Arsenic in rice

High levels in hundreds of rice products

Today, the magazine Consumer Reports  released a report  on independent laboratory tests that found inorganic arsenic – a known carcinogen – in some 200 rice products purchased in grocery stores across the United States. The admitted point was to pressure the U.S. Food and Drug Administration into setting a safety standard for arsenic in the American food supply, something the FDA has been embarrassingly reluctant to do.

In a neatly choreographed response, the FDA promptly released its own sample results from – yes – some 200 rice products which turned up a comparable amount of inorganic arsenic in the selected foods, which ranged from baby cereal to rice cakes to bagged rice. As The Washington Post reported, the agency also reiterated that it is still testing another 1,000 rice samples and plans to release a more complete report by the end of the year.

As readers of this blog know, there’s nothing incredibly new in these results; scientists have been publishing studies on arsenic in rice for more than a decade. You can find links to some of that research, in an earlier post, The Arsenic Diet. And as I wrote back in February, there’s a straightforward reason for this. Of all the commercially grown grains, the rice plant is best designed to uptake arsenic – a widespread and naturally occurring element – from the soil, using the same mechanisms that allow it to store minerals like silicon that help strengthen the rice grains. It’s not surprising that Consumer Reports found that inorganic arsenic levels in rice cereals were “at least five times more than has been found in alternatives such as oatmeal.”

Still there are a few points from these latest findings that are definitely worth repeating. As the magazine also notes, “White rice grown in Arkansas, Louisiana, Missouri and Texas, which accounts for 76 percent of domestic rice, generally had higher levels of total arsenic and inorganic arsenic in our tests than rice samples from elsewhere.”

What does this mean?

Well, first, “total arsenic” refers to the fact that the tests look at two forms, or species, of the poison – organic and inorganic. Organic, of course, refers to an arsenic compound that includes the element carbon. Inorganic arsenic – as an example, the very poisonous compound arsenic trioxide (As2O3) is notably carbon free. And this matters because, as it turns out, the human body does a very reasonable job of metabolizing organic arsenic. In other words, it’s not nearly as risky to us as arsenic in its inorganic forms. As I wrote in a post titled, “Is Arsenic the Worst Chemical in the World?”, inorganic arsenic is basic bad news.

Second, why is rice from the American south popping here? One of the leading theories is that in these states, rice is now growing in fields that used to be home to cotton. For a large part of the 20th century, the primary pesticides used to beat back insects like the boll weevil were lead arsenate compounds, which have left a long-lasting residue in southern soils. There’s another theory – which the magazine Mother Jones has been arguing – that this is related to runoff from nearby chicken farms, thanks to the use of arsenic additives in chicken feed. (Use of these organic arsenic additives has been temporarily suspended due to the finding that they may convert to inorganic arsenic.)

Third, although Southern states produce primarily white rice, recent testing found that arsenic levels overall tend to be higher in brown rice species. This is because as white rice is processed, much of the rice hull is removed and that tends to be a place where the mineral is concentrated. The Dartmouth College toxic metals program offers a very helpful FAQ regarding its own findings on arsenic contamination of brown rice products.

Finally - and this is where the FDA has left all of us hanging – do the levels of inorganic arsenic found in rice pose an actual health threat? So far the agency and, not surprisingly, the USA Rice Federation,  insist not – that these are only trace amounts in a product generally considered a healthy food. And that’s a valid point although it’s unclear what the agency, at least, bases those assurances on as, so far, the only government safety standard comes from the  U.S. Environmental Protection Agency and is aimed at well water.

Drinking water standards aren’t a reliable measure for food safety – we just don’t consume food and water in the same way. So while, the EPA drinking water standard is 10 ppb in a liter of water and while the rice readings are higher than that – roughly between 20 and 400 ppb total arsenic load per serving - they can’t be measured against each other in a meaningful way. Yes, the EPA standard tells us that we should be wary of low levels of arsenic. But intake of water – which tends to be a steady, all-day consumption – is very different from the on-and-off, usually varied way we consume food.

Of course, this also suggests that we should avoid a rice-rich diet and that some groups who more frequently consume rice – Asians, Latinos, those on a gluten-free diet – may be at more risk. And it’s on this note, I think, that our government is letting us down on the consumer protection front. The general assurances and advice that we eat a varied diet which seems to the current FDA approach is not really a substitute for the very specific answers needed.

Here’s commissioner Margaret Hamberg in an AP story today: “Our advice right now is that consumers should continue to eat a balanced diet that includes a wide variety of grains – not only for good nutrition but also to minimize any potential consequences from consuming any one particular food,” And this is what I call a statement on “one particular food”  that raises questions rather than answers them.

As I said, Consumer Reports is largely doing these studies (it focused last year on arsenic in fruit juice) to pressure the FDA into setting a reasonable standard on arsenic in the diet. That end of the year FDA report I mentioned was supposed to be out this spring – I’ve asked about it so many times that the FDA press office  has quit answering my e-mails. So let’s hope this tactic actually works. No one – not rice producers, not consumers, – is served by an agency that continues to add confusion rather than clarity to a question of public safety.