In my previous books on health and nutrition, I have translated the research findings of my team and others into steps to help people conquer diabetes, cholesterol problems, chronic pain, and other health concerns. However, this book did not start with our research studies. It started with my own family.
My mother’s father was a physician in a small Iowa town back when house calls and home births were everyday parts of a doctor’s work. His diet, like that of the rest of the family, was typical Iowa fare, which is to say it was long on meat and potatoes and short on green vegetables and fruits. Long before the advent of health insurance, patients did not always have money to pay for his services. So people often paid with a chicken or a cut of beef.
At around age sixty, he suffered his first heart attack. And not long after that, his behavior started to change. He became confused. Sometimes he set out for walks without seeming to know where he was going. Cars had to stop as he wandered across busy streets. Once in a while, a motorist knew him and brought him back home. With time, things got worse. He became aggressive and was put into a hospital, where another heart attack eventually killed him.
We never knew if his problems were due to Alzheimer’s disease, a series of strokes, or something else. His wife, my grandmother, lived longer, but her memory went, too. “By the time I get to the end of an article in the newspaper, I’ve forgotten the beginning,” she told me. Memory gaps here and there began to coalesce into ever-bigger caverns where she was unable to find her way. It was tragically downhill from there, as she fell into severe dementia.
Both of my father’s parents suffered the same fate—a gradual decline into more and more severe cognitive problems to the point where they were essentially unresponsive to the world around them. They existed this way for years before finally dying.
Fast-forward. Not long after I got out of medical school, I became concerned about my mother. Her memory was fine at the time. It was her cholesterol that was a problem. She and my father lived in Fargo, North Dakota, where they and their five children took full advantage of a typical Midwestern diet, and the results showed up on her cholesterol test.
A diet change would have helped, but it was a tough sell for my dear, stubborn mom. It was not until her personal physician threatened to put her on cholesterol-lowering medication for the rest of her life that she decided to try some changes in the kitchen. And, to her credit, she eventually did throw out the cholesterol-laden meat, dairy products, eggs, and greasy foods, adopting a vegan diet for seven weeks before going back to see her doctor. And her doctor could not believe the change. Her cholesterol had dropped nearly 80 points, which he thought had to be the result of some kind of mistake in the laboratory! But the effect was real, and my mother no longer needed medicines at all.
She continued on a healthy diet and lured my father into healthier eating habits, too. At family get-togethers, my mother and I prepared healthful foods and did our best to rebuff the contributions of family members who remained loyal to our not-so-healthful North Dakota traditions.
Sometime later, my parents moved into a retirement home. And there healthy diets were not the order of the day. The management felt that people in their “golden years” were not interested in healthful eating, and meaty, cheesy fare was on the menu at every meal. My parents soon drifted back into unhealthful diets, and she and my father dug into whatever foods were in front of them.
My mother’s cholesterol skyrocketed again. As time went by she developed a severe blockage in one of the carotid arteries that lead to the brain. And she began to complain that her memory was going.
My father started to have memory problems, too. As they became more severe, he had a battery of medical tests, none of which showed any treatable cause. His dementia worsened, and eventually he became expressionless, nearly mute, and immobile.
Were my family’s problems all genetic? Or did the blame go to their Midwestern diet, or perhaps a lack of exercise? Were they missing out on the vital nutrients that protect the brain?
At that time, none of us had a clue about how to protect the brain. Even today, most people—including many doctors—have never learned about the nutritional steps or exercises that shore up brain function and cut the risk of memory loss. That is why I wrote this book.
Let me give you a quick overview of where we’re headed.
Did you ever wonder how you remember a name, a face, a fact, or a song? Or how your brain holds on to all the coordinated movements it takes to ride a bicycle or drive a car so that it’s all second nature? How do we remember the layout of our home or our neighborhood?
When your brain lays down a new memory trace, it does not create a new brain cell—a neuron—to stuff a fact into. Rather, it makes new connections—called synapses—between brain cells. Or it strengthens existing connections. So a rickety one-lane bridge that could accommodate a pedestrian or two becomes a two-lane bridge, a four-lane bridge, or an eight-lane thoroughfare.
