Context of questionable relevance
It was exactly one year ago today that I first uttered the phrase, “paleo is a logical framework applied to modern humans, not a historical reenactment.” That idea seemed pretty straightforward to me, and it was well-received to the point of being quoted in a real life book (you should buy it, but not just for that reason). And sure, Robb and Andy misattributed it to somebody else in a podcast in the distant past, but I already forgave them for that. So here I am, still beating the drum of the paleo framework despite internal and external attempts to refute it, supersede it, minimize it, water it down, or exact (Exacto?) its death by a thousand cuts. Well folks, it still works. But really, this should come as no surprise…
“This guy is irritatingly correct, time and time again, even when he has limited evidence.” – E. O. Wilson on Charles Darwin
Maybe the blogs I read and the people I talk and listen to aren’t representative of the paleo community, and maybe I’m just imagining things, but the paleo zeitgeist has seemed rather buddy buddy with the white devils of late. Of course, I refer here to rice and the [non-sweet] potato. Support seems to come along the lines of, “potatoes/rice are starches. starch is good for you. therefore potatoes/rice are good for you”; “sure, raw potatoes/rice might have saponins or glycoalkaloids or lectins or phytates, but those compounds aren’t always bad, and they’re destroyed by cooking anyway”‘; “sure, rice is a grain, but what about population X and population Y who eat rice and don’t drop dead from these supposedly ‘toxic’ substances”; and commonly included with one of the first two, “I love potatoes/rice” or “potatoes/rice are good”. Even setting aside the restless and ubiquitous specter of The Self-Justification Diet™, there are significant problems with these arguments. I’m not going to deconstruct them at length here, but suffice it to say that they’re all logical fallacies of one stripe or another.
Even if I convince you that the individual arguments are flawed, the endeavor still wouldn’t tell you the paleo framework was correct or useful. So rather than that, I’ll introduce recent research that those looking at things from a microscopic perspective have been missing all along. Not surprisingly, the research demonstrates proximate effects that were effectively predictable with the paleo framework.
The two relevant components of the basic paleo framework are:
- Humans are probabilistically less likely to be adapted to foods introduced more recently into the human diet. This applies to the potato, which is indigenous to South America, and was not available to humans in Africa, Asia, Europe, Australia, or myriad island populations, until the Spanish brought them back to Europe in the late 16th century. All of those populations have been consuming potatoes for only 300-400 (I’m being generous with that second number) years.
- Because they can’t run away or fight back like animals, many plants have evolved chemical defense mechanisms. Because the ultimate goal of evolution is reproduction, and not survival, we can predict that chemical defense mechanisms are likely to be concentrated in the reproductive parts of plants. In many cases, this is the seed. Rice is a seed of a plant, and is therefore probabilistically likely to have chemical defense mechanisms.
The Meat
Why miRNAs are important
As a wise man once said, “Reprogram your genes for effortless weight loss, vibrant health, and boundless energy.” Without delving into genetics, let’s just agree that gene expression is a proven concept. Roughly, your genome consists of a lot of conditional statements that result in the production of proteins which have wildly varied effects. Our genetic code is shaped by the environment in which we evolved. By matching the inputs of our environment to the conditions ‘expected’ by our genes, we may optimize the expression of our genes. Please know that this is a vast oversimplification, but is useful for thinking about our individual health and well-being.
For now, let’s just say that RNA relates to gene expression, and miRNA is short for “micro RNA”, which is just a subset of RNA.
“…the rapidly developing new field of miRNA, which plays an important role in modulating virtually all biological processes (e.g., cell proliferation, development, differentiation, adhesion, migration, interaction, and apoptosis) through its fine tuning of gene regulation.” (Sun, et al. 2010)
“miRNAs have been widely shown to modulate various critical biological processes, including differentiation, apoptosis, proliferation, the immune response, and the maintenance of cell and tissue identity. Dysregulation of miRNAs has been linked to cancer and other diseases.” (Zhang, et al. 2011)
The study
This study was recently published in the journal Nature (September 2011). It contains novel findings that miRNA from plants remains stable after cooking and digestion by humans. This plant miRNA has been found in significant quantities in human blood and tissue. Further, it has been demonstrated to interfere with human miRNA by mimicking it and binding to the receptors, then influencing gene expression in ways different from the miRNA produced naturally by our bodies.
Unless otherwise noted, all following quotations refer to Zhang, et al. 2011. Emphasis has been added by me.
Abstract
Our previous studies have demonstrated that stable microRNAs (miRNAs) in mammalian serum and plasma are actively secreted from tissues and cells and can serve as a novel class of biomarkers for diseases, and act as signaling molecules in intercellular communication. Here, we report the surprising finding that exogenous plant miRNAs are present in the sera and tissues of various animals and that these exogenous plant miRNAs are primarily acquired orally, through food intake. MIR168a is abundant in rice and is one of the most highly enriched exogenous plant miRNAs in the sera of Chinese subjects. Functional studies in vitro and in vivo demonstrated that MIR168a could bind to the human/mouse low-density lipoprotein receptor adapter protein 1 (LDLRAP1) mRNA, inhibit LDLRAP1 expression in liver, and consequently decrease LDL removal from mouse plasma. These findings demonstrate that exogenous plant miRNAs in food can regulate the expression of target genes in mammals.
This wasn’t a gender thing:
” Upon investigation of the global miRNA expression profile in human serum, we found that exogenous plant miRNAs were consistently present in the serum of healthy… men and women.”
This effect was not tiny. Significant amounts of plant miRNA were found in humans:
“the tested plant miRNAs were clearly present in sera from humans, mice, and calves… when compared to the endogenous mammalian miRNAs known to be stably present in animal serum, these plant miRNAs were relatively lower, but in a similar concentration range.”
The following quote demonstrates that not all plant miRNA is digested. Some is digested more than others, and some is not digested at all:
“the levels of MIR168a and MIR156a, the two plant miRNAs with the highest levels in the sera of [human] subjects, and MIR166a, a plant miRNA with modest level, were assessed… MIR161, whose expression level was undetectable, served as a negative control.”
The three plant miRNAs found were present in different levels in different plants. Note that cooking influenced the miRNA content differently by specific miRNA and by plant. While levels in rice decreased dramatically with cooking, levels in wheat increased with cooking. After cooking, all MIR156a levels remained significantly high.
It is worth noting that these three plant miRNAs, MIR168a, MIR156a, and MIR166a, were detected in [rice and] other foods, including Chinese cabbage (Brassica rapa pekinensis), wheat (Triticum aestivum), and potato (Solanum tuberosum).
“Interestingly, plant miRNAs were stable in cooked foods.”
It is important to note the following context. Much of the study was centered around MIR168a in rice. This was not because rice or MIR168a have better or worse effects in humans, but because the effect of each miRNA across each gene locus is unknown at this time. The effects of MIR156a are unknown, so we cannot draw the same conclusions about wheat or potatoes as we can about rice. It is known that plant miRNAs have a tendency to interfere with gene expression, but that precise expression remains a question as large as the numbers of gene expressions that can be interfered with against the number or miRNAs we might ingest from all over the plant kingdom.
