Arsenic: The Dark Side of Rice


The Nutritarian diet is largely focused on vegetables, beans, fruits, seeds and nuts with all of their health promoting vitamins, minerals and phytochemicals, as can be seen on my Nutritarian Food Plate, and whole grains, including whole grain rice.

As the most widely consumed grain worldwide, rice serves as a staple food for a large part of the world. However, not all rice is equally healthful. Rice varies by type and origin, which contribute to both its nutritional content and potential level of arsenic contamination.

Among the layers of grains, the germ is the nutritional jewel

 A whole grain contains a complete “kernel” that consists of three edible parts; the bran, endosperm, and germ.Whole grain rice is classified by the color of its bran and there are four groups: brown, black, purple, and red. Wild rice is similar, but technically not in the rice family.

Part

Purpose

Contains mostly

Bran

Protects the seed

Fiber

Endosperm

Energy source

Carbohydrates

Germ

Seed for new plant

Micronutrients

The most commonly grown commercial rice is brown rice. When brown rice has its bran and germ removed it is called white rice.

This processing allows white rice to have a longer shelf life and shorter cooking time, but the healthful fiber in the bran and beneficial nutrients in the germ are lost. More colorful pigmented whole grain rice varieties are becoming increasingly popular and red, black, and purple rice exhibit higher antioxidant activity as compared to brown rice.

Overall, black rice, which is rich in anthocyanins, showed the highest antioxidant levels of all rice varieties, followed by red and purple, then brown, and lastly white rice.1

Arsenic: the dark side of rice

One of the four principles of the Nutritarian diet is to limit our exposure to contaminants, infectious agents and toxins. Arsenic is a toxic element that is naturally present in the earth’s crust. As such, it is found in the soil, water and some foods.

In addition, some areas have increased concentrations of arsenic as a result of industrial pollution, the use of arsenic-based drugs in poultry production, and arsenic-containing pesticides and fertilizers2-3

All plants can absorb some arsenic, but rice can absorb up to ten times as much as other grains.4-5This is due to how the rice (including wild rice) is grown, in flooded paddy fields. The soil in the fields, when covered with water, creates conditions that allow arsenic to be converted to more readily absorbable forms.4 Arsenic accumulates most in the outer layer of rice, which is the reason that whole grain rice, with its bran intact, can have up to 80 percent more arsenic than white rice.2 White rice is high glycemic food that is low in nutrients, so don’t think it is the better alternative.

Arsenic can occur in two main forms: organic and inorganic compounds. This use of “organic” is a chemistry term and generally means “containing carbon,” unlike the agricultural term, which refers to food production, pesticide use, and farming practices.

Inorganic arsenic is more abundant and more toxic, but both forms are considered a public health concern. Arsenic is well recognized as a human carcinogen and chronic exposure (via inhalation or from high-arsenic drinking water) is a known cause of skin, lung, and bladder cancer and is also associated with other cancers such as kidney, liver, and prostate.2

Studies have also demonstrated associations with noncancerous conditions, such as diabetes, heart and lung diseases, immunological effects, and impaired cognitive function.2,6-8

Although whole grain forms of rice have a superior nutritional profile compared to white rice, they also have a higher risk of arsenic contamination. When you do eat whole grain rice, these are some ways to minimize arsenic exposure:

Find out where rice was grown

  • Consumer Reports found that brown basmati rice from California, India or Pakistan has about a third of the inorganic arsenic as compared to brown rice from other regions and would be the best choice
  • Rice grown in Arkansas, Texas, Louisiana, and most other U.S. locations had the highest inorganic arsenic levels, so would be better to avoid or minimize
  • Check companies websites. Some rice growers conduct independent testing for arsenic levels in their rice and post the results
  • There are also companies that harvest wild-growing rice from northern Wisconsin and Canada without the use of commercial fertilizers
  • Keep in mind that organically-farmed rice may mean there is less pesticide use, but does not necessarily mean there are lower arsenic levels

Preparation and Cooking

  • Rinsing raw rice reduces arsenic content. Rinse rice until the water becomes clear
  • Cook rice in high water volume. Research has shown that the amount of arsenic in rice can be reduced by approximately 40 percent if the rice is boiled in a large volume of water. Cook rice using a 1-to-6 cup rice-to-water ratio, drain and discard the excess water

Eat a variety of starches—not just rice

On a Nutritarian diet, the most emphasized starch sources are beans, lentils and other legumes. There are also healthful starchy vegetables such as butternut squash, winter squash, carrots, beets, parsnips, rutabaga and turnips, and a variety of whole grains such as amaranth, barley, buckwheat, bulgur, farro, millet, and quinoa.

If you utilize a variety of these foods, arsenic exposure from the occasional serving of rice will not be a concern. However, as a result of this arsenic issue, brown rice should not be eaten often and regularly.

The recipes in the Member Center Recipe Guide can help you plan delicious grain meals. For example, the Broccoli Mushroom Casserole can be made with either farro or another grain.

 
References
  1. Goufo P, Trindade H. Rice antioxidants: phenolic acids, flavonoids, anthocyanins, proanthocyanidins, tocopherols, tocotrienols, y-oryzanol, and phytic acid. Food Sci Nutr. 2014 Mar; 2(2): 75-104.
  2. Consumer Reports. Report: Analysis of Arsenic in Rice and Other Grains. Executive Summary. Yonkers, NY: Consumer Reports (2014). Available at: http://www.greenerchoices.org/pdf/CR_FSASC_Arsenic_Analysis_Nov2014.pdf. Accessed February 17, 2015.
  3. Fisher DF, Yonkos LT, Staver KW. Environmental concerns of roxarsone in broiler poultry feed and litter in Maryland, USA. Environ Sci Technol. 2015 Feb 17;49(4):1999-2012.
  4. Raab A, Baskaran C, Feldmann J, Meharg A. Cooking rice in a high water to rice ratio reduces inorganic arsenic content.J Environ Monit. 2009;11:41-44.
  5. William PN, et al. Greatly enhanced arsenic shoot assimilation in rice leads to elevated grain levels compared to wheat and barley. Environ Sci Technol. 2007 Oct 1;41(19);6854-9.
  6. Moon KA, et al. Association between low to moderate arsenic exposure and incident cardiovascular disease. A prospective cohort study. Ann Intern Med. 2013 Nov 19;159(10):649-659.
  7. Parvez F, et al. Arsenic exposure and impaired lung function. Findings from a large population-based prospective cohort study. Am J Respir Crit Care Med. 2013 Oct 1; 188(7):813-819.
  8. Wasserman GA, et al. A cross-sectional study of well water arsenic and child IQ in Maine schoolchildren. Environ Health. 2014, 13:23.