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Explaining My Wife’s Diabetes
It really bothered me when my wife started defining
herself as a diabetic! How could she go from grandmother to diabetic in so
few days? She let me sit in on sessions with her doctor and diabetes
counselor. In answer to my many questions about this most common form of
diabetes, we received lots of brochures, white papers and even the loan of a
hefty book on diabetes. Although diabetes is a complicated disease, I formed
a useful mental image of Type 2 Diabetes to guide our actions as my wife
overcame her diabetes.
Decorated with Sugar
Her doctor’s diagnosis used a test called HbA1C,
which the doctor said was a three-month average of blood sugar (glucose)
levels. At first I couldn’t understand how a single blood test could give a
three-month average. Now I visualize all “new-born” red blood cells being
permanently decorated with a sprinkling of glucose as soon as they enter the
blood stream. If there’s lots of glucose in the liquid blood, the decoration
attached to the outside of their cell membranes is heavy. If there’s not
much glucose in the blood, the decoration is light. Each new blood cell
wears its original decoration of glucose until it dies about three months
later. So one test can measure the average amount of glucose that decorates
red blood cells, which range in age from new-born to ready-to-die, thereby
indicating what blood sugar levels were like during the previous three
months.
So how did my wife’s blood sugar levels get so high
that it could be dangerous to her health? The short answer is that she was
“fat” and sedentary. I take credit for the sedentary part, because for years
she wanted us to begin an exercise program, but I think I should let her
take credit for the “fat” part. She was not grotesquely obese, but she had a
generous layer of padding twixt her skin and bones.
Attacking the Problem
We bought her a blood sugar testing kit and the
medicine that her doctor had prescribed. With the gentle persuasion of my
benevolent skepticism, she delayed starting the diabetic medication for a
week while we tested and recorded her blood sugar several times each day. We
used our computer’s spreadsheet to graph the tests results to see
differences before and after medication started. The graph verified that the
medication lowered her blood glucose levels, but sometimes it got too low
and she felt “shaky.” Following the diabetes counselor’s advice, she began
to restrict how much she ate and paid careful attention to the number of
“carbs” (carbohydrates) that she consumed. I remodeled a spare bedroom where
we put a treadmill for exercise.
I wasn’t the only one who was surprised by how much
weight she lost with her careful control of her diet. Over the next nine
months, she dropped from over 180 pounds down to about 140 pounds. At 160
pounds her doctor told her she could quit taking diabetes medication. She
continued exercising and testing her blood. Her diabetes was under control
and she looked trim! It was fun to see her timidly shop for new, slimmer
clothes.
Visualizing Diabetes
Here’s my simple mental image of the cause and cure of
my wife’s Type 2 Diabetes. It may not be a perfect model for such a complex
disease, but it fits our experience and the diabetes literature we’ve
studied:
Carbohydrates in our diet (sugars and starches, which
are sometimes called “carbs”) are essentially short or long chains of
glucose molecules. Digestion breaks the chemical bonds in the carbohydrate
chain and releases glucose molecules individually into the blood stream. You
can read this paper because your brain cells are absorbing glucose from your
blood and “burning” it to power the work of reading. Just as burning
gasoline in a car produces power, heat, and exhaust, so burning glucose
inside a brain cell produces brain power, body heat, and carbon dioxide
“exhaust” in your exhaled breath. Just as gasoline needs to be replaced to
keep a car running, so glucose needs to be replenished to keep brain cells
functioning.
Whose turn is it?
The human body has some wonderful, self-regulatory
mechanisms (called homeostasis). Blood sugar regulation is a good example.
The body regulates blood sugar to keep it above the minimum required for
proper brain function (about 55 mg/dL) and below the maximum that the
blood-filtering kidneys can handle (about 140 mg/dL). Glucose is the brain’s
primary energy source. The brain absorbs glucose from the blood
without the aid of insulin. Insulin, which is produced by the
pancreas, tells liver, muscle and fat tissues when it is their turn to
absorb glucose from the blood. Those three tissues are where the body stores
most of its energy fuels. Unchecked those storage tissues could take so much
glucose out of the blood that the brain and other organs couldn’t function
properly.
Insulin Presses the “Door Bell”
After a meal, high levels of glucose in the blood
stimulate the pancreas to produce insulin. I picture an insulin molecule
arriving at an energy storage cell, finding the right place to press itself
against the cell’s outer membrane, which (like pressing a door bell button)
sends a biochemical message into the cell that glucose is available. The
cell reacts by sending glucose transporters (GLUT4 molecules) through
special areas of the cell membrane to identify and “hook up” with glucose
molecules that are on the outside of the cell. The GLUT4 molecules then pull
glucose molecules through the cell membrane into the interior of the cell.
The storage cell then converts glucose into either glycogen or energy-rich
fat, depending on which type of cell it is. Liver and muscle cells convert
and store glucose as glycogen. About 1% of the body’s expendable energy is
stored in the liver; about 2 ½ % is stored in the muscles, but most (about
96%) is stored as fat in fat tissues.
Between meals, the brain gets its glucose energy mainly
from the liver. The liver converts stored glycogen back into glucose, which
the blood then transports to the brain. Muscles keep a supply of glycogen
readily available inside themselves for quick bursts of energy when the body
needs to accelerate into motion. When glycogen energy is drained from liver
and muscles, energy is drawn from fat cells. Meals replenish liver and
muscle energy stores and the excess glucose goes into fat. Logically, we
need to consider the problem of what could happen if a body’s liver, muscles
and fat tissues became completely full! Glucose in the blood from a meal
would have no convenient place to go, so it would accumulate at high levels
in the blood.
Ballooning Fat Cells
“Insulin resistance” is a characteristic of Type 2
Diabetes. We could imagine that if liver, muscle and fat cells are filled to
capacity with stored energy, they could resist insulin’s biochemical message
to take in more glucose. Some medications can force more glucose out of the
blood into storage cells. I envision those poor fat cells being pumped up
like big tight balloons! A low “carb” diet can help lower blood sugar levels
by reducing the amount of glucose put into the blood by digestion. If,
however, the low “carb” diet just substitutes fat-based calories for
carbohydrate calories, the dietary fat will go to fat cells for storage,
causing more ballooning. My wife’s alternative was serious attention to how
much she ate and regular exercise. Weight loss, by reducing the amount
eaten, can transform tightly inflated fat cells into shriveled fat cells
that are ready and willing to respond to insulin’s biochemical message to
take glucose out of the blood. Exercised muscles use up their stored
glycogen and are ready to draw blood sugar into themselves when insulin and
glucose show up together in the blood. Reduced food intake and increased
exercise make space for glucose. Insulin encounters less resistance as it
does the job of clearing excess glucose from the blood. Liver, muscles and
fat cells turn glucose into useful energy storage for the body. The natural,
self-regulatory mechanisms for blood sugar just don’t work well in a “fat,”
unexercised human body, and Type 2 Diabetes results.
Diabetes is a complex group of diseases that share
elevated blood sugar levels as a defining symptom. Causes of diabetes differ
among people. What worked for us will not work for everyone diagnosed with
diabetes. My wife keeps her new slim figure with her low calorie diet and
regular exercise. She’s convinced that’s the reason her blood sugar levels
now stay within the proper range. I confess that she pokes my fingers for
blood to check my blood sugar levels. She restricts my diet and has me take
my turn on the treadmill. I suppose weight loss and exercise might even help
me….
Wanless Southwick - February 9, 2004
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