“most plant miRNAs can act like RNA interference… [W]e performed bioinformatic analysis to identify any sequences in the human, mouse, or rat genome with perfect or near-perfect match to MIR168a. Approximately 50 putative target genes were identified as the target genes of MIR168a”
This known mechanism is why this study focused on MIR168a and rice:
“LDL is the major cholesterol-carrying lipoprotein of human plasma and plays an essential role in the pathogenesis of atherosclerosis. Downregulation of LDLRAP1 in the liver causes decreased endocytosis of LDL by liver cells and impairs the removal of LDL from plasma… Concomitant with a significant elevation in MIR168a levels in the livers of mice after 1 day of fresh rice feeding , LDLRAP1 expression dramatically decreased in the group of fresh rice-fed mice. In these experiments… LDL levels in mouse plasma were significantly elevated on days 3 and 7 after fresh rice feeding… the level of liver LDLRAP1 was not related to the levels of plasma cholesterol or triglycerides… the elevation of fresh rice-derived MIR168a… specifically decreased liver LDLRAP1 expression and thus caused an elevated LDL level in… plasma.”
Plant miRNAs mimic endogenous mammalian miRNA, bind to their receptors, and inhibit protein expression:
“Plant miRNAs execute their function in mammalian cells… in a fashion of mammalian miRNA…the results that MIR168a was also able to target the artificially expressed LDLRAP1 protein in 293T cells (Figure 3I-3K) strongly demonstrate that plant MIR168a could bind to its binding site located in exon 4 of mammalian LDLRAP1 gene, and then inhibit LDLRAP1 protein expression.”
Why the focus on disruptive plant foods, and not animal foods?
This was one of the biggest questions I had before and after reading the study. Unless I missed it, no specific mention is made of what happens when humans or other mammals ingest mammalian miRNA. This leaves the question open as to the scope of miRNA influence we may obtain through food. Upon closer examination, I did find one point of entry into further inquiry on this question. It seems that there is a difference across the board between mammalian miRNA and plant miRNA. This does not mean that all plants are bad to eat or that all mammals are good to eat. Nor does it mean that all plants are good to eat or that all mammals are bad to eat. It’s likely still true that there is no such thing as food and that everything we might ingest simply exists on a multi-dimensional spectrum of healthful to toxic.
“Plant miRNAs are 2′-O-methyl modified on their terminal nucleotide, which renders them resistant to periodate. In contrast, mammalian miRNAs with free 2′ and 3′ hydroxyls are sensitive to periodate… Indeed, as shown in Figure 1E, most mammalian miRNAs in human serum, such as miR-423-5p, miR-320a, miR-483-5p, miR-16, and miR-221, had an unmodified 2′, 3′ hydroxyls and were therefore oxidized… In contrast, MIR156a, MIR168a, and MIR166a in human serum remained unchanged…”
Whether mammalian miRNAs found in human serum were exogenous or endogenous is not specified. If we knew that they were exogenous, and they were oxidized, we would have a significant difference in mechanism between plant and mammal miRNA. If we assume that the mammalian miRNAs mentioned are all endogenous, we can still see a significant difference, but the question remains open as to whether ingested mammalian miRNAs remain stable after ingestion, are oxidized in the digestion process, or are metabolized via another mechanism.
Still a lot of unknowns
At this point, we can’t definitively say a lot about the effects of plant miRNAs (or mammalian for that matter). Is it possible that the cooking-stable, digestion-stable MIR168a found in rice is the only plant miRNA that interferes with human gene expression? Sure. But is that probable? Nope.
Is it possible that there is an unknown benefit to gene expressions altered by miRNA? Sure. From an evolutionary standpoint, it’s possible that humans have adapted to use plant miRNAs as a cellular signaling mechanism to activate conditional clauses wherein different genes are expressed in order to optimize phenotypic adaptation to a plant-rich environment. What is the probability of this? It is not improbable that an organism would adapt to such a signaling mechanism given sufficient evolutionary pressure, genetic variance, and time. However, there are issues with this line of reasoning. First, in non-agricultural phases of human evolution, the plants would be engaged in an evolutionary arms race to continue to evolve their chemical defense mechanisms as humans adapted to them. Second, it currently appears that this effect does not exert acute deleterious effects on individual humans that would effect survival and reproduction enough to provide significantly strong selection pressure. Third, while time is less important than selection pressure in evolution, it remains true that a few hundred years is indeed very short in evolutionary time, and this period of time is not unknown to history. Had this sort of selection taken place, we wouldn’t have stories of the Irish potato famine (too few calories), we’d have stories of the Irish potato poisoning, in which thousands upon thousands would have died from eating potatoes (too many toxins).
There are many other unknowns. Perhaps you’ll share some in the comments.
Commonly questioned practices this study got right
There are often complaints that studies on mice cannot be extrapolated to humans. This can be a fair criticism, but is not likely to be used to mount a successful challenge to this study. Wherever ethically acceptable, humans were tested.
In particular, actual human blood and tissue samples were taken. These samples convincingly demonstrated the presence of plant miRNA in human blood and tissue in levels relatively equal to miRNA produced naturally by humans.
Further, these levels were compared against mice and calves. An example of the data is shown to the left. Note that the mice tended to demonstrate the lowest relative levels of miRNA. Humans represent the highest levels for the most relevant miRNA. Therefore, it is more reasonable to expect the effects measured in mice would be more pronounced in humans if we could control humans’ diets enough to conduct this experiment.
What conventional medicine should be saying about this study
It seems pretty simple: Rice elevates MIR168a in humans. Elevated MIR168a impairs the liver’s removal of LDL, or “bad cholesterol”. Increased LDL cholesterol causes atherosclerosis which leads to cardiovascular disease. Rice increases LDL cholesterol, and therefore, eating rice causes cardiovascular disease.
Now, I don’t completely buy into this narrative — particularly because there’s no mention of LDL particle size in this study. However, this article was published in Nature, one of the most prestigious journals on the planet, and there’s no uproar. If this study had concluded that eating red meat interferes with the liver in a way that raises “bad cholesterol”, would it not be the cover story everywhere?
How this study might fit with a paleo diet framework.
It’s hard to say anything definitive about this study beyond the convincing proof that rice miRNAs interfere with human gene expression. That said, we can use the paleo framework to make some predictions. We can predict that miRNAs that are evolutionarily novel are more likely to be deleterious to human health than beneficial. We can also suppose that even if the bulk of miRNAs are deleterious to humans, there may be a minority that are beneficial to most humans, and a few might be beneficial to humans with particular alleles.
The view that known individual components are not always harmful, and therefore shouldn’t be totally avoided, still leaves big gaps in our knowledge, and makes our daily decisions about what to eat susceptible to the undiscovered.
Paleo is bigger than lectins and phytates and saponins.
We’ve been presented with many past arguments about rice and potatoes being fine, but too high in carbohydrates to recommend for everyone.
The paleo framework is bigger than metabolic syndrome.
The more we learn about wheat, the more nefarious compounds we find.
Paleo is bigger than gluten free.
Although I personally think bok choy sucks based on taste, I never had a health reason for disliking it…
Paleo doesn’t know everything.
Potatoes and rice, still not paleo.
What I’m doing differently in light of this study
- Less likely to deviate from sashimi at sushi restaurants.
- Downgrading potatoes and rice from “neutral nutrient-poor waste of time” to “sneaky untrustworthy bastards”.
- Downgrading wheat from “probably a bad idea for everyone” to “all the shitty stuff about wheat plus the shitty stuff about soy”.
