Sugar May Be Bad, But This Sweetener Is Far More Deadly -- Part 3 of 3

Carbohydrate Biochemistry 101

I promised you a crash course in biochemistry -- so here we go.

Much of the following information comes from the important work of Dr. Robert Lustig[i] Professor of Pediatrics in the Division of Endocrinology at the University of California, San Francisco.

In order to appreciate just how damaging fructose is to your body, it is crucial to have a basic understanding of how different types of carbohydrates are metabolized.

We’ll start with glucose since it’s the basic carbohydrate energy source for all living cells.

I. Glucose Metabolism

Glucose is the basic fuel for living organisms, from bacteria to humans, and is the primary energy source for your brain. It is a product of photosynthesis and is found in rice, corn and other grains, and bread and pasta.

Once you take in glucose from a meal -- like, say, from two slices of bread -- 80 percent of it is used by all of the organs of your body -- every single cell. The remaining 20 percent goes to your liver to be metabolized and stored.

The following is what happens to that 20 percent, once it reaches your liver:

• Whatever glucose your body doesn’t need immediately gets converted into glycogen for storage in the liver. Glycogen is your body’s non-toxic short-term energy storage package, where it can be easily converted to energy when you need it. Your liver has no limit to how much glycogen it can store without detrimental effects. (That is what athletes take advantage of when they “carbo-load.”)
• A small amount of pyruvate is produced, which ends up being converted to ATP  (the chemical storage form of energy) and carbon dioxide. An even smaller quantity of citrate is produced from this process through the “citrate shuttle,” which ends up as VLDL (very low density lipoproteins, the bad ones) in a process known as de novo lipogenesis -- but we’re talking about a very small amount (less than one calorie from two slices of bread).
• Insulin is released by your pancreas in response to the rise in blood glucose (i.e., blood sugar), which helps the glucose get into your cells. Without insulin, your cells would not be able to process the glucose and therefore would have no energy for movement, growth, repair, or other functions. Insulin is key to unlocking the door of the cell to allow the glucose to be transferred from the bloodstream into the cell.
• When you consume 120 calories of glucose, less than one calorie contributes to adverse metabolic outcomes.

This is all very normal, and it’s how you were designed to operate.

II. Ethanol Metabolism

Ethanol, or ethyl alcohol, is the favorite carbohydrate of many. But it is also a carbohydrate that undergoes a very different metabolic process, leaving in its wake a trail of toxins a mile long.

Ethanol is an acute central nervous system toxin and a chronic hepatotoxin due to the fact that it must be metabolized almost completely in the liver.

After consuming an alcoholic beverage, 10 percent of the ethanol gets broken down by the stomach and intestine as a “first pass” effect, and another 10 percent is metabolized by the brain and other organs. The fact that ethanol is partially metabolized in your brain is the reason you experience that familiar “buzz.”

The remaining 80 percent hits the liver, where it must be broken down. This is four times the load on the liver as the same number of calories from glucose.

But the metabolic process in the liver is quite different from that of glucose.

This metabolic cascade can be summarized as follows:

• The liver converts ethanol to aldehydes, which produce free radicals that damage proteins in the liver.
• Some of these aldehydes are converted to glucose, but a large amount of excess citrate is formed in the process, stimulating “junk chemicals” that result in free fatty acids (FFAs), VLDL and triglycerides. As compared to the 1 calorie from glucose that was converted to VLDL (see previous section), the same caloric intake from ethanol produces 30 calories of VLDL that are transported to your fat cells and contribute to your obesity, or participate in plaque formation. This is what leads to the dyslipidemia of alcoholism.
• The resulting lipids, together with the ethanol, lead to an enzyme that begins an inflammation cascade, which in turn causes hepatic insulin resistance, liver inflammation and cirrhosis.
• Fat globules accumulate in the liver as well, which can lead to fatty liver disease.
• Free fatty acids (FFAs) leave the liver and cause your skeletal muscles to become insulin resistant. This is a worse form of insulin resistance than hepatic insulin resistance and can lead to type II diabetes.
• After a 120-calorie bolus of ethanol, a large fraction (about 40 calories) can contribute to disease.

Why am I including a discussion of ethanol metabolism in a report about fructose?

Because, in nearly every way, fructose is metabolized the same way as ethanol, creating the same toxins in your body.

III. Fructose Metabolism

Now we finally come to fructose.

