Power Foods for the Brain (8 page)

In all these places, people’s food choices have one thing in common: They emphasize foods from plant sources. That means sweet potatoes, rice, and vegetables in Okinawa; vegetables, beans, and fruit in Loma Linda; whole-wheat bread, fava beans, and nuts in Sardinia; corn and beans in Costa Rica; bread, olives, greens, and beans in Ikaria.

Fargo, North Dakota, is not a blue zone. Growing up in Fargo, our summers were green, our winters were very white, and you could always smell the sugar beet factory when the wind was in the right direction. My paternal grandfather was a Midwestern rancher. So was my great-grandfather and every generation before that, so far as I could trace. If it walked on four legs, it was likely to end up on the table.

Two legs, too. Ducks and geese flew over the North Dakota wetlands, and every fall my father took his sons out hunting. Eviscerating the smelly carcasses on our cement basement floor, we would not have qualified for
Top Chef
. We had very limited appreciation for vegetables or fruits.

My own meat-laden diet was made worse by my summer job, tending the deep-fryer at McDonald’s. By the end of my
shift, I probably had more grease soaked into my clothes than Masu ate in an entire month.

Our meal choices didn’t help us very much. As I mentioned in
chapter 1
, all of my grandparents developed severe dementia. The last years of their lives were miserable. So what’s the difference between Fargo and Okinawa? Or, for that matter, between Illinois, Iowa, or Kentucky, on the one hand, and Loma Linda or Ikaria, Greece, on the other? Is it just a question of food? Certainly we eat differently. But you have to wonder if some of the credit for the good health people enjoy in the blue zones should go to clean air or genetics.

Researchers at Loma Linda University wondered, too. And they decided to find out. They invited people to join a study and put them into groups of four. Everyone lived in more or less the same area. But each group included one person following a vegetarian diet, one following a vegan diet (no animal products at all), and two people on typical American diets. In all, 272 people were part of the study. And then the researchers just sat back and waited.

What happened next was striking—and it did not say much for California air. Even though everyone lived in the same community, breathed the same air, and had more or less similar genetic risks, those who skipped meat were only
one-third as likely to develop Alzheimer’s disease
compared with those who routinely ate meat.
¹
Chalk one up for food. While other aspects of a healthy lifestyle are important, as we’ll see shortly, it looks like food choices weigh in big.

In the last chapter, we saw how Chicago researchers had identified copper as a suspect in cognitive decline. The blame, it seems, goes to copper’s tendency to accumulate in plaques
and produce free radicals that can damage cells. But copper’s dangers seemed to depend, oddly enough, on how much fat people were eating. That is, people whose diets included a lot of copper, along with a good dose of
saturated fat
or
partially hydrogenated oils
, were much more likely to lose their mental faculties over time. Those who generally avoided these fats were more likely to stay sharp—regardless of how much copper was in their diets. Copper seemed to be dangerous only when the diet also held a fair amount of saturated fat.

You’ve seen saturated fat. It is what makes up the white streaks marbling through a chunk of bacon or steak. It is what makes whole milk creamy and cheese waxy. Its name comes from the fact that the fat molecule—if you could look at it under a powerful microscope—is completely covered with hydrogen atoms. That is, it is
saturated
with them. But you don’t need to
be a chemist to spot saturated fat. At room temperature, it is solid. So lard and cheese are obviously loaded with it, while corn oil and olive oil, which are easily pourable, are not.

In the American diet, the biggest source of saturated fat is from dairy products—cheese, ice cream, butter, and milk. Meats—chicken, sausage, burgers, and roast beef—are a close second.
²

So copper plus bad fats equals a higher risk of brain problems. However, the Chicago researchers found that saturated fat is apparently harmful
all by itself.
Over a four-year period, people who got around 25 grams of saturated fat each day had at least twice the risk of developing Alzheimer’s disease compared with those who got only about half that much.
³
Typical vegetable oils had the opposite effect, reducing the risk of Alzheimer’s.

