The following is an excerpt from the new book, GRAIN BRAIN: The Surprising Truth About Wheat, Carbs, and Sugar - Your Brain's Silent Killers by Dr. David Perlmutter (Little, Brown and Co., 2013).
Imagine being transported back to the Paleolithic era of early humans who lived in caves and roamed the savannas tens of thousands of years ago. Pretend, for a moment, that language is not a barrier and you can communicate easily. You have the opportunity to tell them what the future is like.
From a cross-legged perch on a dirt floor in front of a warm fire, you start by describing the wonders of our high-tech world, with its planes, trains, and automobiles, city skyscrapers, computers, televisions, smart phones, and the information highway that is the Internet. Humans have already traveled to the moon and back. At some point, the conversation moves to other lifestyle topics and what it's like to really live in the twenty-first century.
You dive into describing modern medicine with its stupendous array of drugs to treat problems and combat diseases and germs. Serious threats to survival are few and far between. Not many people need to worry about crouching tigers, famine, and pestilence. You explain what it's like to shop at grocery stores and supermarkets, a totally foreign concept to these individuals. Food is plentiful, and you mention things like cheeseburgers, French fries, soda, pizza, bagels, bread, cinnamon rolls, pancakes, waffles, scones, pasta, cake, chips, crackers, cereal, ice cream, and candy. You can eat fruit all year long and access virtually any kind of food at the touch of a button or short drive away. Water and juice come in bottles for transportability.
Although you try to avoid brand names, it's hard to resist because they have become such a part of life - Starbucks, Wonder Bread, Pepperidge Farm, Pillsbury, Lucky Charms, Skittles, Domino's, Subway, McDonald's, Gatorade, Haagen-Dazs, Cheerios, Yoplait, Cheez-It, Coke, Hershey's, and Budweiser. The list goes on.
They are in awe, barely able to picture this future. Most of the features you chronicle are unfathomable; they can't even visualize a fast-food restaurant or bread bar. The term "junk food" is impossible to put into words these people understand. Before you can even begin to mention some of the milestones that humans had to achieve over millennia, such as farming and herding, and later food manufacturing, they ask about the challenges modern people deal with. The obesity epidemic, which has gotten so much attention in your media lately, comes first to mind.
This isn't an easy matter for their lean and toned bodies to grasp, and neither is your account of the chronic illnesses that pervade - heart disease, diabetes, depression, autoimmune disorders, cancer, and dementia. These are totally unfamiliar to them, and they ask a lot of questions. What is an "autoimmune disorder"? What causes "diabetes"? What is "dementia"? At this point you're speaking a different language. In fact, as you give them a rundown of what kills most people in the future, doing your best to define each condition, you are met with looks of confusion and disbelief. You've painted a beautiful, exotic picture of the future in these people's minds, but then you tear it down with causes of death that seem to be more frightening than dying from an infection or being eaten by a predator higher up on the food chain. The thought of living with a chronic condition that slowly and painfully leads to death sounds awful. And when you try to convince them that ongoing, degenerative disease is possibly the trade-off for potentially living much longer than they do, your prehistoric ancestors don't buy it. And, soon enough, neither do you. Something seems wrong with this picture.
As a species, we are genetically and physiologically identical to these humans that lived before the dawn of agriculture. And we are the product of an optimal design - shaped by nature over thousands of generations. We may not call ourselves hunters and gatherers any more, but our bodies certainly behave as such from a biological perspective. In fact, genetically we are identical.
Now, let's say that during your time travel back to the present day, you begin to ponder your experience with these ancestors. It's easy to marvel at how far we've come from a purely technological standpoint, but it's also a no brainer to consider the struggles that millions of your contemporary comrades suffer needlessly. You may even feel overwhelmed by the fact that preventable, non-communicable diseases account for more deaths worldwide today than all other diseases combined. This is tough to swallow. Indeed, we may be living longer than our ancient relatives, but that doesn't make up for the fact we could be living much better - enjoying our lives sickness-free - especially during the second half of life when the risk of illness rises. While it's true that we are living longer than previous generations, most of our gains are due to improvements in infant mortality and child health. In other words, we've gotten better at surviving the accidents and illnesses of childhood. We haven't, unfortunately, gotten better at preventing and combating illnesses that strike us when we're older. And while we can certainly make a case for having much more effective treatments now for many illnesses, that still doesn't erase the fact that millions of people suffer needlessly from conditions that could have been avoided. When we applaud the average life expectancy in America today, we shouldn't forget about quality of life.
