Arsenic in Brown and White Rice

I recently added more rice into my diet and wanted to understand the nutritional value of switching from white to brown rice. Then I recalled hearing about the potential risk of more arsenic so I dug into the research.

This 2016 risk assessment from the FDA provided baseline numbers of the amount of arsenic in rice and rice products as well as a quantitative estimate of lung and bladder cancer risk from long-term exposure of these products.

We found that average concentrations of inorganic arsenic – the more toxic form of arsenic – were as follows:

• 92 parts per billion (ppb) in white rice

• 154 ppb in brown rice

• 104 ppb in infants’ dry white-rice cereal

• 119 ppb in infants’ dry brown-rice cereal

The primary culprit of damage is inorganic arsenic in foods, which I learned in not a traditional heavy metal but a "toxic metalloid". The good news is this means inorganic arsenic doesn't bioaccumulate the same way other heavy metals do. The risk however is still continuous exposure over a long period of time which can damage DNA, the skin, and the vascular system.

Dr. Michael Greger also provides a good summary and insights in his video

Which Rice Has Less Arsenic: Black, Brown, Red, White or Wild?Evaluating differences in rice, we can observe:

• brown rice contains more arsenic than white rice

• long grain contains more than shorter grains, though this may be due more to where these grains are grown

• arsenic accumulates in the rice bran, which is why brown rice contain so much more arsenic

• many of the varieties of colored rice were worse than white rice for the reason above

• children under 6 should almost definitely avoid rice AND rice products, with regulations in the EU now adding more conservative limits on the amount of acceptable arsenic in rice products for infants

One bit of good news is brown rice MAY make the arsenic less bio-available as shown in this population study. As Dr. Greger says:

So, if you test the urine of thousands of Americans who don’t eat rice at all, they’re still peeing out about eight micrograms of toxic, carcinogenic arsenic a day. It’s in the air; it’s in the water; there’s a little bit in nearly all foods. But, eat just one food—a cup or more of white rice a day—and your exposure shoots up 65%.

Okay. But, what about those who eat a cup or more a day of brown rice, which technically contains even more arsenic? Your exposure shoots up the same 65%. No difference between the urine arsenic levels of white rice-eaters compared to brown rice-eaters. Now, this was not an interventional study, where they feed people the same amount of rice to see what happened, which would have been ideal. This was a population study. So, maybe the reason the levels are the same is that white rice-eaters eat more rice than brown rice-eaters. So, that’s why they ended up with the same levels? We don’t know, but it should help to put the minds of brown rice-eaters at rest.

So what is the risk? This analysis from the EPA used a Bayesian approach to estimate the dose response of inorganic arsenic exposure from water. It found a linear relationship of more arsenic exposure with bladder and lung cancer. If we extrapolate the EPA's 2025 upper-bound estimate: one daily cup of brown rice for life adds up to 0.42 percentage points of bladder or lung cancer risk (+5.5% relative to a 7.6% baseline); white adds 0.25 (+3%). At three cups: 1.45 (+19%) for brown and 0.8 (+10%) for white.

A more direct causal study would need to prove out this relationship, but this definitely took me aback. For rice staple cultures, three cups of rice daily is pretty normal. These upper bound figures begin to look similar to increased risk of cancer from a daily beer or alcoholic drink.

Unfortunately rinsing rice does little to remove arsenic, especially in brown rice. But researchers did find a parboil method could dramatically reduce the amount of arsenic, removing 54% & 73% iAs from brown & white rice.

My takeaway? We are exposed to arsenic across a number of ways. The increased cancer risks are linear from exposure, which means rice is only one factor, meaning arsenic exposure is a real concern due to the variety of vectors. If I was a country with a population of rice eaters, I would set significantly more regulations to reduce the health impacts. Individually, it doesn't seem worth eating rice regularly, especially brown rice.