Power Foods for the Brain (4 page)

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.
⁷
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.)
  
• Visual hallucinations
  
• Disordered movements
  

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!

W
ithin 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.