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Authors: Neal Barnard
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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 .
“Good” Fats
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 eighteencarbons 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
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 .
“Good” Fats
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 eighteencarbons 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
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