Your brain is taking in your experiences, making sense of them, and then deciding what it needs to hold on to and what it can let go of. Important events and emotional moments stay, while today’s weather forecast, a restaurant phone number, and movie showtimes get pitched into the recycling bin.
Sleep plays a vital role in the process. That is when your brain integrates memories—carefully filing them away so you can retrieve them later.
Unfortunately, our brain circuits are fragile. They are easily knocked off-kilter by a lack of certain nutrients, poor sleep, or a medication side effect. And sometimes synapses break. You might have trouble finding a name or a word that you know is in your memory banks somewhere, if only you could figure out where. And for some people, memory problems become serious.
What if your memory is sputtering and misfiring? What if you’re having lapses more frequently than normal?
If that is happening to you, it is important to know that there is a surprising range of things that can derail your memory and cloud your thinking—problems that are often easy to identify and treat. Sometimes it is as simple as correcting your sleep habits. Many people are chronically sleep-deprived, often without realizing it, with noticeable effects on their memory function.
Other times it’s a question of looking at medications you may be taking. As we will see in chapter 8, common medications can throw a wrench into your gray matter. Sometimes a medication causes no problem when used by itself but causes all manner of problems when prescribed in combination with other drugs.
There are many medical problems that affect the brain, too, from vitamin deficiencies to thyroid problems. So you’ll want to have a medical evaluation, and I’ll show you what you need to look out for so you can correct the problem.
If memory problems continue and no cause can be spotted, your doctor would label the problem mild cognitive impairment. This term refers to a situation in which you are doing fine in other respects—you’re able to socialize, take care of yourself, and enjoy life—but your memory and thinking are not as sharp as they were. You might be a bit slower when it comes to paying bills or balancing your checkbook, and you might forget to pick up your dry cleaning. You may have trouble with names and words. You may also have trouble solving problems, planning ahead, or focusing your attention.
How can you tell whether mild cognitive impairment will turn into something more serious? The answer is, you can’t at first. Only as time goes on does the picture become clearer.
Your doctor will want to track how you are doing over time. He or she is likely to give you some simple tests, such as asking you to memorize a name and address—John Smith, 103 Orchard Street, Springfield—and to recall it a few minutes later. Or he or she might show you three common objects—a pen, a stapler, and a book, for example—and place them around the room, asking you to remember each object and its location later on. What your doctor is looking at is your ability to learn and hold on to new information, because that is an indicator of how likely it is that more serious problems lie ahead.
These quick tests sometimes are followed by more formal testing, which can be repeated as often as needed. Some researchers add special examinations to try to predict who might be headed for Alzheimer’s disease. Drawing a sample of spinal fluid, they would look for two proteins, called beta-amyloid 42 and tau. A low level of beta-amyloid 42 suggests that beta-amyloid, which is linked to Alzheimer’s disease, has been deposited in the brain. A high level of tau protein suggests that neurons have been damaged.
Using an MRI or other scanning methods, they can look for brain shrinkage (particularly in a part of the brain called the hippocampus), reduced brain activity, or signs that amyloid has been deposited in the brain.
If you have mild cognitive impairment, you’ll want to use each of the steps in the following chapters to regain function if you can and to prevent further loss.
Frances and her younger sister Mary Lou were born in Milwaukee, Wisconsin, and have lived there all their lives. They inherited a large grocery store from their parents and worked there throughout their careers, making a comfortable living.
Both reported that around the time they turned sixty, they felt less sharp than before. For Mary Lou, that meant memory problems, which worsened over time. She found that she would often draw a blank for names and sometimes could not remember the words for common objects. She also found that she was no longer the math wizard she had been as a youngster, and she was not as able to keep her attention focused. In part as a result of these problems, she retired from her job. As the years went by, she found these problems annoying, and her doctor labeled them mild cognitive impairment. However, the condition never deteriorated into Alzheimer’s disease, and she still lives in the same house she has been in for the past four decades.
Frances’s situation was different. She, too, noticed that it often took a bit longer to remember names, but she observed no other problems at all, and even her difficulty with names did not get any worse. She is now in her mid-eighties and still works in the same job in the family store.
