Goals for the Care of Diabetes Mellitus

Dr. Rex L. Mahnensmith Internist Waterbury, Connecticut

Dr. Rex Mahnensmith is an internist practicing in Southington and Waterbury, Connecticut. Dr. Mahnensmith specializes in Internal Medicine, Nephrology, Metabolism, Diabetes, Nutrition, and Urgent Care.

Diabetes Mellitus is defined by elevated blood glucose concentrations. 

Blood glucose concentrations should reside below 100 mg/dL during fasting time periods. Biologic Normal Blood Glucose is 70-99 mg/dL when "fasting."

"Fasting Time Periods" refer to any time frame beyond 2 hours after eating, until next intake. If one eats breakfast at 7 AM, then the time frame from 9 AM until lunch is consumed, such as 12 PM, is a Fasting Time Period.  Then, the time from 2 PM until evening meal is consumed, such as 6 PM is another Fasting Time Period. And the time period from 8 PM until breakfast is another Fasting Time Period.  

Fasting means abstaining from food and caloric beverage. Of course, a snack will interrupt a Fasting Time Period.  This can be harmful if one has Diabetes Mellitus, because glucose will elevate above biologic normal after any eating.

If fasting blood glucose values exceed 125 mg/dL, then Diabetes Mellitus exists. If fasting blood glucose values reside between 100 mg/dL and 125 md/dL, then "Pre-Diabetes" exists.  "Pre-Diabetes" can definitely evolve to true "Diabetes Mellitus" and will do so in over 50% of individuals who are noted to have "Pre-Diabetes."  "Pre-Diabetes" can be reversed to normal with several changes in diet, body weight, activity, and eating patterns.  More about this in Part 3. 

Focusing on true Diabetes Mellitus: The definition is "fasting blood glucose values exceed 125 mg/dL" on more than one occasion. And blood glucose values will rise after eating to values much higher, very often above 200 mg/dL and even to values above 600 mg/dL. Elevated blood glucose values are harmful. Hence, Diabetes Mellitus is a chronic illness. 

Glucose concentrations do fluctuate in every person with diabetes mellitus, but blood glucose concentrations above normal do exert continuous harmful effects. 

Elevated blood glucose leads to glucose spillage in the urine with associated loss of water, salt and potassium from the diuretic effect of glucose in the urine. The kidney is designed to reabsorb high glucose that appears in the forming urine, but if the forming urine has concentrations of glucose higher than 160 mg/dL, then the kidney tissues cannot reabsorb the excess glucose.  The threshold for reabsorption of glucose in forming urine is set at 160 mg/dL.  If forming urine has a higher glucose concentration, then the higher glucose will not be reabsorbed and will pass on through the kidney and appear in final outgoing urine. Urine output consequently increases and will easily exceed an individual's fluid and mineral oral intake.  This higher urine output is referred to as "polyuria," meaning continuously abundant urine output. Thus, vascular dehydration occurs with lower arterial blood pressures, lower vital organ nutrient and oxygen delivery, weakness, fatigue, mental changes, and muscle weakness all evolve with this. 

Elevated blood glucose also causes tissue dehydration. Tissue water shifts from inside the cells of tissues to the blood stream because of a strong "osmotic" effect that prolonged circulating glucose exerts on cell water when glucose concentrations are high in the blood stream but not high inside the cells of tissues. Water is thus out of cells and then this water is rapidly excreted by the diuretic effect of high glucose in urine. The cells of vital tissues can suffer injury from this effect. Vital tissue cells do shrink and suffer from prolonged hyperglycemia.

Glucose molecules that do not promptly enter a cell to provide fuel and energy continue
to circulate in the blood. Diabetes mellitus thus features elevated blood glucose as its
central problem.

