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. This is a specific method that requires a lot water that is then tossed out but it does retain a lot of the same nutrients.

My takeaway? We are exposed to arsenic across a number of ways; through our air, water, and food. The increased cancer risks are linear from continued exposure, which means the amount of arsenic consumption scales with risk. If I was a regulatory body in a country where rice is a staple food, I would set significantly stricter regulations to evaluate and limit the amounts in rice and rice products.

Personally, it doesn't seem worth eating rice regularly, especially brown rice. I'll probably try to have less than 3 to 4 servings a week and mix in other grains. I'd be especially careful with infants and rice products that may concentrate the arsenic levels.

Health Impacts of Haze from Indonesia Pt. 1

The haze from the Indonesian fires continues its hazardous pass through Malaysia and Singapore, causing alarm and frustration from impacted residents. Walking around Singapore has been a crazy experience as the visible haze feels dystopian compared to Singapore's usual hyper cleanliness. I wanted to deep dive into the known health impacts and what exactly to expect from exposure in this series.

PSI/API Index and PM2.5

Both Singapore and Malaysia use a pollutant index to warn citizens on the risks of air pollution. Singapore's Pollutant Standards Index (PSI) and Malaysia's Air Pollutant Index (API) both calculate a number of air pollutants and translate the impacts to a 0 to 500+ scale. Both denote unhealthy levels starting at 101, very unhealthy above 200, and hazardous above 300. Malaysia declares a Haze Emergency Declaration at 500. Singapore peaked this year at 164 while some regions in Malaysia saw numbers as high as 476 to 520 such as Serian, Sarawak.

While the two systems have slightly different ways of calculating the index, both measure PM2.5 among others air pollutants. PM2.5 calculates the amount of fine atmospheric particulate matter at or below 2.5 micrometers in the air. This is the most relevant group of pollutants to track as it measures the chemicals related to the haze stemming from Indonesia's smouldering peatland fires. PM10 similarly measures particulate matter, but larger at or below 10 micrometers. PM2.5 is more toxic and harmful due to its smaller size, making them more likely to be absorbed in the bloodstream and more chemically active due to the greater surface area.

This 2017 study found the chemical makeup from haze is dominantly Organic Carbon (OC) with Polycyclic Aromatic Hydrocarbons (PAHs) and toxic heavy metals like Cadmium, Nickel, Lead, and Chromium. The latter two categories make up a much smaller portion of the haze and while repeated exposure is not good, it is less of a concern than OC which dominates the mix.

What may be more alarming is this haze is categorized as aged smoke vs raw smoke, chemically altered by UV exposure from the days the smoke took to travel to the impacted areas. As this paper examines this could lead the chemicals in the haze to cause more oxidative stress on the system, though not all studies align to this conclusion.

Known Health Impacts - Respiratory and Cardiovascular

I will deep dive into this a bit more in a subsequent post, but the tldr is there are limited long-term health studies that can give us good evidence on repeated exposure and cancers or cardiovascular disease.

What is clear are the short term impacts. Haze exposure even in the moderate zone can lead to respiratory infections and illnesses. In Malaysia, where the haze is more severe, higher unhealthy zones can lead to respiratory fatalities. This study in the Klang Valley found that haze days were associated with a 19% rise in natural-cause respiratory mortality overall, and higher among specific groups: roughly 30% for children under 14 and about 30% for men on the day of exposure. Effects persisted a day or two after.

Singapore is not safe from haze related fatalities though. While haze effects are less and of shorter duration, moderate to unhealthy levels can still lead to greater cardiovascular issues like heart attack and stroke. That's why Singapore warns citizens to avoid rigorous exercise during unhealthy haze periods, especially if you have underlying pre-existing issues.

X-posting my KCup microplastics research here

The "carnivore diet" may promote weight loss, but risks nutrient deficiencies and high cholesterol.

We should probably parboil rice, to remove harmful heavy metals

Building on a prior post that highlights harmful arsenic levels in rice.

Found this paper that says parboiling rice: "removed 77.9% of toxic metals and 68.4% of essential metals."

The cons are "essential metals" are removed as well, but on balance it's probably safer.

I'm not sure the exact method the paper used to parboil, but here's a recipe!How to parboil rice

Hot drinks cause cancer

Saw this really interesting article in The Guardian, about a new study linking hot drinks with esophagus cancer.

Apparently this link (between hot drinks and cancer) had already been suspected, as this 2016 WHO note highlights.

Anyway, this is the latest 2026 study that the Guardian article spotlights.

Does flying increase cancer risk?

Going on a tangent from another Board. We were talking about "space weather" and landed on the question of "flying and radiation".

Found this literature review found that:

aircrew have higher rates of certain cancers, such as melanoma, non-melanoma skin cancer, and breast cancer in female flight attendants, compared to the general population. However, the evidence does not clearly prove that cosmic ionizing radiation alone causes these cancers, because other factors—like disrupted sleep patterns, lifestyle, and exposure to chemicals—also affect risk.

(Quoting the Credo summary)

To me, it sounds plausible. Flight attendants, pilots, and frequent flyers beware!

I should probably drink more coffee

Think coffee is a bad habit? Research actually suggests otherwise. This umbrella review of 218 meta-analyses concludes that 3-4 cups a day is associated with lower risk for heart disease and all-cause mortality. Check out the source to read more!

Plant-based diet - is it fine?

I'm an occasional vegetarian - for health, and environmental and ethical reasons. I think most would already agree that one can have a complete diet, without meat. Nonetheles, I found this paper useful.

It's a narrative review of evidence. A few helpful takeaways (gleaned from the Credo summary):

• A plant-based diet has health benefits, and is better environmentally.

• A plant-based diet can be complete, but there are some potential drawbacks. E.g. it's harder for the body to absorb certain nutrients from plant sources.

• And so, if you're a vegetarian or vegan, you do have to put in some thought, to ensure your diet is complete. (Though the same could be said of any diet!)

Do knee exoskeletons help people with knee joint problems? Or does it just help people move faster (which wouldn't help joints, and may even worsen joint problems!)