Plants readily absorb arsenic from the soil. According to John M. Duxbury, PhD, a professor of soil science and international agriculture at Cornell University, “All plants pick up arsenic. Concentrations in leaves of plants are much higher than in grains of plants. Thus, leafy vegetables can contain higher levels of arsenic than rice, especially when they are grown on arsenic-contaminated soils.”(1) He indicates that our arsenic intake is low because he assumes that we eat a much lower volume of leafy greens compared to other foods. Rice grows in water (paddies), making it more vulnerable to arsenic contamination because arsenic dissolves easily in water, which allows rice to take up and store more arsenic than plants grown in drier soils.(1,2)
Arsenic concentrates in the outer layers and the germ of the rice grain. Once the inedible husk is removed, leaving brown rice, the milling and polishing processes remove the outer layers of the brown rice to produce white rice. As a result, more arsenic remains in brown rice than in white rice.(1,2)
Just last week on September 6, 2013, the FDA released the analytical results of 1,300 samples of rice and rice products (1,100 new samples and 200 samples tested in 2012) as part of a major effort to understand and manage possible arsenic-related risks associated with the consumption of these foods.(4) According to the FDA report on Arsenic in Rice and Rice Products:
“The levels FDA found in its testing are too low to cause immediate or short-term adverse health effects. FDA’s work going forward will center on long-term risk and ways to manage it with a focus on long-term exposure.”(4)
In other words, they’re saying that it’s okay to eat rice and rice products at this point, which can change in the future once they've collected more data. However, they are recommending that alternatives to rice cereal be considered for an infant’s first solid food.(5)
There are two main forms of arsenic: inorganic and organic, and there are several species of each. Inorganic arsenic is of the most concern because it’s toxic; organic arsenic is less toxic.(1,2,3) However, the extent of toxicity of organic arsenic is not fully understood. Scientists at the FDA and in academic laboratories are developing new methods and improving old ones for identifying and quantifying arsenic in its various forms.(3) In the meantime, arsenic levels are reported as total arsenic (in parts per billion, ppb) and inorganic arsenic (ppb and in micrograms per serving; a serving of rice is 45 grams dry, about 1 cup of cooked rice). The FDA found varying levels of inorganic arsenic levels in rice ranging from 2.6 – 7.2 micrograms per serving, with instant rice (the most processed) being the lowest and brown rice being the highest.(4) These results are consistent with the 2012 Consumer Reports study.(2) While I didn’t find it indicated in the data that was just released last week, both the original FDA study of 200 samples and the Consumer Reports study of 223 samples showed that rice from the southeastern U.S. (rice and rice products) have higher levels of arsenic than rice from California.
Although the FDA has standards for arsenic in water of 10 micrograms per liter, the FDA has no standards for arsenic in food. In fact, little is known about arsenic levels in foods because the FDA analyzes arsenic only on a case-by-case basis. Long-term studies that track health effects from extended exposure of arsenic in rice are recent, and epidemiological studies of lower-level arsenic intake from rice are needed.(2)
According to Consumer Reports, the EPA assumes there is actually no “safe” level of exposure to inorganic arsenic.(2) No federal limit exists for arsenic in most foods, and there is a need for a standard of arsenic in food. I personally believe that part of setting standards for arsenic in foods involves an understanding of the levels of arsenic found in all plant-based foods that we consume. Up to this point, arsenic levels have only been studied in rice, rice products, and apple juice.
Exposure to lower levels of arsenic can cause nausea, vomiting, abnormal heart rhythm, decreased production of red and white blood cells, impaired nerve function, damage to blood vessels, skin warts and corns, and red or swelling skin. Repeated exposure to arsenic can damage the liver and kidneys, cause stomach problems, and cause a darkening of the skin. Breathing high levels of arsenic can cause a sore throat or irritated lungs.(6) Emerging evidence suggests that arsenic may cause problems with brain development in children.(2) More evidence suggests that moderate levels of exposure may cause cardiovascular disease and chronic exposure may also effect the lungs, leading to breathing problems.(2) Chronic exposure to arsenic has very few symptoms, however, long-term exposure to arsenic from water is known to cause skin discoloration that looks like freckles or small moles on the hands, feet, or trunk.(2)
Here’s what you can do to limit your exposure to arsenic in rice:
- Purchase rice that was grown in regions with lower levels of arsenic in the top soils such as California, India, and Thailand.
- Rinse your rice well before cooking and use the traditional method of cooking rice in Asia, that is, use a 6:1 water to rice ratio (instead of the typical 2:1 ratio). In other words, use 6 cups of water for every 1 cup of rice you cook. Using that much water means that like pasta, it won’t all get absorbed, and you will have to drain the excess water. Research has shown that this technique of rinsing and using excess water will remove roughly 30% of the rice’s inorganic arsenic.
- Use a variety of whole grains in addition to rice, including wheat, oats, quinoa, amaranth, and millet.
- Eat a well-balanced diet and avoid eating an excess of any one food.
- Instead of rice cereal, consider using an alternative for an infant’s first solid food.