- Downgrading bok choy from “Hey, I’m not going to eat this, would you like it?” to “I’m not making out with you if you eat that”.
What I’m doing the same in light of this study
- Preferentially consuming animal foods.
- Scaling carbohydrate/starches daily in relation to activity levels
- Eating carrots and sweet potatoes when I want to ingest subterranean plant storage organs (because orange is sexier than white).
- Remaining skeptical of the applicability of populations isolated by geography like islands (Kitavans) and other extremes (Inuit) to humans in general.
- Aping Darwin while recognizing that Science™ provides us with limited evidence for us to use in our everyday lives, yet trying to be irritatingly correct anyway.
<sarcasm>Eat your vegetables folks, particularly if you want your gene expression impaired by the plant kingdom.</sarcasm>
Final thought: Think like a geek. Eat like a hunter. Train like a fighter. Look like a model. (Play and live like you don’t live in a zoo is always implied)
References
Sun, W., Julie Li, Y.-S., Huang, H.-D., Shyy, J. Y.-J., & Chien, S. (2010). microRNA: A Master Regulator of Cellular Processes for Bioengineering Systems. Annual review of biomedical engineering, 12, 1-27. [full-text PDF]
Zhang, L., Hou, D., Chen, X., Li, D., Zhu, L., Zhang, Y., Li, J., et al. (2011). Exogenous plant MIR168a specifically targets mammalian LDLRAP1: evidence of cross-kingdom regulation by microRNA. Cell Research, 1-20
So you don't take issue with the fact that the sweet potato is of South American origin?
I'm so tired by people spreading the word that potatoes are "dangerous" and sweet potatoes are paleo (because Cordain included them in his book?) and therefore fine to eat…
Personally, I think Cordain made a bunch of unsupportable pronouncements. A food's geographical origin is less important than demonstrable health issues caused by eating said food, IMHO
It's possible that potatoes could be a problem due to lack of intrinsic ethnographic adaptations to consuming them, but that just presents a hypothesis which should be tested.
Aren't sweet potatoes from South America, too, and most people would've gotten access to them at around the same time? I remember reading this about it: http://huntgatherlove.com/content/yam-confusion-w…
All in all before I freak out about this I'd like to see some numbers for some other seemingly innocuous vegetables.
With my current understanding, I classify sweet potatoes as something that are not paleo from a historical reenactment category, but seem fine from the paleo framework perspective. There are some significant differences between the two.
Bottom line: If they'd been listed as a plant with miRNA that ends up in human blood and tissue after digestion, then disrupts human gene expression, I'd have downgraded them as well.
I would agree that adding rice and such to the paleo diet canon is problematic, and sort of illogical. But I only see that as a problem of marketing and dogmatism.
I certainly am not deluding myself into thinking that I am eating paleo when I eat rice. I don't eat paleo all the time – obviously. If you regard the paleo diet as a tool, which I do, then you wil use the right tool for the right job. Really sick and overweight? Tool = paleo diet. Self-employed writer making little money? Tool = supplemental calories from rice.
The problem is, so many people desire to label themselves with the " I'm a paleeeo " sticker that they need to have rice, etc. included in the fold so they can eat their favorite foods without appearing like a hypocrite. The real solution is to just admit that they don't eat paleo all the time. I think Richard Nikoley has done this well, but he is facilitated by the fact that he doesn't give a shit what people think, Hah!
The original nature of this movement peaked with the notion that everybody is gluten intolerant and shouldn't eat starches, and now it's gone almost to the exact opposite end of the spectrum to where people are recommending to eat tons of starches and maybe it's just the type of wheat that is problematic.
I think the truth is probably a huge grey area occupying the relative middle area of this spectrum, with dietary pronouncements being incredibly individual in nature, and dependent on ancestry and financial constraints.
Sure, people should eat what they want and have access to. Studies like this make me want to eat potatoes and rice less.
I also think it's important for people to realize that this stuff is more complex than "do X and see if I lose weight". Altering gene expression is potentially a serious thing. If people want to experiment with throwing themselves into the buzzsaw of evolution, tinkering with things that interfere with gene expression might be a good way to do it. The mechanism of evolution isn't really about striving to test the limits, it's about avoiding selection pressure.
The study you cite raises the question: If plant miRNA appears in human blood, how did it get there?
In particular, what effect does gut-permeability have on blood levels of plant miRNA?
If gut permeability was the effect being measured, one thing we might predict would be that levels of various miRNA in the blood would be simliar to miRNA ingested. Since this was controlled for using the plant sourced MIR161, it's harder to jump to the conclusion of gut permeability.
I'm curious how if rice raises LDL so much why do the Japanese have one of the lowest heart disease rates in developed nations?
I know that the report doesn't answer that question but I think it must be asked before banishing rice to the danger zone.
Personally, having traveled extensively in Asia, I feel better and my body works better on a rice-based diet.
Gluten is, for me, a problem and I'm staying away from that.
And milk products are fine for me, too.
As you say, it's a probabilistic issue and until we have a clearer notion of the genetics and relationship of gut bacteria to digestive products we won't really know what we can and can't eat to be healthy.
Fish is mostly contaminated with mercury, red meats do cause heart disease (you'll find eastern European nations have very high incidence of heart disease and high meat / fat diet – trust me I'm in Poland right now). Wheat, rye, and barley are out. Soy affects hormones. Now, if we're to add this research to the list bok choy (what about other cabbages?) , rice, and potatoes.
All in all, what's left? I know, there is a lot. The point is, there are too many missing pieces to truly determine what makes a healthy diet.
Personally, until there are some better answers, I'm going to stick what what feels good in my body and rice is on that list.
This post just creates more diet hysteria and pushes more towards an all meat diet. I agree with Kenneth you could find a study out there that says air is bad for you, does that mean we should stop breathing? We truly need to model those people who had success in the neolithic era with food not paleolithic. Whats the point of going backwards? we are obviously evolving we can’t just go back we have to move forward with what we have. Whether or not these foods “cause” disease is highly debatable. They may “encourage” stress levels and bad response in some and may be helpful for others.
I like to take a step back and just think about what people ate 200 years ago when the word “diet” had never been created. Even my Grand mother, 96 and still going, said that when she was my age no one dieted or cut food out of their life ( such as grains, and starch). Some countries don;t even have a word for celiac disease and they eat bread every day. Others don’t have diabetes or heart disease and Eat tons of rice and potatoes.
It posts like this that are truly pointless and don’t prove anything but simply cause more debate over the same thing over and over again. All large populations lived on a starch based diet. This is the rule not the exception. If this food(starch) is so bad for us wouldn’t we have figured that out 10,000 years ago? It’s hard to believe we were that dumb. We built pyramids and studied the stars for Christ sake, you would think we would know what food is good or bad for us. Maybe a little out there but hey I said it, o well.
I can’t wait for the research surrounding the flying spaghetti monster. I know that he or she is truly the cause of all these health problems. Damn spaghetti monster we will get you one day!!!
This comment is all over the place, yet somehow manages never to stray toward a reasonable point.
It's important to recognize the difference between 'diet' the verb and 'diet' the noun. The "paleo diet" is a noun to describe what humans ate across evolutionary time, not a verb to describe what a cheerleader is going to do to attain an unhealthy low weight over the next 3 days.