Later on, we will look at what may have made the difference in these two women’s experiences.
Not everyone with mild cognitive impairment progresses to Alzheimer’s disease, but many do. As we’ve seen, Alzheimer’s is extremely common among older folks. But the fact is that we are now at a turning point in Alzheimer’s disease research, with the emergence of what appear to be powerful tools for reducing the likelihood that you will develop it. Unfortunately, treatments for people who already have Alzheimer’s are not at all what they should be, but research studies suggest an effective preventive strategy, which I’ll lay out for you in the next several chapters.
When Alzheimer’s disease takes hold, it attacks your brain’s centers for learning, memory, reasoning, and language. Here are the common symptoms:
Difficulty learning and remembering new things. You might misplace personal belongings more frequently than normal. You might ask the same questions repeatedly, or get lost on what had been a familiar route.
Poor reasoning, judgment, or problem solving. It becomes harder to make decisions, plan activities, handle routine finances, or take the usual steps to protect yourself (e.g., looking out for traffic before crossing a street).
Poor visuospatial abilities. You might have trouble recognizing faces or using simple objects, or find it harder than it should be to do routine things like putting on your shoes or doing up buttons.
Losing language skills. Words may elude you, and reading and writing can be more difficult.
Personality changes. You could become irritable, agitated, or eventually just apathetic.
Alzheimer’s is different from mild cognitive impairment in that cognitive problems are no longer just a nuisance; they are now interfering with your day-to-day activities. To reach the diagnosis, a doctor would look for at least two of the above symptoms. Typically these changes come on insidiously, unlike the more sudden cognitive problems caused by a stroke, trauma, or infection.
To separate Alzheimer’s disease from other brain conditions, your doctor will do a physical exam and laboratory tests, and will also test your ability to learn and remember and can check your language skills. Sometimes doctors check cerebrospinal fluid, drawn via spinal tap, for beta-amyloid 42 and tau. Special brain scans can spot amyloid deposits in the brain or shrinkage or reduced function in certain parts of the brain.
But even with sophisticated testing, your doctor cannot be entirely sure of the diagnosis. If it looks like Alzheimer’s, the diagnosis will be called “possible” or “probable.” A definitive diagnosis relies on an examination of the brain itself.
If you were to look within the brain of a person with Alzheimer’s disease, you would not find normal, healthy brain tissue. Here and there between the brain cells are tiny deposits of beta-amyloid protein. Doctors refer to these deposits as plaques. They are microscopic, but they are not doing the brain any good. They are a sign of a disease process.
I should mention that “plaque” is a generic word that refers to any sort of unwanted deposit. So you could have plaque on your teeth, plaques clogging your arteries, or microscopic plaques in your brain. They have nothing in common, except that the same word is used in each case.
Scientists have teased these beta-amyloid plaques apart to see what is in them. After feverish research, we now have a good picture of what they are made of. What is actually inside those plaques is surprising. As we’ll see in the next chapter, we can put this finding to use, starting today, to work toward preventing the buildup of these plaques in the first place.
Aside from the beta-amyloid plaques that lie between the brain cells, there is also something wrong inside the brain cells themselves. They contain what look like tangled balls of yarn.
Normally your brain cells have microscopic tubes—which scientists call microtubules—that maintain the cell’s structure and help it to transport various things from place to place within the cell. To stabilize these microtubules, your cells use tau proteins (tau is just the Greek letter that is the equivalent of our letter “T”). And it’s those tau proteins that are balled up in what neurologists call neurofibrillary tangles.
In 1906, German physician Alois Alzheimer spotted these odd plaques and tangles in the brain of a patient who had died in her mid-fifties after suffering from memory loss and behavioral problems. Although Dr. Alzheimer dutifully reported the existence of plaques and tangles, he had no idea what had caused them, and for the past century, researchers have struggled to find out.
A person assaulted by Alzheimer’s disease has also lost brain cells, along with many of the synapses between brain cells—the connections they need to communicate with each other.
