About the Author
----------------
Neal Barnard, M.D., is a physician, clinical researcher, and
adjunct associate professor of medicine at the George Washington
University School of Medicine. His books include Breaking the
Food Seduction, Turn Off the Genes, and Foods That Fight
Pain.
Excerpt. © Reprinted by permission. All rights reserved.
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CHAPTER 1
The Basics Have Changed
In the past few years, much of what we thought we knew about
es has been turned on its head. What is now coming into
focus is an understanding of its fundamental causes, and that
gives us power we never had before.
To make sure we are at the same starting point, let me walk you
through the basics: symptoms, es types, and typical
s as they are currently used. Then I will show you
what's new.
HOW DO WE KNOW IT'S ES?
First, let's make sense of the symptoms. es may arrive with
no symptoms at all, but often it starts with igue. For no
apparent reason, your spark is just no longer there. It may also
seem that you are losing water more rapidly than you should be,
which is to say that you make trips to the bathroom more often
than usual. And you are thirsty: You find yourself drinking a
surprising a of water.
Here is what is going on: The fundamental problem is that sugar
is not able to pass from your bloodstream into the cells of your
body. From that single problem come a great many others, like one
domino knocking over another and another and another.
The sugar we are speaking of is glucose--one of the smallest and
simplest sugar molecules. In this case, sugar is not just another
word for junk food or empty calories. The fact is that the cells
of your body use this kind of sugar--glucose--as an energy
source. Like oline for your car or jet fuel for an airplane,
glucose is your body's fuel. It powers your movements, your
thoughts, and more or less everything you do.
And that is exactly the problem. If glucose is unable to enter
your cells, they are deprived of their basic fuel, so you lose
your energy. That is why you are igued. If your muscles do not
have the glucose they need for power, you tire easily.
Meanwhile, the glucose that cannot get into your muscle cells
builds up in your bloodstream. It becomes more and more
concentrated in the blood, and eventually it starts to pass
through the kidneys and ends up in your urine.*
Now, as glucose passes through your kidneys, it carries water
along with it- -lots of water, hence all those trips to the
bathroom. What follows, naturally, is thirst--you are losing all
those fluids. So igue, frequent urination, and thirst are all
symptoms of one problem: glucose having trouble getting into your
cells.
You may also find that you are losing weight. And no, this is not
an especially welcome event--not in this situation. You lose
weight because your cells are in essence starving. ents
cannot enter your cells, so your body is malnourished. Yes, even
if you are eating plenty of food, ents and fuel are unable
to get where they are needed.
Every day, people arrive at doctors' offices complaining of
igue, frequent urination, thirst, and sometimes unexplained
. The doctor takes a blood sample, finds an unusually
high level of glucose in the blood, and diagnoses es. The
doctor then advises the patient that it is essential to get blood
sugar under control. An overly large a of glucose flooding
through the bloodstream day after day can harm the arteries. Left
unchecked, it can damage the heart and the delicate blood vessels
of the eyes, kidneys, and extremities.
But as we have shown in our research studies, the road to high
blood sugar is a two-way street. When you change your diet and
make other ful improvements, a rising glucose level can
fall. Sometimes the change can be so dramatic that no doctor
looking at you afterward would ever guess that you had once been
diagnosed with es.
* The passage of glucose from the bloodstream into the urine led
to the technical name doctors use for es: es
mellitus. es comes from a Greek word meaning "to pass
through," and mellitus is the Latin word for "honey" or "sweet."
How Doctors Diagnose es
Doctors diagnose es if:
. You have symptoms of es (frequent urination, unusual
thirst, unexplained ) and your blood glucose level is
200 milligrams per deciliter (mg/dl)--(or 11.1 millimoles per
liter (mmol/l)*--or higher, regardless of the time of day or
whether you are fasting, or . Your blood glucose level is 126
mg/dl (7.0 mmol/l) or higher after an 8-hour fast.
