• 1What are Carbohydrates? (VIDEO)
  • 2Carbohydrates: Fuel for You
  • 3Cell Food
  • 4Fiber
  • 5Slow & Steady Wins the Race
  • 6Simple Carbohydrates
  • 7All Carbs are Sugars
  • 8How Many Sugars?
  • 9Pick a Carb, Any Carb
  • 10Insulin Is the Key
  • 11Blood Sugar Gone Awry
  • 12Glycemic Index
  • 13Waistline Enemy #1?
  • 14Prebiotics & Probiotics
CHAPTER 10

Insulin Is the Key

PART 1

Insulin: A Tiny Hormone with a Big Job

Insulin is a hormone and protein with a critical job. It unlocks the calories stored in glucose (blood sugar) so that the body’s cells, including blood, muscle, and fat cells, can access the glucose for energy. The pancreas, an organ that also produces digestive enzymes and other hormones, secretes insulin in response to dietary sugars. READ MORE

After we eat, most of the carbohydrates (sugars) in food are absorbed from the intestines into the bloodstream. The pancreas detects this increase in blood sugar and secretes insulin in response. Most cells of the body have insulin receptors, which bind to the insulin. The cell then turns on other receptors that absorb the glucose from the blood stream into the cell.

Just like the cells need oxygen from the air we breathe, they need glucose from the carbohydrates we eat. Insulin is essential to the process, allowing glucose to enter the cells. Without insulin, you could starve, even if you ate lots of food. LESS
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PART 2

The Glucagon-Glucose Connection

Key Word
Glucose, Glycogen, Glucagon
Another important hormone produced by the pancreas is glucagon. It is secreted by the alpha cells of the pancreatic islets (insulin is secreted by the beta cells). The islets, which are clusters of cells, only emit glucagon when blood glucose is low, such as between meals or during exercise. READ MORE

Glucagon has a major effect on many of the tissues of the body, but most importantly on the liver. It causes the liver to release stored glucose (glycogen) into the blood stream, increasing the level of blood sugar in the body. Glucagon also helps the liver build glucose from the body’s nutrients. LESS
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PART 3

Dysfunction Junction

Just the Facts
Journey to the Islets of Langerhans
The body’s production — or non-production — of insulin and glucagon determines if a patient has diabetes, hypoglycemia, or some other sugar problem. People with type 1 diabetes (a.k.a. diabetes mellitus type 1) can’t secrete insulin from the pancreatic cells. People with type 2 diabetes (diabetes mellitus type 2) produce too little insulin or have become resistant to it; that is, the cells ignore whatever insulin is produced. READ MORE

Hypo vs. Hyper

The body has a very narrow range of what it considers normal blood glucose levels — between 70 mg/dl and 100 mg/dl (mg/dl means milligrams of glucose in 100 milliliters of blood). If your glucose levels drop below 70, you have hypoglycemia, meaning too little glucose.

Levels higher than 110 can still be normal if you’ve eaten in the past two or three hours. Even after eating, however, your blood glucose level should be below 180. Anything above this is termed hyperglycemia, meaning too much glucose. LESS
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PART 4

Insulin: A Brief History

While diabetes has been recognized as a medical condition for at least 3,500 years, it was not until the 1800s that scientists began to gain insight into the role of insulin. Two European researchers, Oskar Minkowski and Josef von Mering, found that when they removed the pancreas gland from dogs, the dogs developed diabetes. READ MORE

Following several scientific leaps, including the discovery of the islets of Langerhans, the chemical later known as insulin was noted to be lacking in people with diabetes. Early in the 20th Century, a group of Canadian researchers led by medical scientist Frederick Banting accomplished the successful removal of insulin from healthy dogs and the injection of it into those with diabetes. Banting, who along with his colleague Charles Best is credited with discovering insulin, shared the Nobel Prize in 1923.

Insulin became the first protein to be crystallized in pure form, and the first to have its amino acid sequence determined, revealing its molecular structure. Recent work led by Colin Ward of CSIRO Molecular and Health Technologies in Australia also demonstrated that insulin molecules are shaped precisely to fit into insulin receptors like a key into a lock. LESS
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