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Diabetes
Diet?
The
Sweet Truth about Diabetes?
What
Kind of Diabetes Do You Have?
Kinds of Diabetes
Diabetes
is not a single disease with a single cause. Rather, it is a collection of
diseases, some more difficult to control than others. All forms of
diabetes involve a hormone (body regulator) from the pancreas called
insulin. If you have diabetes, either you lack insulin or the insulin you
have is not doing its job properly. The result is that instead of being
stored for energy through the action of insulin, the foods you eat
(primarily the starches or carbohydrates) raise your blood sugar to
higher-than-normal levels. Without treatment, your blood sugar remains
high and has the potential of adversely affecting every organ and system
in your body. With treatment, the insulin problem can be solved, and your
blood sugar can be brought down or normalized so that the body is not
damaged. A person with diabetes can thus remain healthy and look forward
to a normal life span.
A
Bit of History
Information
written on ancient Egyptian papyrus described diabetes as a disease that
caused a person to melt into the loins and the resulting urine to attract
ants (because of the sugar content). The name itself indicates the loss of
valuable body fluids: diabetes is from a Greek word, meaning "to
siphon." Mellitus, a Latin word, relates to a word meaning
"honey" or "sweet tasting." Yes, due to the high sugar
content and the lack of earlier testing methodologies, actually tasting
the urine did give an indication that the person had sugar diabetes! In
fact, Mother Nature was fooling the disease's early observers, who saw the
crystalline content of the urine after its liquid contents had evaporated.
In the fourteenth century, this was actually thought to be a salt (people
were not into taste-testing at that time, we suppose).
Diabetes
mellitus was treated, over time, by various means aimed at lowering the
sugar content in the urine or decreasing the loss of fluid. Some patients
fasted and feasted on alternating days, weeks, or months. Others were
taught to eat rancid meat or vegetables cooked three times in their own
water. Others survived on eggs or cereal. The association of food and
fluid was passed down through time. Eventually, the discovery was made
that the hormone insulin, secreted by cells called beta cells in the
islets of Langerhans, needed to be replaced in the body in order for
normal blood-glucose levels to be achieved.
Many
people contributed to the knowledge about monitoring blood-glucose levels.
Insulin could not be analyzed or its significant content noted until the
1960s. We learned that other hormones, such as glucagon, might help cause
the disease. We also learned that diabetes is not the result of a single
event in the body but of several events that lead to a series of immune
responses, with the end result being that the majority of insulin-making
cells (beta cells, found in the islets of Langerhans) are no longer
working.
With
the discovery of insulin, many people believed that diabetes had been
cured. The medical community soon discovered that if the person lived
longer, and especially when the blood-glucose levels were not
significantly controlled or normalized the majority of the time,
complications occurred (for example, blindness, heart disease, or the need
for amputation). Many of these complications can now be prevented through
present knowledge of this process or through getting to the doctor in
time. Eyes (retinopathy) are being stabilized and vision returned (a risk
reduction of 76 percent). In one case, a young man had 350/20 vision in
the right eye, 400/20 in the left eye, a detached retina in the left eye,
cataract development in both eyes, and cloudy fluid in the eyes due to
past hemorrhages. With the lasering of the total retina surface, a
procedure that reattached the retina to the back surface of the eye,
replacement of the eye fluid, and lens removal and implant of a new lens,
the eyes changed to 30/20 in the left eye and 40/20 in the right eye.
Amputation, a procedure most associated with diabetes in its earlier days,
can be prevented in an increasing number of cases (risk reduction of nerve
disease or neuropathy: 60 percent). Other problems associated with other
parts of the body (i.e., risk of kidney disease or nephropathy: 56
percent) are reversed earlier or treated with transplantation, something
unheard of twenty-five or more years ago.
Education
of the diabetes patient is one of the major keys to attaining such high
degrees of control. Since health professionals cannot be with the person
and his or her family on a day-in, day-out basis, self-management
education is a must. Demand it.
Types
of Diabetes
Diabetes
has been divided into three groups: Type 1, or insulin-dependent diabetes
mellitus, in which insulin must be injected daily; Type 2, or
insulin-resistant diabetes mellitus, in which insulin injection is usually
not necessary; and secondary diabetes (due to pancreatic surgery or
overactive glands, such as the pituitary or the adrenals). We are
concerned here only with Type 1 and Type 2 diabetes.
