Glycemia and Gastric Emptying Disturbances in Diabetes Mellitus

What Is Glycemia?

Glycemia refers to the presence of sugar in the blood. It is classified into two types which include:

• Hyperglycemia: An increase in the sugar levels in the blood is termed hyperglycemia. A fasting blood sugar level above 130 milligrams per deciliter causes this condition.

• Hypoglycemia: A decrease in sugar levels in the blood is termed hypoglycemia. A fasting blood sugar level below 70 milligrams per deciliter causes this condition.

What Is Diabetes?

A disease that occurs when too much sugar is in the blood. It is classified into two types:

• Type 1 Diabetes: A long-term condition in which the pancreas, an organ responsible for producing insulin, does not produce enough.

• Type 2 Diabetes: A condition in which the way glucose is processed is impaired. In this type, the necessary amount of insulin is not produced by the body, or the body combats insulin production.

What Are the Causes of Hyperglycemia?

This condition occurs when there is increased sugar in the blood, which happens when the body has lower insulin or if the body cannot use the insulin properly, such as type 2 diabetes. Some of the causes include:

• The insulin dose or the medications the patient takes for diabetes is insufficient.

  Related Topics

  ---

  How do unhealthy dietary habits contribute to diabetes mellitus?

  Is there any established time interval and quantity to feed infants?

  Gastroparesis - Symptoms, Causes, Diagnosis, Treatment, and Complications

• The amount of carbohydrates the patient takes when eating is not balanced with the amount of insulin the body is secreting or the amount of insulin injected in case of diabetes.

• When the individual is less active than usual.

• When there is physical stress that is caused because of an illness such as a cold, flu, or infection.

• Taking steroids for some conditions.

• The dawn phenomenon is where there is a surge of hormones in the body early in the morning which also causes the blood sugar to rise.

• Pancreatic diseases include pancreatitis (inflammation of the pancreas), pancreatic cancer, and cystic fibrosis (a disorder that affects the cells producing mucus, sweat, and digestive juices).

What Are the Causes of Hypoglycemia?

This condition occurs when too much insulin is in the body, resulting in low blood sugar levels. It is most prevalent in people with type 1 diabetes and those with type 2 diabetes who take insulin or certain medications. For people without diabetes, hypoglycemia is rare.

• Stomach surgery can sometimes cause the food to pass too quickly into the small intestine.

• Taking medicines such as Salicylates, sulfa drugs, and Pentamidine (a drug used in treating pneumonia) or Quinine (a drug used in treating malaria).

• Consumption of alcohol.

• In low levels, hormones such as cortisol, growth hormone, glucagon, or epinephrine are present.

• Tumors in the pancreas produce more insulin resulting in hypoglycemia.

What Is Gastric Emptying?

Gastric emptying is a test measuring the time the food takes to get emptied from the stomach and enter the small intestine. The gastric emptying rate is a critical determinant of postprandial glycemia (glucose concentration in the blood after eating). It is also essential in maintaining blood glucose homeostasis (the self-regulating process by which the body tends to maintain stability). Disordered gastric emptying frequently occurs in type 1 and 2 diabetes.

Most management strategies for patients with type 2 diabetes mellitus target gastric emptying. A two-way relationship exists between the rate of gastric emptying and glycemia, in which acute changes in blood glucose concentrations modulate the rate of gastric emptying. Some evidence suggests that even a mild increase in sugar level in the blood (hyperglycemia) is an independent risk factor for delayed gastric emptying in type 1 diabetes.

What Happens in the Stomach?

The stomach is responsible for food intake, mixing up the contents to form a semi-solid form of food called the chyme and provision of highly regulated timely calorie load to the intestines.

The intestinal nutrient load determines

• Glucose levels in the blood.

• Utilization of blood glucose by secretion of incretins (hormones released from the gut into the bloodstream in response to the ingestion of food).

• Secretion of insulin (hormone created by the pancreas that controls glucose in the bloodstream).

• Suppression of glucagon secretion (a hormone formed in the pancreas which assists in the breakdown of glycogen to glucose in the liver).

Thus gastric emptying plays a significant role in postprandial hyperglycemia. The effect of gastric emptying on blood glucose levels depends on multiple factors, which include:

• Size, content, and timing of the meals.

• Glucose absorption rate in the blood.

• Release of intestinal hormones such as incretins.

• Release of insulin.

• Reactive hypoglycemia (low blood sugar after meals, usually within four hours of eating).

• Severe postprandial hyperglycemia due to insufficient incretins or insulin.

What Is the Relationship Between Hyperglycemia and Diabetes Mellitus?

In 1956, Stunkard et al. observed that glucose administered intravenously abolished hunger contractions in healthy people, which implied that acute hyperglycemia could affect gastric motor activity in humans. A preliminary study in 1962 stated that acute hyperglycemia delayed gastric emptying in healthy people. It also showed that when comparing marked hyperglycemia (blood glucose level of 16-20 millimoles/liter) in type 1 diabetes, the gastric emptying of solids was prolonged by an average time of 17 minutes. Hyperglycemia also prolongs the gastric emptying of liquids. Even mild hyperglycemia was associated with a greater level of retention of solids and liquids.

Conclusion

Thus, short-term hyperglycemia delays the gastric emptying of type 1 diabetic patients. Long-term hyperglycemia is an independent risk factor for delayed gastric emptying in type 1 diabetic patients. Thus while performing a gastric emptying test, if the blood glucose level is greater than 275 mg/dL in the morning of the test, the glucose level should be lowered with insulin to 275 mg/dL before commencing the test. Studies show that improved long-term control of glycemia can improve gastric emptying in type 2 diabetic patients. Another finding suggests that delayed gastric emptying can be a predisposing factor for hypoglycemia, but it has not been thoroughly evaluated.

ADVERTISEMENT