My son Jordan challenged me to revisit my views on Steven Gundry’s book The Plant Paradox. In order to revisit those views, I googled around to find blog posts and articles online that were critical of Gundry and followed the links. I’ll insert images of these blog posts and articles where I discuss each.
There are two parts to this reexamination of Steven Gundry’s book The Plant Paradox.. One is to revisit the key hypotheses I emphasized in my blog post review of The Plant Paradox: What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet. These I summarized as follows:
The War Between Plants and Animals. This is the idea that many of the natural insecticides plants produce to avoid getting eaten quite as often may have negative effects on human health.
Old and New Natural Insecticides: We and Our Gut Microbiome Have Evolved to Deal With Some Natural Insecticides, But Not Others. This is a key qualification: humans and their gut microbes should have evolved to deal with the natural insecticides from plants that our ancestors have eaten for a hundred thousand years or more, with some significant adaptation to deal with these natural insecticides for things our ancestors have eaten for ten thousand years or more.
More generally, apart from natural insecticides, the longer our ancestors have eaten a particular type of food, prepared in the way it is now prepared, the more assurance we have of its safety. Overall, the dietary there are at least four big dietary changes evolution may not have fully adapted us for:
The Agricultural Revolution, with its Emphasis on Grain
The A-1 Mutation in Cows, which Affects Milk Proteins
The Introduction of New World Plant Food
Highly Processed Food
The other views based on The Plant Paradox to reexamine are Steven Gundry’s claims about specific foods.
Note that none of this about the particular class of natural insecticides called “lectins” in general being bad, which is, I think, a distortion of Steven Gundry’s views, and certainly not something I would agree with. Lectins in foods that humans and their gut microbes have had plenty of time to adapt to should be fine. (The exception to the idea that truly ancient foods should be safe for the typical person is that one might have problems if one’s dietary patterns and other environmental factors had killed off a large share of the types of microbes that are important for dealing with the lectins in those foods.)
I view all of these claims are important hypotheses that have not been falsified by existing data. One already meets with a general consensus by scholars: (4) the idea that the highly processed food so common in modern diets is quite bad for us. I write about why in “The Problem with Processed Food.”
Another claim for which I consider the evidence to be strong—though not gold-standard evidence—is (2) the claim that A-1 milk is a problem. On that, see my posts
On claim (1), Grain is generally a problem because of its high insulin index. (See “Forget Calorie Counting; It's the Insulin Index, Stupid.”) Whether it is also a problem because of lectins is more speculative. This matters a lot for oatmeal, which is one of the grains that is lowest on the insulin index. I don’t know what to think about oatmeal. Because it is relatively low on the insulin index and has some components that are especially satiating, oatmeal has some real benefits for weight loss that may outweigh whatever lectin dangers it presents.
(Rice is fairly high on the insulin index; for rice there is a mystery about why eating a lot of rice hasn’t led to more obesity in East Asia. I certainly feel very hungry a couple of hours after I eat any substantial amount of rice. I don’t know the answer to why heavy rice-eating hasn’t led to more obesity among East Asians, especially in the context of increasing available of food to eat if the insulin kick from rice makes them hungry. I wish I knew. Two possibilities that don’t seem sufficient to explain the puzzle are (a) Jason Fung suggests that eating sour things with rice as the Japanese do at least at some meals might reduce the insulin kick from rice, (b) natural selection may have given many East Asians adaptations for rice eating—maybe, maybe such adaptations are easier than for other grains. As far as lectins go, white rice may not be very high in lectins.)
Claim (3), that new world plant food is likely to be problematic, is an especially interesting claim. Near the end of this post, I discuss tomatoes in some detail. Potatoes, like grain, are quite high on the insulin index, so I think potatoes are very unhealthy quite apart from lectins. But it is possible that lectins make them worse. Steven Gundry has gotten me worried about cashews and peanuts.
As for the other hypotheses, Stephen Guyenet agrees with me on that. In the post shown above, he repeatedly indicates his interest in these hypotheses as hypotheses, and writes:
We believe the ideas in this book should have been presented as hypotheses to be tested rather than as scientific findings.
He rates the following claims by Steven Gundry on a 0 to 4 scale as follows (I combined the text of the claim as summarized by Stephen Guyenet with the rating he gives a few paragraphs later.)
Claim 1: Lectins from grains, legumes, certain types of dairy, fruit, and nightshade and cucumber-family vegetables cause an increase in intestinal permeability (“leaky gut”). Rating: 1.7 out of 4.
Claim 2: Grains, legumes, certain types of dairy, fruit, and nightshade and cucumber-family vegetables are fattening foods because their high content of lectins stimulate energy storage and appetite. Rating: .7 out of 4.
Claim 3: Inside the body, lectins from grains, legumes, certain types of dairy, fruit, and nightshade and cucumber-family vegetables cause chronic autoimmune or other inflammatory reactions leading to a wide range of chronic diseases. 1 out of 4.
On Claim 2, I need to say that I never found Steven Gundry’s claim that nightshades and cucumber-family vegetables are fattening very convincing. (I have worried about them being harmful in ways other than their being fattening.) Grains (even whole grains), legumes and fruit can be fattening simply because they are somewhat high on the insulin index, which need not have much to do with lectins. (See “Forget Calorie Counting; It's the Insulin Index, Stupid.”) Given the number of patients that Steven Gundry has seen who have chronic autoimmune or other inflammatory reactions, and has treated with dietary restrictions, I give a fair amount of credence to the interrelated Claims 1 and 3. I agree with Stephen Guyenet that if this is indeed true, Steven Gundry needs to publish peer-reviewed articles backing up what he claims he sees in his patients with chronic autoimmune or other inflammatory reactions. If he doesn’t do so, someone else should test this. It is an important enough and credible enough claim to be worth either falsifying or confirming, whatever a careful study would show.