"Whats the point of going backwards?"
This is a very linear and ethnocentric way to look at evolution. But mostly, it's just wrong and misleading to use this mental framework.
"Some countries don;t even have a word for celiac disease and they eat bread every day."
That's entirely a comment on their lack of scientific understanding than it is about the prevalence of celiac disease.
"If this food(starch) is so bad for us wouldn't we have figured that out 10,000 years ago?"
No.
I agree with Andrew on this.
I don't think I was saying that we could find a study on just anything that proves everything is unhealthy.
Yes, some studies are good and some bad. That doesn't mean that everything is bad and I'm not suggesting that the study Andrew wrote about was flawed, just confusing. I think it leads to more questions than answers but that's the nature of scientific progress sometimes.
What I am saying is that our understanding is, at the moment, still very incomplete. Incomplete to the point of being, in many cases, useless for determining diet choices (the noun, not the verb).
Taking gluten, as a case in point, I grew up eating wheat, rye, and barley products and wish I could now. I don't have celiac, just sensitivity.
If you want to know what my experience is, follow my link above.
The fact that nobody knew and that we're only now finding out that gluten is unhealthy for some (possibly large) percentage of the population is perfectly plausible. Celiac disease is serious enough to be genetically selected against.
Gluten sensitivity? Not so much. I would say the pressures are mild, at best, and possibly below the levels of genetic selection in neolithic environments.
As our understanding of this issue increases, we'll be better able to make smart diet choices. In the meantime, we're all just guessing.
I want to thank Andrew for doing his best to present the information that is out there without too much hype and only a little bias 😉
It's what makes me a reader even though I'm not a paleo follower. There is good information here.
Thanks Andrew.
In any human group endeavor, there are believers and there are True Believers. I guess most of our paleo brethren are those that are paleo most of the time.
I fall, I suppose, in the True Believer category because being as close to non-carb as possible saved my life or at least made the future rosier. In 2009 I had very high blood pressure, was obese, and was diagnosed as pre-diabetic. (I was 57 at the time.) After spending a small fortune for my very first prescription of blood pressure pills, I went home in a seriously blue funk. Heart pills? For me? Insulin shots for me? Goddy mighty, life suddenly sucked. After a couple of days of moping around the house I decided this situation would not be allowed to stand and I Would Do Something About It.
I stumbled upon Mark’s Daily Apple and things rapidly expanded from there. It all made sense to me. The doctor’s visit was the first week of January 2009 and by Febuary 1st I was full-blown paleo. By the end of that February my blood pressure was way down, my blood glucose stayed below 93 mg/dl, and I even lost a few pounds.
Over the last three years I’ve done a lot of N=1 experimenting. My conclusion is, FOR ME, high-carb foods are Evil Incarnate. Potatoes or rice drive my glood glucose into the 120 – 140 mg/dl range, sometimes for several hours.
My point, boys and girls, is do what works for you. That is not an original statement but it’s as true a statement as you can find in this new Paleo/Primal thingie we have here. If you can eat rice and remain well, get after it. You like white potatoes because they make you Superman? Most excellent. I am not denigrating the various studies; I find most (many?) interesting and they do contribute to our widening knowledge base but, man, read these studies within the context of your body.
Since red rice contains tocotrienols which lower LDL, would it be a healthy thing to eat?
Yes — in general to everything that has been said previously. But there's an additional issue — If (as I do) you buy into the viewpoint that the sexual genetic recombination is both ~extremely~ expensive, and primarily evolved to thwart the fast evolution times of pathogens, then the consumption and possible use of the pathogen-resistance already evolved in various lineages of plants could possibly, at least in part, have benefits in managing both pathogens generally as well as the compositions of gut bacteria. (Lately I've been a big fan of garlic by the way.) The question then becomes are the risks and costs of plant toxins worth the benefit? (Kenneth Benjamin may have been suggesting this already.)
I'm thinking more along the lines that Andrew suggests, that there is no such thing as 'food' but that everything we ingest has some benefit and some risk.
The goal here is to minimize risk and maximize return.
What we're all debating is how to do that.
It's good to talk about our experiences and share what researchers are discovering. Just keep your eye on the bigger picture.
All meat, all grains, no milk, no gluten. Each has its role but not for everyone all the time.
Until we understand how the mechanisms of eating work, we're mostly guessing. Let's hope we guess well. In the long run, our lives depend upon it.
Hey Andrew,
Thanks for bringing up this really interesting study.
I agree with you that a number of statements in your introduction are logical fallacies, but this one is not:
"Sure, rice is a grain, but what about population X and population Y who eat rice and don’t drop dead from these supposedly ‘toxic’ substances."
It can't be a logical fallacy, because it's a question rather than a logical inference. There are appropriate and important logical inferences we can derive from observations of populations that are free of the diseases of civilization. It would be a logical fallacy to argue that population X lacks these diseases and eats rice, therefore rice must be health-promoting. It is, however, an important and logically appropriate inference to say that population X lacks these diseases and eats rice, therefore it is possible to include rice as a staple and lack these diseases.
This does not demonstrate whether it is beneficial to eat rice, and does not even demonstrate that rice is not toxic. But it shows something that even epidemiological studies within populations cannot show — that consuming the food is consistent with good health independent of individual idiosyncrasies. This narrows down our conclusions to the following range: either a) the food is intrinsically neutral or beneficial, or b) the food becomes neutral or beneficial when combined with some population-level idiosyncrasy.
This then allows us to look for population-level idiosyncrasies. They might be heritable, in which case the observation may have little import to individuals that do not share the heritable factors, or they might instead pertain to certain combinations with other dietary and/or lifestyle factors. If the latter is the case, then it becomes meaningful because we can emulate those dietary and/or lifestyle factors.
Alternatively, we observe that this is consistent with good health in a number of disparate populations with little in common, and we as much as we investigate we do not uncover any shared idiosyncrasies. Then it becomes more likely that the food is intrinsically neutral or beneficial.
The point here is that we can easily make a massive overstatement from such an observation that constitutes an obvious logical fallacy, but this in no means invalidates the importance of the observation because it is useful for makes some simple statements of fact and for guiding further investigation.
Chris
There’s a gaping chasm between “health” in the epidemiological/statistical sense and phenotypic expression of the human genome. There are likely multiple routes to peak longevity — some with sub-optimal phenotypic expression — that influence quality of life and well-being.
I am moving away from reducing the human experience to incidence of cardiovascular disease and life expectancy, and toward humans in the ecological context… more of an ethology angle. Admittedly, that’s not elucidated in the post, but that’s why I care about gene expression.
It’s possible that we’re both “right”, but I don’t think we’re really talking about the same thing. I’m skeptical that epidemiology could even hope to capture the things I think are important.
Unfortunately for people like me, with (apparently) hi risk of heart disease, those end points do matter, lots.. For me, most things can come second to reducing my heart disease risk, lest I leave my children fatherless at age 12 (hyperbole yes)
Well yes, certainly a major limitation of all research is that the questions ask are the ones that are generally considered by the establishment to be of the most public health import. And the questions that we've asked in research might be some 0.0001% of the questions we could have asked. At the same time, although I don't know precisely what you have in mind, I suspect that whatever is under-researched in epidemiology or nutritional anthropology is much more under-researched in terms of orally absorbed miRNAs.