Besides tissue water losses and vascular salt and water and potassium losses, persistent glucose above normal in the blood stream leads to harmful secondary reactions. These reactions are called "glycation" reactions, and these reactions simply feature the attachment of a fractured glucose molecule to a cell membrane or other large molecule, thus changing the basic nature and function of that essential molecule. It is a biological fact that the simple nutrient glucose molecule, which is a simple circle of 6 carbon atoms with attached hydrogen and oxygen, can fracture while circulating in the blood stream.  And it is a biological fact that any and every eaten and absorbed glucose molecule that enters the blood stream after eating will normally be absorbed as an intact circular glucose molecule into tissue cells within about 60 minutes.  It is a well-known fact, also, that if any glucose molecule is not absorbed into a tissue cell within 60 minutes and continues to circulate in the blood stream, the molecule will "fracture" or "oxidize" and thus become irreversibly attached to another molecule in the circulation network.  Most of the time, these irreversible attachments occur to vascular membranes or the hemoglobin molecule in red blood cells.  This "oxidation" reaction is irreversible, and it is referred to as "glycation," indicating "glucose attached."  

Glycation of organ and tissue cell membranes is the real hazard of diabetes mellitus. Circulating glucose molecules will glycate capillary walls of any organ. We worry about glycation of the retina. This certainly happens causing retinal change and vision changes. We worry about glycation of kidney tissue.  This certainly happens as kidney blood flow per hour is immense and glycation happens in the filtering capillary membranes when the glucose molecules have been circulating too long.  This causes protein to spill into the urine and eventually causes kidney scarring and reduced function all the way to kidney failure. 

We worry immensely about glycation of heart muscle membranes and coronary artery membranes. This certainly happens in uncontrolled or partially controlled diabetes mellitus.  Consequently, organ functions change. Blood vessels stiffen and narrow. Blood flow through these affected arteries and arterioles and capillaries declines.  Oxygen and nutrient deliver thus declines.  This is harmful. Heart attack risk rises, and heart function weakens evolving to congestive heart failure

We worry immensely as well about glycation of brain cell membranes and nerve cell membranes. This certainly happens. Each glycation event changes the nature of the now-­glycated molecule. Each glycation event definitely alters structure and function of the glycated tissues. Brain function changes. Vision changes. Nerves to arms, hands, legs, and feet change and numbness, weakness, and pains evolve because of this glycation over time. Intestinal muscle changes. Nerve functions to the intestine change. Thus, nausea, vomiting, and constipation evolve. Bladder function weakens, too.

The care of the person who has diabetes mellitus thus focuses on preventing glycation
events on tissue cell membranes. Prevention of these harmful glycation events requires consistent normalization of blood glucose concentrations.

After eating, blood glucose concentrations normally increase slightly. In non­diabetic
individuals, the rise in blood glucose after eating should not exceed 130 mg/dL. As
glucose enters our blood stream from food or beverage, our pancreas should release a
proportional amount of insulin, which serves to transport new glucose from the blood
stream into tissues for either immediate tissue energy or to be stored for eventual energy when the individual is not eating.

The person with diabetes mellitus will often exhibit a surge in blood glucose after food or beverage ingestion that exceeds 140 mg/dL. For the person who knows that they are
afflicted with diabetes, the proper goal is to prevent their glucose levels after eating from rising above 160 mg/dL.

The explanation resides with the observation that deliberate control of glucose elevations with medication can be too extreme and cause below ­normal blood glucose values. Thus, formal Diabetes Management Guidelines provide glucose targets judged to be safe and that minimize glycation reactions by normalizing blood glucose concentrations.

A third parameter is tracked routinely: glycated hemoglobin, also called Hemoglobin A1c. Hemoglobin that resides in our red blood cells is one of the molecules that reacts with circulating glucose and becomes glycated. Hence, glycated hemoglobin values measured from routine blood samples indicate "quality" of control of blood glucose from the medications prescribed along with diet adjustments.

The goal for glycated hemoglobin is less than 7% for all persons with diabetes mellitus.
The caution is to avoid inducing very low blood glucose concentrations with medication, which can result in harm.

Thus, Personal Goals for Diabetes Mellitus are:
Fasting glucose less than 130 mg/dL, but not below 70 mg/dL.
After eating glucose less than 160 mg/dL.
Glycated hemoglobin (A1c) less than 7%.

Harmony is essential: harmony between food quantity, food type, carbohydrate
quantities, fat quantities, AND any and all medications prescribed. Harm and
hazard strikes when best harmony is not achieved or sustained AND glucose
concentrations thus fluctuate widely.