Power Foods for the Brain (9 page)

Could it really be that simple? Could toxic fats really push us toward Alzheimer’s disease, and could avoiding them make a difference? Well, first, let’s understand the numbers. What would it take to get to the amount that turned out to be particularly dangerous in the Chicago study—that is, 25 grams of saturated fat?

It is surprisingly easy. Dairy products, meat, and eggs are loaded with it. So if you had just one egg with bacon for breakfast, a grilled cheese sandwich for lunch, and a moderate serving of meat for dinner, they would add up to 25 grams of “bad” fat.

Or have a glass of milk for breakfast, a serving of salmon for lunch, and half a cheese pizza for dinner. Bingo. You’re already at 25 grams of saturated fat.

“Yikes!” I hear you say. “That’s the way most people eat!” True enough. The North Dakota breakfasts I grew up on are not looking so good. We had an egg or two every morning, sometimes with bacon or sausage. We never used butter, but we topped our toast with margarine made from partially hydrogenated fat. We poured milk on our cereal and had another glass of milk on the side. My parents led the way, thinking they were providing nutritious meals for themselves and their children.

Sometimes I wonder what would have happened if my grandfather had not raised cattle for a living. It sounds silly to even
raise the question, but what if, instead of living on beef, chicken, and milk, our family’s staples had been like those in Loma Linda or Okinawa or Sardinia, or any of the other places where people live long, healthy lives? Could the long, slow mental decline that preceded my grandparents’ deaths have been prevented?

There is no way of telling for sure. But the good news is that there are plenty of healthful foods that we can take advantage of today. Vegetables, fruits, beans, and grains have essentially no “bad” fats at all. So maybe you’d like Masu’s sweet potatoes, rice, and green vegetables, or Ellsworth’s baked beans, corn on the cob, and soy yogurt. But how about paging through the recipe section of this book, where you’ll find Spiced Pumpkin Bread and Blueberry Buckwheat Pancakes for breakfast, Creamy
Pumpkin Bisque, Easy Colorful Pasta Salad, Sweet Potato Burritos, or White Bean Chili for lunch, followed by Red Lentil or Potato Leek Soup, and Baked Ziti or Risotto Primavera for dinner, with a nice Warm Apple Cherry Compote, Baked Apples, or Chocolate Pudding for dessert? The choices are endless.

If the main sources of saturated fat are dairy products and meats, you may be asking, how much meat and dairy products do we actually need?

The answer is, none at all. The healthiest diets exclude animal products completely. I must admit I was slow to come to this realization, which I will blame on my Midwestern upbringing. But studies show that people who choose the veggie burger over the meat variety and top their spaghetti with chunky tomatoes, fresh basil, and asparagus tips instead of meat and cheese get an enormous return on their investment. They are healthier. People who make this change, even late in life, find that excess weight trims away, artery blockages begin to reverse, diabetes improves and sometimes even disappears, blood pressure comes back toward where it ought to be, and their brain cells breathe a huge sigh of relief.

For many people this feels like a tall order. But we have found a way to give you a no-risk test-drive of a 100 percent healthy diet. You’ll see it in
chapter 9
.

As we have seen, saturated fat and partially hydrogenated oils are really quite unhelpful. But not all fats are so ill-bred. Some are actually good for you. Here’s the reason:

Every cell in your body is surrounded by a cell membrane. This membrane has three layers—two protein layers with a layer of fat sandwiched in between.

If you were to take a close look at this membrane, that fatty middle layer might look unimportant. But it determines a great deal about how the cell works. Imagine that the engine in your car has new, fine motor oil coursing through its moving parts. Everything works great. Now, what if that oil were replaced by thick, black tar? Nothing would work right. Well, the type of fat that is in your cell membranes affects how they work, too. If your cell membranes have “good” fats, they tend to stay healthy.