The other “bad” fat is
partially hydrogenated oil,
sometimes called
trans
fat. It is produced by a process called
hydrogenation,
which food manufacturers use to turn liquid oils into solid fats. With a buttery mouthfeel and a long shelf life, these artificial fats are packed into pastries, snack foods, and french fries. Unfortunately, they don’t extend
your
shelf life. The Chicago research team found that people consuming the most partially hydrogenated oils had more than double the risk of Alzheimer’s compared with people who generally avoid these fats.
³

Similar findings turned up in New York, where Columbia University researchers tracked 908 elderly New Yorkers. All were free of Alzheimer’s disease when the study began. But over the next four years, those who ate the most calories and fat were more than twice as likely to develop Alzheimer’s compared with those who ate more modestly.
⁴
The New York team then brought more volunteers into the study, and much the same pattern held. Those who tended to favor meat and dairy products had a higher risk of developing Alzheimer’s disease compared with those who chose what the researchers called a “Mediterranean”
pattern of more healthful foods.
⁵
In both the Chicago and the New York studies, people who had fewer “bad” fats in their diets had less risk, and this was true
even if they had APOE e4 allele
.

A study in Finland came up with much the same result: Saturated fat increased the risk of dementia in people with APOE e4 allele.
⁶
A Dutch study broke from the pattern, suggesting that diet mattered in the first few years of observation but not after that, for reasons that are not clear.
⁷
Overall, the jury says that something about the fat in meat and dairy products poses a problem for the brain.

So it looks like these “bad” fats are linked to Alzheimer’s disease, and teaming up with copper makes things all the worse.

Compare the Saturated Fat Content

Saturated fat, trans fats—is some of this sounding familiar? If so, it is because these same “bad” fats assault the heart. Saturated
fats and partially hydrogenated oils cause your body to make more cholesterol, which, in turn, encourages plaques to form in the arteries to your heart and to your brain—plaques that gradually pinch off the passage of blood.

If these “bad” fats are a regular part of your diet, your cholesterol level is likely to rise. And studies show that people with high cholesterol levels are more likely to develop Alzheimer’s. Compared with a person whose cholesterol level is under 200 milligrams per deciliter, if your cholesterol is around 220, you are not just courting a heart attack. Your Alzheimer’s risk is higher, too—about 25 percent higher. And if your cholesterol is in the 250 range or higher, your likelihood of developing Alzheimer’s would be about 50 percent higher.
⁸
These numbers come from a study of 9,844 Kaiser Permanente subscribers in California who had their cholesterols checked when they were in their early forties.
A high cholesterol level in midlife predicted their Alzheimer’s risk twenty to thirty years later.

It had once been thought that cholesterol in the bloodstream had nothing to do with cholesterol in the brain;
⁹
the brain actually makes its own cholesterol. But researchers now believe the situation is not so simple. They are teasing apart the reasons why fat and cholesterol that cause heart problems are linked to brain problems, too.

The field of Alzheimer’s disease research sometimes feels like a huge jigsaw puzzle where pieces are starting to fit together, even while many gaps remain. Here are some of the pieces researchers are linking together:

• People who eat more saturated fat and partially hydrogenated oils are at higher risk of developing Alzheimer’s. Both of these “bad” fats boost cholesterol production in the body, and high cholesterol levels are linked to Alzheimer’s risk, too.
  
• The APOE gene makes a protein that transports cholesterol. It turns out, in fact, to be the
  main transporter of cholesterol
  within the brain. People who have the e4 version (allele) of this gene—the version linked to Alzheimer’s risk—absorb cholesterol more easily from their digestive tracts compared with people who do not have this allele. They tend to have higher cholesterol levels and higher risk of both heart disease and stroke.
  ¹⁰
  
• Cholesterol increases the production of beta-amyloid and plays a role in the formation of the beta-amyloid plaques that can lead to Alzheimer’s disease.
  ⁹
  

Suddenly the puzzle is starting to make sense. Toxic fats cause your body to make cholesterol. And cholesterol, carried by the apoE protein, encourages the production of the beta-amyloid that is so hard on your brain cells. Metals aggravate this process, as we saw in the last chapter, with zinc causing the beta-amyloid to clump together and copper and iron making free radicals that destroy our brain cells. And bit by bit, the neuronal connections that recorded your grandchildren’s names, what you did yesterday, and what you ate for breakfast start to go haywire.

As biological explanations like this begin to take shape, researchers protest that the jigsaw puzzle is by no means complete, and they are right. Even so, the message that emerges is strikingly optimistic. Let’s say you have the APOE e4 gene, which busily makes proteins that are eager to escort cholesterol around your body, like so many shopping carts waiting at the
meat counter. Presumably you’re at risk. Well, what if you were to change your diet? What if you were to bypass the meat counter altogether and favor vegetables, fruits, whole grains, and beans instead? Your body would make less cholesterol, your absorption of metals would diminish, and your risk would fall. Means of protecting ourselves are starting to become clear, even if genes would otherwise be working against us.
³
,
⁴
,
¹¹