Grain Brain – Dr. Perlmutter’s Controversial Book on Dietary Grain Perils

Consuming too many carb-laden foods over time leads to high blood sugar, insulin resistance, and chronic inflammation.

Dr. Perlmutter proposes that our high-gluten/high-carb diets can cause just about any brain disorder but are especially destructive when it comes to Alzheimer's disease and other forms of dementia.

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Why on earth would you give up the “staff of life”? To prevent and treat brain-related diseases—everything from chronic headaches to depression to Alzheimer’s, asserts Dr. Perlmutter in his controversial book, Grain Brain.

Dr. Perlmutter proposes that our high-gluten/high-carb diets can cause just about any brain disorder but are especially destructive when it comes to Alzheimer’s disease and other forms of dementia. He wants his readers to understand what the medical literature clearly suggests but is largely ignored—that Alzheimer’s is largely preventable with diet and lifestyle changes centered on carbohydrate restriction. It’s not just the simple, refined, processed carbs like white bread and sugar that have to go, he argues, but even the healthy ones like whole grains and most fruit.

The reason? Consuming too many of these carb-laden foods over time leads to high blood sugar, insulin resistance, and chronic inflammation. Dementia is still largely viewed as the inevitable result of bad genes and aging. But the truth is that high blood sugar, insulin resistance, and chronic inflammation are each destructive to the brain and have been identified as underlying causes of Alzheimer’s disease and other brain maladies.

Alzheimer’s dementia is “type 3 diabetes”

Carb-heavy, grain-loaded diets elevate blood sugar levels and cause insulin resistance, the condition in which cells fail to respond to the normal actions of the hormone insulin, leading to more and more insulin production. High blood sugar and insulin levels cause chronic inflammation which in turn leads to excessive free radical production and oxidation. This oxidative stress then fuels what is known as mitochondrial dysfunction within nerve cells, leading to their degeneration and destruction. In the end, both high blood sugar and insulin resistance are significantly correlated with brain shrinkage and increased risk of cognitive impairment and Alzheimer’s disease. This link between blood sugar metabolism and Alzheimer’s disease has already prompted a number of medical researchers to label Alzheimer’s as “type 3 diabetes.”

Why is gluten bad for you?

Besides the type 3 diabetes nissue, there is an additional way in which our current high-carb diet causes inflammation and brain cell destruction, according to Dr. Permutter: gluten. His gluten argument is similar to that of the Paleo diet advocates; he contends that today’s wheat varieties contain unprecedented amounts of gluten—a group of addictive proteins to which we are neither genetically nor physiologically adapted.

Dr. Perlmutter controversially claims that gluten sensitivity affects about a third of us (other researchers have calculated the number to be 6%, while full-blown celiac disease is estimated to afflict another 1% of the population). The answer to the question, “Is gluten bad for you?” may depend on whether you’re sensitive to it or not. Researchers have now clearly demonstrated how both celiac disease and gluten sensitivity can cause immune dysregulation and inflammation that can attack numerous body systems including the brain and nervous system and can manifest as any number of conditions, including dementia and other disorders of the brain and nervous system, without “typical” digestive symptoms.

Is a grain-free diet for you?

The good news is that we know what causes high blood sugar, insulin resistance, and chronic inflammation; and we know how to prevent and treat these conditions with dietary and lifestyle therapies. By eliminating gluten, drastically decreasing total carb consumption, and increasing healthy fats like those found in fish, avocado, coconut, and nuts, Dr. Perlmutter argues that brain diseases are largely preventable. To keep your most precious organ—your brain—in tip-top shape, make vegetables, high-quality proteins and healthy fats the foundation of your diet.

Not surprisingly, Dr. Perlmutter has his fair share of critics. Some point out that vegan, vegetarian, and plant-based diets like the traditional Mediterranean diet are all typically high-carb, yet have been found in numerous studies to be associated with lower rates of cancer, heart disease, and many other chronic diseases, including dementia. Meat-centric diets, on the other hand, are often correlated with increased risk of chronic disease. Critics have also questioned the potentially negative impact of saturated fat and cholesterol on cardiovascular health. Others doubt the sustainability and affordability of grass-fed, free-range, and/or wild animal products.

What’s your experience with Grain Brain?

Have you read Grain Brain? Are you willing to go low-carb or follow a grain-free diet for the sake of your brain? What do you think about this intriguing concept presented by Dr. Perlmutter? Let us know what you think in the comments section below.


This post originally appear in 2013 and has been updated.

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  • I follow the ketogenic diet which is a grain-free low carb diet and am amazed at how much better I feel. I do have a friend who cut out gluten even though she wasn’t gluten-sensitive, and now she is SEVERELY gluten-sensitive. So, I’m torn as to whether going totally gluten-free is a good thing for everybody, but I’m certainly off the bread and sugar and that’s a start. 🙂

  • My family tries to go “gluten reduced” and “grain reduced” because we are not gluten sensitive but we realize the potential adverse effects of gluten on gut health and grains on blood sugar health. But Dr. Perlmutter’s assertion that high-gluten/high-carb diets can cause Alzheimer’s and other forms of dementia will cause us to be even more diligent.

    Association of Alzheimer disease pathology with abnormal lipid metabolism: the Hisayama Study.


    The relationship between lipid profiles and Alzheimer disease (AD) pathology at the population level is unclear. We searched for evidence of AD-related pathologic risk of abnormal lipid metabolism.

