Arsenic in Food Could Threaten Our Health – But It’s Not Being Regulated

rice on plate

Researchers have known for some time that the food and drink we all consume contains arsenic.

Should we be concerned? Aren’t we protected by federal regulations? Actually, no – we are not. In the US, as in many countries, the government regulates the concentration of arsenic in drinking water, but does not regulate the concentration of arsenic in any other drink or food. We have a mercury-in-food regulation; why don’t we have an arsenic-in-food regulation?

One important difference is that all of the compounds of mercury we find in food are equally toxic. This is not the case for arsenic. Although we normally think of arsenic compounds as potentially harmful, most of the arsenic we eat is harmless. Seafood, which contains by far the highest concentrations of arsenic, delivers it as arsenobetaine, an organic chemical containing arsenic that is innocuous to us humans.

How then should arsenic in food be regulated? To do that well, we need to develop better ways to determine the amounts of arsenic and other chemicals in our foods.

Arsenic in Food

Scientists are still in the early days of collecting data on the arsenic content of food. So far, we think the only widely consumed foodstuffs with the potential for long-term health problems due to the arsenic content are rice and all rice-derived products, such as flour, cakes, crackers and infant formulas.

Chemical analyses show that regardless of the origin of the rice, four arsenic-containing compounds account for about 95 percent of the arsenic that is released from rice on cooking. Two of the compounds, together known as inorganic arsenic, are known human carcinogens, and two (monomethyl and dimethylated arsenic) are possibly carcinogenic to humans, according the International Agency for Research on Cancer.

There’s a wide range of arsenic concentrations in food. If an in-food safety limit were set based on a concentration level only, it would designate all food from the aquatic environment to be unfit for human consumption, even though there is no health risk. So an arsenic-in-food standard needs to specify which arsenic compounds are to be regulated.

Also, the health risks depend on the concentrations of the carcinogenic inorganic arsenic, the amount of rice consumed and how often rice is consumed. Some researchers consider that to keep the risk of getting an arsenic-induced cancer to an acceptable level, the daily adult intake should not exceed a quarter cup of uncooked rice containing no more than 50 parts per billion (ppb), and that children should consume even less in proportion to their body weight.

The results from the analysis of a large number of rice and rice products presented by both Consumer Reports and the US Food and Drug Administration show almost all rice tested contained concentrations in excess – sometimes well in excess – of this 50 ppb limit. Brown rice has, in general, concentrations of arsenic higher than those in white rice.

A rice plant in Thailand. Credit nayladen/ Shutterstock

A rice plant in Thailand. Credit nayladen/ Shutterstock

Why Arsenic in Rice

We do not know how long we have been exposed. Only relatively recently have advances in chemical measurement technology made it possible to detect arsenic compounds at relevant concentrations in foodstuffs.

The first results for the measurement of arsenic in rice were made in 1998. The global extent of the contamination was not apparent until 2005, when it was realized that some of the highest concentrations of both inorganic and methylated arsenic compounds are found in rice grown in the US. Results so far show that all rice, regardless of variety and origin, contains easily measurable concentrations of arsenic compounds.

Why is there arsenic in rice? Rice is often grown in fields formerly used for cotton, whose production involved spraying with cacodylic acid (the dimethyl arsenic compound) to kill boll weevil pests, and then with arsenic acid to kill and desiccate the plant prior to mechanical harvesting. Rice also assimilates arsenic to a greater extent than other crops, such as wheat and barley.

Many of the arsenic-containing compounds that we eat and drink also come from processes involving naturally occurring arsenic, which is widely distributed on the Earth’s crust. All lifeforms, ranging from bacteria to primates, are capable of transforming the inorganic arsenic compounds derived from the minerals that get into the food web into a series of organic compounds, rendering them less toxic.

Since 2012, advocacy group Consumers Union has been calling for an arsenic-in-food standard and the implementation of arsenic reduction strategies, such as phasing out the use of arsenic-containing pesticides. However, the FDA is working on a study of the long-term risks and will not consider taking any action until this is complete.

Those of us who do not eat more than the amounts recommended by Consumer Reports can probably afford to wait. But some groups within the population, whose diet consists of largely of rice, such as sufferers from celiac disease, infants, and Asian Americans, should be hoping for action sooner rather than later. Asian Americans are the only US racial/ethnic population for whom cancer is the leading cause of death and a diet heavy on rice could contribute to this.

Flawed Measuring Methods

Not all scientists agree on how to assess the health risks of consuming inorganic and methylated arsenic compounds. But no matter what the basis, at the very least, a meaningful arsenic-in-rice regulation has to be supported by reliable information on the inorganic arsenic concentration. Unfortunately, the chemical measurement community is making slow progress towards this capability.

A recent round-robin proficiency test, in which almost 100 expert laboratories spread across 35 countries participated, involved the determination of the total arsenic and the inorganic arsenic in a carefully prepared rice flour reference material.

Depending on how stringent the evaluation criteria applied were, between 23 and 41 percent of the participants did not get a satisfactory result for the determination of total arsenic, and between 25 and 43 percent did not get a satisfactory result for the determination of inorganic arsenic. Furthermore, only a third of the participants actually submitted a result for the inorganic arsenic content, which probably means they were unable to determine the concentration of the most-harmful form.

We know enough to be concerned, and consumers should be demanding more information. Incentives are needed not only to get rice suppliers to implement arsenic-reduction strategies but also to get analytical chemists to collaborate on the development of reliable methods.