(Interestingly, Stephen Guyenet’s tone in discussing Steven Gundry’s highly speculative hypotheses is much more friendly than his discussion of Gary Taubes’s claim that sugar is very, very, very bad—a claim that has much better evidence to back it up. See “The Case Against Sugar: Stephan Guyenet vs. Gary Taubes” and “Layne Norton Discusses the Stephan Guyenet vs. Gary Taubes Debate (a Debate on Joe Rogan’s Podcast).” One possible reason for the difference in tone is that Steven Gundry, as a medical doctor, is much more “in the guild” than Gary Taubes, who is a journalist with physics training.)
Stephen Guyenet, like many others questioning Steven Gundry’s claims, points to abundant evidence that whole grains, legumes, fruit, nightshades and cucumber-family vegetables help reduce obesity and lead to other good outcomes. There is a very basic point to make here. Oversimplifying, suppose you could rank all foods (perhaps within category), from most health to least healthy. Given the fact that a large share of people are eating very unhealthy foods, if medium unhealthy food replaces very unhealthy food, that is a win. I don’t have a general index of the healthiness of foods, but in the particular direction of being fattening, let me take the insulin index as a reasonably good measure of how fattening a particular food is. Then this idea can be made very concrete. Eating more lentils that have an insulin index of 42 is a big improvement in relation to weight loss if those lentils are replacing potatoes, which have an insulin index of 88; but if lentils are displacing walnuts that have an insulin index of about 5, that substitution of lentils for walnuts may be a fattening change. Similarly, substituting eating whole fruit instead of candy or cake or fruit juice is a huge improvement. But acting as if eating three peach-sized pieces of fruit is as healthy as eating a similar quantity of green leafy vegetables is a mistake.
To put a point on it: whenever people cite evidence about how healthy a particular type of food is, one always needs to ask “Eaten instead of what?” Even extremely good evidence that a particular type of food is an improvement on the typical American diet does not mean that type of food isn’t problematic in ways that could be avoided by eating something even healthier.
The big problem in Michael Gregor’s attack on Steven Gundry in the video shown just above is Michael Greger’s uncritical acceptance of evidence that a certain type of food is a big improvement on what it replaces in the typical American diet as if it were evidence that food was “healthy” full stop. (That is also the big problem with Joel Kahn’s blog post “The Plant Paradox and The Oxygen Paradox: Don’t Hold Your Breath for Health” and Toby Amidor’s blog post “Ask the Expert: Clearing Up Lectin Misconceptions.”)
The other problem with this video is that Steven Gundry is not, in the end, anti-bean and anti-lentil. He simply says that they need to be cooked carefully—he recommends presoaking and pressure-cooking—in order to destroy as many of the lectins as possible. Presoaking is not at all an unusual type of preparation for beans and lentils. Some people claim that regular cooking is adequate without pressure-cooking. That is indeed a dispute, but not a huge dispute.
Steven Gundry takes his view that animal protein is problematic from T. Colin Campbell and Thomas Campbell, as I do. (See “Meat Is Amazingly Nutritious—But Is It Amazingly Nutritious for Cancer Cells, Too?” and “How Sugar, Too Much Protein, Inflammation and Injury Could Drive Epigenetic Cellular Evolution Toward Cancer.”) But the Campbells do not seem to realize that Steven Gundry is an ally. As strong proponents of a vegan diet, the Campbells seem to be concerned that by recommending some plant foods over others, Steven is unduly limiting the range of options for a vegan diet. They also are concerned that Steven Gundry allows animal foods in moderation in his recommendations.
The most useful aspect of the Campbell’s article shown above is that it details how inappropriate Steven Gundry is with his citations. The citations often are to low-quality sources or to sources that don’t back up what Steven Gundry is saying at all. The Campbells are especially convincing that Steven Gundry is not completely trustworthy in what he says. This of course does not make Steven Gundry’s hypotheses bad hypotheses. It does mean that Steven Gundry can’t be trusted to give us the information to carefully evaluate the limited evidence so far on whether those hypotheses are true or not.
The most interesting thing about “larkasaur’s” review of The Plant Paradox shown just above is his nice discussion of the evidence for anticancer properties of lectins. Larkasaur writes:
Some lectins have anti-cancer properties - but at the same time, this means they are powerful substances that might also cause harm, as Dr. Gundry proposes.
Indeed, a hole in Steven Gundry’s argument that natural insecticides might be hard on cells is that they might be even harder on cancer cells in a way that made them a very mild, and relatively safe type of preventive “chemotherapy.” Of course, I think that fasting is a much better way to go for a likely effective, mild and safe form of preventive “chemotherapy.” My diet and health posts focusing on cancer give a fairly good treatment of this idea:
The bottom-line is that if lectins are more harmful to otherwise healthy cells than fasting is, and no harder on cancer than fasting, then fasting rather than lectins is the better way to try to prevent cancer. Of course, if certain lectins work as chemotherapy after someone has already been diagnosed with cancer, that would be great. (See for example this abstract: “Lectins as bioactive plant proteins: a potential in cancer treatment.”) And any anti-cancer effects of lectins have to be weighed in the balance when judging particular foods. Here one would want to know “How hard on cancer?” and “How hard on healthy cells?” for each different type of lectin.
One place where larkasaur powerfully countered one of Steven Gundry’s claims about a specific lectin is this passage, which begins with a quotation from The Plant Paradox, followed by larkasaur’s counter:
The lectin WGA (wheat germ agglutinin) ... can attach to the insulin docking port as if it were the actual insulin molecule, but unlike the real hormone, it never lets go - with devastating results, including reduced muscle mass, starved brain and nerve cells, and plenty of fat.
His reference for this is Effects of wheat germ agglutinin on insulin binding and insulin sensitivity of fat cells. I didn't see the full paper, but from the abstract, this was an in vitro study where WGA actually increased insulin sensitivity at low concentrations, but decreased it at high concentrations. I couldn't find evidence from other studies that the actual blood concentrations of WGA that someone might get from their diet, could affect insulin sensitivity. I did find some evidence that increased intake of whole grains vs refined grains (and whole grains have more WGA) improves insulin sensitivity - e.g. Effect of whole grains on insulin sensitivity in overweight hyperinsulinemic adults. I even found something about wheat germ supplementation alleviating insulin resistance. Wheat germ has a lot more WGA than other wheat products.