So where is all this leading? Ultimately, many people with Alzheimer’s disease die of pneumonia, often because the disease has affected their ability to swallow, and food particles end up in their lungs.
All of these problems are what we now aim to prevent.
Genes play a role in Alzheimer’s disease. Chromosomes 21, 14, and 1 hold genes that produce proteins (called beta-amyloid precursor protein, presenilin 1, and presenilin 2) that are involved in making the beta-amyloid that ends up in plaques. Mutations in these genes cause aggressive forms of Alzheimer’s disease that can strike when people are just in their thirties, forties, or fifties.
Fortunately, these cases are rare. For the vast majority of people, the effect of genes is weaker.
The best-known genetic contributor is a gene called APOE. Located on chromosome 19, it holds the instructions for producing a protein called apolipoprotein E (which scientists abbreviate with small letters as apoE, to differentiate it from the gene). ApoE’s job is to help carry fat and cholesterol from place to place. It also repairs brain cells and builds connections from one neuron to another.
Here is what counts: There are three different common versions (alleles) for the APOE gene, called e2, e3, and e4. The e4 variant is the one that has raised concerns about Alzheimer’s risk. Compared with people who got the e3 allele from both parents, those who inherit the e4 allele from one parent have about three times the risk of developing Alzheimer’s disease. People who get the e4 allele from both parents have ten to fifteen times the risk.,
People with the e2 allele have less Alzheimer’s risk. But e2 has problems of its own, causing a higher risk of rare cholesterol problems and cardiovascular disease.
It is important to understand that genes work in many different ways. Certainly, some genes are dictators—the genes for hair or eye color, for example. If they call for you to have blond hair or brown eyes, that’s it. Those dictatorial genes won’t take no for an answer.
But the genes for Alzheimer’s disease are more like committees. They don’t give orders; they make suggestions. And research suggests that changes in diet and lifestyle—the steps you will read about shortly—can keep those genes from expressing themselves. Like dry seeds on the desert floor, they simply lie dormant. If you don’t water them, they’ll never sprout.
So even though the e4 allele is linked to increased risk of Alzheimer’s disease, some people who have the e4 allele—even from both parents—never get the disease. And at least one-third of Alzheimer’s patients do not have the e4 allele. Research suggests that food and lifestyle choices can help protect you, whatever genetic hand you’ve been dealt.
Alzheimer’s is not the only neurodegenerative condition. Here are other common types:
The blood vessels of the brain can be gradually damaged and narrowed. In the process, they no longer give the brain the oxygen it needs. Sometimes the narrowing is very much like that which occurs in the arteries to the heart. At these narrowed spots, blood clots can form, plugging the artery like a cork in a bottle. Clots and debris can also break free, passing downstream and plugging smaller blood vessels farther along. Sometimes arteries actually break open, leaking blood into the brain tissue.
When a loss of blood flow kills off brain cells, doctors diagnose a stroke (which they will call an infarct), and the result can be weakness or paralysis, as well as cognitive problems. Sometimes small, imperceptible strokes add up in what is called multi-infarct dementia.
In other cases, the problem is more diffuse, with gradual damage along the walls of the small vessels in the brain, disrupting blood flow to the brain.
Brain imaging techniques often allow doctors to see small strokes and loss of blood flow. These scans look different from those in Alzheimer’s disease, where imaging would be likely to show brain shrinkage, especially in the hippocampus and parts of the cortex. Not uncommonly, vascular dementia and Alzheimer’s disease occur in the same person, so the symptoms and brain imaging findings will reflect both.
The good news is that vascular dementia is, to a large degree, preventable. By making food choices that reduce your blood pressure and cholesterol level, avoiding smoking, and getting plenty of exercise, you’ll have more power to keep your arteries healthy.
Stroke is a common cause of dementia, often accompanied by physical weakness. Here is what you need to know:
Even though it makes up only about 2 percent of your body, your brain gets a good 20 percent of your blood supply, and for good reason. There are more cells in your brain than there are lightbulbs in Las Vegas (that is, 100 billion neurons and 10 times that many glial cells supporting them), and you need a steady stream of oxygen and nutrients to power them all. A failure in the blood supply to the brain can result in stroke, and stroke is one of the leading causes of memory loss.