A hard-to-meet inorganic arsenic-in-rice standard of less than 100 parts per billion would be a good start. In the meantime, choose white rice (basmati or sushi), rinse it in cold water, and cook it in excess water – arsenic-free, of course.

The Conversation

This article was originally published on The Conversation.

Top image by Navin Penrat / Shutterstock

CATEGORIZED UNDER: Environment, Top Posts
MORE ABOUT: nutrition
  • Michael Klein

    This article is yet another ill-informed, alarmist story about the alleged dangers of arsenic in rice that we’ve seen from Dr. Oz and others.

    The article opens with a false claim and builds from there. Professor Tyson writes that “the only widely consumed foodstuffs with the potential for long-term health problems due to the arsenic content are rice and all rice-derived products, such as flour, cakes, crackers and infant formulas.”

    Actually, the U.S. Environmental Protection Agency (EPA), has
    said that rice is not even the main source of limited arsenic consumption. The EPA’s dietary evaluation of arsenic intake from foods found that the highest food contributors of inorganic arsenic are vegetables (24 percent), fruit juices and fruits (18 percent), rice (17 percent), beer and wine (12 percent), and flour, corn, and wheat (11 percent).

    A rigorous evaluation of the copious amount of data available would never have allowed Tyson to suggest adults limit daily rice intake to one quarter cup with arsenic levels of 50 parts per billion (ppb). There is no scientific basis for either the serving size or the suggested arsenic level.

    In 2013, the World Health Organization’s (WHO) Codex Committee on Contaminants in Food (CCCF), charged with protecting human health
    around the globe, established a maximum level of arsenic in white rice of 200 ppb and is considering a level of 350 ppb for brown rice. Tyson’s 50 is arbitrary and has no relationship to either established and accepted toxicology or risk science.

    Tyson offers no support for the 50 ppb figure, however, we suspect this is based on the often miscited and widely discredited EPA risk
    assessment that was actually about soluble arsenic levels in drinking water – not in food.

    Tyson also falls into another common trap — the false assumption that the presence of a toxin is automatically a problem. This isn’t so, and while the word “arsenic” can sound scary, especially when discussing our food, the responsible thing is to provide sufficient context. Trace levels of arsenic are present in many of the foods we eat, but do not present any measurable health risk.

    Considerable scientific evidence on arsenic toxicology indicates that risk at low levels such as in the normal diet would be inconsequential[i].

    According to the U.S. EPA and their Science Advisory Board, this organic arsenic form is not carcinogenic at low doses such as would be present in food[ii]. And the CODEX committee found that rice grown in
    the United States has the lowest levels of inorganic arsenic of any rice tested[iii].

    But Tyson doesn’t just get the science wrong. He gets the agriculture wrong as well. Tyson says “[r]ice is often grown in fields formerly used for cotton, whose production involved spraying with [arsenical pesticides].” It’s simply not true. Rice and cotton are not grown in the same soil type, because cotton requires heavy drainage, and rice the opposite. There is very little crossover of field plots.

    Perhaps the most troubling distortion by Tyson is this one: “Asian
    Americans are the only U.S. ra ial/ethnic population for whom cancer is the leading cause of death and a diet heavy on rice could contribute to this.”

    This statement is a wholly misleading interpretation of the U.S.
    cancer statistics, and does not mention important facts such as Asians live longer than other ethnic groups, have fewer rates of major diseases such as heart disease, and actually have lower rates of cancers in general and those specific to arsenic (e.g., lung and bladder) compared to whites (lower rice eating groups) and other groups.

    Simply put, Asian Americans are not dying early of cancer because of something they are eating. They are living longer, perhaps thanks to diet, and getting cancer later in life, as is expected.

    Worldwide cancer statistics from the International Agency for Research on Cancer (IARC) also indicate that rice-eating countries actually have lower risks of bladder and lung cancer than non-rice eating countries such as the United States and European countries.[iv]

    The article goes on to claim, “[c]ertain groups are at more risk than others, depending on diet.” However, those who eat rice are actually more likely to experience significant health advantages.

    No tangible evidence indicates negative health effects are occurring for arsenic exposures at the levels normally present in foods in the United States.

    Rice eaters have more beneficial health and diet parameters; compared with non–rice eaters, those who eat rice are less likely to have risk factors associated with cardiovascular disease, type 2 diabetes, and metabolic syndrome and they are more likely to have an overall better diet quality.[v] The nutritional benefits of rice are unparalleled. Rice is fortified with essential nutrients like folic acid and iron, helping to contribute to a wholesome diet.

    All of this being said, it is important to understand that the U.S. rice industry is dedicated to producing a safe, sustainable crop and that the industry is funding research to try to mitigate the already low levels of arsenic present in rice.

    Arsenic in our food supply is a serious issue, however, taking a responsible, science-based approach is vital. Professor Tyson widely missed the mark here, but we hope he will stay engaged in the issue going forward.

  • Inhibitors

    Arsenic exists in food in many forms including acid, sulfide, bromide and etc. Most of them are of no harms.

  • Abortion Clinic Johannesburg

    like one of the comments addressed claims it being false from his or her aspect what actual is needed? secondly does it not imply to the most tinned or processed food we but from the stores?

  • Ninfa Shock

    My children were wanting a form several days ago and saw an online platform that hosts 6 million forms . If others need to fill out it too , here’s


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