Larkasaur also questions some specific claims about Neu5AC and Neu5GC. I was convinced that I should disregard Steven Gundry’s claims about Neu5AC and Neu5GC (which I didn’t pay very much attention to when I read The Plant Paradox in any case).
I really like larkasaur’s discussion of Steven Gundry’s study. Larkasaur writes:
He did a trial on 1000 people, which was presented at an American Heart Assoc. conference. 800 of them had either an autoimmune disease themselves or a family member with an autoimmune disease. They were asked to eat his diet, which "consisted of avoidance of grains, sprouted grains, pseudo-grains, beans and legumes, soy, peanuts, cashews, nightshades, melons and squashes, and non-Southern European cow milk products (Casein A1), and grain and/or bean fed animals.", and adiponectin and TNF-alpha levels were measured every 3 months.
Their levels of TNF-alpha normalized within 6 months, but the adiponectin levels remained elevated.
So he concluded that "TNF-alpha can be used as a marker for gluten/lectin exposure in sensitive individuals."
But he doesn't say how those 1000 people were selected. Maybe they were cherry-picked to show a good result.
And, he didn't have a control group. A control group might consist of people eating his Plant Paradox diet, but also taking a capsule with wheat germ agglutinin (wheat lectin), so that they would be getting the same amount of lectins that people eating the average American diet do. And there would also be a test group, of people eating his Plant Paradox diet and taking a capsule with placebo. That would test whether WGA actually has the effects that he thinks it does.
In addition to dismissing the dangers of A-1 milk to quickly, Larkasaur is too trusting of the official recommendations about the daily requirement for Vitamin D. On that, see
Michael Matthews has a strongly worded title to his long post: “Dr. Gundry’s Plant Paradox Debunked: 7 Science-Based Reasons It’s a Scam.” Here are his Michael’s “7 Science-Based Reasons It’s a Scame”:
The healthiest people in the world eat a lot of lectins.
There’s no real scientific debate about the nutritional value of fruits and vegetables.
Lectins don’t make you fat, overeating does.
Lectins don’t give you heart disease.
Lectins don’t cause “leaky gut” unless you have celiac disease.
Humans have been eating lectins a very, very long time.
Cooking lectins nullifies any potential negative side effects.
1 and 2 are subject to my point above that a food can be demonstrably better than the typical American diet or other typical modern diet, but still have problematic elements. 1 and 6 are subject to the point that Steven Gundry is not claiming that all lectins are harmful, but only that lectins we have not had adequate evolutionary time to adapt to are harmful (though Steven Gundry may be somewhat inconsistent in realizing that this is the position he has to be taking given his logic). On 3, the Michael saying that “overeating makes you fat” leaves unanswered the key question: “What makes you overeat?” Steven Gundry is trying to answer the question of “What makes you overeat?” Anyone who thinks the answer to the question “What makes you overeat?” is either uninteresting or obvious is misguided given where we are in the science. As for 4 and 5, at least in his section headings, Michael is treating “unproven” as the same as “proven false.” No! These are important hypotheses that we don’t have adequate evidence on either way. Finally, on 7, Michael might be right. This is the debate I mentioned earlier about whether pressure-cooking is necessary to destroy most lectins, as Steven Gundry says, or whether regular cooking is enough. As a minor cavil, I do think that Michael Matthews uses the word “nullify” inappropriately about the effect of soaking in reducing lectins by 50%. But the following passage as a whole is useful:
According to a study conducted by scientists at the University of Sao Paulo, boiling beans and other lectin-containing foods for 15 minutes is enough to eliminate almost all of the lectin content. If you use a pressure cooker you can achieve the same effect in just 7.5 minutes, but the end result is the same.
As the scientists put it, “In relation to lectins, there seems to be no residual activity left in properly processed legumes.”
Soaking is another effective method for nullifying lectins. In a study conducted by scientists at Michigan State University, soaking red kidney beans for 12 hours reduced the lectin content by 50%.
Fruit, Nightshades and Other Vegetables with Seeds
Overall, while I think fruit should be eaten in moderation, I think Steven Gundry’s views are too negative about fruit. Many types of fruit are relative high on the insulin index. But I doubt the lectins in fruits are a particular problem. Hence, in relation to fruit, let me recommend that you stick with what I said about fruit in “Forget Calorie Counting; It's the Insulin Index, Stupid” and ignore what Steven Gundry says about fruit. I am a little torn about whether or not it is OK to eat the skin, which Steven Gundry advises against.
Other than the nightshades, such as tomatoes, peppers, potatoes, and eggplant, the same principles should apply to the botanical fruits that we usually call vegetables, such as cucumbers—except that eating the seeds (or the skin) might be a problem.
On the nightshades, Steven Gundry recommends that they be deskinned, deseeded and pressure cooked. This may be reasonably close to the way many tomato products are made. Because I love fresh tomatoes, I have tried to research whether there is strong positive evidence that they are healthy that could overturn Steven Gundry’s claims that they are problematic. But what I have found is that the bulk of the evidence in nutritional trials about tomatoes is about tomato products that have been processed in the sorts of ways Steven Gundry recommends.
Looking for evidence about the dietary effects of fresh tomatoes, I did find a set of references in the article shown above: “Whole Food versus Supplement: Comparing the Clinical Evidence of Tomato Intake and Lycopene Supplementation on Cardiovascular Risk Factors.”