When I was in medical school decades ago, my education revolved around diagnosing disease and knowing how to treat or, in some cases, cure each disease with a drug or other therapy. I learned how to understand symptoms and arrive at a solution that matched those symptoms. A lot has changed since then, because not only are we less likely to encounter easily treatable and curable illnesses, but we've come to understand many of our modern, chronic diseases through the lens of a common denominator: inflammation. So, rather than spotting infectious diseases and addressing sicknesses with known culprits, such as germs, viruses, or bacteria, today doctors are faced with myriad conditions that don't have clear-cut answers. I can't write a prescription to cure someone's cancer, vanquish inexplicable pain, instantly reverse diabetes, or restore a brain that's been washed away by Alzheimer's disease. I can certainly try to mask or lessen symptoms and manage the body's reactions, but there's a big difference between treating an illness at its root and just keeping symptoms at bay. Now that one of my own kids is in medical school, I see how times have changed in teaching circles. Doctors in training are no longer taught just how to diagnose and treat; they are equipped with ways of thinking that help them to address today's epidemics, many of which are rooted in inflammatory pathways run amok.
Before I get to the connection between inflammation and the brain, let's consider what I think is arguably one of the most monumental discoveries of our era: the origin of brain disease is in many cases predominantly dietary. Although several factors play into the genesis and progression of brain disorders, to a large extent numerous neurological afflictions often reflect the mistake of consuming too many carbs and too few healthy fats. The best way to comprehend this truth is to consider the most dreaded neurological ailment of all - Alzheimer's - and view it within the context of a type of diabetes triggered by diet alone. We all know that poor diet can lead to obesity and diabetes, but a busted brain?
Alzheimer's disease - Type 3 diabetes?
Flash back to your moment with those hunters and gatherers. Their brains are not too different from yours. Both have evolved to seek out foods high in fat and sugar. After all, it's a survival mechanism. The problem is that your hunting efforts end quickly because you live in the age of plenty, and you're more likely to find processed fats and sugars. Your cavemen counterparts are likely to spend a long time searching, only to come across fat from animals and natural sugar from plants and berries if the season is right. So while your brain might operate similarly, your sources of nutrition are anything but. In fact, take a look at the following graphic that depicts the main differences between our diet and that of our forebears:
And what, exactly, does this difference in dietary habits have to do with how well we age and whether or not we suffer from a neurological disorder or disease?
The studies describing Alzheimer's as a third type of diabetes began to emerge in 2005,1 but the link between poor diet and Alzheimer's has only recently been brought to light with newer studies showing how this can happen. These studies are both convincingly horrifying and empowering at the same time. To think we can prevent Alzheimer's just by changing the food we eat is, well, astonishing. This has many implications for preventing not just Alzheimer's disease but all other brain disorders, as you'll soon discover in the upcoming chapters. But first, a brief tour on what diabetes and the brain have in common.
Evolutionarily, our bodies have designed a brilliant way to turn the fuel from food into energy for our cells to use. For almost the entire existence of our species, glucose - the body's major source of energy for most cells - has been scarce. This pushed us to develop ways to store glucose and convert other things into it. The body can manufacture glucose from fat or protein if necessary through a process called gluconeogenesis. But this requires more energy than the conversion of starches and sugar into glucose, which is a more straightforward reaction.
The process by which our cells accept and utilize glucose is an elaborate one. The cells don't just suck up glucose passing by them in the bloodstream. This vital sugar molecule has to be allowed into the cell by the hormone insulin, which is produced by the pancreas. Insulin, as you may already know, is one of the most important biological substances for cellular metabolism. Its job is to ferry glucose from the bloodstream into muscle, fat, and liver cells. Once there, it can be used as fuel. Normal, healthy cells have a high sensitivity to insulin. But when cells are constantly exposed to high levels of insulin as a result of a persistent intake of glucose (much of which is caused by an overconsumption of hyperprocessed foods filled with refined sugars that spike insulin levels beyond a healthy limit), our cells adapt by reducing the number of receptors on their surfaces to respond to insulin. In other words, our cells de-sensitize themselves to insulin, rendering a condition called insulin resistance, which allows them to ignore the insulin and fail to retrieve glucose from the blood. The pancreas then responds by pumping out more insulin. So higher levels of insulin become needed for sugar to go into the cells. This creates a cyclical problem that eventually culminates in type-2 diabetes. People with diabetes have high blood sugar because their body cannot transport sugar into cells where it can be safely stored for energy. And this sugar in the blood presents many problems - too many to mention. Like a shard of glass, the toxic sugar inflicts a lot of damage, leading to blindness, infections, nerve damage, heart disease, and yes, Alzheimer's as well. Throughout this chain of events, inflammation runs rampant in the body.
