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.

Claim: AI is “Much Better Informed Than Any Doctor in the Country”

Verdict: False and misleading

“You may have a medical record that is a thousand pages long. You have six minutes with a doctor today. He is not gonna be able to review it, but the AI can and it can distill it. It can give you a second opinion that is much better informed than any doctor in the country.”

– RFK Jr.

VP Vance speaks at MAHA Summit with HHS Sec. Kennedy

Speaking at the MAHA Summit in Washington, last week RFK Jr. claimed that AI is “much better informed than any doctor in the country.” While RFK Jr. did mention some undeniable advantages – quickly reading long medical histories, for instance – how does the overall claim stack up?

What Do Doctors Think?

Major medical organisations, including the American Medical Association, pushed back RFK Jr.’s statement, stressing the value of physicians’ years of training and experience. The statement emphasises the benefit of using the technology responsibly, as a tool to help doctors, guided by the “humanity of clinical practice.”

What Does the Evidence Say?

There are some studies showing a benefit of AI systems over human doctors, including one oft-cited meta-analysis result on empathy. This study typifies an issue with much of the research in the area. Of 15 studies included in the study, 13 showed higher empathy ratings for AI, compared to human doctors. However, the interactions studied were only through text. This severely limits applicability to real-world situations, where most medical evaluations are face-to-face.

Another meta-analysis compared diagnostic capabilities of AI with human doctors, based on 83 studies. The results showed that AI performed roughly as well as physicians overall, or non-expert physicians. However, it was worse than expert physicians.

A controlled study touched on the “second opinion” aspect of RFK Jr.’s claim, looking at whether LLMs can help members of the public choose accurate diagnoses and treatments. Generally, this study found that the LLM did better alone than it did assisting a human. When assisting non-experts – who may not communicate clearly – it does no better than participants findings their own online sources. 

The Final Verdict

LLMs may play many valid roles in healthcare both now and in the future, but they certainly are not better informed than any doctor in the US. Nor is it a particularly useful option for non-experts seeking medical advice.

Getting an Infection during the period of "Morning Sickness", poses Higher Risks of Congenital Heart Disease?

One of the most unexpected parts of the conversation was Jimmy Carr’s discussion of morning sickness. 🫣

It sent me down a rabbit hole because there is an interesting evolutionary theory behind why morning sickness tends to occur during this particular period of pregnancy.

The Maternal and Embryo Protection Hypothesis, an evolutionary theory about morning sickness, where:

1. Organogenesis: Morning sickness typically peaks between weeks 6 and 14 of pregnancy. When the embryo’s major organs (including the heart, brain, and limbs) are forming and are most vulnerable to damage from toxins or pathogens.

2. The "Shield" Effect: Because pregnancy naturally suppresses a woman's immune system (to prevent her body from rejecting the fetus), she becomes more sensitive to foodborne pathogens. Evolutionary biologists believe nausea and vomiting evolved to force mothers to avoid or expel potentially toxic or bacteria-laden foods during this window.

3. The Shift: Once the organs are fully formed (around the second trimester) and the baby enters the growth-only phase, morning sickness usually stops for most women.

EVIDENCE for Infection & Congenital Heart Disease ﮩ٨ـﮩﮩ٨ـ🫀ﮩ٨ـﮩﮩ٨ـ

A link from two meta-analyses, between First Trimester Maternal Infections and Fetal Congenital Heart Defects has been found, especially in regards to rubella virus, coxsackievirus, respiratory infections, and influenza.

⚠️ Though there is an important distinction here to make:

This does NOT mean that morning sickness itself is linked to congenital heart defects.

But the same period of pregnancy in which morning sickness may have evolved to reduce exposure to potentially harmful substances is also a period when the developing embryo is particularly vulnerable to certain environmental insults, including infections.