When you consume fructose, one hundred percent of it goes directly to your liver to be metabolized. This is why it is a hepatotoxin -- it overloads the liver. Fructose metabolism creates the following adverse effects:

• Fructose is immediately converted to fructose-1-phosphate (F1P), depleting your liver cells of phosphates.
• The above process produces waste products in the form of uric acid. Uric acid blocks an enzyme that makes nitric oxide. Nitric oxide is your body’s natural blood pressure regulator, so when it is blocked, your blood pressure rises -- leading to hypertension. Elevated uric acid levels can also cause gout.
• Almost all of the F1P is turned into pyruvate, ending up as citrate, which results in de novo lipogenesis, the end products of which are FFAs, VLDLs, and triglycerides. The result -- hyperlipidemia.
• Fructose stimulates g-3-p (activated glycerol), which you will recall is the crucial molecule for turning FFAs into triglycerides within the fat cells. Remember, the rate of deposition of fat into fat cells is dependent on the presence of g-3-p. The more g-3-p that is available, the more fat is deposited. Fructose is the carbohydrate most efficiently converted into g-3-p11. In other words, fructose is the most lipophilic carbohydrate.
• FFAs are exported from the liver and taken up in skeletal muscle, causing skeletal muscle insulin resistance.
• Some of the FFAs stay in the liver, leading to fat droplet accumulation, hepatic insulin resistance and nonalcoholic fatty liver disease (NAFLD)[ii][iii].
• Insulin resistance stresses the pancreas, which pumps out more insulin in response to rising blood sugar as your cells are unable to get the sugar out of your bloodstream, and this can progress to type II diabetes.
• As with a bolus dose of ethanol, a 120-calorie bolus of fructose results in a large fraction (again, about 40 calories) that directly contributes to disease.

Do these symptoms sound a bit familiar to you? Hypertension, lipogenesis and dyslipidemia, obesity, inflammation, insulin resistance, and central nervous system leptin resistance?

If you are thinking it sounds a lot like classic metabolic syndrome, you are dead on!

The point to take away is: consuming fructose is consuming fat. Fructose is not really a carbohydrate -- a high fructose diet is a HIGH FAT diet. A high fat diet that creates a vicious cycle of consumption that won’t turn itself off.

You can see by comparing the metabolism of fructose with the metabolism of ethanol that they are very similar. In fact, when you compare the metabolism of 150 calories of soda with 150 calories of beer (a 12 ounce can of each), about 90 calories reach the liver in either case. Fructose causes most of the same toxic effects as ethanol because both come from sugar fermentation.

Both ethanol metabolism and fructose metabolism lead to visceral adiposity (belly fat), insulin resistance and metabolic syndrome.

Studies are accumulating that bear this out.

For example, high-fructose diets were shown to cause dyslipidemia in healthy people with and without a family history of type II diabetes, a recent study showed[iv].

Two other studies were done using medical students, both looking at biological responses to fructose loading. In the first, the med students were given either a large glucose load or a large fructose load. In the students given fructose, almost 30 percent of the calories ended up as fat. In the students given glucose, almost none ended up as fat.

In the second study, medical students were given a high fructose diet for 6 days. In just that short time, their insulin resistance and triglycerides doubled!

The Neurochemical Basis for Gluttony

You eat as a result of the activation of the “reward pathway” (also known as the hedonic pathway) of your brain. Your brain’s pleasure center (aka ventral tegmental area, or VTA, and nucleus accumbens, or NA) is the root of all behavior, driven by chemical messengers that are intimately tied into the energy processes I have outlined above.

The part of your brain that responds to what you eat is the same part that responds to nicotine, morphine, amphetamine, ethanol, sex and exercise! That is why people taking narcotics tend to overeat.

Leptin and insulin are modulators of these reward responses, decreasing this VTA-NA activity. In other words, leptin and insulin cause your brain to send you signals to stop eating.

Fructose undermines these normal satiety signals, increasing caloric consumption both directly and indirectly:

1.      Fructose does not stimulate a leptin rise, so your satiety signals are diminished.

2.      Glucose suppresses ghrelin (the hunger hormone—it makes you want more food), but fructose does not.

3.      By raising triglycerides, fructose reduces the amount of leptin crossing your blood-brain barrier.

4.      Fructose increases insulin levels, interfering with the communication between leptin and your hypothalamus, so your pleasure signals aren’t extinguished. Your brain senses starvation and prompts you to eat more.

5.      Fructose decreases the production of malonyl-CoA, which may help promote a sense of energy adequacy.

Along with causing insulin resistance, fructose alters the hedonic response to food thereby driving excessive caloric intake, setting up a positive feedback loop for overconsumption.

Big Fat Lies From the Corn Industry

Now that scientific studies have shown the metabolic similarity between HFCS and sucrose, the Corn Refiners Association has embarked on a vociferous campaign to convince the public that their product is equal to table sugar, that it is “natural” and safe.

Of course, many things are “natural” -- cocaine is natural, but you wouldn’t want to use 141 pounds of it each year.

The food and beverage industry doesn’t want you to realize how truly pervasive HFCS is in your diet -- not just from soft drinks and juices, but also in salad dressings and condiments and virtually every processed food. The introduction of HFCS into the Western diet in 1975 has been a multi-billion dollar boon for the corn industry.

Now the corn industry has come up with another product it’s using in beverages called “crystalline fructose.”  This is produced by allowing the fructose to crystallize from a fructose-enriched corn syrup, resulting in a product that is 99.5 percent pure fructose -- a fructose level twice as high as regular HFCS!

