Grain Brain

“While it’s well established that processed foods and refined carbohydrates have contributed to our challenges with obesity and so-called food allergies, no one has explained the relationship between grains and other ingredients and brain health and, in the broader outlook, DNA. It’s pretty straightforward: Our genes determine not just how we process food but, more important, how we respond to the foods we eat. There is little doubt that one of the largest and most wide-reaching events in the ultimate decline of brain health in modern society has been the introduction of wheat grain into the human diet. While it’s true that our Neolithic ancestors consumed minuscule amounts of this grain, what we now call wheat bears little resemblance to the wild einkorn variety that our forebears consumed on rare occasions. With modern hybridization and gene-modifying technology, the 133 pounds of wheat that the average American consumes each year shares almost no genetic, structural, or chemical likeness to what hunter-gatherers might have stumbled upon. And therein lies the problem: We are increasingly challenging our physiology with ingredients for which we are not genetically prepared.”

“Researchers for some time now have known that the cornerstone of all degenerative conditions, including brain disorders, is inflammation. But what they didn’t have 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. What’s most disturbing about this discovery, however, is that we often don’t know when our brains are being negatively affected. Digestive disorders and food allergies are much easier to spot because symptoms such as gas, bloating, pain, constipation, and diarrhea emerge relatively quickly. But the brain is a more elusive organ. It could be enduring assaults at a molecular level without your feeling it. Unless you’re nursing a headache or managing a neurological problem that’s clearly evident, it can be hard to know what’s going on in the brain until it’s too late. When it comes to brain disease, once the diagnosis is in for something like dementia, turning the train around is hard.”

“When I give lectures to members of the medical community, one of my favorite slides is a photo of four common foods: (1) a slice of whole-wheat bread, (2) a Snickers bar, (3) a tablespoon of pure white sugar, and (4) a banana. I then ask the audience to guess which one produces the greatest surge in blood sugar—or which has the highest glycemic index (GI), a numerical rating that reflects a measure of how quickly blood sugar levels rise after eating a particular type of food. The glycemic index encompasses a scale of 0 to 100, with higher values given to foods that cause the most rapid rise in blood sugar. The reference point is pure glucose, which has a GI of 100.

Nine times out of ten, people pick the wrong food. No, it’s not the sugar (GI = 68), it’s not the candy bar (GI = 55), and it’s not the banana (GI = 54). It’s the whole-wheat bread at a whopping GI of 71, putting it on par with white bread (so much for thinking whole wheat is better than white). We’ve known for more than thirty years that wheat increases blood sugar more than table sugar, but we still somehow think that’s not possible. It seems counterintuitive. But it’s a fact that few foods produce as much of a surge in blood glucose as those made with wheat.”

“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 2 diabetes, extinguish obsessive-compulsive behavior, and cure many neurological challenges, from brain fog to bipolar disorder.”

“Interestingly, the human dietary requirement for carbohydrate is virtually zero; we can survive on a minimal amount of carbohydrate, which can be furnished by the liver as needed. But we can’t go long without fat. Unfortunately, most of us equate the idea of eating fat to being fat, when in reality, obesity—and its metabolic consequences—has almost nothing to do with dietary fat consumption and everything to do with our addiction to carbs. The same is true about cholesterol: Eating high-cholesterol foods has no impact on our actual cholesterol levels, and the alleged correlation between high cholesterol and higher cardiac risk is an absolute fallacy.

Of all the lessons in this book, the one I hope you take seriously is the following: Respect your genome. Fat—not carbohydrate—is the preferred fuel for human metabolism and has been for all of human evolution. We have consumed a high-fat diet for the past two million years, and it is only since the advent of agriculture about ten thousand years ago that carbohydrates have become abundant in our food supply. We still have a hunter-gatherer genome.”

“We hear so much these days about omega-3 and omega-6 fats. Overall, omega-6 fats fall under the ‘bad fat’ category; they are somewhat pro-inflammatory, and there is evidence that higher consumption of these fats is related to brain disorders. Unfortunately, the American diet is extremely high in omega-6 fats, which are found in many vegetable oils, including safflower oil, corn oil, canola oil, sunflower oil, and soybean oil; vegetable oil represents the number one source of fat in the American diet. According to anthropological research, our hunter-gatherer ancestors consumed omega-6 and omega-3 fats in a ratio of roughly 1:1. Today we consume ten to twenty-five times more omega-6 fats than evolutionary norms, and we’ve dramatically reduced our intake of healthy, brain-boosting omega-3 fats (some experts believe our increased consumption of brain-healthy omega-3 fatty acids was responsible for the threefold increase in the size of the human brain).”

“The more sugars we eat, the more we tell our bodies to transfer them to fat. This happens not only in the liver, leading to a condition called fatty liver disease, but elsewhere in the body as well. Hello, love handles, muffin tops, beer bellies, and the worst kind of fat of all—invisible visceral fat that hugs our vital organs.

I love how Taubes draws a parallel between the cause-and-effect relationship uniting carbohydrates and obesity, and the link between smoking and cancer: If the world had never invented cigarettes, lung cancer would be a rare disease. Likewise, if we didn’t eat such high-carb diets, obesity would be a rare condition. I’d bet that other related conditions would be uncommon as well, including diabetes, heart disease, dementia, and cancer. And if I had to name the kingpin here in terms of avoiding all manner of disease, I’d say ‘diabetes.’ That is to say, don’t become diabetic.”

“A logical question: How does depression relate to a damaged intestine? … The vast majority of feel-good hormones and chemicals are produced around your intestines by what scientists now call your ‘second brain.’ The nerve cells in your gut are not only regulating muscles, immune cells, and hormones, but also manufacturing an estimated 80 to 90 percent of your body’s serotonin. In fact, your intestinal brain makes more serotonin than the brain that rests in your skull.”

“Pop quiz! What’s going to make you smarter and less prone to brain disease? Is it A. solving a complex brainteaser, or B. taking a walk? If you guessed A, I won’t come down hard on you, but I will encourage you to go for a walk first (as fast as you can) and then sit down to work on a brainy puzzle. The answer, it turns out, is B. The simple act of moving your body will do more for your brain than any riddle, math equation, mystery book, or even thinking itself.

Exercise has numerous pro-health effects on the body—especially on the brain. It’s a powerful player in the world of epigenetics. Put simply, when you exercise, you literally exercise your genetic makeup. Aerobic exercise not only turns on genes linked to longevity, but also targets the gene that codes for BDNF, the brain’s ‘growth hormone.’ Aerobic exercise has been shown to revers memory decline in the elderly and increase the growth of new brain cells in the brain’s memory center.”