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Whole grain breads that is argued to be harmful

Grain Brain

In his updated book, Grain Brain, David Perlmutter, MD, explains how blood sugar determines brain health, how insulin resistance relates to Alzheimer’s risk, and how gluten sensitivity is a key culprit in brain disease.

Scientifically reviewed by Dr. Gary Gonzalez, MD, in October 2024. Written by: David Perlmutter, MD.

Neurodegenerative diseases like Alzheimer’s are expected to become a “global epidemic” by 2050, with the number of patients predicted to reach 135 million worldwide, according to the World Health Organization.

Dr. David Perlmutter, board-certified neurologist and a Fellow of the American College of Nutrition, believes he has found the answer to this burgeoning epidemic. According to Perlmutter, the culprit isn’t found in your genes; it’s on your plate.

In his book, Grain Brain, Perlmutter details how wheat, carbs, and sugar are toxic substances that are poisoning our brains. When it was first released in 2013, it became a New York Times best seller, with more than 1.5 million copies sold, and it established Perlmutter as the leading authority on the dangers of eating wheat, carbs, and sugar.

Perlmutter has released a five-year-anniversary edition that has been completely revised and updated to reflect the latest nutritional and neurological science. This new edition includes details on how blood sugar determines brain health, how insulin resistance relates to Alzheimer’s risk, and how being gluten sensitive is a key culprit behind brain diseases ranging from depression to dementia.

More importantly, Perlmutter helps you make the transition away from relying on harmful carbs—and toward a more brain-healthy lifestyle—with his detailed four-week plan of action. He includes meal plans and recipes, the best nutrients for brain health, and tips for maintaining these healthy habits for life.

“From my perspective, getting the word out that people can make simple changes to prevent a disease like Alzheimer’s, for which there is no meaningful treatment, not only makes sense, but is imperative,” said Perlmutter. “Now that so many physicians seem steeped in providing drug remedies, it is the right time to take a step back, review current science, and get the word out that the patients for whom we care can make choices, today, to remain healthy.”

In this exclusive interview with Life Extension®, Perlmutter talks in more detail about how grains are destroying our brains, and how, through simple dietary changes, you have the power to prevent—and even reverse—brain conditions ranging from headaches, anxiety, and depression, to ADHD, insomnia, and even dementia.

—Laurie Mathena

LE: Many people believe that brain diseases like Alzheimer’s are genetic, but you have a different explanation.

Dr. Perlmutter: There are plenty of perpetual myths about the basket of brain-degenerating maladies, which include Alzheimer’s:It’s in the genes, it’s inevitable with age, and it’s a given if you live into your eighties and beyond.

Not so fast.

Woman holding head

I’m here to tell you that the fate of your brain is not in your genes. It’s not unavoidable. And if you’re someone who suffers from another type of brain disorder, such as chronic headaches, depression, epilepsy, or extreme moodiness, the culprit may not be encoded in your DNA.

It’s largely in the food you eat.

LE: What is the number one culprit responsible for brain diseases?

Dr. Perlmutter: If the thought of your brain suffering over a bowl of savory pasta or plate of sweet French toast seems far-fetched, brace yourself. You probably already knew that processed sugars and carbs weren’t all that great for you, especially in excess, but so-called healthy carbohydrates like whole grains and natural sugars? Welcome to the whole grain truth.

Modern grains are silently destroying your brain. By “modern,” I’m not just referring to the refined white flours, pastas, and rice that have already been demonized by the anti-obesity folks. I’m referring to all the grains that so many of us have embraced as being healthful—whole wheat, whole grain, multigrain, seven-grain, live grain, stone-ground, and so on. Basically, I am calling what is arguably our most beloved dietary staple a terrorist group that bullies our most precious organ, the brain.

In the fall of 2012, a report in the Journal of Alzheimer’s Disease published research from the Mayo Clinic revealing that older people who fill their plates with carbohydrates have nearly four times the risk of developing mild cognitive impairment (MCI), generally considered a precursor to Alzheimer’s disease.

LE: What exactly is gluten?

Dr. Perlmutter: Gluten—which is Latin for “glue”—is a protein composite that acts as an adhesive material, holding flour together to make bread products, including crackers, baked goods, and pizza dough.