Microplastics from Keurig K-cups or Capsule machines

I know that a leading factor for microplastic leaching is heat, especially hot water, interacting with plastic. So I dug into what we know about plastic K-cups and microplastics. Effectively there is no research on the topic that I could turn up, which is pretty surprising. The closest study I could find was this 2025 study on beverage products from the UK. This study was linked to by a number of articles like this from microplastics app or Do Coffee Pods Release Microplastics? What the Research Actually Says that cited ~43 microplastic particles (MP) per liter. These article findings fed into AI results like Claude and Gemini, but I found the takeaways provided were incorrect.

The main finding from the study:

Hot coffee prepared in 3 domestic machines (Table SI-3) showed considerable variation in MP levels, with the oldest model (8 years old with water tank made of PET) releasing higher MPs concentrations (17 ± 2 MPs per cup) compared to newer machines (1 and 0.5 years old with ABS water tank releasing 10 ± 2 MPs per cup and 7 ± 2 MPs per cup, respectively). This is consistent with existing research indicating that material degradation over time leads to increased MP shedding (Luo et al., 2022). The higher MP concentrations in coffee prepared using the older coffee machine may be due to wear and tear of the plastic water tank and other materials, a trend also observed in other products like water bottles (Schymanski et al., 2018).

This ended up being one of the largest amounts of microplastics found compared to the other beverages except for Hot Tea. The other comparisons being iced coffee, iced tea, soft drinks, energy drinks, and juices. The problem with this study being repeated for Kcups is a few fold:

• The 43 MP figure was for the Hot Coffee category overall which included other sources like hot coffee from large chains served in takeaway cups, hot coffee made in sachets served in glass cups, and coffee made from capsules.

• The capsules weren't specifically specified as Kcup, this being a UK study, these are more likely nespresso pods. I'll email the paper author to see if I can get the exact types as its not listed in the study and attach what I hear in the comments

• When comparing the capsule results to other Hot Coffee sources, the capsules didn't perform worse overall when you scale the figures above to MP/liter. The authors suggested differences came from degradation of the water tank rather than the capsules themselves. But because we don't know if these were Kcups, we can't be sure this neutral outcome means the pods are the same.

• Some of the articles I listed said the results showed Polypropylene (PP) in the microplastic results which is the primary material for Kcups. However, the authors said this is probably from leaching from the takeaway cup lids in the Hot Coffee category, which is a repeated result from other studies.

• This study only tested for MP sizes greater than 10μm and excludes cellulose, organic microplastic. This makes these results less comparable to prior studies that may have found more microplastics.

TLDR; There's no studies I've found showing Kcup generated microplastics, the amount generated is unknown. Further articles claiming results are likely incorrect or misleading. The biological impacts of microplastics remain debated with unclear risk thresholds for consumption. But I'll leave what the UK study says about impacts below.

Microplastic (MP) ingestion raises health concerns due to their potential to cross biological barriers and accumulate in tissues. Studies suggest that MPs can physically damage gut cells, alter the gut microbiota, and trigger inflammatory responses, which may lead to immune dysregulation and metabolic disturbances (Cox et al., 2019; Deng et al., 2017). MPs can also act as carriers for hazardous chemicals, including heavy metals and endocrine-disrupting compounds such as bisphenol-A, which may leach into the body upon ingestion and disrupt hormonal functions, affecting processes like reproduction and metabolism (Gallo et al., 2020; Hahladakis et al., 2018). The degree of impact is influenced by MP size, shape, and polymer type, with evidence from studies conducted on polystyrene, polyethylene, and polypropylene MPs suggesting that smaller particles and fragment-shaped MPs are more prone to tissue penetration and chemical release upon ingestion (Banaei et al., 2023). The cumulative effect of MPs and associated chemicals in human tissues highlights the importance of establishing standards to limit MP exposure in food and beverages, given the potential for long-term health risks (Schwabl et al., 2019).

Season 17, Episode 58: Why Does String Theory Have So Many Dimensions?