Your doctor will consider this a provisional diagnosis until it
is confirmed by similar testing on a separate day. In some cases,
doctors perform a glucose tolerance test, in which you drink a
containing 75 grams of glucose. If your blood glucose value
is 200 mg/dl (11.1 mmol/l) or higher 2 hours later, your doctor
will diagnose es.
Normal fasting blood glucose is less than 100 mg/dl (5.6 mmol/l).
After a 2- hour glucose tolerance test, the value should be less
than 140 mg/dl (7.8 mmol/l). If your values are above the normal
limit but not high enough for a diagnosis of es, your
doctor will diagnose prees (impaired glucose tolerance),
which often precedes an eventual es diagnosis.
* US medical laboratories measure glucose in milligrams per
deciliter (mg/dl). In most other countries, glucose is measured
in millimoles per liter (mmol/l). As you will see, the same units
are used in cholesterol measurements.
es Types
A diagnosis of es--or prees--means the insulin in
your body is not doing its job adequately. Insulin is a hormone
that moves sugar from your bloodstream into the cells of your
body, among other functions. It acts like a key, opening a door
to the cell, so to speak, and allowing ents inside. When
insulin arrives at the cell's surface and opens the door, glucose
is able to enter the cell, which uses it for power.
If for some reason your body is not making insulin, the result is
rising blood glucose levels. Similarly, your blood glucose rises
if your cells resist insulin's actions--the key goes in the lock,
but the door will not open. Over the long run, high blood glucose
levels can damage your nerves, eyes, kidneys, and other parts of
your body.
es comes in three main types, called type 1, type 2, and
gestational es. Let's look at each one.
Type 1 es usually manifests in childhood or young
adulthood. It used to be called childhood-onset or
insulin-dependent es. In type 1 es, something has
damaged the pancreas's ability to produce insulin, and you need
to get it from an outside source--typically by injection.
However, recent research has revealed a great deal about how diet
changes can dramatically reduce the risk that es will bring
any serious complications your way, as you will see in Chapter 3.
In addition, we know more than ever about the causes of the
disease, arming us with more power to prevent it. The damage to
the insulin-producing cells is caused by the biological
equivalent of "friendly fire." That is, it is caused by the
body's immune system--our white blood cells that are supposed to
fight bacteria and viruses. These cells ought to protect you, but
instead they have attacked the cells of the pancreas, destroying
its ability to produce insulin. In Chapter 3, we will look at
what triggers this process. It may surprise you to learn that
foods--particularly the foods infants are fed within the first
months oflife--are leading suspects.
Type 2 es used to be called adult-onset es, or
sometimes non- insulin-dependent es. About 9 out of 10
people with es have type 2. Most people with this form of
the disease still produce insulin; the problem is that their
cells resist it. Insulin tries to bring glucose into the cells,
but the cells respond like a door with a malfunctioning lock. In
response to these sluggish cells, your body produces more and
more insulin, trying to overcome the resistance. If the body's
insulin supply cannot overcome the resistance, glucose simply
builds up in your blood.
es drugs work to counteract this problem: Some make your
cells more responsive to insulin. Others cause your pancreas to
release more insulin into the bloodstream or block your liver
from sending extra glucose into the blood.
Until now, most es diets have tried to compensate for the
cells' resistance to insulin's action, too. They limit the a
of sugar in your diet. They also limit starch (complex
carbohydrate) because starch is actually made from many glucose
molecules joined together in a chain. During digestion, starch
breaks down to release natural sugars into the blood. The idea is
that if you do not get too much carbohydrate at any one time,
your cells will not be overwhelmed with too much glucose. For
people on medications, typical diet plans to keep the a
of glucose or starch fairly constant from meal to meal and from
day to day so the a of medication required to help your body
process glucose--your daily dosage- -can stay the same, too. In
short, these diets guide you on what, when, and how much to eat.