    This study included brain specimens from a series of 147 autopsies performed between 1998 and 2003 of residents in Hisayama town, Japan (76 men and 71 women), who underwent clinical examinations in 1988. Lipid profiles, such as total cholesterol (TC), triglycerides, and high-density lipoprotein cholesterol (HDLC), were measured in 1988. Low-density lipoprotein cholesterol (LDLC) was calculated using the Friedewald formula. Neuritic plaques (NPs) were assessed according to the Consortium to Establish a Registry for Alzheimer’s Disease guidelines (CERAD) and neurofibrillary tangles (NFTs) were assessed according to Braak stage. Associations between each lipid profile and AD pathology were examined by analysis of covariance and logistic regression analyses.

    Adjusted means of TC, LDLC, TC/HDLC, LDLC/HDLC, and non-HDLC (defined as TC-HDLC) were significantly higher in subjects with NPs, even in sparse to moderate stages (CERAD = 1 or 2), compared to subjects without NPs in multivariate models including APOE ε4 carrier and other confounding factors. The subjects in the highest quartiles of these lipid profiles had significantly higher risks of NPs compared to subjects in the lower respective quartiles, which may suggest a threshold effect. Conversely, there was no relationship between any lipid profile and NFTs.

    The results of this study suggest that dyslipidemia increases the risk of plaque-type pathology.
    For the study, which is published in the journal Neurology, researchers used blood tests to measure cholesterol in 147 Japanese adults 10 to 15 years before their deaths. Fifty of them (or 34%) had been diagnosed with dementia.

    Tissue samples from their brains were then examined on autopsy.

    Those who had total cholesterol levels over 224 mg/dL in mid- to late life, before they had any symptoms of Alzheimer’s, were at least seven times more likely to have beta-amyloid plaques in their brains by the time they died, compared to people whose cholesterol was under 173 mg/dL. The American Heart Association considers total cholesterol levels below 200 mg/dL to be desirable.

    LDL, or “bad,” cholesterol over 155 mg/dL was also strongly associated with the likelihood of developing beta-amyloid plaques, compared to people whose LDL was lower than 106 mg/dL. People with high LDL levels were at least eight times more likely to display pathologic features of Alzheimer’s disease. Ideal LDL levels are felt to fall below 100 mg/dL, according to the AHA.

    The relationship to cholesterol values remained after researchers adjusted for other things that are thought to influence the risk of Alzheimer’s disease, like age, sex, body weight, aerobic exercise, blood pressure, a history of stroke, and blood sugar and insulin levels.

  • Absolutely correct! I have idiopathic neuropathy in my feet. A very low carb diet helps my feet and I have more energy. All this low fat diet stuff is misguided. The ADA has it backwards!

  • cvictorg, thank you for the information regarding the study showing the direct relationship between LDL and Alzheimer’s disease.

  • Been trying out the diet, just to see how it feels. I’ve been mostly constipated but can help it with Ayurveda etc, however with this diet I need to go to the toilet five six times a day, if not more. I am not sure if this is good either, does anybody have some useful advice? I’ve been searching the web if other people have this effect, can’t find anything.

  • I friendly reminder that Grain Brain is not Dr. Perlmutter’s “latest” book. He recently published “Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life”. It was completely different than Grain Brain — did not cover the evil of grains at all.

    While first reaction to his recommendations is that it’s not necessary to reduce carbs that low for a healthy brain. However, I think a surprising number of people would benefit from reducing or eliminating wheat. I recommend cutting it out for a month and notice what happens. The first thing I found was that my hunger diminished dramatically and that alone made it worth the effort. Now I’m in control of what I eat so I make healthier choices.

  • The only “diet” I have ever followed is Sean Croxton’s JERF (Just Eat Real Foods) Diet. The only foods that I make a point of avoiding are: (a) anything that contains any artificial ingredients (virtually all processed foods, including processed vegetable oils); (b) any produce contaminated with pesticides; and (c) any “factory farmed” (CAFO) animal products where the animals are treated with hormones and/or antibiotics, and are fed foods they would not ordinarily eat, like feeding soy and corn to cows producing dairy or butchered for meat.

    Of course we hear a lot from strict “Paleo” advocates who claim that everyone should avoid eating any and all grains on the grounds that they have been so recently introduced into the human diet that we simply haven’t had time, as a species, to “evolve” the ability to properly digest them. However, these days even Dr. Perlmutter is totally on board with the fact that our intestinal microbiome, which contains 90% of the cells and 99% of the genetic information in our bodies, makes an enormous contribution to every aspect of our health. Of course those microbes evolve and adapt as species orders of magnitude faster than we do because their individual lifespans are so short. There is also enormous variability among us in terms of what particular micro-organisms our microbiomes contain. On top of that, we have recently been hearing so much about the veritably exploding new field known as epigenetics, where our genes are selectively turned on and off in response to environmental influences, with the possibility of even passing along at least some of those adaptations to subsequent generations.

    Personally, I try to minimize my consumption of refined products generally, especially concentrated carbohydrates like wheat flour, sugar and fruit juices, with a goal of keeping my blood glucose levels on an even keel and preventing the kind of spikes that can eventually lead to such conditions as chronic inflammation, insulin resistance and Type II Diabetes. But that is hardly going to keep me from enjoying 6 or 8 Wasa rye crackers per week as part of my regular diet just because there happens to be some, maybe even many others who find that their health improves significantly when they eschew either all grains or just specific grains like wheat and rye. In my own case, I believe that not stirring a tablespoon of sugar into each cup of green tea I drink is far more important for my brain health than whether or not I choose to occasionally accompany it with a Wasa cracker topped with butter and natural aged cheese from grass-fed cows.

    The bottom line, for me, is that each of us is a physiologically unique individual, and the “right” thing for us in terms of our personal diets can only be learned by listening carefully to our own bodies, not by anything we may read in this book or that. And of course even the authors of those books (like Dr. Perlmutter, whose work I very much admire) may very well have significantly modified their own views between the time they wrote them and the time we read them.

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