Diabetes Explained

Diabetes. One word with a big meaning. In order to explain what to eat if you’re a diabetic, it’s important to first establish that there are two types of Diabetes (technically three when including gestational diabetes) Type I and Type II; and they’re different from one another.

In order to distinguish the two, it’s important to understand how exactly glucose finds its way from our stomachs to our cells.

After ingestions of a large carbohydrate meal, the beta cells of the pancreas release the hormone insulin. Insulin signals receptors to travel to the brush border of the lumen allowing glucose to enter the liver, muscle, or blood cells in the form of glucose6phosphate. Here, glycolysis occurs converting the glucose into pyruvate, further oxidized into AcetylCoA where it combines with oxaloacetate for the citric acid cycle to take place extracting ATP and delivering energy to your cells. GLUT2 receptors in the liver, beta cells of the pancreas, and kidney are responsible for transporting glucose into the blood. Once in the blood, GLUT4 receptors transport glucose to the heart and muscle.

Confused? Picture it like this…. You find your neighbor’s dog loose in your back yard, immediately go outside and manage to get him on a leash to walk him home. You knock on your neighbor’s door because you don’t have a key. On the other side of the door is your neighbor (Hey John!! I found Rex loose in my yard). John grabs the leash and takes Rex inside, thanks you and shuts the door. YOU are insulin. Rex is glucose. And John, aside from an irresponsible dog owner, is the GLUT receptor waiting to let glucose (Rex) into the cell (John’s house).

So what makes Type I different from Type II?

By definition, “Type I Diabetes is an autoimmune disease. The primary defect is pancreas Beta cell destruction, usually leading to an absolute insulin deficiency resulting in hyperglycemia, polyuria, polydipsia, weight loss, dehydration, and ketoacidosis.” The rate of beta cell destruction can vary; proceeding rapidly in some, but more slowly in others. The capacity of a healthy pancreas to secrete insulin is far in excess what is needed and can be preceded by a period of months to years during which beta cells ae undergoing chronic destruction.

This type of diabetes is typically diagnosed by early to mid-childhood and accounts for 5-10% of all diabetes cases. People with Type I can must take exogenous insulin which comes in an array of types: short or rapid acting, intermediate, or long term.

Type II Diabetes is a different story. This type of Diabetes accounts for 90-95% of all diagnosed cases. Leading contributors to Type II include adiposity and long-duration obesity. Typically, 90% of Type II cases are obese but occasionally there are people diagnosed who aren’t obese.

In most cases Type II Diabetes results from a combination of insulin resistance and beta cell failure. So, what is insulin resistance? Simply put, “decreased sensitivity or responsiveness to insulin and as a result, hyperglycemia (high blood sugar) ensues.”

A cup of spinach has between 10-12gm of carbohydrate, but also up to 8gm of fiber. Not much work on your pancreas. A 20oz coke however, well that’s 65gm of pure sugar, and no fiber to slow things down. Americans certainly drink more coke than they eat spinach, so it’s like expecting a BIC lighter to do the work of a bonfire.

Remember Rex? Well imagine you find Rex in your yard again for the 4th time today (did somebody leave the gate open?). Instead of immediately returning him home when you hear him in your yard, you finish up a few emails, wash the dishes, and finally go out and grab him. You walk him over to John’s, but he doesn’t answer right away. You stand there getting impatient because this keeps happening and after a few minutes of tapping your foot…John finally answers. “Hey man, yeah thanks. I was watching Bird Box on Netflix and it was right at the end so…..”. Rex finally finds his way home.

Rex is glucose. And frankly, him getting loose in your yard has just made you exhausted and you’re tired of dropping everything to walk him home. This is how your pancreas feels after constantly being stressed over and over after chronic exposure to excessive glucose. So as insulin, you’re over it. Rex needs to keep his butt home. So you take your time, and so does John. As a result, Rex is hanging in limbo (like glucose in the blood stream) for a while before he finds his way home.

With Type II Diabetes, the exact mechanism of action hasn’t been found yet, but it appears the over time, the chronic stress on the pancreas causes an abnormal pattern of insulin secretion and action and also decreased cellular uptake of glucose.

Insulin resistance typically is seen primarily in muscle and adipose tissue. Inside an insulin resistant muscle, insulin loses its ability to stimulate glucose uptake. In adipose tissue, it no longer prevents free fatty acid release. Within the liver and kidney, the elevated insulin levels stimulate liver triglyceride synthesis leading to higher serum triglyceride levels. As a result, the kidney responds by increasing sodium retention but decreasing uric acid clearance. Too much uric acid is a bad thing. Erosion of organs by acid is not pleasant.

A formal diagnosis for Type II Diabetes is done with several laboratory measures.

Fasting blood glucose is taken after at least 8hrs without food. For a healthy individual, a normal blood glucose panel is 70-100mg/dl. The “at risk” range is between 100-125mg/dl. There’s also another type of blood glucose test called casual plasma glucose, which just means it wasn’t fasted and an individual most likely ate prior to the test. These levels are ideally under 200mg/dl but anything higher is an indication of type II diabetes.

High levels of glucose form a chemical bond with hemoglobin called glycosylated hemoglobin or A1C. Below 5.7% is ideal for a healthy individual whereas an A1C in the range of 5.7-6.4% suggest risk for Type II.

Physical symptoms of the disease include excessive thirst, frequent urination, polyphagia (uncontrollable hunger), and weight loss. Wait…weight LOSS? Why? Well, if suddenly insulin isn’t working well and glucose remains trapped in your blood stream, your other cells need glucose and ATP somehow. Guess what doesn’t require insulin: fat metabolism. Your body starts aggressively burning ketone bodies in order to provide some form of fuel while excessive glucose remains in your blood stream, trapped. Type II Diabetes is typically diagnosed with physical symptoms combined with fasting plasma glucose of 126mg/dl or higher.

A diagnosis can lead to interventions including medication, lifestyle changes, and calorie restriction. Recommendations for Type II Diabetics are to maintain normal blood glucose, optimal serum lipid levels, and healthy blood pressure. Some medical treatment for lowering glucose include Glucotrol which promote insulin secretion, and Glucophage (metformin) to enhance insulin action.

With long-term obesity as one of the leading contributors to Type II Diabetes, diet and exercise seem like obvious interventions to alleviate the severity of the disease. As a health enthusiast and coach, arming yourselves with efficacious dietary strategies to help Type II Diabetic clients; which is exactly what part II in this series will offer. Stay tuned.

Originally written for the Nutrition Coaching Institute; ncicertifications.com

References

  1. Mahan LK, Escott-Stump S. Krauses Food & Nutrition Therapy. St. Louis, MO: Saunders/Elsevier; 2008
  2. Gropper SAS, Smith JL, Carr TP. Advanced Nutrition and Human Metabolism. Boston, MA: Cengage Learning; 2018

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