Gluten is our generation’s tobacco. Gluten sensitivity is far more prevalent than we realize—potentially harming all of us to some degree without our knowing it—and gluten is hiding where you least suspect it. It’s in our seasonings, condiments, and cocktails, and even in cosmetics, hand cream, and ice cream. It’s disguised in soups, sweeteners, and soy products.

LE: Why is gluten so harmful to the brain?

Dr. Perlmutter: Researchers have known for some time now that the cornerstone of all degenerative conditions, including brain disorders, is inflammation. But what they hadn’t documented until now are the instigators of that inflammation—the first missteps that prompt this deadly reaction. And what they are finding is that gluten, and a high-carbohydrate diet for that matter—are among the most prominent stimulators of inflammatory pathways that reach the brain.

In 2017 a consortium of scientists from high-profile institutions reported in the journal Neurology that high levels of inflammatory markers in the blood during midlife were associated with smaller brain volumes in late life.

Woman Checking Blood Sugar

But even casting aside the gluten factor, I should point out that one of the main reasons why consuming so many grains and carbs can be so harmful is that they raise blood sugar in ways that other foods, such as meat, fish, poultry, and vegetables, do not.

LE: Speaking of blood sugar, what is the connection between diabetes and dementia?

Dr. Perlmutter: First, if you’re insulin resistant, not only will you starve brain cells and spur their death, but your body may not be able to break down the amyloid protein that forms those infamous plaques associated with brain disease.

Second, high blood sugar provokes menacing biological reactions that injure the body by producing certain oxygen-containing molecules that damage cells and cause inflammation that can result in hardening and narrowing of the arteries in the brain (not to mention elsewhere in the body). This condition, known as atherosclerosis, can lead to vascular dementia, which occurs when blockages and strokes kill brain tissue.

Newer research is now documenting how controlling blood sugar and reducing risk factors for type II diabetes can significantly reduce dementia risk.

LE: Is this impact of high blood sugar only a problem for diabetics?

Dr. Perlmutter: What I find really interesting is that newer studies are showing that people with high blood sugar—whether or not they have diabetes—have a higher rate of cognitive decline than those with normal blood sugar. This was true in one particularly disturbing longitudinal study from 2018 following more than 5,000 people over 10 years. Their rate of cognitive decline—regardless of whether or not they were diabetic—hinged on blood sugar levels. The higher the blood sugar, the faster the decline—even in the non-diabetics.

Woman turning down bread

LE: Gluten is known to be problematic for people with celiac disease, but what about those without celiac?

Dr. Perlmutter: Gluten isn’t just an issue for those with bona fide celiac disease. As many as 40% of us can’t properly process gluten, and the remaining 60% could be in harm’s way. The question we all need to be asking ourselves is this: What if we’re all sensitive to gluten from the perspective of the brain?

Gluten sensitivity in particular is caused by elevated levels of antibodies against the gliadin component of gluten. When the antibody combines with this protein (creating an anti-gliadin antibody), specific genes are turned on in a special type of immune cell in the body. Once these genes are activated, inflammatory cytokine chemicals collect and can attack the brain. Cytokines are highly antagonistic to the brain, damaging tissue and leaving the brain vulnerable to dysfunction and disease especially if the assault continues.

Given this, it’s no wonder that elevated cytokines are seen in Alzheimer’s disease, Parkinson’s disease, major depression, multiple sclerosis, and even autism.

LE: Does this mean everyone should get tested for gluten sensitivity?

Dr. Perlmutter: I no longer recommend testing for gluten sensitivity because it’s best to assume that you are sensitive to gluten and avoid it entirely—even if you have no celiac and have tested negative to gluten sensitivity in the past.

LE: But you do recommend getting a fasting insulin test. Why is that?

Dr. Perlmutter: Having normal blood sugar levels may mean that the pancreas is working overtime to keep that blood sugar normal. Based upon this understanding, you can see that high insulin levels will happen long before blood sugar rises and a person becomes diabetic. That’s why it’s so important to check not only your fasting blood sugar, but also your fasting insulin level. An elevated fasting insulin level is an indicator that your pancreas is trying hard to normalize your blood sugar. It’s also a clear signal that you are consuming too much carbohydrate.