Insulin is Made in the Pancreas
Insulin is made in the pancreas, an organ located just behind
your stomach that is about the size and shape of a TV remote
control. In fact, remote control is what the pancreas is all
about. It sends insulin into the bloodstream to travel to the
cells of your body to help them take in glucose from the
bloodstream. In type 1 es, the pancreas has stopped making
insulin. In type 2 and gestational es, the pancreas is
usually able to make insulin, but the body's cells resist its
action.
New research has changed everything, however. We can now use diet
changes to influence insulin sensitivity directly. So, as you
will see shortly, the tion prescription has been completely
rewritten to take advantage of this new understanding.
Gestational es is similar to type 2 except that it occurs
during pregnancy. While it typically disappears after childbirth,
it is a sign of insulin resistance, and that means that type 2
es may be around the corner. With the same sorts of steps
that tackle type 2 es, we can often stop gestational
es from ever turning into type 2.
GENES ARE NOT DESTINY
es runs in families, but don't take that to mean that if
one of your parents has es, a similar diagnosis has to be
your e as well. You can change things.
Let's take a look at type 1 es first. Many children are
born with genes that make it possible for them to develop type 1
es, but most of them never do. In fact, even among
identical twins, when one twin has type 1 es, the other has
less than a 40 percent chance of having it.1 What makes the
difference, apparently, is the environment, particularly the
foods the child is exposed to early in life, viral infections,
and perhaps other factors.
Genes play a similar role in type 2 es. Many years before
es ever manifests, special tests can detect insulin
resistance in young adults who have inherited a tendency toward
type 2 es from their parents. If they eat the same kinds of
foods their parents did, they are very likely headed for a
diagnosis. Abundant evidence shows, however, that changes in diet
and lifestyle can cut the odds that es will occur. When it
does occur, diet can dramatically alter its course.
The point is this: Some genes are dictators, and others are not.
The genes for hair color or eye color, for example, really are
dictators. If they call for you to have brown hair or blue eyes,
you can't argue. But the genes for es are more like
committees. They do not give orders; they make suggestions.
If our genes call for es, we do not necessarily have to
listen to them. We have more control than you might imagine.
HEMOGLOBIN A1C
As you have seen, doctors diagnose es based on your blood
glucose level, and tracking your blood glucose is an important
way to track the effects of diet and medication dosages. As
helpful as glucose testing is, though, it really indicates only
how you are doing at the time you take the test. The best way to
tell how you are doing over the long run is with a test called
hemoglobin A1c, or A1c for short. This is the main way you will
track your progress in controlling es.
Hemoglobin is the pigment that gives color to your red blood
cells and whose job it is to carry oxygen. What the A1c test
actually measures is how much glucose has entered your red blood
cells and become stuck to hemoglobin. If you have had a lot of
glucose in your blood, a fair a of it gets into your cells
and sticks to your hemoglobin. If you have not had much glucose
in your blood, your hemoglobin has much less stuck to it.
Since red blood cells have a fairly short life span (about 4
months), the test indicates how well your blood sugar has been
controlled over the preceding 3 months or so. The American
es Association (ADA) recommends that people with es
get their A1c values below 7 percent. Research shows, however,
that lower values cut the risk of complications, so many experts
now call for targets of 6.5 or even 6 percent.
ES DIETS
If you have es, chances are you were given printed
guidelines on what to eat and what to avoid. Perhaps you have met
with a dietitian, and you may have been referred to a es
class. Unfortunately, most people do not get the ongoing support
they need to make dietary changes, and as a result, this
well-meaning effort may not have much effect. If you are like
many people, you may have found your diet tough to sustain.
For many years, the ADA has offered diet recommendations designed
to provide basic tion while also keeping calorie intake and
food choices reasonably stable over the course of the day and
from one day to the next, as you saw above. The idea was that if
you had no carbohydrates for breakfast but then had a big
carb-fest later in the day, your blood sugar would change
erratically. Similarly, if you had lots of starchy foods on
Monday but went low-carb the rest of the week, your blood sugar
would be all over the , and your medications could not keep up
with you.