In 2003, French researchers sampled red blood cells of 246 older people, finding that those whose cell membranes were rich in a certain type of fats, called
omega-3
fats, were more likely to maintain their cognitive functions compared with other people.
¹³
An earlier study had shown a similar result: A high level of omega-3s in people’s blood seemed to protect against cognitive decline and Alzheimer’s disease, at least to a degree.
¹⁴

Not every study has shown this benefit,
¹⁵
but overall, evidence suggests that having “good” fats in your cell membranes may be helpful. So what are they and how do you get them there?

Let’s start by taking a look at a sprig of broccoli. As you look at it, you can see that it doesn’t have very much fat, of course. But it actually does have some, surprisingly enough. And there is one particular fat hidden there that your body needs. It is an omega-3 fat called
ALA
, or
alpha-linolenic acid
.

Putting that ALA molecule under a powerful microscope, we see that it is actually a chain of eighteen carbon atoms joined together. If you were to swallow a bit of broccoli, these healthy fat molecules would pass into your bloodstream. Your body would then lengthen the molecular chain from eighteen
carbons to twenty, making a new fat called
EPA (eicosapentaenoic acid)
. You would then tack on two more carbons to make the 22-carbon
DHA (docosahexaenoic acid)
. And it is DHA that the brain needs. So it all starts with ALA, the basic “good” fat in food, and you end up with DHA for your brain.

Now, broccoli is just an example. There are traces of ALA in many vegetables, fruits, and beans, and much larger amounts in other foods, especially walnuts, seeds, flax and flax oil, and canola oil. With these foods in your diet, you’ll have the raw material for building the fats your brain can use.

But there’s a complication here. In order to elongate ALA from eighteen carbons to twenty and eventually to twenty-two carbons—that is, in order to make the fats the brain is looking for—ALA depends on enzymes. Enzymes are the factory workers that take the ALA chain and bolt on the extra carbons to deliver DHA to your brain. And like factory workers everywhere, they can only do so much.

There are certain other fats—called omega-6s—that are just as eager to have extra carbons bolted into place. They tie up the enzymes you need to handle your omega-3s. Omega-6 fats are found in certain cooking oils—safflower oil, sunflower oil, corn oil, cottonseed oil, soybean oil, and grapeseed oil. And there is a whole lot more omega-6 fat in a bottle of any one of these oils than there is omega-3 in broccoli or any other green vegetable. So if you are slathering these oils all over your foods, they slip into your bloodstream and occupy the enzymes that should be handling ALA.
¹⁶
And suddenly your brain is wondering what happened to the “good” fats it needs.

Now, you do need a little bit of omega-6. But most people’s diets include so much of these oils that they crowd out everything else. Their enzymes are all tied up, and only a fraction of their ALA is ever converted to the longer-chain forms.

So, omega-3s are good, and if you have too much omega-6, it will crowd out your omega-3s. What should you do?

The first step is to have ALA-rich foods in your diet. Have plenty of vegetables, fruits, and beans, and, if you like, top your salad with slivered walnuts or ground flaxseed, for example.

The second step is to greatly limit competing fats. Take a look at the low-fat cooking techniques described in
chapter 9
and in the recipe section. You’ll be able to sauté onions and garlic without drowning them in grease. And you’ll be able to top a salad with lighter, healthier dressings.

You already want to avoid animal fat and partially hydrogenated oils because of the harm they do. Limiting or avoiding cooking oils is a good idea, too.

It’s really a question of balance—getting an adequate amount of ALA while limiting the competing oils. The balance your body is looking for is somewhere around 2:1 to 4:1—that is, 2 to 4 grams of omega-6 for every gram of omega-3.
¹⁶
That is the ratio that maximizes your body’s ability to use the omega-3 to build the longer-chain fats your brain uses. If your menu emphasizes vegetables, fruits, and beans, your foods would give you a pretty good balance of fats naturally. While these healthful foods don’t have a great deal of any sort of fat, what they do have is proportionately rich in omega-3s, as opposed to other kinds of fat.