Here are abstracts for four articles involving fresh tomatoes:
My summary of these abstracts is that while tomato products might reduce inflammation, whole tomatoes are neutral for inflammation, which one might imagine was due to an inflammation-reducing effect of the rest of the tomato (at least when cooked) combined with inflammation-increasing effects of the skin and seeds. But there is some evidence that whole tomatoes seem to reduce blood pressure, raise good cholesterol and reduce oxidative damage. So, overall, fresh tomatoes sound good overall, though skinned, deseeded, cooked tomatoes might be better. The big question I have about these studies are whether those benefits are only when tomatoes are added to a typical American diet (likely displacing some very bad foods), or whether those benefits would be there for me given the diet I am starting from (which currently doesn’t include any fresh tomatoes).
Sometime I should try to do similar kind of online searching for research about eggplant and peppers. (As I mentioned above, I don’t feel I need to do more research about potatoes because they are so high on the insulin index, I am confident they are best avoided.)
Some Favorable Evidence for Steven Gundry’s Claims
On the basic idea that lectins are powerful in their effects on humans, take a look at this abstract:
Finally, here is a post that is relatively supportive of Steven Gundry’s claims:
Here are some of John O’Connors grades for Steven Gundry claims, along with quotations from some of the associated text:
Altered gut microbiome drives lectin sensitivity: C+
Add to the list of medications we take the presence of toxic chemicals in everything from cookware to mattresses, and the rise of GMO crops sprayed with known carcinogens like glyphosate, it’s not unreasonable to assume some people might not be equipped with the microbes to properly digest certain lectins. Lectins are controversial, but increased pollution, prescription medications and widespread use of antibiotics seems to be changing the shape of our microbiomes. In his paper, Do Dietary Lectins Cause Disease, allergist David L.J. Freed theorizes that a serious infection could be the triggering event that alters the microbiome in such a way that we become prone to lectin sensitivity and certain autoimmune conditions.
The altered microbiome theory is gaining traction as consensus fact, and it’s imbalances of the gut that drive Gundry’s claims about lectin. Some have cast him as an outsider, but he’s right in the mainstream of functional medicine. He argues that many people are so used to low levels of inflammation caused by lectin that a state of reduced performance is their “new normal.” But even assuming that a large percentage of the population thrives on lectin, that doesn’t mean we all do.
For example, could a C-section birth, which is thought to be deprive babies of important foundational microbes, combined with a serious infection and a few rounds of broad spectrum antibiotics be just what the doctor ordered for a problem with digesting lectins down the road?
Lectins travel to distant organs: B-
There is even some evidence that lectins can travel to the brain. This study is footnote #5 in the Plant Paradox, and it demonstrates (albeit in a worm model) that lectins can travel from the gut to the brain by way of the Vagus nerve where they impact the function of neurons, offering an alternative theory on the cause and development of Parkinson’s disease.
Again, the study cited by Gundry is a worm model, and it’s on the frontier of nutrition science, but nonetheless, there are other papers that show benefits to mental health when removing grains, so it’s something to experiment with and keep in mind when testing out theories behind anxiety for example. This Danish study showed a 40% reduction in Parkinson’s disease in people who had their Vagus nerve removed.
Lectins and heart disease: C
Peanut oil is high in lectin. In a study titled “Lectin may contribute to the atherogenicity of peanut oil,” researchers found that when lectin was reduced in peanut oil by washing, incidence of heart disease dropped significantly in animal models (mice, rabbits and primates).
Lectins can break down the gut wall: A
Wheat proteins do us harm by attacking the gut lining, making the barrier between our intestines and the inside of the body more permeable, which for some, can lead to symptoms ranging from digestive issues to achy joints to problems with mental health. (R) Zonulin, a protein which can break apart the “intracellular tight junctions” of the gut wall, is produced when we eat wheat. The theory of leaky gut is that the resulting intestinal permeability lets all sorts of bad guys into our blood stream and the immune system goes wild as a result. (R) One of the most successful dietary interventions used to treat Rheumatoid Arthritis is a gluten free Vegan/Vegetarian diet. Of note: some of these RA diet studies have found an “association between disease activity and intestinal flora indicating impact of diet on disease progression.”
Steven Gundry’s hypotheses should be taken very seriously. Both Steven Gundry himself and other researchers should take them as important claims to be proven or disproven by solid evidence. In the meantime, eating low on the insulin index is likely to get you most of the benefits of the Gundry diet. But if you have any chronic autoimmune or other inflammatory reactions, my recommendation is that it would be worth your while to try to follow the full Gundry yes and no list of foods, see if it helps, and if it does, only reintroduce foods you have subtracted one at a time so you can see if some particular food is a problem for you.
For annotated links to other posts on diet and health, see “Miles Kimball on Diet and Health: A Reader's Guide.”
Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.
In this passage, those who had a hand in crafting the Declaration of Independence show their knowledge of John Locke’s 2d Treatise on Government: Of Civil Government. In Chapter XIX, sections 223-225, John Locke writes:
§. 223. To this perhaps it will be said, that the people being ignorant, and always discontented, to lay the foundation of government in the unsteady opinion and uncertain humour of the people, is to expose it to certain ruin; and no government will be able long to subsist, if the people may set up a new legislative, whenever they take offence at the old one. To this I answer, Quite the contrary. People are not so easily got out of their old forms, as some are apt to suggest. They are hardly to be prevailed with to amend the acknowledged faults in the frame they have been accustomed to. And if there be any original defects, or adventitious ones introduced by time, or corruption; it is not an easy thing to be changed, even when all the world sees there is an opportunity for it. This slowness and aversion in the people to quit their old constitutions, has, in the many revolutions which have been seen in this kingdom, in this and former ages, still kept us to, or, after some interval of fruitless attempts, still brought us back again to our old legislative of king, lords and commons: and whatever provocations have made the crown be taken from some of our princes heads, they never carried the people so far as to place it in another line.