Type
1 diabetes is believed to be caused by a combination of genetics and
environmental stressors. The individual who develops Type 1 diabetes has
an inability to make insulin. When insulin is absent, the cells are in a
state of starvation, while an excess of sugar in the form of glucose is
available in the blood. This state of high blood-glucose is called
hyperglycemia or, in this case, diabetes mellitus. (Hyperglycemia may be
caused by a number of stressors, but when it is due to problems with
insulin it is called diabetes mellitus.) Despite eating vast amounts of
food the person remains in a condition of starvation until adequate
insulin is available and can get the food into the cells. Body fat is
burned as an alternate fuel to sugar; a by-product, ketone bodies, is
created as a source of energy. But ketones cause the accumulation of acids
and upset the body's buffer system. The body develops a serious problem
known as ketoacidosis, a chemical imbalance of the body accompanied by
high blood sugar and also excess acid. This creates the classic symptoms
of out-of-control diabetes: frequent urination (polyuria), excessive
thirst (polydipsia), and excessive hunger (polyphagia). If neglected,
ketoacidosis can eventually lead to death.
Type
2 diabetes, besides being called non-insulin dependent diabetes, has also
been known by many other names, such as maturity onset diabetes, insulin
resistant diabetes, non-ketosis prone, ketosis resistant, and even MODY or
Maturity Onset Diabetes in the Young. Eighty to 85 percent of the diabetes
population is diagnosed as having Type 2 diabetes. Of these, 88 percent or
so are overweight. Many of the so-called borderline diabetics are Type 2s
who have been mislabeled.
Insulin
is still the key factor in this disease, but often there is an excess
rather than a lack. The increase in insulin is believed to be the result
of overeating. The excess insulin causes a decrease in the cell's number
of insulin-receptor sites (that is, links to get the insulin into the
cell). In the absence of receptor sites, the insulin does not work, and
the result is diabetes (hyperglycemia). While the elevation in
blood-glucose levels may lead to polyuria, polydipsia, and polyphagia, as
in Type 1 diabetes, a key difference exists.
Insulin
is the key factor in all forms of diabetes. In the case of Type 1 diabetes
the problem is the lack of insulin. With Type 2 diabetes there may, at
least early in the course of the disease, be an excess of the hormone. The
cause of this excess is not entirely understood, but at least in part is
due to an interaction of inherited characteristics interacting with some
lifestyle problems. The life problems are aging, obesity, and inactivity.
Though the inheritance for Type 2 diabetes is probably widespread through
all peoples of the world, the disease is primarily seen in industrialized
countries. This is thought to be due to the insulin resistance that comes
from the excess food intake and decreased energy expenditure that results
in obesity. When there is obesity in persons who have the inheritance for
diabetes 2, for some reason the insulin does not work right at the
periferal (muscle and fat) cell, and the pancreas must then produce more
insulin to get the same result. This excess insulin production ultimately
leads to exhaustion of the insulin-producing cells leading to decreased
production. Now we have two defects: insulin resistance with increased
insulin need, and insulin deficiency due to lack of production. The result
will be increased blood sugar and diabetes with its resulting symptoms of
excess urination (polyuria), excess thirst (polydipsia), and excess hunger
(polyphagia). These symptoms are very prominent in Type 1 diabetes but may
not be present in Type 2 diabetes until very late in the course of the
disease when there is a marked lack of insulin.
In
Type 1 diabetes there is a lack of insulin and polyphagia is usually
accompanied by weight loss, but with Type 2 diabetes there more likely
will be weight gain. The major function of insulin is storage of excess
food so the weight gain is easily understandable. Overeating and obesity
cause excess insulin that stores the excess food, causing more fat, which
causes more insulin resistance and more insulin secretion, which stores
more food, and so on. Decreasing food intake and increasing energy
expenditure (exercising) to reduce obesity and take the strain off the
pancreas to produce extra insulin are vital to treating this disease.
The
cause of the insulin resistance is not known. We know there is an
inherited defect, but its actual identity, is not known. Indeed there may
be many inherited defects that can cause insulin resistance in the
presence of obesity. These defects may include a defect in the number or
shape of the chemical on the cell membrane which accepts the insulin
(called a receptor) or in a variety of defects that can occur inside the
cell so that the insulin cannot work properly. Many possible defects have
been identified so that there can be many kinds of Type 2 diabetes. All,
though, are related to obesity as the precipitating phenomenon leading to
insulin resistance, excess insulin production, beta cell exhaustion, and
decreased insulin production, (i.e. insulin deficiency). The result is
high blood sugar which itself can be toxic to the insulin-producing cell
and further damage them, leading to a greater decrease in insulin
production, more insulin deficiency, and more increase in the blood sugar,
resulting in a vicious cycle. Treatment should occur as early as possible
to preserve the beta cell function and insulin production.
Type
1 diabetes is most often diagnosed in children with a peak incidence
during the pre-adolescent growth spurt. The disease can occur at any age
and must never be misdiagnosed just because the person is older. Type 2
diabetes is more common in people over age 35, but it can also occur at
any age. We are in fact seeing an increase in this form of the disease in
children associated with an increase in obesity of our children. People
with newly diagnosed Type 1 diabetes have a tendency to be thin and have
lost weight. People with Type 2 diabetes are usually obese and will have
gradually gained weight. Both types may require insulin for treatment.