Hey StarTalkians! Episode 58 of season 17 was another Cosmic Queries edition, with guest and string theorist Professor Lara Andersson, Neil and Jordan. Many of the questions concerned the – seemingly excessive – number of dimensions in string theory. This one really gets to the heart of the matter:

Quantum Anomalies with Lara Anderson - StarTalk Radio

(from 30:30)

Professor Andersson explains it very well in layman’s terms. Truthfully, it’s difficult to convey without a lot of mathematics, but here, I’ll try to address the core issue in a little more detail.

Why Does String Theory Have Extra Dimensions?

String theory is an attempt to unify all four fundamental forces – thus creating a “theory of everything.” When you’re doing this, it’s probably wise to not make any assumptions about the number of dimensions there are. After all, it’s possible that we aren’t aware of all of them.

So you can develop the ideas of string theory in a “dimension agnostic” way, just putting d in place of anything dependent on the number of dimensions.

Working this way, you eventually run into an issue. Any such theory would have to be invariant under a transformation called a Weyl transformation, but this can be broken by quantum mechanical effects. In order to form a consistent theory with these “Weyl anomalies,” they have to cancel out.

That’s when d comes back. It was found that with d = 26 (in the case of bosonic – force-related – string theory) or d = 10 (in the case of fermionic – matter related – superstring theory), you can ensure the cancellation. In this way, the dimensions kind of just come out of the theory, if it is to work at all.

How Many Extra Dimensions?

It depends on the specific theory. Five different variants of string theory quickly developed, which physicists found connections between by rescaling so-called “coupling constants” which appear in each. In 1995, Ed Witten realized that these five theories were just special cases of “M theory” – the mother of all string theories.

In M theory, there are 11 dimensions. This is therefore the best answer to how many dimensions are present in string theory.

So... Where Are They?  

As explained on the podcast, the complete lack of these dimensions in our experience is explained by “compactification.” This is questionable, from a philosophical perspective, but does fix the problem of “where are the extra dimensions?”.

Childcare : what the science says

The article reviews research on childcare, arguing that its effects depend on a child’s age, hours in care, and family environment. It highlights research associating long hours of daycare at younger ages with later behavioral difficulties and poorer social skills, while noting differences by socioeconomic status.

This article seems to suggest that starting daycare later (after 2.5) is better. Also potentially more pronounced benefits of daycare for lower socio-economic status families/households. Would love to understand whether this evidence suggested in this article is reflective of the larger literature and people's thoughts in general.

Its a meeting of 2 comedy greats: Jimmy Carr and Trevor Noah. 🎭

Just listened to Trevor Noah’s conversation with Jimmy Carr. It was such a riveting conversation traversing AI, comedy, psychology, mortality, relationships, economics, technology, community, ideology and more.

What Now? With Trevor Noah - Jimmy Carr: Convenience is Stealing Your Life

Jimmy Carr: Convenience is Stealing Your Life

Both Trevor and Jimmy are incredibly well-read, and I’ve always found their takes, be it controversial or unconventional, pretty interesting, and they may be right or they might just be wrong. This long-form conversation between them was quite fascinating indeed, and here are some I'd thought I'd share:

Jimmy starts off introducing the concept of Mankind's Three Humiliations 📜

1. Copernicus: Earth isn't the centre of the universe. > "We are not the centre of the universe."

2. Darwin: Humans evolved from animals, and are biologically in the category of animals > "We are just the same as other animals."

3. Freud: Our conscious mind isn't fully in control of ourselves. > "Our subconscious and actions aren't really under our control"

He then shares his take of AI being the the upcoming Fourth Humiliation, where we, as humans, can no longer claim to be the smartest being in the room.

He later mentions in regards to AI dependence - “Don't outsource any skill you're not comfortable losing” .🚨

I think its truly a thought worth pondering on. 💡 Convenience has a hidden cost: when we can outsource it, the skill itself can become unnecessary. And once a skill becomes unnecessary, there may be little incentive to maintain it. Then, one day, we just lose it.

They also had conversations on economics, tax, society, which linked to an interesting circle of thought:

Asking how would you define a revolution? And are we in one now?

In the podcast, Jimmy defines a revolution as the replacement of elites.

