Fructose Short-Circuits Glycolysis

First some terminology.

Fructose ... a five carbon sugar that occurs naturally in fruit, does not cause as much insulin to be secreted as glucose and tastes sweeter than glucose.

Glucose ... a six carbon sugar that is the breakdown product of glycogen(a polymer of glucose, multiple glucose units hooked together) that occurs naturally in potatoes and grains.

Glycogen ... multiple units of glucose hooked together (a polymer). What is typically called "complex carbohydrate" today.

Glycolysis ... derived from the Greek stem glyk- "sweet" and lysis meaning dissolution. The metabolic pathway for the initial utilization of glucose.

Phosphofructokinase ... the enzyme that catalyzes the reaction of fructose 6-phosphate to fructose 1,6-biphosphate. You don't need to understand anything more about this reaction other than the fact that if fructose comes from a source other than the degradation of glucose, it blocks this step for glucose until all the non-glucose derived fructose has been metabolized.

Glucose and Fructose Are Both Metabolized via Gylcolysis

Both fructose and glucose are metabolized via glycolysis. Both end up at some point as three carbon fragments. In order for glucose to be broken down into three carbon fragments it must first be metabolized to a five carbon sugar, actually fructose. This is where the trouble starts, since fructose is already a five carbon sugar. The following analogy I hope will aid in explaining this. The analogy, however, is far from perfect.

Whether we start out with separate glucose and fructose as in high fructose corn syrup or honey, or with fructose and glucose hooked together as in sucrose(common table sugar), makes no difference. As soon as sucrose hits the bloodstream, it is immediately broken down (hydrolyzed) to fructose and glucose.

Freda Fructose gets married to Gary (Glucose) Sucrose. They live happily on Sugar Lane. Both work in muscle and liver cells where they are metabolized usually into fat and slow the immune system to a crawl. They get up early in the morning and both have to get on the Glycolysis Road to get to work. Gary (Glucose) is one carbon atom heavier than Freda Fructose and because of that, he cannot cross the river on one of the lighter and faster bridges on their way to work. Freda Fructose however, being lighter, has no problem crossing the faster bridge and making the short-cut to the Glycolysis Road. Gary Glucose, however, has to get on the road well above the short-cut, since he is too heavy to take the lighter bridge short-cut.

The Phosphofructokinase Intersection

As usual Freda Fructose gets to the Phosphofructokinase intersection well before Gary Glucose. By the time Gary Glucose gets to the intersection, the traffic directing policeman is once again allowing all the Freda Fructoses to make the turn onto Glycolysis Road while, all the Gary Glucoses can do is sit in traffic and wait. Once again, Gary, and all the other Glucoses on their way to work, must sit and wait for all the Freda Fructoses to get on Glycolysis Road before they can continue.

LA Traffic Control

Traffic control sees all these Glucoses sitting stuck in traffic, just like traffic backs up everyday in LA. It reacts by injecting a lot of green lights (insulin) into the pathway for the Glucoses to get to work. Finally, all the Fructoses pass and now because there are too many green lights, all the Glucoses pass quickly. All of the sudden there are no Glucoses to be found on the Glycolysis Road. All the cells along the way that used to be able to snag some Glucose can't because there isn't any. Whether it is the excessive insulin that is the cause of so many of the lifestyle diseases we see today or, all the backed up Gary Glucoses decide to cause their own damage to the arteries they are in, I don't know. It is however, clearly established that the ingestion of sucrose (fructose and glucose) is related to many of our lifestyle diseases today including the extensive damage to the vascular system that occurs with adult onset diabetes mellitus. I know, my damaged arteries are up on this site.

Hypoglycemia

Now you begin to feel lightheaded, dizzy and a bit disoriented. Traffic control has injected too many green lights and the concentration of glucose drops precipitously. The brain starts to complain because it no longer has enough glucose to function. If the blood sugar gets low enough, serious complications can occur.

Fructose and Glucose Together

The combination of fructose and glucose should be avoided as much as possible. When you eat your fruit, try to allow at least an hour or preferably two, before eating potatoes, whole grains or rice. Also avoid as much as you can sucrose, high fructose corn syrup, honey and maple syrup or, any sweetener that has as it main ingredients, fructose and glucose.

Other Sweeteners

Brown Rice Syrup

Brown rice syrup is roughly about 45% maltose (two glucose units hooked together), 50% complex carbohydrates and 3% glucose. No glucose and fructose together but still sweet and I have known some people who can even get hypoglycemic from it.

Barley Malt Syrup

Made from whole barley it is about 65% Maltose and 30% complex carbohydrates.

Fruit Concentrates

These are usually combinations of glucose, fructose and sucrose and should be avoided.

Maple Syrup

Maple syrup is about 65% sucrose and should be avoided.

Today's Health Tip:

If you want sweet, you are safest with stevia. Next would be sweeteners derived from rice and barley. Sucrose, high fructose corn syrup, maple syrup and fruit juice concentrates should be avoided.

