How to Reduce Risk of Consuming Arsenic in Rice
The Federal Drug Administration is investigating research that has found some rice contains inorganic arsenic levels being characterized as “worrisome.” Their review of the research may result in their finally setting a maximum limit of inorganic arsenic in our foods.
While this should be good news to consumers, the media’s coverage seems to be missing some crucial information. Like where the arsenic comes from and how we can avoid it.
The real story of arsenic levels in rice
The FDA’s data found inorganic arsenic levels between 3.5 and 6.7 micrograms per serving in their sampling. And a recent Consumer Reports study found similar levels.
Numerous studies have been published over the past decade documenting arsenic content in rice grown from around the world. As we reported previously on the topic of rice and arsenic, significant research comes from Dr. Andrew Meharg, a professor of biogeochemistry at the University of Aberdeen. Dr. Meharg has led or been part of the research teams in many of these studies.
In 2007, Dr. Meharg led a study that measured arsenic levels among rice grown throughout the U.S. He and his team analyzed 107 samples of rice grown in Louisiana, Mississippi, Texas, Missouri, and Florida, and 27 samples of rice grown in California.
Meharg and his team found that the 107 southern US and central US rice samples averaged .30 micrograms per gram of arsenic (equivalent to 4.4 micrograms per serving), and the California rice samples averaged 0.17 micrograms/gram (ppm) (about 2.5 mcg per serving).
However, Organic brown rice grown in California had the lowest levels of all 134 samples, with 0.10 micrograms/gram. This is equivalent to about 1.5 micrograms per serving – far less than the “worrisome” levels found in the FDA and Consumer Reports data. This indicates that organic rice will most likely be significantly lower in arsenic.
It should also be noted that these findings were on total arsenic content. Organic arsenic is a natural component of soils and is considered a trace mineral necessary for health. Inorganic arsenic is another creature altogether.
Inorganic arsenic is carcinogenic
Organic arsenic in its unoxidized form is not necessarily harmful to the body in trace amounts. The body utilizes and metabolizes this form. The inorganic forms – oxidized versions such as arsenic oxides or arsenic trioxide, are produced with synthetic chemicals. These are the forms that have been found to be the most carcinogenic, although large amounts of organic arsenic are considered harmful and possibly even carcinogenic.
Dr. John Duxbury of Cornell University studied U.S. rice samples from different regions and found the total arsenic content averaged 22% inorganic, while Dr. Meharg’s findings showed that the percentage of inorganic arsenic to total arsenic content averaged 42%. This is explained by the fact that different soils have different levels of chemical contamination.
In other words, organic arsenic is readily present in natural soils, while inorganic arsenic is found in soils that have been sprayed with arsenic-based chemical pesticides, or watered with water containing chemicals high in arsenic. And since the plants will readily retain and store both forms, foods grown in soils that undergo chemical spraying – or have in the past – will contain higher levels of inorganic arsenic.
For example, cotton has been known to contain some of the highest levels of arsenic among U.S. crops. This is because cotton crops have historically been sprayed heavily with arsenic-based pesticides to control boll weevils.
Accordingly, Louisiana rice – where a fair amount of rice is grown in soils previously farmed in cotton – had the highest levels of arsenic in Dr. Meharg’s research. Louisiana rice had 0.66 micrograms/gram of arsenic. This means that the arsenic levels of the organic rice were 15% of the arsenic levels of the Louisiana conventional (non-organic) rice.
Other sources of arsenic contamination
In addition to cotton, fruit trees were sprayed with lead hydrogen arsenate for many decades. Now, conventional fruit trees are often sprayed with disodium methyl arsenate (DSMA) or monosodium methyl arsenates. These yield oxidized arsenic, but without the lead. Oxidized arsenic is also used in wood preservatives, antifungals and many other chemicals.
While there is no arsenic standard in food, there is an arsenic standard for drinking water, set by the U.S. Environmental Protection Agency. Using the average arsenic levels found in Dr. Meharg’s research, one would have to consume over 115 grams of rice to exceed the EPA’s standard of 10 micrograms/liter, equivalent to 10 parts per billion (ppb). The average American consumes only about 12 grams of rice per day. Asian Americans, however, average more than 115 grams of rice in a day.
A more recent Meharg study from Spain showed that most rice-based infant formulas – which used conventionally grown rice from around the world – also contained high arsenic content.
Other studies by Dr. Meharg found that arsenic levels in rice milk often exceed the U.S. as well as E.U. arsenic drinking water limits. Dr. Meharg and his team found that 80% of rice milk samples tested from supermarkets in 2008 exceeded the 10 microgram/liter limit. Rice cakes and crackers also contained higher levels of arsenic according to another study.
Dr. Meharg’s research also found that cooking rice in good water lowered inorganic arsenic content.
Research has illustrated that rice from Bangladesh has some of the highest arsenic levels in the world. This is not surprising, since Bangladesh has been faced with an arsenic catastrophe stemming from contaminated groundwater sources.
Dr. Duxbury’s research found that using less water to grow rice will dramatically reduce the arsenic content in the harvested rice.
Dr. Meharg and his associates also studied arsenic levels in China’s rice. They found that most of the varieties contained less than .15 micrograms/gram, but rice grown in regions that were near or on previous mining sites had as much as .64 micrograms/gram.
Dr. Meharg’s research also discovered that some of the lowest arsenic levels among foreign rice are found in basmati rice from India and Pakistan and jasmine rice from Thailand.
How to lower exposure to inorganic arsenic
The research clearly indicates that eating organic rice will dramatically lower one’s total arsenic exposure. Organic rice will lower one’s exposure to inorganic arsenic to an even greater degree because these fields are not sprayed with arsenic oxide-rich chemicals.
Organic rice may also contain traces of inorganic arsenic due to the fact that inorganic arsenic is floating in our atmosphere from pollution, and some of our polluted waterways contain chemicals. Soils used for non-organic farming in the past may also contain arsenic. But conventional rice contains these and more, caused by a constant barrage of arsenic-loaded chemicals being sprayed on the crops.
Choosing organic rice grown in farming regions that have been farmed organically or lay fallow prior to being farmed will assure an even lower arsenic content in the rice. One of these growers is Lundberg Farms, a long-time California family farm that has been growing organic rice for decades (the author and website have no affiliation with Lundberg).
The Lundberg Farms’ organic rice is also grown with less water. As Dr. Duxbury’s studies showed, this decreases the uptake of arsenic in the rice.
If foreign rice is preferred, basmati rice imported from India or jasmine rice imported from Thailand are better bets, especially if these rices are also certified organic.
An antioxidant-rich diet will also help reduce oxidized arsenic levels within the body.
Learn other strategies to cleanse toxins:
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Raab A, Baskaran C, Feldmann J, Meharg AA. Cooking rice in a high water to rice ratio reduces inorganic arsenic content. J Environ Monit. 2009 Jan;11(1):41-4. Epub 2008 Nov 20.