Some people take a third step, which is to make sure they have DHA in their diets. Their rationale is that for most people very little ALA is actually lengthened to EPA and DHA, so they aim to get DHA directly. Their problem, of course, may be that they are getting too much omega-6, and it is tying up their conversion enzymes. So cutting out those competing oils is important. Still, if you do decide to include DHA in your diet, the most healthful source is a DHA supplement, which you will find at
any health food store. Vegan brands are preferable. Their DHA is derived from algae rather than from fish, and they contain no animal-derived ingredients.

That said, omega-3 supplements have not yet proved their worth for preventing dementia. In a two-year English study, 867 elderly people were given a capsule that contained two different omega-3s: 200 milligrams of EPA plus 500 milligrams of DHA. It did nothing to forestall memory loss. The participants’ reaction time, spatial memory, and processing speed were no better than for people given a placebo.
¹⁷
A Dutch study showed the same result.
¹⁸
It may be that omega-3 supplements would show more benefit in people who had low omega-3 intake to start with.

Fish oil supplements have also been tested in people who have Alzheimer’s disease to see if they can slow the disease process. So far, results are disappointing. An eighteen-month test of fish oil (2 grams of DHA) in Alzheimer’s patients showed no benefit.
¹⁹

The take-home message is not to rely on pills. Instead, put omega-3-rich foods on your daily menu.

Some people take a different approach, choosing foods with more vegetable oils than I have been suggesting and adding fish to their diets. Indeed, compared with beef fat or chicken fat, vegetable oils and fish oils have less saturated fat, and fish has more omega-3 fatty acids. In the Chicago study, people who favored vegetable oils and fish had a reduced risk of dementia compared with people who focused on meatier fare, and several other studies have shown much the same thing.
²⁰
,
²¹

However, a serving of fish is much more like beef than it is like broccoli. As a group, people who eat fish have more
weight problems and have a higher risk of diabetes compared with people who skip animal products altogether.
²²
And excess body weight and diabetes can both put you at higher risk for Alzheimer’s disease. So, if you are already following a healthful plant-based diet, fish is really a step backward.

Part of the problem is that many fish species are fatty. Atlantic salmon, for example, is about 40 percent fat. Chinook salmon is around 50 percent.

“But it’s
good
fat,” you say. Well, yes, some of it is. But fish fat is always a mixture. About 15 to 30 percent of the fat in fish is omega-3, depending on which species you buy. The other 70 to 85 percent is not “good” fat. It is just a blend of saturated and various unsaturated fats. And every last fat gram packs 9 calories, which is why fatty fish can easily add to your waistline.

Fish also contains cholesterol, just as other animal products do. Some—particularly shellfish like shrimp and lobster—have more cholesterol than red meat. That, plus the methylmercury and other pollutants found in many species (such as tuna), makes fish a less-than-attractive choice. There are other sources of omega-3s that are much more healthful.

It may be that the “benefits” of fish seen in some studies are simply a compensation for the harm of red meat. In other words, fish’s anti-inflammatory or anticoagulant tendencies counteract the opposite tendencies of other meats.
²³

Not surprisingly, in the blue zones, fish is not a large part of the diet—not even in Okinawa or Sardinia. The diet staples come from plant sources.

Some people promote a “Mediterranean diet,” meaning one that emphasizes vegetables, fruits, beans, and pasta, fish rather than
red meat, olive oil instead of butter, and perhaps wine. It’s an easy sell. To North Americans, the word “Mediterranean” conjures up sunny images of places they would rather be.

Earlier I mentioned a Columbia University study in which researchers rated the diets of New Yorkers. Those who emphasized vegetables, fruits, legumes, grains, and fish, while having less meat and dairy products, along with mild to moderate alcohol consumption, cut the risk of developing Alzheimer’s disease over the next five years by 32 to 40 percent.
⁵