• And the first signs of that is the masses no longer trusting institutions,

• Which lead to conspiracy theories

He also mentions that:

We can live without truth pretty easily. But we can't live without trust. But we need truth to make trust.

👀 But where do we go from there? 🧐 Which ones would you agree with?

Definitely one of those conversations that made me pause and rethink many things. 💭

Season 17, Episode 60: Next Stop, Alpha Centauri! How Light Sails Could Allow Interstellar Travel

Hey StarTalkians! Episode 60 of season 17 was a basic, Neil-and-Chuck Cosmic Queries edition, with topics ranging from fractals to the boundaries between universes. One listener asked about how we could actually make it to Alpha Centauri:

Cosmic Queries – Light Sails & Quantum Scales - StarTalk Radio

(from 17:45)

Neil brings up light sails, which is one of the most promising approaches we’ve come up with so far, and one specific project that intended to use them. Here’s how it would work.

The Physics of Light Sails

The core concept underpinning light sails is that light has momentum. The momentum (p) of a photon can be simply calculated based on its energy divided by the speed of light (p = E / c), or as Planck’s constant divided by the wavelength (p = h / λ). This is what pushes the tails of comets away from the sun, for example.

A 1971 NASA paper goes into detail about the force you’d expect from solar radiation acting on a flat surface. While there’s a lot more detail, basically the momentum comes from photons which reflect off the surface, and is strongest if the light hits perpendicular to the surface (dropping off with the square of cosine of the angle).

The Challenges of Making a Working Light Sail

Many of the key challenges were outlined a paper by Philip Lubin. In particular – and as you might guess – the actual amount of momentum from light is not huge. This means that you need two things right off the bat: as big a sail as possible, and as lightweight a craft as possible.

Lubin proposes a “spacecraft on a wafer,” and suggests boosting the power to the sail by using lasers rather than sunlight, but both aspects of this are challenging. As discussed on the podcast, he calculates that this could achieve a quarter of the speed of light in a matter of minutes.

Other serious issues include the problem of decelerating when the craft arrives at its destination.

The Failure of Breakthrough Starshot

The project Neil mentioned, though, ultimately did not achieve these goals. As detailed by Scientific American, the project intended to use a fleet of tiny spacecraft powered by laser-light to make a relatively quick 20-year journey to Alpha Centauri. The article has all the details, but the short version is that the billionaire funder seemed to lose interest.

AI doesn't help us self diagnose -- yet!

Saw this paper on another board. From what I gather, the paper finds that ai chatbots don't help patients make accurate diagnoses or treatment solutions (vs their normal / non-ai information sources).

With model assistance, participants identified relevant conditions in fewer than 34.5% of cases, doing worse than controls; care choices were correct in fewer than 44.2%, with no significant improvement over controls. [Credo tldr]

I don't think this means "ai isn't helpful at all" e.g. doctors obviously use it as an aid. And I imagine using a combination of chatbots and other info gathering methods can increase efficiency (if not accuracy).

But the evidence (from the paper) is -- using ai can't replace a good ol' doctor's visit -- just yet!

Do house plants clean your air?

Verdict: yes, though you'd need a lot (but an achievable amount) of plants.

I saw this hopeful video on 9gag, of researchers studying how well house plants filter out petrol vapour.

Interestingly, most the cleaning is done around the roots of the plants – not the leaves!

I wanted to learn more, and found this Guardian article, which (I think) interviews the same researchers, and the actual research paper.

The researchers "tested commercial green walls measuring 725 by 725 mm, each holding four plants, in sealed 216-liter chambers" and found the "planted walls reduced total VOCs by 42.47% over eight hours" (credo tldr).

Pretty impressive! A caveat of course is the researchers used a lot of plant (~72cm^2 square) for the given volume (~60cm^3 cube). So to have the same effect in a room, you'd need a lot of house plants!

In the Guardian article, researchers recommend using wall mounted plants, to help squish more plants in. Intuitively (looking at the math above), if you cover your whole wall with plants, you'd probably get a noticeable (maybe not ~40%) filtering effect!