To add insult to injury, I should also point out that insulin can be viewed as an accomplice to the events that unfold when blood sugar cannot be managed well. Unfortunately, insulin doesn't just escort glucose into our cells. It's also an anabolic hormone, meaning it stimulates growth, promotes fat formation and retention, and is a pro-inflammatory hormone. When insulin levels are high, other hormones can become adversely affected, either increased or decreased due to insulin's domineering presence. This, in turn, plunges the body further into unhealthy patterns of chaos that cripple its ability to recover its normal metabolism.
Genetics are certainly involved in whether or not a person becomes diabetic, and genetics can also determine at what point the body's diabetes switch gets turned on, once its cells can no longer tolerate the high blood sugar. For the record, type-1 diabetes is a separate disease thought to be an autoimmune disorder - accounting for only 5 percent of all cases. People with type-1 diabetes make little or no insulin because their immune system attacks and destroys the cells in the pancreas that produce insulin, so daily injections of this important hormone are needed to keep blood sugars balanced. Unlike type 2, which is usually diagnosed in adults after their bodies have been abused by too much glucose over time, type-1 diabetes is typically diagnosed in children and adolescents. And unlike type 2, which is reversible through diet and lifestyle changes, there is no cure for type 1. That said, it's important to keep in mind that even though genes strongly influence the risk of developing type-1 diabetes, the environment can play a role, too. It has long been known that type 1 results from both genetic and environmental influences, but the rising incidence over the last several decades has led some researchers to conclude that environmental factors are increasingly involved in the development of type 1 and may be more important than genetic predisposition.
What we're beginning to understand is that insulin resistance, as it relates to Alzheimer's disease, sparks the formation of those infamous plaques that are present in diseased brains. These plaques are the build-up of an odd protein that essentially hijacks the brain and takes the place of normal brain cells. And the fact that we can associate low levels of insulin with brain disease is why talk of "type-3 diabetes" is starting to circulate among researchers. It's all the more telling to note that obese people are at a much greater risk of impaired brain function, and that those with diabetes are at least twice as likely to develop Alzheimer's disease.
This statement is not meant to imply that diabetes causes Alzheimer's disease, only that they both share the same origin. They both spring from foods that force the body to develop biological pathways leading to dysfunction and, farther down the road, illness. While it's true that someone with diabetes and another person with dementia may look and act differently, they have a lot more in common than we previously thought.
In the last decade, we've witnessed a parallel rise in the number of type-2 diabetes cases alongside obesity. Now, however, we're starting to see a pattern among those with dementia, too, as the rate of Alzheimer's disease increases in sync with type-2 diabetes. I don't think this is an arbitrary observation. It's a reality we all have to face as we shoulder the weight of soaring healthcare costs and an aging population. New estimates indicate that Alzheimer's will likely affect 100 million people by 2050, a crippling number for our health care system that will dwarf our obesity epidemic. The prevalence of type-2 diabetes, which accounts for 90 to 95 percent of all diabetes cases in the US, has tripled in the past forty years.
No wonder the U.S. government is anxiously looking to researchers to improve the prognosis and avert this catastrophe. And in the next forty years, more than 115 million new cases of Alzheimer's are expected globally, costing us more than $1 trillion dollars (in today's dollars). According to the Centers for Disease Control and Prevention, 18.8 million Americans were diagnosed in 2010 with diabetes and another 7 million went undetected. Between 1995 and 2010, the number of diagnosed cases of diabetes jumped by 50 percent or more in 42 states, and by 100 percent or more in 18 states ( via alternet.org ).