Are Carbs Messing with Your Brain?
In his new book, Grain Brain, out today, Dr. David Perlmutter attempts to close the case on the devastating effects of gluten, carbs, and sugar on our bodies. But it's not just our waistlines that are in jeopardy, he says-these ingredients could be wreaking even bigger havoc on our brains by causing Alzheimer's, or what he calls "type 3" diabetes. By Meghann Foye, REDBOOK.
In Grain Brain you make a very strong case linking wheat, carbs, and sugar with an increased likelihood of many degenerative and chronic diseases, but most definitively brain dysfunction, and namely Alzheimer's, which you call "type 3" diabetes. Can you explain the science behind the link?
The science supporting the relationship between carbohydrates and dementia is quite exciting, as it paves the way for lifestyle changes that can profoundly affect a person's chances of remaining intact, at least from a brain perspective. In a recent study published by the Mayo Clinic, those consuming a higher-fat, lower-carbohydrate diet had an astounding 65 percent risk reduction for dementia. Likely the advantage to the lower-carbohydrate diet stems from its effect on lowering blood sugar, as studies have clearly linked lower blood sugars to reduced risk of dementia, and specifically Alzheimer's disease. As blood sugar elevates, it dramatically changes brain proteins leading to increased production of damaging chemicals called free radicals, as well as increasing damaging chemical mediators of inflammation. Both of these processes are now recognized as pivotal players in the degeneration of the brain seen in Alzheimer's disease. Moreover, research (also from the Mayo Clinic) now connects gluten sensitivity to brain inflammation and dementia. So it's important not only to maintain a low-carbohydrate diet, but to remain strictly gluten-free, especially if laboratory testing reveals gluten sensitivity.
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You say that while as many as one in 30 may have celiac disease, you believe most of us probably have some level of inflammation response in the brain from ingesting gluten and should avoid it altogether if we want to preserve our health-that the mentally foggy feeling we may have after a carb-loaded meal isn't something to write off.
New research reveals that all humans have a response to consuming gluten that actually makes the intestinal wall more permeable, or "leaky." This sets the stage for allowing the entrance of proteins into the bloodstream where they would have otherwise been excluded. These proteins, including gliadin, which is derived from gluten, challenge the immune system and induce inflammation, a cornerstone of Alzheimer's and other neurodegenerative diseases. The story of gluten as it relates to the brain throws a wide net, so much more encompassing than the inflammation of a small section of the small intestine that characterizes celiac disease.
Is it the gluten? The carbs? Or all the manmade and processed additives that we typically find in commercial bread and other baked goods-or a mixture of all three-that is really the issue?
Carbohydrates, whether derived from gluten-containing foods or other sources including fruit, sweetened beverages, and starchy vegetables, are dangerous as they relate to brain health in and of themselves. Many gluten-containing foods are also high in carbohydrates, and therefore provide a double-dose of risk as it relates to brain health, since gluten is linked to inflammation. But even beyond those concerns, these days there are plenty of preservatives, coloring agents, and flavoring agents used in commercial food preparation, not to mention the concerns over genetic modification. So it makes sense to avoid commercially-prepared foods and opt for low-carbohydrate, gluten-free, organic choices whenever possible.
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What are the main nutrients our diets are lacking, and what supplements can we take to make sure we're getting what we need?
What comes as the biggest surprise to most people is the idea that their diets are deficient in one of the most important keys to maintaining health: fat. Our fat phobia has exploded on the scene since the early 1990s, and nothing could be worse for human health. Clearly there are fats to be avoided-the modified and trans fats so ubiquitous in prepared foods. But healthful, omega-3 rich fats, monounsaturated, and even saturated fats have been a part of the human diet for over 2 million years, and are vital to human health.
What is the ideal diet for health maintenance, and what's your typical daily meal plan?
The best diet for overall health, and specifically for heart, brain, and cancer risk reduction, is a diet that's aggressively low in carbohydrates with an abundance of healthful fat, and this is the central theme of Grain Brain. I choose to focus on eating above-ground colorful vegetables, wild fish, nuts, seeds, free-range eggs, occasional grass-fed red meat, and an abundance of fat from foods like olive oil, avocados, and coconut oil. And coffee is absolutely on the list.
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There have been many conflicting studies about how much and what types of exercise we need to do to stay healthy. What's your advice?
Aerobic exercise, above all else, has been demonstrated to actually turn on the genes that code for BDNF, a specific protein that acts as a growth hormone in the brain's memory center. Studies have confirmed that we as humans actually retain the ability to grow new brain cells, a process called neurogenesis. And neurogenesis is enhanced by aerobic activity. This is an empowering consideration. You can choose to grow new brain cells based on your dedication to exercise! I generally recommend a 20-minute aerobic program six days each week as a minimum.
Paleo, plant-based, gluten-free-this fall alone there are dozens of big-name diet books on the market, all making opposing claims about the perfect ratio of protein, fat, and carbs for optimal health. What do you say to people who may be feeling "diet fatigue" right now while trying to sift through everything out there to find a diet that really works for them?
Just look at the best-seller list. There is a dizzying array of dietary recommendations, and every week there is something new that guarantees weight loss, longevity, and who knows what else? But there are two powerful arguments supporting the choice to dramatically reduce sugars and carbs while increasing dietary fat. First, current science, as published in highly-respected journals like the New England Journal of Medicine, and the Journal of the American Medical Association, has now supported this approach as being the most sound dietary plan. But even more fundamentally, we as humans have never consumed any significant level of carbohydrates, or gluten for that matter, in the entire 2.6 million years that we have walked the planet.
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