To make sure your brain’s blood supply doesn’t fail, your heart uses not one but two separate sets of arteries. The carotid arteries are in the front of your neck, one on the left and the other on the right. If you gently place a finger just to the side of your windpipe, you’ll feel a carotid artery beating. A second set, called the vertebral arteries, is deeper in the neck, passing up along the spine. This quartet of arteries join together at the base of the brain, so if one artery is blocked or damaged, blood can shuttle in from another.
From there, branches extend to the front of your brain, where your thoughts take shape and you plan your movements. Other branches reach the back of your brain, where vision is processed. Near the center of the brain is the limbic system, where brain cells cook up emotions. A dense network of nerves connects and coordinates all these regions. With a good blood supply, these structures will last a lifetime.
As well designed as the system is, things go wrong surprisingly often. As we saw earlier, arteries can become narrowed, clots can form, and bits of clot can end up plugging small arteries deep inside the brain.
A clot may also originate in the heart. In a condition called atrial fibrillation, an erratic heartbeat leads to pooling of blood within the heart, forming clots that can break away and flow upward toward the brain. The result is a stroke—or, in medical terms, a cerebrovascular accident—meaning that part of the brain has died.
Blood vessels can also break open. If an artery bursts in the brain, blood spills into the brain tissue, like water spraying out of a nick in a fire hose. The resulting pressure can kill brain cells.
While Alzheimer’s disease begins very gradually, a stroke is not usually so subtle. If you are lucky, the affected area will be tiny, so symptoms are imperceptible. But small strokes can add up. Strokes that are too small to show up on brain scans occur surprisingly often and, collectively, they can affect a broad range of brain functions. Often a single large stroke can wipe out a large part of the brain in one go. It can occur out of the blue, with paralysis, speech difficulties, and confusion that can be very sudden and frightening.
Doctors can often tell where a stroke has occurred based on the symptoms. Because the nerves cross over from one side of the body to the other, a stroke on one side of the brain manifests as weakness on the opposite side. The parts of the brain that control speech are mainly on the left. Vision is in the back.
Diagnosing a stroke:
When doctors suspect a stroke, they conduct a careful neurological examination that checks your strength, senses (including vision), reflexes, and ability to speak and understand. They will also check your blood pressure and may listen for a “bruit” (pronounced BROO-ee, the French word for “noise”) in your neck—a sound produced by disturbed blood flow in a carotid artery.
Brain imaging methods, including CT (computed tomography) and MRI (magnetic resonance imaging), allow doctors to see abnormalities within the brain. Doctors will also check the health of your heart and the arteries to the brain and run blood tests that detect clotting abnormalities, diabetes, and cholesterol problems. If your doctor suspects bleeding, he or she may do a spinal tap.
Doctors run through a checklist of medical conditions that could be mistaken for a stroke: migraine, low or high blood sugar, a seizure, an infection, multiple sclerosis, or a brain tumor.
The good news about strokes is that the brain can recover, at least to a degree. Even so, it is not an easy process by any means. Stroke recovery is often only partial, and it is often complicated by medical problems, including depression, as the brain seemingly shuts down other functions in order to focus on healing.
The steps outlined in the next several chapters will give you new power for controlling your weight, blood pressure, blood sugar, and cholesterol, which, in turn, will cut your risk of stroke.
This common cause of dementia is marked by the presence of Lewy bodies, which are clumps of proteins inside brain cells. They are named for Friedrich Lewy, the researcher who discovered them in the early 1900s.
Dr. Lewy found these abnormalities in patients with Parkinson’s disease, the movement disorder made well-known by Muhammad Ali and Michael J. Fox, and, in recent years, researchers have shown that dementia with Lewy bodies and Parkinson’s disease are related. Both conditions present problems with movement and mental function.
To separate dementia with Lewy bodies from Alzheimer’s disease, doctors look for three main findings:
Changes in alertness (An affected person may be alert at times, then become drowsy or stare off into space for prolonged periods.)
