High Fructose Corn Syrup Part 3 Metabolism

Let’s continue to explore the effects of high fructose corn syrup on the body by gaining an understanding of how the body metabolizes it and compare fructose metabolism with sucrose (table sugar) metabolism.

From a chemical standpoint high fructose corn syrup and sucrose are remarkably the same, each containing approximately 50% glucose and 50% fructose.

However there is a difference. To metabolize sucrose our bodies have to secrete an enzyme called sucrase that breaks the bond between the glucose and fructose before these individual molecules can be metabolized.

In high fructose corn syrup the glucose and fructose are already separated, thus they may enter the bloodstream more quickly than the monosaccharides from sucrose.

After that the digestion, absorption and metabolism of fructose differs significantly from that of glucose. Absorption of fructose occurs farther down in the small intestine while glucose absorption occurs higher in the small intestine.

They both then enter the large vein that carries them to the liver or they pass into the general circulation. In the liver fructose can be converted into glucose.

Glucose stimulates insulin release from the pancreas but fructose does not stimulate insulin release. That’s why fructose may look like a good substitute sugar for diabetics because it causes a lesser rise in blood glucose levels and less stimulation of insulin release.

However there is a caveat. After drinking a high fructose corn syrup sweetened soft drink, fructose floods into the liver. The liver converts that fructose into fat that not only gets stored on the body as extra weight but also can be stored in the liver. We’ll cover the disastrous effects that may occur as more and more fat accumulates in the liver in the next article.

And another problem with fructose as opposed to glucose ingestion:

Glucose stimulates insulin release which in turn triggers the release of a hormone called leptin. Now that’s your friendly hormone that acts in a feedback mechanism to suppress appetite.

So what happens with eating food that has high levels of fructose in it? By deduction fructose induces less insulin which in turn induces less leptin. Therefore you stay hungry when you have had plenty of calories. So you pile on the fat. See how fructose is tricking you?

Also, insulin transports glucose into the brain cells. The brain cells then realize that they’ve been well fed which acts to tell you that you’ve had enough to eat. Once again you feel satisfied.

Fructose cannot enter the brain cells because insulin will not carry it across. That leaves the brain cells feeling starved. Brain cells cannot survive very long without their fuel source, glucose. Therefore the brain sends strong signals “eat more”.

So you grab something else sweet and if it’s another high fructose corn syrup sweetened food you enter right back into the vicious cycle. You eat, but you’re not satisfied, so you eat more. No wonder the weight piles on and your liver starts to suffer.

In summary:

1. Fructose easily turns to fat.

2. Fructose sets up a vicious cycle that keeps you eating and drinking calories that you don’t need because fructose does not satisfy your appetite.

Americans consume the greatest percentage of high fructose corn syrup in the form of soft drinks and fruit type drinks or juices. Simply eliminating that source of high fructose corn syrup in the diet would go a long ways to decreasing obesity and other health problems.

If you like reading the scientific research on fructose here’s the link:

http://www.ajcn.org/content/79/4/537.full

Watch for the next article discussing the research that implicates fructose as a cause of some major debilitating and death inducing disease processes.

Blessings,

Dr. Jo

If you missed the preceding articles on High Fructose Corn Syrup, you can find them at:

HFCS Part 1

HFCS Part 2

And for the next article:

HFCS Part 4