And make no mistake about it: Even being insulin resistant is a powerful risk factor for brain degeneration and cognitive impairment.

Consider an Italian study done back in 2005 that looked at 523 people aged 70 to 90, who did not have diabetes or even elevated blood sugar. Many of them were insulin resistant, however, as determined by their fasting insulin levels. The study revealed that those individuals who were insulin resistant had a dramatically increased risk of cognitive impairment compared to those within the normal range.

LE: What other neurological problems can gluten impact?

Dr. Perlmutter: The facts of “grain brain” go far beyond just hampering neurogenesis and increasing your risk for cognitive challenges that will progress stealthily over time. A diet heavy in inflammatory carbs and low in healthy fats messes with the mind in more ways than one—affecting risk not just for dementia but for common neurological ailments such as ADHD, anxiety disorder, Tourette’s syndrome, mental illness, migraines, and even autism.

LE: You discuss shifting away from carbs and toward healthy fats like those found in fish, olive oil, avocado, and nuts. Why is fat so critical for brain health?

Dr. Perlmutter: Fat is and always has been a fundamental pillar of our nutrition. Beyond the fact that the human brain consists of more than 70% fat, fat plays a pivotal role in regulating the immune system. Simply stated, good fats like omega‑3s and monounsaturated fats reduce inflammation, while modified hydrogenated fats, so common in commercially prepared foods, dramatically increase inflammation.

Certain vitamins, notably A, D, E, and K, require fat to get absorbed properly in the body, which is why dietary fat is necessary to transport these “fat-soluble” vitamins. Because these vitamins do not dissolve in water, they can be absorbed from your small intestine only in combination with fat. Deficiencies due to incomplete absorption of these vitally important vitamins are always serious, and any such deficiency can be linked to brain illness, among many other conditions.

LE: Are there nutrients you can take that will help protect the brain from the harmful effects of grains and other carbs?

Gluten free

Dr. Perlmutter: Perhaps no other brain-boosting molecule is receiving as much attention lately as is docosahexaenoic acid (DHA). For the past several decades, scientists have been aggressively studying this critical brain fat for at least three reasons.

First, more than two-thirds of the dry weight of the human brain is fat, and of that fat, one-quarter is DHA. Structurally, DHA is an important building block for the membranes surrounding brain cells, particularly the synapses, which lie at the heart of efficient brain function.

Second, DHA is an important regulator of inflammation. It naturally reduces the activity of the COX-2 enzyme, which turns on the production of damaging inflammatory chemicals. DHA also acts like a warrior in many ways when it enters hostile territory brought on by poor diet.

It can fight back inflammation when a war ensues within the intestinal lining of a gut that is gluten sensitive. And it can block the damaging effects of a diet high in sugar, especially fructose, and help prevent metabolic dysfunctions in the brain that can result from too many carbs in the diet.

The third, and arguably most exciting, activity of DHA is its role in regulating gene expression for production of BDNF (which plays a key role in creating new neurons). Put simply, DHA helps orchestrate the production, connectivity, and viability of brain cells, while at the same time enhancing function.

LE: In your book, you take readers through a four-week plan of action to remove grains and other carbohydrates from their diet. Besides helping prevent dementia, what other results can be expected from following your grain-free program?

Dr. Perlmutter: Some of my most remarkable case studies involve people transforming their lives and health through the total elimination of gluten from their diets and a new appreciation for fats instead of carbs. I’ve watched this single dietary shift lift depression, relieve chronic fatigue, reverse type II diabetes, extinguish obsessive-compulsive behavior, and cure many neurological challenges, from brain fog to bipolar disorder.

LE: The information about diet and brain disorders is actually very encouraging.

Dr. Perlmutter: The idea that we can treat—and in some cases, totally eliminate—common neurological ailments through diet alone is empowering. Most people immediately turn to drugs when seeking a solution, oblivious to the cure that awaits them in a few lifestyle shifts that are highly practical and absolutely free.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

Excerpted from Grain Brain (Revised Edition). Copyright © 2018 by David Perlmutter, MD and Kristin Loberg. Used with permission of Little, Brown and Company,
New York. All rights reserved.

Grain Brain
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