by Julie G. Hughes

Created on: January 19, 2009

In any discussion of blood glucose levels, it is helpful to understand how the body creates and processes sugar, and how imbalances happen.

DIGESTIVE PROCESS:

During digestion, the breakdown of carbohydrates and starches creates glucose, a simple sugar that is a primary food for many types of cells. Some glucose is immediately sent to feed brain cells, with any excess stored in the liver and muscles as glycogen. As the body needs energy, the liver converts the glycogen back to glucose and releases it into the bloodstream.

In response to food intake and the production of glucose, the pancreas releases insulin. This hormone tells the body to pull glucose from the blood, keeping levels from rising too high and providing nourishment to many types of cells. Insulin also signals the liver to stop converting and releasing this sugar, providing necessary checks and balances.

RECOMMENDED LEVELS:
When this process works correctly, blood glucose levels remain at what are considered normal levels. Two organizations, the American Diabetes Association (ADA) and the American Association of Clinical Endocrinologists (AACE), have created guidelines for healthy blood glucose levels. Their recommended values are similar.

The ADA has determined that blood glucose levels, prior to eating, should be 90-130 mg/dl. One to two hours after a meal, those levels should stay <180 mg/dl. Guidelines from the AACE recommend that pre-meal levels should stay <110 mg/dl, with a post-meal rise to <140 mg/dl deemed to be acceptable. Many diagnostic tests use the AACE recommended levels.

IMBALANCES:
There are two types of blood glucose imbalances that can occur too high (hyperglycemia) and too low (hypoglycemia).

Hyperglycemia, commonly called diabetes, occurs when the pancreas doesn't generate enough insulin. In Type I diabetes, the pancreas completely stops producing insulin and patients must inject insulin to correct the imbalance. Type II diabetes, formerly called adult-onset, occurs when the pancreas doesn't produce enough insulin or the body becomes resistant and cells ignore the insulin. Management of Type II ranges from diet and exercise, to medications that stimulate the pancreas, to insulin injections.

In hypoglycemia there is also an imbalance between the liver and the pancreas, but in the opposite direction. The pancreas produces too much insulin, over-responding to the release of sugar into the bloodstream, signaling the liver to not release glucose, even when the body needs it. This keeps blood glucose levels too low.

Both conditions can, if left untreated, lead to complications affecting vision, nerves, heart and blood vessels, and kidneys. In extreme cases, coma and death can occur with extremely low glucose levels.

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