§. 224. But it will be said, this hypothesis lays a ferment for frequent rebellion. To which I answer, 19 First, No more than any other hypothesis: for when the people are made miserable, and find themselves exposed to the ill usage of arbitrary power, cry up their governors, as much as you will, for sons of Jupiter; let them be sacred and divine, descended, or authorized from heaven: give them out for whom or what you please, the same will happen. The people generally ill treated, and contrary to right, will be ready upon any occasion to ease themselves of a burden that sits heavy upon them. They will wish, and seek for the opportunity, which in the change, weakness and accidents of human affairs, seldom delays long to offer itself. He must have lived but a little while in the world, who has not seen examples of this in his time: and he must have read very little, who cannot produce examples of it in all sorts of governments in the world.
§. 225. Secondly, I answer, such revolutions happen not upon every little mismanagement in public affairs. Great mistakes in the ruling part, many wrong and inconvenient laws, and all the slips of human frailty, will be borne by the people without mutiny or murmur. But if a long train of abuses, prevarications and artifices, all tending the same way, make the design visible to the people, and they cannot but feel what they lie under, and see whither they are going; it is not to be wondered at, that they should then rouze themselves, and endeavour to put the rule into such hands which may secure to them the ends for which government was at first erected; and without which, ancient names, and specious forms, are so far from being better, that they are much worse, than the state of nature, or pure anarchy; the inconveniences being all as great and as near, but the remedy farther off and more difficult.
On a much larger scale, this claim is like the claim that for every person who complains about a product, there are many, many other people who felt the same way, but felt it was too much trouble or too scary to lodge a complaint. Dissatisfaction with a government passes through a strong filter before any revolution comes out.
We live in a time when new political forces are arising both on the right and on the left. One might ask “Is this just polarization, or has our government genuinely heaped a long train of abuses on the American people that partisans interpret in different ways?” I tend to thing the answer is still that it is just polarization. What the right complains about is quite different from what the left complains about. And in US presidential elections, the electorate seems close to evenly divided in complaining about very different things. So I don’t think it is time to change the US government in any big way. Regular elections should give the American people a chance to change what is wrong with government decisions if they can agree on which government decisions are wrong.
For links to other John Locke posts, see these John Locke aggregator posts:
Here is a quotation from Prateek Agarwal’s email to me about this honor:
… your blog, Confessions of a Supply Side Liberal has been featured in the Top 100 Economics Blogs of 2019. Congratulations!
One of the significant changes this year has been the removal of newspaper blogs such as Bloomberg View and Real Time Exchange to focus on more niche blogs. The lack of female economist (and bloggers) has been a common criticism of this list. I've made an effort to include more female bloggers, but if you have any suggestions, I can consider them for the 2020 list.
I’d be glad for suggestions from readers of good blogs by female economists that didn’t make it onto this list that I can pass on to Prateek.
I have a simple rule of thumb: if we have known of a disease for a long time, but understand it even less well then we understand cancer, it is probably an autoimmune disease or the side effect of an immune system reaction to diet, infection, toxins or physical trauma. I am thinking in particular of two black beasts (bêtes noires) of old age: Alzheimer’s disease and Parkinson’s disease. In both of these two cases, suspecting that they may be autoimmune diseases is well within the scope of the current scholarly debate (Alzheimer’s, Parkinson’s). And the immune system process of inflammation is seen as a risk factor for Alzheimers. (On inflammation more generally, see my post “Jonathan Shaw: Could Inflammation Be the Cause of Myriad Chronic Diseases?”
For those who either have or think they might have an autoimmune disease or are worried about diseases such as Alzheimer’s and Parkinson’s that might be autoimmune diseases or diseases with an important part of the causal mechanism involving the immune system, it is worth knowing about Steven Gundry’s hypothesis that leaky gut and certain foods often generate or aggravate autoimmune disorders. See “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet.”
In this post, let me focus in on Alzheimer’s disease and leave Parkinson’s disease for another day. Researchers haven’t been able to provide gold standard evidence for anything as a preventative against Alzheimer’s disease. In her Wall Street Journal article “Should You Find Out if You’re at Risk of Alzheimer’s?”, Sumathi Reddy reports:
There is no advice derived from randomized-controlled trials—the gold standard in medicine—on preventing Alzheimer’s disease.
The title of Sumathi’s article alludes to these three facts:
Genetic tests are getting a lot better at predicting Alzheimer’s disease
They’ll get better still by adding in the effects of more genes and pinning down the effect of each gene more and more precisely.
In the absence of good evidence about how to try to prevent Alzheimer’s disease, you may or may not want to know about your genetic level of Alzheimer’s risk.
But even in the absence of solid evidence, many researchers and doctors have the intuition that what is good for avoiding heart disease may also be good for fighting Alzheimer’s disease. (Cynically, I wonder a little if they say that because even if they are wrong about the effects on Alzheimer’s they won’t get in trouble for recommending those things.) Let’s look at some specific statements by researchers and doctors. In each case, let me add bold italics to emphasize the key message in each of the quotations from Sumathi’s article.
Rudy Tanzi’s Advice for Trying to Prevent Alzheimer’s Disease
But most doctors agree that regular exercise, adequate sleep and a heart-healthy diet can lower the risk. “The Healing Self,” which Dr. Tanzi wrote with Deepak Chopra, advocates for protecting the brain by focusing on sleep, exercising, learning things, controlling stress and hypertension, as well as maintaining social interaction and a healthy diet.
David Holtzman’s Advice for Trying to Prevent Alzheimer’s
David Holtzman, professor and chair of neurology at Washington University School of Medicine in St. Louis, says there is no objective data that specific strategies work aside from a 2015 study conducted in Finland that showed that elderly people who were cognitively normal or had a mild impairment maintained or increased their cognitive ability over two years with exercise, cognitive training and vascular-risk monitoring.
“Right now,” Dr. Holtzman said, “if you lead an active, heart-healthy, pro-brain lifestyle, there’s not much that we can tell somebody that they should do differently.”
