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Stanford University School of Medicine

On the road to diabetes: A look at what’s happening inside the body

This is the first in a series of blogs by Randall Stafford, MD, PhD, discussing prediabetes and Type 2 diabetes.

Diabetes is one of the most serious chronic disease problem in the U.S. Roughly 30 million Americans -- 12 percent of adults -- have diabetes, and its complications include heart disease, stroke, kidney failure, blindness and amputations.

But even worse: Another 85 million — or 34 percent of adults — have early indications that they're developing diabetes, a condition called prediabetes. The good news for those on the road to diabetes is that the disease process can be stopped and even reversed.

The population affected by prediabetes is diverse. But to get a better sense of what it is like, let's check in on a man we'll call Gary:

Gary is a married, 45 year-old computer engineer who has steadily gained weight over the past 10 years. He now weighs 204 pounds, which for his height of 5 feet 8 inches means an obese body mass index of 31.0. He says that his weight gain is due to a lack of physical activity and the readily available high calorie food provided at his company. He often works 12 hours a day and says he has little time for anything other than work and family. Right now he takes no medications but is worried about developing high blood pressure and diabetes.

Diabetes mellitus literally means “excessive sweet tasting urine.” This happens when the amount of sugar in the blood stream reaches very high levels. Types of diabetes, or high blood sugar, include:

In general, once you have Type 1 or Type 2 diabetes, you have it for life.

But Type 2 diabetes doesn't appear overnight. Long before it's diagnosed, the body begins to struggle to deal with sugars and other carbohydrates. After a meal, the pancreas (a candy cane-shaped organ hidden behind the stomach) releases insulin, a chemical messenger. The arrival of insulin notifies muscle and liver cells to take sugar out of the bloodstream. They use the sugar for energy or store it for later use.

In normal conditions:

  • Blood sugar increases as food is digested
  • The pancreas responds by secreting insulin
  • Muscles and the liver react by taking sugar out of the blood and putting it into storage
  • As a result, blood sugar returns to a normal level

The first thing that happens in pre-diabetes is that muscles and liver cells don't respond normally to insulin. It's as if the cells are too preoccupied to pay attention and they don't react the way the should. The preoccupied muscle and liver cells become "resistant" -- they don't remove enough sugar out of the blood based on normal insulin signals, and blood sugar rises as a result.

Insulin resistance results from a combination of increased belly fat, physical inactivity, a diet high in processed carbs, reduced sleep, increasing age, and genetic predisposition -- Gary is affected by many of these. These factors tend to activate the immune system, which produces inflammation throughout the body, including the slow-to-respond muscle and liver cells.

Early on, the pancreas can make up for the insulin resistance of muscles and the liver by simply releasing more and more insulin into the bloodstream. The louder volume is able to get the attention of the muscles and the liver so that they work hard enough to reduce blood sugar levels to near normal. The increased levels of insulin, however, can cause new problems, including increased heart disease and high blood pressure.

Over time, insulin resistance becomes so severe that the pancreas cannot produce enough insulin to fully compensate. At this point, blood sugar remains high and never returns to normal. Diabetes is diagnosed when blood sugar measured during fasting is above a level of 125 mg/dL (less than 100 is normal).

Being on the road to diabetes is bad news, but there's still a chance to stop the process and even reverse insulin resistance. Unfortunately, the opportunity for reversal is limited once diabetes is present.

This is the first in a series of blogs discussing prediabetes and Type 2 diabetes. The next installment focuses on how you know that you’re on the road to developing diabetes and what you can do about it.

Randall Stafford, MD, PhD, a professor of medicine and director of the Program on Prevention Outcomes and Practices, practices primary care internal medicine at Stanford. He is developing practical strategies to improve how physicians and consumers approach chronic disease treatment and prevention.

Previously: Examining the potential benefits of canagliflozin for patients with diabetes, Diabetes hampers activity of bone stem cells, Stanford researchers find and New models may help predict diabetes progression
Photo by why kei

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