Type 1 patients are insulin dependent, i.e. they will die without the
hormone replacement, while Type 2 may require insulin to control the blood
sugar but will not die soon without it, although they will develop the
long-term complications that ultimately will be fatal. Sometimes these two
forms of diabetes are difficult to tell apart. Some tests can be done to
differentiate them but these tests can be expensive, and family history
and symptoms are more often used and are usually effective in
differentiating the two types.
In
1997, new criteria for diagnosis and classification terminology were
developed. These are shown in Tables 1-1 and 1-2. All diabetes is
diagnosed by one of three criteria: (1) a fasting plasma glucose level (FPG)
of 126 mg/dl or 7 mmol (the measure used in most countries other than the
USA- the conversion factor is 18) on two occasions, (2) a value of 200
mg/dl or 11 mmol at two hours after an oral glucose load (rarely used
anymore), or (3) a random value greater than 200 mg/dl or 11 mmol if
associated with symptoms usually associated with diabetes. These are the
criteria that should be used today for diagnosis in all patients. If the
FPG is greater than normal (105 mg/dl-6 mmol) but less than (126 mg/dl-7
mmol) or the 2-hour value on the oral glucose tolerance test is greater
than 140 mg/dl-7.08 mmol but less than 199 mg/dl-11.1 mmol, the diagnosis
is Impaired Fasting Glucose or Impaired Glucose Tolerance. We no longer
use the term a borderline diabetic which used to be used for these
intermediate states since that term has no meaningful criteria and is
subject to any physician's interpretation. The above terms have precise
definitions and are the same from doctor to doctor.
Type
1 diabetes has two subcategories: (1) autoimmune and (2) ideopathic. By
this we mean that class 1 are of known cause in that there is absolute
insulin deficiency caused by a defect in the immune system that destroys
the beta cells of the pancreas. Ideopathic means that some other cause
such as removal of the pancreas, destruction of the pancreas by infection,
inflammation or chemicals, or some unknown cause has destroyed the beta
cells or the entire pancreas so again there is complete insulin deficiency
but not from destruction by the immune system. Type 2 diabetes can be
subclassed as well but the subclasses are still being developed. Most are
adult and most are obese. The next classification is Impaired Fasting
Glucose (IFG) or Impaired Glucose Tolerance (IGT), and the last class is
Gestational Diabetes, which will be discussed later.
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CLASSIFICATION
OF DIABETES
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Stage
Glucose
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Fasting
Plasma Glucose
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Casual
Plasma Glucose (Random)
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2
Hr. Plasma Glucose
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Diabetes
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>
or = 126 mg/dl
(7.0
per mmol/l)
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>
or = 200 mg/dl
(11.11
mmol/l + symptoms)
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>
or = 200 mg/dl
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Impaired
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126
mg/dl
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>
200 mg/dl (1 hour)
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>
or = 140-199 mg/dl
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Glucose
Homeostasis
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Normal
< 110 mg/dl
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<
180 mg/dl (1 hour)
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<
140 mg/dl
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Report
of the Expert Committee on the Diagnosis and Classification of
Diabetes Mellitus. Diabetes Care 20(7) 1997, 1183*1197.
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Problems
Associated with Diabetes
With
Type 1 (insulin-dependent) diabetes, after the acute episode (diabetic
ketoacidosis) or early symptoms leading to the diagnosis (frequent passing
of urine, normal eating with weight loss, extreme thirst), there may be a
partial remission period (the honeymoon) in which the body appears to be
able to make some insulin again. This period usually lasts from three to
six months, but it may last longer, depending on the suppression of the
insulin-making ability of the beta cells through an external
insulin-injection program. Illness, poor blood sugar control, or extreme
emotional stress appear to aid in further destruction of the beta cells,
as does growth, and may shorten the remission period. Eventually, the
person becomes totally insulin dependent, especially if more than 90
percent of the beta cells become inactive. Except during the honeymoon or
period of partial remission, people with Type 1 diabetes cannot make
insulin. There will be no measurable insulin levels except that which is
injected and no measurable levels of any of the by-products of internal
insulin secretion such as a protein called C-Peptide which can
differentiate internal and external insulin when it is present.
C-Peptide
is present in persons with Type 2 diabetes often in large amounts
consistent with the elevated insulin levels and can be used to
differentiate Type 1 from Type 2 diabetes. As time goes on and insulin
secretion is decreased in Type 2 diabetes, C-Peptide will decrease as well
and make this tool use less to differentiate the different kinds of
diabetes. C-Peptide is expensive and not of much value except in a
research setting.
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