Dale Bredesen’t Advice for Trying to Prevent and Fight Alzheimer’s Disease
Dale Bredesen, a professor in the department of molecular and medical pharmacology at UCLA and founding president of the Buck Institute for Research on Aging, advocates for specific changes. His protocol—which costs $75 a month—entails getting regular blood tests to track markers such as insulin resistance and inflammation, as well as following a low-carb, high-fat diet, fasting intermittently and taking supplements. Dr. Bredesen says he has published two small studies and one 100-person study showing that his protocol can reverse cognitive decline in patients with mild cognitive impairment or Alzheimer’s disease.
Dale has gotten some pushback on this. He answers that he is working toward getting more solid evidence:
But experts pointed out that his studies aren’t randomized controlled ones. Dr. Bredesen said he needs to build up anecdotal evidence to be able to do one. Many members of the ApoeE4.Info group, including Ms. Braymer, said they follow the principles of Dr. Bredesen’s protocol.
It is interesting to look at the Journal of Alzheimer’s Disease & Parkinsonism article “Reversal of Cognitive Decline: 100 Patients” that Dale Bredesen is the first author for.
Here are some informative quotations from that article, again with my emphasis added both by bold italics on the words of the article and by adding explanations in square brackets:
… what is referred to as Alzheimer’s disease is a protective, network-downsizing response to several classes of insults: pathogens/inflammation, toxins, and withdrawal of nutrients, hormones, or trophic [diet-related] factors.
This notion has led to a treatment regimen in which … a personalized program is generated … Some examples include: (1) identifying and treating pathogens such as Borrelia, Babesia, or Herpes family viruses; (2) identifying gastrointestinal hyperpermeability, repairing the gut, and enhancing the microbiome [leaky gut and a messed-up gut microbiome—the causal nexus Steven Gundry emphasizes]; (3) identifying insulin resistance and protein glycation [sugar molecules messing up proteins], and returning insulin sensitivity and reduced protein glycation; (4) identifying and correcting suboptimal nutrient, hormone, or trophic [diet-related] support (including vascular support); (5) identifying toxins (metallotoxins and other inorganics, organic toxins, or biotoxins), reducing toxin exposure, and detoxifying.
Here we have taken a very different approach, evaluating and addressing the many potential contributors to cognitive decline for each patient. This has led to unprecedented improvements in cognition. Most importantly, the improvement is typically sustained unless the protocol is discontinued, and even the initial patients treated in 2012 have demonstrated sustained improvement. This effect implies that the root cause(s) of the degenerative process are being targeted, and thus the process itself is impacted, rather than circumventing the process with a monotherapeutic that does not affect the pathophysiology.
Let’s hope that some of this advice for trying to prevent Alzheimer’s is right, or that better advice is coming soon.
For annotated links to other posts on diet and health, see “Miles Kimball on Diet and Health: A Reader's Guide.”
In relation to Cancer, which I mentioned at the beginning of this post, you might be interested in these:
I was quite interested to read the scientific article “Association Between Religious Service Attendance and Lower Suicide Rates Among US Women,” by Tyler J. VanderWeele, Shanshan Li, Alexander C. Tsai and Ichiro Kawachi. I was wondering by what magic they were hoping to get the causal effect of religious attendance on suicide from the non-experimental data in the Nurse’s Health Study. (I wrote about dietary evidence in the Nurse’s Health Study and the statistical issues in interpreting that evidence in “Hints for Healthy Eating from the Nurse's Health Study.”)
It would have been interesting to see the regression coefficient for a change in religious attendance. Unfortunately, it seems they didn’t look at that, but rather “controlled” for past religious attendance. “Controlling” for a variable by including it in a regression isn’t really controlling for what that variable is intended to measure or is proxying for when that variable is measured with error relative to what it is proxying for. It is only partially controlling. Whether or not one is “controlling” for variables can only be verified when one explicitly thinks through measurement error issues. And “controlling” for variables is seldom achieved without thinking through measurement error issues. (The advantage of using the first difference of religious attendance as a right-hand-side variable is that the first difference of religious attendance should measure the true change in whatever religious attendance is intended as a proxy, plus error. The error should bias the coefficient toward zero, but is less likely to change the sign and statistical significance of the sign of the coefficient.)
But the biggest issue with the paper lies in a different direction. They recognize the issue and try to parry it in these passages:
For an unmeasured confounder to explain the HR estimate of 0.16 (95% CI, 0.06-0.46), the unmeasured confounder would have to both increase the likelihood of religious service attendance and decrease the likelihood of suicide by 12-fold above and beyond the measured confounders; weaker confounding would not suffice. To bring the estimate’s upper confidence limit of 0.46 above 1.0, the unmeasured confounder would still have to both increase the likelihood of religious service attendance and decrease the likelihood of suicide by 3.7-fold above and beyond the measured confounders.
Our study made use of observational data. Although we adjusted for major confounders regarding the association between religious service attendance and suicide, the results may still be subject to unmeasured confounding by personality, impulsivity, feelings of hopelessness, or other cognitive factors. However, in sensitivity analysis, for an unmeasured confounder to explain the effect of religious service attendance on suicide, it would have to both increase the likelihood of religious service attendance and decrease the likelihood of suicide by greater than 10-fold above and beyond the measured covariates. Such substantial confounding by unmeasured factors seems unlikely, given adjustment for an extensive set of covariates and the known risk factor associations for suicide.
Unlike the authors, it is not hard for me to think of a very powerful potential confounder. Having one’s life be a mess could easily both reduce religious attendance powerfully and powerfully increase the probability of suicide. That is a story in which there wouldn’t have to be any causal effect of religious attendance on suicide at all.
Note that one’s life being a mess could both lead to more suicide and reduce any kind of social engagement and community support. So this is a problem not just for showing that religiosity can reduce suicide—which it might through social support and community—but for showing that any other kind of social support and community reduces suicide.