Chris
Or c) that environment + gene interaction with diet is benficial/non-detrimental, which means that other populations with similar environmental artifact will not get harm from the specific food. This environmental stuff even has some scientific support behind it as studies with different mice strains and methodologies on different locations may produc different results.
As always, context matters.
And I apologize for proofreading my comment after posting it, and thus for the grammatical mistakes. 😛
Chris
I wouldn't be surprised if sweet potatoes ended up having these MiRNAs too. I also wouldn't be surprised if there is an effect distribution similar to Neu5Gc (http://huntgatherlove.com/content/neu5gc), a potentially immunogenic molecule in meat that some vegans use as a reason to demonize meat.
Either way, my motto is eat as much meat as you can and as much plants as you have to. If I had unlimited time and money, I'd eat mainly raw meat and fish. I've been poor and relied a bit on rice and I also find it has a calming effect on my stomach, but bananas have that same effect too and are more nutritious. But then again, I think they will also have some potentially bad MIRNAs.
Yeah, I fully expect these to show up everywhere. It will be interesting to see if those that are more evolutionarily novel have different effects.
I'm curious as to whether there's already an answer to the difference between mammalian and plant miRNA in terms of digestible stability. I kinda suspect it's out there, but I find searching for research in this field tedious.
Truly an excellent post, Andrew! Thank you.
Also, thank you to the various commenters, in particular, thanks to @milissamecewen for this: "…eat as much meat as you can and as much plants as you have to." This sounds like my own rewording of Michael Pollen's credo; "Eat real food, mostly plants." to "Eat real food, mostly animals." I'm sure I'm not the only one who feels that way, but I think of it more as a Shibboleth. At any rate, if I may, the only thing I might adjust in that statement is to say "…eat as much animal as you can…"
Anyway …
Good on all of you (I'm a long time lurker on all of your blogs )
Juan
Sorry, wrong spelling: should be, @melissamcewen
I can’t even remember where I first read this article, but it made me feel like, “fuck it!” and “No shit!” at the same time. All food probably “communicates” with our bodies somehow. Isn’t that the point of eating “healthy”? I also don’t care that this miRNA effects LDL receptor uptake as I now don’t give a shit about “cholesterol”! I’m glad it raises LDL as it has been shown to be an agent in immunity as well. Chris, you’re a beast and I simply will never be able to keep up with your level of insight and foresight. Andrew, keep up the fight!
Just as some additional information of interest there has been some work on microRNA found in breast milk.
http://www.ncbi.nlm.nih.gov/pubmed/20226005 (microRNA as a new immune-regulatory agent in breast milk.)
"Our findings provide new insight into how breast milk can modulate the development of the infant's immune system. This study suggests the transfer of genetic material as miRNA from human to human occurs by means other than through sexual reproduction."
There seems to be quite a lot of microRNA in bovine milk. Be interesting to see what effects they turn out to have.
http://www.ncbi.nlm.nih.gov/pubmed/20434431 (Isolation of bovine milk-derived microvesicles carrying mRNAs and microRNAs.)
"Our findings suggest that bovine breast milk contains RNAs capable for being transferred to living cells and involved in the development of calf's gastrointestinal and immune systems."
http://www.ncbi.nlm.nih.gov/pubmed/20548333 (Identification and characterization of microRNAs in raw milk…)
"First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miRNAs in raw milk."
Ohhh Nooooeeess…I can't wait for the low-micro-RNA-diet by Dr. Spaztard to be published…
I have seen bok choi fuel cancer http://www.youtube.com/watch?v=wANwzA8QKYA&feature=B...
And avocado genotoxic http://www.youtube.com/watch?v=QWoghsATQu4&fe… and broccoli genotoxic http://is.gd/RROANc
and genotoxicity in soy http://www.youtube.com/watch?v=UH7-z9PgxrM&feature=B...
Good post. Interesting study. The recent (largely) unsupported or poorly supported advocacy of "safe starches" like potatoes and rice among a few paleo-related bloggers has been nauseating. It seemed more quasi-political than anything. Nice to see more reasoned pushback beyond the excellent Pal Jabek and Peter Dobromylskyj.
I too started eating carrots and orange kumara (small quantities) instead of potatoes, swedes, turnips, etc. after I read your carotenoid post…
Great article. Thx.
The most important thing is IMO, how that miRNAs get into the body. They should get digested from what I know but I understand that they are small (up to 25 nucleotides) and hence there might be possibility that there are some transporters in the body. It seems likely given the other papers. The experiment should probably be repeated with different people/animals of different age with some/all of them tested on leaky gut syndrome.
Other then that, we currently don't know how this miRNA actually affects genome expression, apart from the LDL observation which was in-vitro using HepG2 cells, and conclusions based upon in-vitro observations can not be translated to live environment in general.
Matthew pointed out to the study researching miRNAs in human breast milk. They said
<backquote>Our study clearly suggests that miRNA is a transferable genetic material from mother to infant. It is estimated that approximately 1.3 × 107 copies/liter/day of miR-181a are received by a breastfed infant. </backquote>
However, nowhere in the study I found that they actually measured if those molecules were actually absorbed by the baby or simply digested and used as resources (I guess its not that easy to do so). There is important contribution of RNA digestion as resources obtained can be used for glycosilation and DNA synthesis. On the other hand, numerous studies link miRNA expression to cell proliferation and differentiation and as such if those not get digested in the baby's gut it could have developmental role. miRNAs might also be there as part of mathernal transfered protection. The other paper referenced by Matthew shows that cow's milk is rich in miR-148a which different regulation might be important in pregnancies of asthmatic and nonasthmatic mothers and higher cell levels might also have anti-cancer properties (From "Altered Expression of MiR-148a and MiR-152 in Gastrointestinal Cancers and Its Clinical Significance"). The other high milk miRNA is mir-99a and according to in-situ/in-silico study "MiRNA expression in psoriatic skin: reciprocal regulation of hsa-miR-99a and IGF-1R." it is this miRNA exhibiting the strongest down-regulation in psoriatic skin". Ineteresting, because dairy is often touted as bad with autoimmune diseases. The third milk miRNA, miR-30d, is suggested to be a negative regulator of insulin gene expression: ". Overexpression of miR-30d increased insulin gene expression, while inhibition of miR-30d abolished glucose stimulation of insulin expression.".
For now, I think its irrelevant. We should at least know precise information about digestion and this should be easy to determine.
I would tend to agree with your conclusions. I didn't mean to suggest the miRNA were bad. If the findings hold true I suspect any effects will be complex, good and bad. I suspect the influence of the breast milk would be the uptake of the RNA by immune cells in the gut wall.
I know. I didn't imply you suggested that. I merely wanted to compare animal and plant miRNAs and to note that if any conclusion is to be derived from rice paper, its that we don't know anything about this sort of phenomena, so basing dietary advice on is wrong.
"personally think bok choy sucks based on taste"
fry up three strips of bacon, them add chopped bok choy or kale to the fat til wilts. yum yum.
Well yeah! But… I like kale.
Maybe the gene is turned off because our bodies do not need it to be on if we are eating rice. So yes there could be a temporary increase in cholesterol but over time if you are not eating cholesterol then it shouldn't be a problem. Rice has no cholesterol. It is a perfect food. And all populations who have eaten it historically not only live the longest but are the healthiest.
