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.

Testing anxiety relieving effects of crystals

Came across this neat study from another board:

Placebo effects in alternative medical treatments for anxiety: false hope or healing potential?

The setup:

The randomized controlled study ... included 138 nonclinical adults: 70 crystal believers and 68 nonbelievers. Within each belief group, participants received rose quartz or a visually similar glass stone, then followed a 14-day routine. Anxiety was measured before and afterward ...

The findings:

anxiety scores declined among believers, whether they received rose quartz or the glass stone; nonbelievers showed no reliable improvement. Crystal users did not improve more than placebo users ... Prior beliefs strongly predicted perceived efficacy and symptom change; pre-study expectations predicted 87.7% of post-study belief ratings.

(Above from the credo summary)

So not surprisingly, crystals don't inherently reduce anxiety.

Eggs seem to slow cognitive decline

Saw this post and wanted to share the evidence here too.

Apparently the evidence is quite clear that eating eggs are associated with slower cognitive decline -- e.g. as suggested by this meta-analysis.

The paper says the max benefits (reduction in risk of cognitive decline by 9%) occurs for those who eat ~50g eggs a day (roughly one egg).

This is good to hear, since I eat a lot of eggs -- like once a day. Sometimes more, but the findings suggest just one is optimal.

Microplastics in drinks -- hot tea the worst!

Some researchers analysed various drinks (in the UK) to see which had the highest microplastic levels:

Synthetic microplastics in hot and cold beverages from the UK market: Comprehensive assessment of human exposure via total beverage intake

The worst culprit? Hot tea.

Why? Based on the factors mentioned in the paper, my guess is it's a combination of:

• Heat. Hot drinks increase microplastic transfer (from container etc) into the drink.

• Teabags. Eventhough teabags are cellulose base, they still have plastics in them. And teabags are soaked a long time in the liquid.

• Material of cup. Even paper cups are lined with plastic.

• Plastic lid. Plastic from lids leak a lot into the drinks.

To say, it's not clear if this level of microplastics are actually bad for us.

But if you're concerned, avoid teabags, and hot drinks in plastic-containing cups.

Indoor plants improve air quality?

Well, sounds like the answer is, "not really in any meaningful way" according to this study at least:

Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies

From what I can gather, the study says: yes plants improve air quality, but you're better off just opening a window or using some other ventilation system.

If you can't open the windows for some reason or just like having plants, then indoor plants will help. But you'd need a lot of plants.

The study estimates you'd need:

10–1000 plants/m2 of a building’s floor space for the combined VOC-removing ability by potted plants to achieve the same removal rate that outdoor-to-indoor air exchange already provides in typical buildings

So even at the lowest end, you'd need 10 plants per m2! Not impossible, but it's a lot (even for wall mounted plants).

But hey, you could always have plants and open the window.

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.