Even if something religious is causally reducing suicide, it definitely doesn’t have to be religious attendance. Anything correlated with religious attendance could also yield the evidence they point to. To see this point, suppose someone very much wanted to attend church, but was geographically too far away to make it feasible. One could easily imagine that if there are religious forces that reduce suicide, many of them might still be operative. Indeed, the authors recognize that it might be a matter of religious belief that both helps lead to religious attendance and reduces suicide:
Although religious service attendance has commonly been used in previous published studies and tends to be the strongest religious predictor of health, religiosity is multidimensional, and different aspects of religion and spirituality may therefore be differently associated with suicide. Data on religious service attendance were collected through a self-reported questionnaire and, moreover, may be subject to measurement error and possible overreporting, although the relative ordering of frequency might still be preserved. Further research could examine other religious practices, mindfulness practices, other aspects of spirituality and religiosity, other race/ethnic and demographic groups, and other forms of social participation.
In the whole paper, the most persuasive evidence about the effect of religiosity on suicide is that religious attendance seemed to have a bigger proportional effect on Catholics than on Protestants. The best I can come up with as confounders for this results are
Relative to Protestant teaching, Catholic teaching doesn’t stop people from committing suicide, but makes people underreport suicide more if they are a believing and attending Catholic. And those who provide or withhold crucial evidence on cause of death often have similar religious beliefs and attendance to the one who died. This could in principle be addressed by looking at differences between the attendance of the one who died versus the attendance of the ones who provided or withheld crucial evidence about the cause of death.
Relative to Protestant teaching, Catholic teaching makes people especially unwilling to attend when their lives are in a mess.
Despite these possible stories (which may or may not be true and may or may not have any oomph to them), the fact that the differential content of Catholicism vs. Protestantism seems to matter is the strongest evidence they have that there is causality running from religiosity to reduced suicide.
I would love to see a paper that tried to get identification to test the effect of church attendance on suicide in the typical way economists try to get identification. For example, do people who live further from the nearest church commit suicide more often? That might be a doable research project. And one could do some good placebo tests by running regressions with closeness to community centers, or stores or bars as well as the regressions on closeness to a church.
For another post at the intersection of religion and statistics, don’t miss “Who Leaves Mormonism?”
Spencer Jakab’s July 5, 2019 Wall Street Journal shown above, “Investors Are Trapped in Bizarro World,” puzzles over why the stock market went down after a better-than-expected job report. Let me propose a simple explanation: a Fed that is beginning to do a part of its job better.
Here is the argument:
The Effect of a Positive Demand Shock on the Stock Market If the Fed is Doing Its Job Right
To a reasonable approximation, optimal monetary policy is pretty close to keeping output (GDP) at its natural level. This is what I mean by “the Fed doing its job right”—not perfectly according to every nuance in the optimal monetary policy literature, but simply keeping the output gap between actual output and natural output zero to the limit of its ability. Note that if the Fed is doing this, it is not itself a big source of demand shocks because it is being appropriately reactive to events.
Define a positive demand shock as anything that leaves the natural level of output the same, but raises the level of the real interest rate necessary to keep the actual level of output at that natural level. Fiscal policy shocks are one possible candidate. But “animal spirits” may be another. In context, I am assuming that a surprisingly good jobs report is often a sign of one of these positive aggregate demand shocks.
Assume that higher output (GDP) has a positive effect on the stream of real future dividends a firm will pay out, while a higher real interest rate has a negative effect on the present value of any given stream of real dividends.
If the Fed is doing its job well, a positive demand shock shouldn’t change actual output much because the job is to match actual output to natural output and by the definition of a demand shock, natural output hasn’t changed. But then by the other part of the definition of a positive demand shock, the real interest rate should go up. In the usual notation, Y same, r up. Note that “r up” may mean that the Fed won’t cut rates as quickly as people had thought. “r up” is all relative to prior expectations.
Y same, so there is no affect on stock prices from that source. But r up tends to make stock prices go down. That’s the end of the argument.
The Effect of a Positive Technology Shock on the Stock Market If the Fed is Doing Its Job Right
Let’s contrast the effect of a demand shock if the Fed is doing its job right to the effect of a technology if the Fed is doing its job right. My argument for a technology shock takes a different angle, and is somewhat simpler.
Keeping the output gap zero as the Fed should be doing, means that the economy is close to doing what a real business cycle model would do.
In what is called the “Divine Coincidence,” keeping the output gap zero also (at least approximately) keeps the rate of inflation steady.
Typically, real business cycle models predict that investment should go up in response to a positive technology shock. (I have been interested in my research in showing that this is quite general.) If investment is going up, then the value of a firm’s preexisting capital should also go up. Even in fairly general models, the value of firms should on average go up if investment in the economy has increased.
Typically, the real interest rate goes up in real business cycle models in response to a positive technology shock. (I have been interested in my research in showing that this is quite general.) This increase in the real interest rate, coupled with inflation unchanged, means the value of a firm’s debt will go down.
The value of the firm going up and the value of its debt going down together imply that stock prices should go up.
I don’t want to be mistaken for saying that the Fed is doing its job right. Indeed, I have a long wishlist for how the Fed should improve its conduct of monetary policy. See my post “Next Generation Monetary Policy.” But it is a sign of progress if the stock market has begun to react in both of the ways described above.
My interest in diet and health makes me curious enough to perservere through overly lengthy informercials giving various diet and health claims. A few days ago, I watched this infomercial for the Trim Down Club. Let me give you a report of what I heard, to save you the time. Although there are a lot of important things about diet and health that the informercial didn’t say, I agreed with everything it did say, with one exception. The exception is that the infomercial gave the usual flawed advice to spread one’s eating out over time. It is possible this is good advice when someone is eating foods that have a big insulin kick (see “Forget Calorie Counting; It's the Insulin Index, Stupid”) so that an especially big meal of those kinds of foods would have a very large insulin kick, but even then the accumulating evidence on the virtues of periodic fasting (often called “intermittent fasting” or IF) calls that advice into question. (A Plea: I would love to know what research article or articles people cite to claim that eating lots of small meals throughout the day is better than a few big meals. I would be eager to write a post on such an article.)