Brain scans are used as well, and may help to differentiate dementia with Lewy bodies from vascular dementia or Alzheimer’s disease. A special type of brain imaging, called SPECT, is sometimes used to show changes in dopamine activity.
This is a group of disorders that mainly affect the frontal and temporal lobes of the brain. Most cases strike early—affecting people in their fifties or sixties—and many appear to have a genetic basis.
The main problems occur with language and behavior. You could have trouble finding words, speaking, or understanding what others are saying. Behavior can become uninhibited and inappropriate, or sometimes just listless and lethargic. Brain scanning methods show shrinkage and reduced activity in the affected areas.
Cognitive problems can also be a complication of Huntington’s disease or Creutzfeldt-Jakob disease, as well as any of the common medical conditions outlined in chapter 8.
Those are the threats we need to be aware of. Some of them—most notably Alzheimer’s disease and stroke—are strongly linked to choices we make.
By now, you are probably frightened, considering all the things that can go wrong. Well, this is the time for action. In the next several chapters, we will draw on scientific research to build a powerful shield to protect your brain.
We will start with a look at foods—foods that help us and other foods that we will want to steer clear of. We will also turn our attention to exercises—mental and physical—that can strengthen the brain. We will see how to give your memory banks the rest they need and how to protect your brain from the surprising array of assaults that can take away your edge.
If Frances stayed reasonably clear all her life, while her sister Mary Lou developed more serious memory problems, what made the difference? Could it be that Frances ate considerably more healthfully? Or could it be the fact that she was a much more avid reader? Or maybe it was the exercise program she went to after work? Or perhaps it was all of these things.
In the following chapters, we will see exactly how to protect your memory. Here’s how we’ll proceed:
First, I want you to understand a few basics of how foods affect brain function. It is easy but important. Certain food components are toxic to the brain, and you are almost certainly exposed to many of them now. I want to point them out to you so you can protect yourself. And there are protective nutrients, too—critically important natural compounds, and I’ll show you where to find them. So please take your time and go through these pages carefully.
• Second, we will want to reinforce your brain synapses with cognitive exercises that are simple and fun. As you will see, this takes very little time, but the results can be quite striking. Then we will pump up blood flow to your brain using an individualized program of physical conditioning. It is extremely easy, and you can build up to however challenging a level you might like. The result can be measurable changes in brain structure.
Third, it is critical to restore your brain’s ability to integrate memories and to retrieve them. That means using sleep for all it’s worth—and many people have an abysmal night’s sleep for months or years on end. I will show you how to take an inventory of your sleep habits and correct them if you need to. It also means looking at medications and medical conditions that cause brain cells to misfire. We will go through them in an easy but systematic way.
I hope you will explore the menus and recipes in this book and have fun with them. If you are surprised that healthful recipes could seem so delicious, the fact is that two top chefs designed them that way. Together, we aim to seduce your taste buds so you cannot help but fall into good health.
Over the short run, you’ll find that you are not only protecting your brain. You’re also enhancing your health. Over the long run, you’ll be less and less likely to succumb to the physical problems that others face.
Healthful eating also opens the doors to a world of delights you had never anticipated. So by using the power of food, adding brain-strengthening exercises, and understanding how medicines and medical conditions interact with brain function, you will have a powerful program for conquering memory problems and being at your best.
So what are we waiting for? Let’s jump in!
Within the gray matter that makes up the outer layer of the brain are the billions of brain cells that allow you to think, speak, move, anticipate the future, and manage your day-to-day life. They link with each other via billions upon billions of synaptic connections and send even more links to other parts of the brain, to the muscles, and to your sense organs.
If you have memory problems, it is a sign that these connections are not working properly. Perhaps the brain cells are not getting the nutrients they need. Maybe they are momentarily misfiring, due to a side effect of some medication. Some connections may be broken, or perhaps the brain cells themselves are no longer there at all.
Researchers have worked long and hard to track down the causes of memory problems so we can take steps to prevent them. As we have seen, there are three key steps for protecting your memory.