Reference:
Stryer Biochemistry Fourth Edition

Copyright John Mericle M.D. 2005 All Rights Reserved

**************
To really get off of sweets and "deprogram a sugar-coated palate," the MericleDiet is hard to beat. Generous servings of organic complex carbohydrates will keep you and your brain happy. To visit the MericleDiet follow the link below.
http://www.DrMericle.com
**************

One of our readers Wendy in the UK writes:

Just to let you know that according to the website below that takes you to Carol Bond Health Foods it is spelt Stevita. I couldn't find it anywhere on the site and through asking the chat section it was spelt differently. Thought you would like to know so that you can let the other newsletter recipients know.
Regards...
Wendy

PS Really enjoy the newsletter. Find it very informing so thank you. Gave up drinking milk last year after reading your article! Feel much healthier as a result.
**************

To take Stevia for a test drive or purchase some online follow the link below. I had luck just searching stevia but you could also search the product "Stevita."
http://www.drmericle.com/rcb.php
Thanks for your time.

DrMericle.com is devoted to achieving optimal health and peak performance through diet and lifestyle change. Dr. Mericle brings together a unique blend of formal training in organic chemistry and biochemistry, medical education, 29 marathons, 3 Hawaii Ironman competitions and a lot of practical real life experience.

---

Reverse Disease and Maintain Optimal Health

PROTEIN DEFICIENT? CHANCES ARE YOU ARE!Did you know that 9... Read More

Inactive Alert: Essential Proteins for Sedentary People

The importance of protein in diet has been clearly established... Read More

How You Can Support Your Immune System

Media coverage of severe acute respiratory syndrome (SARS) has incited... Read More

Death, Aging, Rejuvenation (Part 4)

Biological clockObviously you need biological clock to time and alarm... Read More

The Great Influence Of Vitamin B to the Nervous System

In order for a person to actually have a healthy... Read More

What Would You Do For a Klondike Bar?

Unfortunately, the words "diet" and "cheating" go hand in hand.... Read More

Fruit for Breakfast ? The Secret to a Healthy Life

Do you want more energy? How about more of the... Read More

Why Digestive Enzymes Are Vital To Good Health!

Most digestive disorders develop because of the bodys inability to... Read More

Glyconutrients

What are Glyconutrients? Glyconutrients are eight newly discovered biologically-active sugars... Read More

Helping Your Immune System Win The War Against Disease

Just as our country is currently engaged in a war... Read More

Eat Right For A Healthy Life

Our diet is an essential factor for the formation of... Read More

Healthy Eating for Executives on the Run

For the executive, maintaining the much-needed balance between career, family,... Read More

You Are What You Eat

Your magnificent machine is, in fact, a symbiotic collection of... Read More

Are Your Cells Talking To Each Other?

Are Your Cells Talking To Each Other?Communication! It permeates our... Read More

Aging Gracefully with the Aid of Various Nutrients

During the past thirty years there has been a steadily... Read More

Calcium Absorption and Information

Ionized minerals, colloidal minerals, chelated minerals . . . What... Read More

Eating ... Gaining Weight ... How to Control the Urge to Splurge

I confess: I'm completely addicted to Pringles. My determination weakens... Read More

What is A Balanced Diet For Losing Weight and Good Health?

The total calories that you should be consuming depend on... Read More

Food Sources That Boost Glutathione Naturally

Copyright © 2004 Priya Shah Glutathione, the body's... Read More

Good Fat Diet or How to Choose the Best Foods for Your Family?

Some fats are good for you. Your body can't function... Read More

Fluoride: A Plot to Dull the American Mind

During the Second World War, the Germans used fluoride as... Read More

High Blood Pressure? Natural Alternatives Can Help!

High blood pressure (hypertension) is a dangerous condition that can... Read More

Is Organic Really Better for You?

I had finally come to a place in my life... Read More

Gift Basket Idea for Senior Citizens

Evidence for the importance of fruit and vegetable intake to... Read More

16 Quick Tips for Eating at Restaurants or Work

Most of us eat at restaurants for a variety of... Read More

The Importance of Nutrition and Lifestyle

Eating healthy and taking care of yourself is essential to... Read More

Fluoride Damages Childrens Bones, Study Says

White-spotted or yellow splotched teeth may reveal more than needed... Read More

Starbucks and Children Health Risks

Do you know the risks to daily intakes of Starbucks... Read More

The Skinny on Oats, Oatmeal, Vitamins, Nutrition for Skin Care and Bath Products

Oats (botanical name Avena sativa)An oat is a grass that... Read More

Learn About Food Nutrition Facts

Food nutrition factsFinding food nutrition facts and dietary nutrition used... Read More

Artificial Sweeteners - Are They Safe?

To research the health risks Sweet 'N Low and other... Read More

Getting Your Target

What is health? Everyone wants this thing called health, and... Read More

Autism and Nutritional Supplements

Unfortunately, it has been proved beyond doubt that a large... Read More