Here are the areas of agreement:
Sugar is bad. Orange juice is a good example of a high-sugar food people falsely think is innocent
Transfats are bad. Old-style margarine is a good example of a food high in transfats. However, they neglected to mention that there is a partial ban on transfats in many countries. (See the Wikipedia article “Trans Fat.”)
Many highly processed foods that pretend to be good are actually bad. Typical types of “whole-wheat bread” are a good example. (See “The Problem with Processed Food.”)
Nonsugar sweeteners are problematic. (See “Which Nonsugar Sweeteners are OK? An Insulin-Index Perspective.”)
Processed soy products are bad.
Processed meat is suspect.
Stress can make one feel hungrier.
Drinking green tea can make you feel less hungry and may have other benefits.
Combining high-insulin-index foods with high-insulin-index foods can reduce the size of the insulin kick and therefore the hunger rebound effect you are likely to face. (In here is an assumption that the total quantity of the high-insulin-index food you eat is likely to go down somewhat when you are also eating a low-insulin-index food. But that may be true for extremely high-insulin-index foods: see “Does Sugar Make Dietary Fat Less OK?”)
Surprisingly, despite the discussion of a lectin-free diet further down on the Trim Down Club webpage flagged above in its current incarnation, the informercial made no direct mentions of lectins (unless I missed it as the infomercial droned on and on). If you are interested in lectin-free diets, see my post “What Steven Gundry's Book 'The Plant Paradox' Adds to the Principles of a Low-Insulin-Index Diet.”
The reason I titled this post “The Better Side of Conventional Wisdom on Diet and Health” is that the infomercial emphasized that the Trim Down Club employed many licensed or certified dietitians. The advice given seems close enough to conventional wisdom, that I can easily believe that a substantial fraction of licensed and certified dietitians would be willing to sign on to this advice. The advice I give in my diet and health posts goes further beyond conventional wisdom. I strive to give reasons for the advice I give that I hope at least give you a way to evaluate my advice.
For annotated links to other posts on diet and health, see “Miles Kimball on Diet and Health: A Reader's Guide.”
Let me be clear that I don’t necessarily think we need to be worried; I am not at all sure that a Democratic president would follow through on these promises.
One of the longest sections in John Locke’s 2d Treatise on Government: Of Civil Government, is section 222, in the final chapter: XIX, “Of the Dissolution of Government.” In reading this, I sense his righteous anger at bad rulers. In the title of this post, it was hard to be as emphatic as he is. “Bad Rulers May Be Removed. Period.” might say it better.
I consider this sentiment to be something deeply ingrained into the human heart by evolution. Our cousins the chimpanzees feel it too, as you can see by following the link to the video shown above. I am in full agreement with John Locke in what he says in Section 222—not only with the substance of what he says, but also with the passion with which he says it:
§. 222. The reason why men enter into society, is the preservation of their property; and the end why they chuse and authorize a legislative, is, that there may be laws made, and rules set, as guards and fences to the properties of all the members of the society, to limit the power, and moderate the dominion of every part and member of the society: for since it can never be supposed to be the will of the society, that the legislative should have a power to destroy that which every one designs to secure, by entering into society, and for which the people submitted themselves to legislators of their own making; whenever the legislators endeavour to take away, and destroy the property of the people, or to reduce them to slavery under arbitrary power, they put themselves into a state of war with the people, who are thereupon absolved from any farther obedience, and are left to the common refuge, which God hath provided for all men, against force and violence. Whensoever therefore the legislative shall transgress this fundamental rule of society; and either by ambition, fear, folly or corruption, endeavour to grasp themselves, or put into the hands of any other, an absolute power over the lives, liberties, and estates of the people; by this breach of trust they forfeit the power the people had put into their hands for quite contrary ends, and it devolves to the people, who have a right to resume their original liberty, and, by the establishment of a new legislative, (such as they shall think fit) provide for their own safety and security, which is the end for which they are in society. What I have said here, concerning the legislative in general, holds true also concerning the supreme executor, who having a double trust put in him, both to have a part in the legislative, and the supreme execution of the law, acts against both, when he goes about to set up his own arbitrary will as the law of the society. He acts also contrary to his trust, when he either employs the force, treasure, and offices of the society, to corrupt the representatives, and gain them to his purposes; or openly pre-engages the electors, and prescribes to their choice, such, whom he has by solicitations, threats, promises, or otherwise, won to his designs; and employs them to bring in such, who have promised beforehand what to vote, and what to enact. Thus to regulate candidates and electors, and new-model the ways of election, what is it but to cut up the government by the roots, and poison the very fountain of public security? for the people having reserved to themselves the choice of their representatives, as the fence to their properties, could do it for no other end, but that they might always be freely chosen, and so chosen, freely act, and advise, as the necessity of the commonwealth, and the public good should upon examination, and mature debate, be judged to require. This, those who give their votes before they hear the debate, and have weighed the reasons on all sides, are not capable of doing. To prepare such an assembly as this, and endeavour to set up the declared abettors of his own will, for the true representatives of the people, and the law-makers of the society, is certainly as great a breach of trust, and as perfect a declaration of a design to subvert the government, as is possible to be met with. To which, if one shall add rewards and punishments visibly employed to the same end, and all the arts of perverted law made use of to take off and destroy all that stand in the way of such a design, and will not comply and consent to betray the liberties of their country, it will be past doubt what is doing. What power they ought to have in the society, who thus employ it contrary to the trust went along with it in its first institution, is easy to determine; and one cannot but see, that he, who has once attempted any such thing as this, cannot any longer be trusted.
I should say that the principle that bad rulers can be removed is, I believe, satisfied relatively well by our periodic elections in the US: our elections have the power to sweep out the bulk of our rulers within a period of six years.
For links to other John Locke posts, see these John Locke aggregator posts:
Hat tip to John L. Davidson.