We’ll begin by zeroing in on what you’re eating. First, certain metals can be toxic to the brain and have turned up in examinations of brain tissue from people with Alzheimer’s. In the following chapter, we will see where they are coming from and how you can protect yourself. You may be shocked to learn where they are hiding. Then, in the next two chapters, we will look at the role of fats—some are distinctly harmful to the brain, surprisingly enough, while others are actually helpful—and at common vitamins that are essential for protecting the brain. It is important to know where to find them and how to put them to work.
The Beatles made an enormous splash in Liverpool. But as big as they were, there was one commodity that was much bigger and much more controversial.
Liverpool is a port city. So ships come and go, carrying coal, timber, grains, steel, crude oil, and endless other commodities. Loaded onto ships leaving Liverpool in the eighteenth century was the most controversial product in English history.
In their holds were bars of copper—that ordinary reddish metal that makes a pot or pan look so shiny and bright. Copper looks innocent enough. But it was the currency of the British slave trade.
The ships sailed from Liverpool to West Africa, where copper and brassware were exchanged for slaves who were then carried across the Atlantic to the Americas. There the human cargo was off-loaded, and rum and sugar from slave plantations were carried back to Britain. This triangular trade route from Britain to Africa to the Americas and back was fueled by copper from Liverpool. It was what African slaveholders wanted.
Copper also kept the ships afloat. Sailing around the North Atlantic, wooden ships worked out well. But as slave ships entered the Caribbean, they encountered a tiny mollusk, called Teredo navalis, which feeds on wood. Or, more accurately, these mollusks have a special organ that carries a bacterium that digests cellulose, dissolving the hulls of ships. A few too many mollusks and your ship is on the ocean bottom.
The answer was to sheathe the hulls in copper. Copper kept the mollusks out, the hulls intact, and the slave ships sailing.
Many Britons called for an end to the slave trade. But copper merchants protested vigorously. They were not getting rich selling pots and pans in Lancashire. The slave trade was the market they wanted to protect. Finally, in 1807, public sentiment turned, and it became illegal for British subjects to traffic in slaves. In 1833, slavery was abolished in all British colonies.
Metals always seem to come in the form of double-edged swords. Lead gave us pipes for plumbing, but it has also poisoned countless children. Mercury gave us thermometers and electrical switches, but it also caused birth defects. Metals build bridges and locomotives, and also bullets, prison cells, and hand grenades.
Metals are a double-edged sword within the human brain, too. In the last chapter, we saw that researchers have found plaques and tangles within the brains of people with Alzheimer’s disease. If you were to analyze a typical plaque—one of the small deposits that are found among the brain cells—you would discover that much of it consists of beta-amyloid protein. But there is something else there, too. Teasing the plaques apart, researchers have found traces of copper. They have found other metals, too, particularly iron and zinc, and perhaps others, as well.
All three of these metals are needed by the body—copper for building enzymes, iron for blood cells, and zinc for nerve transmission, among many other functions. You get them in the foods you eat. But it turns out that if you get too much of any of them, they can damage your brain cells. The difference between a safe amount and a toxic amount is surprisingly small. And that is exactly the problem.
Iron and copper are unstable. Just pour a little water into a cast-iron pan and let it sit for a bit. The rust you see is oxidation. Copper oxidizes, too, which is why a bright shiny penny soon darkens, sometimes combining with other elements and turning green.
Pretty colors, yes. What is not so pretty is when these chemical reactions happen inside your body. That’s when iron and copper spark the production of free radicals—highly unstable and destructive oxygen molecules that can damage your brain cells and accelerate the aging process. In a nutshell, iron and copper cause free radicals to form, and those free radicals are like torpedoes attacking your cells.
So, am I saying that memory problems might be caused by ordinary metals like copper, iron, and zinc? To help answer that question, let me take you to Rome, where a research team studied sixty-four women. All were over age fifty but perfectly healthy. The researchers drew blood samples to measure copper in their blood and then gave them a variety of tests to check their memory, reasoning, language comprehension, and ability to concentrate.
Now, overall the women did just fine. None had any major impairment. But some did noticeably better than others on one test or another. And those who had the least mental difficulties turned out to be those with lower levels of copper in their blood. They had adequate copper for the body’s needs but were free of excesses, and that apparently did them a big favor. The difference was especially noticeable on tests that required focused attention.
