http://water.usgs.gov/nawqa/trace/arsenic/
World Health Organization. Exposure to Arsenic: A Major Public Health Concern. 2010. Available at: http://www.who.int/ipcs/features/arsenic.pdf
US Food and Drug Administration. Bottled Water: Arsenic. 2011. Available at: http://tinyurl.com/4rexje2
US Food and Drug Administration. Arsenic in Rice. 2012. Available at: http://www.fda.gov/Food/FoodSafety/FoodContaminantsAdulteration/Metals/ucm319870.htm
© 2012 by Tricia Thompson, MS, RD. All rights reserved.
This article may not be reprinted, reposted, or republished without the express written permission of Tricia Thompson