Rice is far from a perfect food. You're perpetuating a myth, and a harmful one at that.
It is factually incorrect to say rice consuming populations live longest and are the healthiest. Such populations are historically unhealthier, physically smaller, more diseased, and suffer from famine more than hunter-gatherer populations.
In traditional Chinese cultures with diets based on rice, there was an elaborate set of rules governing the exchange of children so adults didn't have to eat their own children. They traded them so they could eat others' children and the others would eat their children. This was sanctioned by the emperor to minimize the psychological trauma associated with the practice.
Rice leads to malnutrition. Rice farming leads to slavery. We have very different ideas of "perfect" foods.
“Rice leads to malnutrition” — quite a statement. Undocumented.
“rice consuming populations…are historically unhealthier, physically smaller, more diseased, and suffer from famine more than hunter-gatherer populations. ”
Yes, physically smaller, etc., BECAUSE OF INSUFFICIENT CALORIES, primarily, combined perhaps with insufficient protein. Small amounts of animal foods would (and do) correct this.
“Suffer from famine more” — yes, and no doubt this is caused by rice-eating! The eating of rice magically causes famine conditions across large geographic areas!
To demonize rice as you are attempting to do, and to make the insinuations you are making, is really a stretch, and sometimes makes you look rather foolish.
Interesting blog, nevertheless.
Rice farming is an environmental disaster. Paddy farming displaces species and dispatches ecosystems like nothing else, and I’ll demonize it from every angle I so choose.
The only thing you’re accidentally hitting on is that it’s not only rice that causes some of these problems, but agriculture in general (grain agriculture in particular).
Reducing nutrition to calories? Now that’s fucking foolish. Your analysis here isn’t as penetrating as you apparently think, so I’ll thank you to drop the judgments and proclamations. Nobody likes a troll.
Rice farming does not have to be an environmental disaster, and indeed was not for millennia. Read King’s book Farmers of Forty Centuries for background on sustainable rice production (and other grain agriculture) in East and NE Asia; the full text is on the web, free, somewhere. Other agroecology literature , and history, would be helpful as well. Although the critics of agriculture (Manning, Zerzan, Diamond, among many others) make some powerful points, they do not have sufficient understanding that they are critiqueing a style and a mindset — an approach to agriculture — not the whole of agriculture, or the thing itself. The very word “agriculture” is too broad to allow the critique that they purport to deliver. Sweeping statements about agriculture are not warranted, and are not possible while retaining intellectual integrity. Of course it is possible, and common, for grain agriculture to be an environmental disaster, but it is hardly inevitable, and there is a rich literature that verifies this.
You wrote “suffer more from famine” as though there were something unique about rice that causes famine. That’s clearly false. The reasons for (e.g.) China’s episodic famines were complex and had nothing to do with rice *per se* (that is, versus some other specie capable of feeding China’s millions). And this idea that “rice farming leads to slavery” is too ridiculous to even attempt a reply. I’m sorry if you find this offensive or trollish, but it is the truth from my point of view.
Yes, you can “demonize rice from every angle you choose” — but not if you wish to be taken seriously as an intellectual. Demonization, and the demons to which it refers, are in the realm of metaphysics or religion, not reason and rational analysis. Intellectuals understand that there are no demons in this world, that everything has both good and bad qualities.
It is a curious academic point about how hunters and gatherers had it good relative to neolithic/agricultural grain consumers. I don’t think anyone denies it anymore. The problem with that point — interesting though it may be — is its very limited relevance to the modern situation. There is no possible way that 7 billion humans (on the way to 10+ billion) could possibly be, or eat like, hunter gatherers. There are numerous important lessons to be learned from a study of “paleo” peoples and dietetic practices; I’ve learned a great deal from it myself. But in terms of practice it must be taken in light of the environmental and resource realities of the modern world. Agriculture is here stay — and a good thing, if one values the survival of the majority of humans.
Reducing nutrition to calories? Hardly. Micronutrients are my big thing. But calories are primary. No single nutrient is more important — a point often lost by rich, calorie-besotted Westerners. Simple calorie deficit is one of the causes of (structural) developmental problems, as well as of functional shortfalls (basic stuff like simply having the physical energy to put in a day’s work), across large populations. You might want to check out the work of Fogel, Komlos and others regarding the importance of calories historically, and in human (and social) development. Interesting stuff.
Although nutrition is certainly not reduceable to calories, it is also true that calories function as a fair proxy, historically, for general nutritional status. Not a good, very good or excellent proxy, but a fair one. Fogel’s and Komlos’ work alludes to this. It also simply stands to reason: a calorie-sufficient diet composed of natural foods (typically a variety) is unlikely — not certain, but unlikely — to be grossly deficient in the other nutrients, with a few exceptions (iodine deficiency in Africa and elsewhere; vitamin A deficiency in people who eat no animal foods; etc.). I am referring of course to “deficiency” in the classic sense.
Rice farming does not have to be an environmental disaster, and indeed was not for millennia. Read King’s book Farmers of Forty Centuries for background on sustainable rice production (and other grain agriculture) in East and NE Asia; the full text is on the web, free, somewhere. Other agroecology literature , and history, would be helpful as well. Although the critics of agriculture (Manning, Zerzan, Diamond, among many others) make some powerful points, they do not have sufficient understanding that they are critiqueing a style and a mindset — an approach to agriculture — not the whole of agriculture, or the thing itself. The very word “agriculture” is too broad to allow the critique that they purport to deliver. Sweeping statements about agriculture are not warranted, and are not possible while retaining intellectual integrity. Of course it is possible, and common, for grain agriculture to be an environmental disaster, but it is hardly inevitable, and there is a rich literature that verifies this.
You wrote “suffer more from famine” as though there were something unique about rice that causes famine. That’s clearly false. The reasons for (e.g.) China’s episodic famines were complex and had nothing to do with rice *per se* (that is, versus some other specie capable of feeding China’s millions). And this idea that “rice farming leads to slavery” is too ridiculous to even attempt a reply. I’m sorry if you find this offensive or trollish, but it is the truth from my point of view.
Yes, you can “demonize rice from every angle you choose” — but not if you wish to be taken seriously as an intellectual. Demonization, and the demons to which it refers, are in the realm of metaphysics or religion, not reason and rational analysis. Intellectuals understand that there are no demons in this world, that everything has both good and bad qualities.
It is a curious academic point about how hunters and gatherers had it good relative to neolithic/agricultural grain consumers. I don’t think anyone denies it anymore. The problem with that point — interesting though it may be — is its very limited relevance to the modern situation. There is no possible way that 7 billion humans (on the way to 10+ billion) could possibly be, or eat like, hunter gatherers. There are numerous important lessons to be learned from a study of “paleo” peoples and dietetic practices; I’ve learned a great deal from it myself. But in terms of practice it must be taken in light of the environmental and resource realities of the modern world. Agriculture is here stay — and a good thing, if one values the survival of the majority of humans.
Reducing nutrition to calories? Hardly. Micronutrients are my big thing. But calories are primary. No single nutrient is more important — a point often lost by rich, calorie-besotted Westerners. Simple calorie deficit is one of the causes of (structural) developmental problems, as well as of functional shortfalls (basic stuff like simply having the physical energy to put in a day’s work), across large populations. You might want to check out the work of Fogel, Komlos and others regarding the importance of calories historically, and in human (and social) development. Interesting stuff.