A study of sixty-four women is not especially large. So let’s next drop in on a research team at the University of California at San Diego that evaluated a much larger group, this one consisting of 1,451 people in Southern California. They found much the same thing. People who had lower copper levels in their blood were mentally clearer compared with those with excessive copper. They had fewer problems with short-term and long-term memory. And the same held true for iron. People with less iron in their blood had fewer memory problems.
So even though both iron and copper are essential in tiny amounts, having too much of either one in your bloodstream seems to spell trouble.
If this sounds surprising, it did not entirely surprise the researchers. Every medical student knows that copper is potentially toxic. Your body uses tiny amounts of it in enzymes for various functions, but the amount you need is extremely small. If you get too much of this unstable metal, it can oxidize and encourage free radicals to form. In fact, the only thing that stops copper from destroying your health early in life is that your liver filters much of it out of your blood and eliminates it. In a rare genetic condition called Wilson’s disease, the liver is unable to eliminate copper normally. As copper builds up in the body tissues, it damages the central nervous system and causes all manner of other problems.
Similarly, excess iron has long been known to cause potentially serious health problems. More on iron in a minute. But first, let’s deal with copper and understand what it is doing to our brains.
I should tell you that copper may contribute to much more serious problems than the minor variations in memory and cognition seen in the Rome and San Diego studies. Starting in 1993, a research team from Rush University Medical Center went door-to-door in three Chicago neighborhoods, aiming to track down the causes of health problems that occur as we age. They invited 6,158 people to join the Chicago Health and Aging Project, and eventually another 3,000 joined in, as well.
The researchers carefully recorded what the volunteers ate. Like people everywhere, some were health conscious, while others were not so particular. The research team then kept in touch with everyone over the years to see who stayed well and who did not—who kept their mental clarity and who had memory problems. They then looked to see if any part of the diet could have predicted who might fall prey to memory loss.
Now, many of the participants got adequate copper in their diets, without excesses. As the years went by, they generally did well on the cognitive tests the researchers gave them. But other participants got quite a bit more of it. Needless to say, none of them were worrying about anything so insignificant as copper. Who would even have known it was in foods, anyway? But as time went on, a particular combination seemed to be especially harmful. Those whose diets included fair amounts of copper along with certain “bad” fats—the fats found in animal products and snack foods—showed a loss of mental function that was the equivalent of an extra nineteen years of aging. It appears that “bad” fats team up with copper to attack the brain. These fats actually assault the brain in many ways, as we’ll see in the next chapter.
The difference in copper intake between those who generally did well and those who did not was surprisingly small. Here are the numbers: For comparison, a penny weighs 2,500 milligrams. The people in the Chicago study who generally avoided cognitive problems got around 1 milligram of copper per day. Those who did not do so well averaged around 3 milligrams per day (2.75 milligrams, to be exact). One milligram, three milligrams—what’s the difference? you might be asking. That is still just a tiny speck of copper. But it turned out to be more than enough to cause serious problems. As we will see shortly, the foods that deliver this innocent-looking, bright, shiny metal are right under our noses, and it damages the brain enough to interfere with attention, learning, and memory—and perhaps even cause Alzheimer’s disease. Or so research seems to show.
Researchers have found a surprising link between copper and the APOE e4 allele—that is, the gene linked to Alzheimer’s risk. As you’ll recall, the proteins made by the APOE e2 and APOE e3 alleles are not associated with increased Alzheimer’s risk. It turns out that these two “safer” genes make proteins that bind copper. They keep it out of harm’s way. The protein produced by APOE e4 does not do that. As far as APOE e4 is concerned, you are on your own. It does nothing to protect you from copper and the shower of free radicals it causes.
Copper is not the only problem. Iron builds up in the body in a condition called hemochromatosis, causing fatigue, weakness, and pain, and ultimately leading to heart disease, diabetes, liver damage, arthritis, and many other problems.
Excerpted from Power Foods for the Brain by Neal Barnard Copyright © 2013 by Neal Barnard. Excerpted by permission.
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