Arsenic warning – should I stop eating rice?

I recently received an email from An Australian friend who became concerned with the arsenic in rice after reading an online article with the title “Arsenic in Rice: How Concerned Should You Be?”[1]. He sent me an email, and I quote:

 “What’s your take on this article?  Anything we can do to reduce the intake of arsenic in rice?  Maybe switch to another whole grain?”  

Rice is the staple food of many Asian cultures

Undeniably, the article does point out a potential public health concern, i.e. the high inorganic arsenic content in rice, which warrants the attention of food regulators, researchers, and consumers [2]. However, we do not need to become so worried until we stop eating rice altogether. Here is my reply to the friend:

Dear friend,

Not to be over concerned arsenic in rice. Although it is undeniable that traces of arsenic are found in rice and arsenic is considered toxic to the body when consumed in large quantity, the amount present in rice that we consume daily is small and we should not be too worried about.  Here are my rationales:

A research paper published in 2014 [3] on arsenic content in rice sold in Australia found the Australian-grown organic brown rice contain the most arsenic content at 438 μg per kg at dry weight uncooked, processed white Australian rice has lower arsenic content (~ 200 μg per kg), whereas imported rice from Bangladeshi, Indian, Pakistani, and Thai all have much lower arsenic content (56-176 200 μg per kg).

Rice is much more efficient at assimilating arsenic into the grain than other staple cereal crops.

Let’s look at some math. 1 cup of rice is about 200mg. So, 1 cup of Australian brown rice contains 87.6 μg of arsenic content. The World Health Organisation (WHO) recommended maximum tolerable daily intake limit for arsenic is 2.1 μg per kg body weight per day [4]. For a small size adult woman weight 50kg, the daily intake limit works out to be 105 μg per day. A 50 kg adult woman rarely eats up to 1 full cup of rice a day, let alone brown rice which is more satiating. Even if she does, the amount is still below the 105 μg daily limit. Not to forget the arsenic content is measured from uncooked rice. Arsenic is water soluble and soaking and cooking process will reduce the arsenic content [5].

Mining activities can lead to the increased emission of arsenic into water sources

Arsenic is a basic element present in nature. With arsenic being highly water soluble, the worry of accumulating of arsenic in the body is much less compared to other heavy metals such as mercury [6]. The body can metabolise and excrete ingested arsenic efficiently. The liver detox and the kidney excrete 50% of the ingested arsenic within 10 hours. Most of the ingested inorganic arsenic can be cleared from the body within a few days. Residual of inorganic arsenic can be deposited into skin, nail, and hair, which will be eventually shed off [7]. It should be reassuring to know that what we know about the toxicity and negative health effects of arsenic poisoning are based on studies on ingestion of arsenic-contaminated drinking water, not rice. Currently, there is no evidence suggesting that staple consumption of cooked rice with less than 200 μg/kg arsenic is harmful to health [8].

Arsenic poisoning are most commonly caused by ingestion of arsenic-contaminated drinking water, not rice

Furthermore, there are many ways to reduce the intake of arsenic from rice. The article does give some good approach, such as pre-soaking and cooking of rice with excess water [5,9], as well as choosing the type of rice that has less arsenic content. Sorry to say, Australian rice does fair badly compare to rice from Asian countries, possibly because of less pollution from mining. So, go for Indian Basmati rice or Thai fragrance rice rather than Australian grown rice [3].    

Cooking rice - cooking with water

Cooking rice in excess water can help to reduce its arsenic content


We can also reduce the reliance on rice by replacing with other grains such as quinoa or millet, an approach which I totally agree with. Intake of a variety of grains is more nutritious and healthier. It will be good to cut out all grains and carbohydrates occasionally for the body to go on ketogenesis to speed up cellular detoxification as well.

Mixed Grains (5662575503)

Mix your rice with other grains – a healthier option

So, not to be overly concerned by what is written in the article. While there is some truth in the writing, we should look at the supporting science behind to make our own assessment. For arsenic content in rice, I will not lose my sleep on it.

Here is my suggestions for reducing exposure to arsenic content in rice:

  1. Choose Indian Basmati rice or Thai fragrance rice, they are known to have less arsenic content.
  2. Soaked your rice with filtered water before cooking, drain the soaking water and cook the rice with excess water. Pour away excess water after rice is cooked.
  3. Eat a healthy diet with a variety of whole grains, not rice alone.

Hope this can help to alleviate your fear. Enjoy your rice.

References

[1]        L. Oberst, Arsenic In Rice: How Concerned Should You Be?, Food Revolut. Netw. (2018). https://foodrevolution.org/blog/arsenic-in-rice/ (accessed March 21, 2018).

[2]        I. Hojsak, C. Braegger, J. Bronsky, C. Campoy, V. Colomb, T. Decsi, M. Domellöf, M. Fewtrell, N.F. Mis, W. Mihatsch, C. Molgaard, J. Van Goudoever, Arsenic in rice: A cause for concern, J. Pediatr. Gastroenterol. Nutr. 60 (2015) 142–145. doi:10.1097/MPG.0000000000000502.

[3]        M.A. Rahman, M.M. Rahman, S.M. Reichman, R.P. Lim, R. Naidu, Arsenic Speciation in Australian-Grown and Imported Rice on Sale in Australia: Implications for Human Health Risk, J. Agric. Food Chem. 62 (2014) 6016–6024. doi:10.1021/jf501077w.

[4]        WHO, Exposure to Arsenic: A Major Public Health Concern, Geneva, Switzerland, 2010. doi:10.1016/j.ecoenv.2011.12.007.

[5]        P.J. Gray, S.D. Conklin, T.I. Todorov, S.M. Kasko, Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain, Food Addit. Contam. Part A. 33 (2015) 1–8. doi:10.1080/19440049.2015.1103906.

[6]        K.M. Rice, E.M. Walker, M. Wu, C. Gillette, E.R. Blough, E.R. Blough, Environmental mercury and its toxic effects., J. Prev. Med. Public Health. 47 (2014) 74–83. doi:10.3961/jpmph.2014.47.2.74.

[7]        Agency for Toxic Substances and Disease Registry (ATSDR), Arsenic Toxicity: What is the Biologic Fate of Arsenic in the Body?, Environ. Heal. Med. Educ. (2011). https://www.atsdr.cdc.gov/csem/csem.asp?csem=1&po=9 (accessed March 21, 2018).

[8]        M. Banerjee, N. Banerjee, P. Bhattacharjee, D. Mondal, P.R. Lythgoe, M. Martínez, J. Pan, D.A. Polya, A.K. Giri, High arsenic in rice is associated with elevated genotoxic effects in humans, Sci. Rep. 3 (2013) 1–8. doi:10.1038/srep02195.

[9]        M. Carey, X. Jiujin, J. Gomes Farias, A.A. Meharg, Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water., PLoS One. 10 (2015) e0131608. doi:10.1371/journal.pone.0131608.

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