Although nutrition is certainly not reduceable to calories, it is also true that calories function as a fair proxy, historically, for general nutritional status. Not a good, very good or excellent proxy, but a fair one. Fogel’s and Komlos’ work alludes to this. It also simply stands to reason: a calorie-sufficient diet composed of natural foods (typically a variety) is unlikely — not certain, but unlikely — to be grossly deficient in the other nutrients, with a few exceptions (iodine deficiency in Africa and elsewhere; vitamin A deficiency in people who eat no animal foods; etc.). I am referring of course to “deficiency” in the classic sense.
Rice farming always has been, is, and will always be an environmental nightmare. All farming requires displacement of ecosystems. The argument falls flat at the simple problems of land area and irrigation, and that’s before a thorough accounting of social, economic, and political realities and externalities. This is not a point that can even be argued against without changing the subject to non-arguments — such as…
“There is no possible way that 7 billion humans (on the way to 10+ billion) could possibly be, or eat like, hunter gatherers.
Employing this argument requires fallacious implementation of the is-ought problem. It is simply absurd to make the argument that “well… we have this massive overpopulation thanks to unsustainable and destructive petroleum based agriculture, and we have to do everything we can to support this massive overpopulation.”
Overshoot. Collapse.
Your assessments of Diamond, et al are unconvincing, and your striving to be practical and judge intellectual integrity (on your terms) invokes commonsencial, but largely irrelevant and pedantic points about use of words. By taking their use of ‘agriculture’ out of the context of lifetimes of work and tens of thousands of pages penned, you’re bringing your own intellectual integrity into question.
Doubling down on agriculture is not a solution to population problems; it merely exacerbates and stalls the issue in deeply disturbing ways. Solving the problems of agrarian-induced monotheism is a much better place to start. The moment all women have full control over their own reproduction is the moment the population issue will begin to resolve itself.
Andrew: “Rice farming always has been, is, and will always be an environmental nightmare.”
False. Verifiably false. See previous post of mine.
A: “All farming requires displacement of ecosystems.”
So what? All everything requires displacement of everything else.
A: “The argument falls flat at the simple problems of land area and irrigation”
Problems that can be, and in some places are being, solved. Agroecology. Permaculture. Regenerative agriculture. Your points have been thoroughly refuted. You just have to read outside the (apparently) narrow zone in which you’ve been confining yourself.
A: “‘There is no possible way that 7 billion humans (on the way to 10+ billion) could possibly be, or eat like, hunter gatherers.’Employing this argument requires fallacious implementation of the is-ought problem. It is simply absurd to make the argument that “well… we have this massive overpopulation thanks to unsustainable and destructive petroleum based agriculture, and we have to do everything we can to support this massive overpopulation.”
We don’t have “massive overpopulation”. We have (correctable) massive overconsumption in the developed world, and (remediable) massive waste built-in to the whole system. Another fundamental fallacy of neo-Malthusians. (One of many. It has taken me about 10 years to identify them.) Only rich Westerners who cannot imagine a different and more-modest way of living speak of “massive overpopulation”.
And yes, obviously (if we have any ethical sense at all) we have to take care of the humans that exist today. We cannot roll back the clock to 1900. Too late. What’s done is done.
A: “your assessments of Diamond, et al are unconvincing, and your striving to be practical and judge intellectual integrity (on your terms) invokes commonsencial, but largely irrelevant and pedantic points about use of words.”
It is not “pedantic” to point out that, say, the word “medicine” embraces an extremely broad range of understandings, knowledge-bases and practices. To pretend that one’s critique of modern Western medicine, say, (or traditional Chinese medicine, or any other school of medicine), is a critique of medicine *per se*, or the entirety of medicine for all time, is silly. Your critique may be excellent, but it is not a critique of medicine *per se* or in its entirety. That’s what the anti-agriculture people are doing. I am not engaging in pedantry; you’re engaging (your anti-ag crowd is engaging) in a massive fallacy of composition.
A: “By taking their use of ‘agriculture’ out of the context of lifetimes of work and tens of thousands of pages penned, you’re bringing your own intellectual integrity into question.”
Amazing! That is precisely what YOU are doing, while I am trying to direct your attention to that very (vast) context.
A: “Doubling down on agriculture is not a solution to population problems; it merely exacerbates and stalls the issue in deeply disturbing ways. Solving the problems of agrarian-induced monotheism is a much better place to start. The moment all women have full control over their own reproduction is the moment the population issue will begin to resolve itself.”
The population issue has been resolving itself since about 1970. Fertility has been dropping off a cliff for decades, almost everywhere except Africa. Commensurate with this, the rate of population growth has been falling steadily and will continue to fall until it plateaus, somewhere around mid-century. And it should be noted that this demographic transition (google for that phrase, to brief yourself) is due in no small part to agriculture. It was the relative wealth and well-being produced by agricultural efficiencies that raised living standards sufficiently to precipitate the demographic transition. This is quite an interesting phenomenon; I urge you to read up on it. In some respects, agriculture is (unexpectedly, but undeniably) solving the problems caused by agriculture.
I could write much more, but no time, and other priorities are pressing.
Frankly, you need to expand the scope of your studies, and read more widely.
Please pardon the duplicated post; go ahead and axe one or the other, if you can.
Jack Weatherford wrote about how the Chinese people who Genghis Khan fought were so weak from a diet that was almost exclusively rice-based that they were easily overcome at every turn. The Mongols, by contrast, ate mostly meat and yogurt, and were markedly stronger and had better endurance than their rice-eating Chinese counterparts.
Forgive me for not citing or discussing molecular structures and metabolic gateways, etc.
"In traditional Chinese cultures with diets based on rice, there was an elaborate set of rules governing the exchange of children so adults didn't have to eat their own children. They traded them so they could eat others' children and the others would eat their children. This was sanctioned by the emperor to minimize the psychological trauma associated with the practice. "
And this has bearing on ALL rice eating populations how? One isolated social phenomenon, and famine, do not apply to all rice eating societies.
Many, many people eat high rice diets into old age, and remain healthy, the world over. Koreans have good stature and well developed dental arches. That's all the proof I need.
Sure, including animal foods and things like kimchi into the diet help, and too much rice would displace important micronutrients. But I see plenty of indication that healthy people live with the rice cooker constantly on.
But this doesn't prove that rice is the health-giving food. Even the China Study found that rice was merely neutral when you consider all the data. It's also highly insulinogenic.
I'd also like to challenge anyone who thinks eating rice is somehow more environmental than meat to Google images on rice paddies.
I mean, eat rice all you want, but don't go rationalizing it or trying to prove something about it that simply doesn't exist.
I'm late to enter the game on this one, and I'm only commenting here because it seems I couldn't reply to a specific comment (of yours) on RW's website and figured it would be better to just write my thoughts here, free of moderation! I'll admit I've stayed out of the potato conflict as A- I don't really care for potatoes one way or the other, so B- I find my time better spent elsewhere, but I have a strong dislike of information being posted on one or two particular sites and thus becoming 'Paleo Law'. I can think of other examples in the past. Unfortunately, it seems like you're the only one willing to take up the battle ax against the potato, where as others were more likely to defend their love of dairy…
But I digress…
I haven't looked into the potato story much, but if I had the time (and perhaps you or someone else has taken the time), I would be interested in a legit argument why sweet potatoes are good and solanum potatoes are bad. Both are relatively 'new' ancestrally for the majority of the paleo community. Certainly those of european descent have a longer family history of wheat consumption than potato consumption. I believe the argument against all nightshades is something to do with alkaloids, yet tomatoes seem to be a fairly common 'paleo' food except among the truly orthodox.