Clearly, all the health problems associated with HFCS could become even more pronounced with this product.

Making matters worse, crystalline fructose may also contain arsenic, lead, chloride and heavy metals -- a virtual laundry list of toxic agents you should clearly avoid. In fact, more than one study has detected unsafe mercury levels in HFCS[v]. If you have children, all of these contaminants can impact your child’s development and long-term health.

Why doesn’t the FDA regulate fructose since it poses the same health risks as ethanol -- and it regulates ethanol?

The FDA doesn’t touch chronic toxins. They regulate only acute toxins, and ethanol falls into that category because it produces immediately toxic neurological effects. Fructose doesn’t get metabolized in the brain, so it’s effects, although damaging, are cumulative and magnify over time.

Also realize that nearly all HFCS is made from genetically modified corn, which comes with its own set of risks.

The FDA classifies fructose as GRAS: Generally Regarded As Safe. Which pretty much means nothing and is based on nothing.

It is interesting to note that soda taxes[vi] have recently been proposed both in New York and California, and legislation for the removal of soft drinks from schools has been enacted in several states.

What’s a Sugarholic to Do?

Ideally, I recommend that you avoid as much sugar as possible. This is especially important if you are overweight or have diabetes, high cholesterol, or high blood pressure.

In fact, I believe that the positive health impacts of breaking the country’s sugar addiction would be even greater than if everyone stopped smoking, because elevated insulin levels are the foundation of nearly every chronic disease known to man, from cancer and arthritis to cardiovascular disease.

I also realize you don’t live in a perfect world, and following rigid dietary guidelines is not always practical or even possible.

If you want to use a sweetener occasionally, this is what I recommend:

1.      Use the herb stevia

2.      Use organic cane sugar in moderation

3.      Use organic raw honey in moderation

Avoid ALL artificial sweeteners, which can damage your health even more quickly than HFCS.

And I don’t recommend agave syrup since it is a highly processed sap that is almost all fructose. Your blood sugar will spike just as it would if you were consuming regular sugar or HFCS. Agave has gained meteoric popularity due to a great marketing campaign, but any health benefits present in the original agave plant are processed away.

Be sure to eat your sugar with fiber ... as in a piece of fruit. As Dr. Lustig says, “When God made the poison, he packaged it with the antidote: fiber.”

Wait 20 minutes before second portions at meals, giving your brain a chance to receive satiety signals.

And exercise regularly. Dr. Ludwig recommends you “buy your screen time with physical activity.”

Exercise is important for several reasons, some of which might surprise you:

• Exercise improves skeletal muscle insulin sensitivity (insulin works best in your muscles)
• Exercise reduces stress and lowers cortisol, which decreases appetite
• Exercise suppresses ghrelin, thereby decreasing appetite
• Exercise speeds up metabolic cycles, reducing citrate levels, thus reducing fat production
• Exercise can make you sharper, reduce arthritis, lift your mood, strengthen your bones, and even slow down aging

Avoid so-called energy drinks and sports drinks because they are loaded with sugar, sodium and chemical additives.

Rehydrating with pure, fresh water is a better choice.

If you or your child is involved in athletics, I recommend you read my article Energy Rules for some great tips on how to optimize your child’s energy levels and physical performance through good nutrition.

A Word of Warning About Infant Formula

And finally, be extremely careful about the infant formula you are feeding your baby. Nearly all infant formulas have as much or more high fructose corn syrup than a can of soda -- in addition to many other things that are extremely detrimental to your baby’s health and development.

You have learned that, metabolically, there is very little difference between ethanol and sugar, so by giving your infant formula, you might as well be giving him a bottle of beer or soda!

And studies have shown that the earlier you expose kids to sweets, the more they crave them later.

It is important for pregnant women to keep their blood sugars well managed not only for their own health, but also for the long-term health of their children.

Researchers have found that children born to mothers with gestational diabetes (high blood sugar during pregnancy) had an 82 percent chance of becoming obese between the ages of 5 and 7 through a phenomenon called “metabolic imprinting.” Even mothers with elevated blood sugar, short of gestational diabetes, had children with a significantly increased risk for obesity.[vii]

I advocate breastfeeding if at all possible -- it is by far the healthiest option.

One of the most clear-cut, non-debatable topics in health care is that breast milk is the best source of nutrition for newborns. The benefits to the baby and the new mom are enormous. Breastfed infants have shown lower obesity rates in later childhood[viii].

Acknowledgements

I would like to thank Dr. Robert H. Lustig, Professor of Pediatrics in the Division of Endocrinology at University of California, San Francisco, for sharing his incredibly important insights, without which this article would not have been possible. Much of the above information came directly from Dr. Lustig’s work related to central regulation of energy balance, and I am very grateful for his willingness to share it with me so that I can pass it along to you.