Anyway- I don't really have much to add to this conversation other than to give an appreciative nod to the fact that you're attempting to make people think about this topic. If nothing else, reversals of 'paleo lore' like this merit a serious discussion, not a light 'we were wrong, yay we can eat what we want'. To those that are now so excited about the healthfulness of the potato, I'd appreciate seeing a 'This is why we thought it was evil, here is where we were wrong' explanation so future (or other) misconceptions can be righted.
I was already with you on the rice and potatoes, but bok choy? Damn! I hope that doesn't mean all Brassicas. I can easily avoid the rapas (turnips and cabbage were never my favorites). But the oleraceas too? I hope not! I love broccoli…
Great article and thanks for pointing out the article. Good material to convince my husband.
Andrew, I really appreciated your post! I am definitely not a scientist or a biologist, just a sensitive American trying to eat healthy! I thought it very interesting how we as humans allow our environment to dictate what we eat and your discussions indirectly revealed this. I think most often, our feelings can cause us to be seduced by the media and food company commercials and all the delectable presentations they offer just to get us to buy their food to eat! Since I am 50 something, I began paying more conscious attention to how my body feels after I ingest food. That was number one. Number two, I bought a book called "Eat right for your blood type! " I don't follow this book to the "T" but I do have a better and more heathy energetic body when I eat foods that are good for my blood type. I think this works! The author of this book gives an interesting take on the evolution of humans and their health and physical habits in regards to geography and blood type.
My question to you is, if I follow foods that are good for my blood type, would this be considered a paleo (relating to the geological past) dietary adventure?
It is my perception that in human physical existence we are sustained by the earth and have evolved from such a condition so I wonder that our blood is also directly connected to this idea in some sort of a geological context?
Again, I really enjoyed your post. You hit a nail on the head in regards to how we allow our environment (not necessarily our geography) to dictate what we eat!! 🙂
Cheers, Cindy Eksuzian
I haven't read that blood type diet stuff. People whose opinions I respect speak of it unfavorably.
Your statement that potatoes’ late additionto the European diet makes them unsuited to their diet, raises questions of genetic tolerances of miRNAs. Does any scientific evidence of such tolerances exist, like documented lactose intolerance among Asians? As a woman whose First Nations ancestors lived on beans and corn, I’d love to see the results of such research. A second point, when discussing beans and grains, both dried foods, is mildew and yeast contamination and mycotoxins, my reason for restricting corn. Beans are a major source of numerous nutrients, and I parboil, drain, and rehydrate them to reduce both contaminants and methane-generating mucopolysaccharides. Shouldn’t this reduce lectins as well? My suspicion is that for many of us with native ancestry and one or more “thrifty” genes, any grains and/or sugars will be seriously toxic.
Now, about the collards, cabbage, and Brussels sprouts…
how do we know that the actions of miRNA from plants are not beneficial to our body? the human genome is complicated and the miRNA mechanism is used frequently (for example, in ALL of our neurons.) miRNA, in order to carry out its action, needs to carry some complementarity to whatever sequence it is inhibiting the expression of.
an interesting study, but from a medical point of view, there's not enough evidence for anyone to really change their lifestyle for it. there are a million other "downstream" events that occur after the preservation/presence of plant miRNA in our cells, and until a study is done looking specifically at these downstream effects and their net meaning, let's not get in an uproar.
very interesting stuff, more work needs to be done! However, I would argue that your comments do not show that you have any significant knowledge of these issues on the molecular level. Please correct me if I'm wrong and thanks to bringing this to everyone's attention.
"how do we know that the actions of miRNA from plants are not beneficial to our body?"
we don't know, but since the plants have a dog in this fight with interests exactly contrary to ours, it's evolutionarily improbable.
here's what we do know:
*plants don't 'want' their seeds to be eaten
*plants don't 'want' their energy storage organs to be eaten
*the aforementioned plant miRNAs influence gene expression in humans
*human consumption of the aforementioned plants is relatively novel
there is currently no reason to believe plant miRNAs are "beneficial" to humans. my position effectively represents the null hypothesis. it's up to you to disprove it.
repeat after me: probability probability probability
"in order to carry out its action, needs to carry some complementarity to whatever sequence it is inhibiting the expression of. "
THIS. does anyone commenting, reading this post realize that plant miRNA and human miRNA might NOT be compatible? + one million other factors?
I don't intend to troll or flame here, but there is a reason that medical advisory committees, the FDA, and numerous studies exist before a recommendation is made to the public. There is not a simple point A to B interpretation of this study that should change the actions of the public. To prematurely interpret it is at best, futile and at worst, harmful. Yes, the science takes a long time to trickle down into a recommendation, and I get that that frustrates people. But judging from what I have read in the comments and this article, studies like this NEED to be distilled in order for the public to understand them.
"To prematurely interpret it is at best, futile and at worst, harmful."
i don't necessarily intend to treat you like a troll, but you are exactly the opposite of correct here. see my reply to Najmul.
medical advisory committees and the FDA? wake up.
Was bored and decided to check this out: http://www.nature.com/cr/journal/vaop/ncurrent/fu…
"Unexpectedly, plant miR168 exhibits a high degree of complementarity with the exon 4 of mammalian LDLRAP1."
very interesting stuff! It looks in this case, the authors have found what seems to be a beneficial effect of this (lowering uptake of LDL, the "bad" cholesterol), but who knows what else is out there. In the meantime, I'll still be eating plants! I enjoy a salad too much, maybe I'm strange.
Touche and thanks for the gracious reply.
Has anyone noticed that while in rice, cabbage and potato the cooking decreased all the microRNAs, in wheat cooking actually increased them. Wtf?
Also, if brown rice was used in the study, then white rice would almost certainly have none of the microRNAs remaining.
Hi Andrew,
I followed a link from Dr. Mercola’s article this morning, looking for research into the harmful effects of lectins, phytates, etc, that used dogs, for a debate that’s going on, on the Dogfoodavisor (.com). Reading your article was a real treat! Thank you!!
If you happen to know of any, that do use dogs in the study, I’d appreciate it if you’d share the links or titles with me. We have one member that refuses to accept any research unless it’s specie specific. It’s been a running debate for sometime. Our position is that grains, lectins, glutinous, etc are bad for dogs, hers is the opposite. Anything you’ve got would be appreciated! Thanks!
[…] may be a better option, because white potatoes have been shown to interfere with human gene expression (this may or may not be a terrible thing – we’re not really sure […]
[…] to have a digestive issue with potatoes, the skin is most likely to be the trigger. [UPDATE: Andrew's work at evolvify gives me some pause on rice and white […]
[…] Potatoes contain some miRNA’s, even when cooked, which seem capable of interfering with human gene expression (Andrew of Evolvify writes a compelling argument against potatoes, rice and wheat – making some logical predictions based on micro RNA (miRNA) studies with rice. Read his outstanding post here.) […]