Note for most people, the issues aren't with fructose from fruit.
The body is fully adapted to processing the sugars in fruit. It's added sugars in processed foods and so-called healthy pure fructose sweeteners like agave nectar that are harmful. (and alcohol, which I'm not going to get into, but there's some info on how that is processed in the liver in one of the references).
Also, note that HFCS has only been around for one generation. It was invented in the late 60s and began being adopted by manufacturers in the 70s. I'm fairly positive that New Coke was a cover up for Coca cola's first attempt at the switch from sugar to HFCS in the 80s.
The below is a mess of stuff I copied from some Mercola articles and their references. I am working on consolidating into a more concise explaination
The difference between sugar from fruits and veggies, table sugar, HFCS and pure fructose such as Agave.
-Glucose is the form of energy you were designed to run on.
Every cell in your body, every bacterium -- and in fact, every living thing on the Earth -- uses glucose for energy.
(Table sugar) is fructose and glucose bound together
and must first be metabolized into glucose and fructose in your intestine. Then the body proceeds to use the glucose for energy and sends the fructose to the liver.
-Fruits and vegetables
contain a combination of free fructose and free glucose and sucrose (bound fructose and glucose) and sometimes other sugars.
is fructose and glucose (in varying ratios that manufacturers don't have to report) Not
bound together. HFCS is a highly processed product that contains similar amounts of unbound fructose and glucose. Sucrose (table sugar), on the other hand, is a larger sugar molecule that is metabolized into glucose and fructose in your intestine.
most fats are formed in your liver, and when sugar enters your liver, it decides whether to store it, burn it or turn it into fat. Fructose, however, bypasses this process and simply turns into fat. Additionally, there’s hard empirical evidence showing that refined man-made fructose like HFCS metabolizes to triglycerides and adipose tissue, not blood glucose.
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:
This is all very normal, and it's how you were designed to operate.
- 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.
Article on the badness of the amount of sugar in our diets today: http://articles.merc...20227_DNL_art_1
of course going off into the particularly bad-ness of HFCS. And even better, see: http://articles.merc...Metabolism.aspx
When you consume fructose, 100 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)[xiii][xiv].
- 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.
Fructose Metabolism Basics
Dr. Robert Lustig http://articles.merc...Metabolism.aspx Professor of Pediatrics in the Division of Endocrinology at the University of California, San Francisco, has been a pioneer in decoding sugar metabolism. His work has highlighted some major differences in how different sugars are broken down and used:
If anyone tries to tell you "sugar is sugar," they are way behind the times. As you can see, there are major differences in how your body processes each one.
- After eating fructose, 100 percent of the metabolic burden rests on your liver. But with glucose, your liver has to break down only 20 percent.
- Every cell in your body, including your brain, utilizes glucose. Therefore, much of it is "burned up" immediately after you consume it. By contrast, fructose is turned into free fatty acids (FFAs), VLDL (the damaging form of cholesterol), and triglycerides, which get stored as fat.
- The fatty acids created during fructose metabolism accumulate as fat droplets in your liver and skeletal muscle tissues, causing insulin resistance and non-alcoholic fatty liver disease (NAFLD). Insulin resistance progresses to metabolic syndrome and type II diabetes.
- Fructose is the most lipophilic carbohydrate. In other words, fructose converts to activated glycerol (g-3-p), which is directly used to turn FFAs into triglycerides. The more g-3-p you have, the more fat you store. Glucose does not do this.
- When you eat 120 calories of glucose, less than one calorie is stored as fat. 120 calories of fructose results in 40 calories being stored as fat. Consuming fructose is essentially consuming fat!
- The metabolism of fructose by your liver creates a long list of waste products and toxins, including a large amount of uric acid, which drives up blood pressure and causes gout.
- Glucose suppresses the hunger hormone ghrelin and stimulates leptin, which suppresses your appetite. Fructose has no effect on ghrelin and interferes with your brain's communication with leptin, resulting in overeating.
The bottom line is: fructose leads to increased belly fat, insulin resistance and metabolic syndrome -- not to mention the long list of chronic diseases that directly result.
Whereas the glucose in other sugars are converted to blood glucose which is used for energy by every cell in the body, fructose is processed entirely by the liver which converts it to fat in the form of triglycerides. It does not stimulate an insulin response or trigger leptin that controls your appetite.
Elevated triglycerides means elevated levels of Pattern B LDL (or VLDLs) -- smaller, denser LDLs that are able to wedge themselves under your epithelial cells and therefore roughen surfaces and stimulate plaque formation.-------------------------------------------------------------------------------------------------------------------------------
If we got our sugar from fruits and vegetables, we'd consume about 15 grams per day. The average American today consumes over 70 which sounds low to me considering how much is in a soda that people might drink multiple times per day, on top of what they eat.
Also, I've read that the USDA recommends people limit their added sugar intake to 40 grams per day. The CDC recommends you limit it to 25 grams per day. There's 39 grams of sugar from HFCS in one can of coke.
(It's important to understand that the USDA is a much bigger advocate for the sugar and corn growers than it is a protector of your health. And the CDC is a member of our medical 'let's treat everything with a drug' establishment. That said, since I consume some added sugar possibly every day, I'm probably in the CDC camps' idea of healthy limits)----------------------------------------------------------------------------------------------------------------------------------It also says that elevated uric acid levels, can be used as a predictor for fructose toxicity. I haven't found details on what is meant by the term[i] fructose toxicity
, but I gather they are referring to being particularly sensitive to it and/or having impaired ability to process it.
According to the latest research in this area, the safest range of uric acid is between 3 and 5.5 milligrams per deciliter, and there appears to be a steady relationship between uric acid levels and blood pressure and cardiovascular risk, even down to the range of 3 to 4 mg/dl. ...Uric acid drives up your blood pressure by inhibiting the nitric oxide in your blood vessels. Nitric oxide helps your vessels maintain their elasticity, so nitric oxide suppression leads to increases in blood pressure.
Anyway, fructose elevates uric acid and elevated uric acid is a sign/contributor to numerous health conditions. It's also processed entirely in the liver where it's converted to triglycerides. http://articles.merc...d-pressure.aspx
So in other words, routinely drinking sodas and other HFCS filled drinks causes high blood pressure.
The difference between HFCS and table sugar and Sugar from fruit.
HFCS is a highly processed product that contains similar amounts of unbound fructose and glucose. Sucrose (table sugar), on the other hand, is a larger sugar molecule that is metabolized into glucose and fructose in your intestine.
And whereas the glucose in other sugars are converted to blood glucose, fructose is a relatively unregulated source of fuel that your liver converts to fat and cholesterol. The danger of that is that fructose does not stimulate your insulin secretion, nor enhance leptin production, which is thought to be involved in appetite regulation.
Chemical tests among 11 different carbonated soft drinks containing HFCS were found to have ‘astonishingly high’ levels of reactive carbonyls. Reactive carbonyls are undesirable and highly-reactive compounds associated with “unbound” fructose and glucose molecules, and are believed to cause tissue damage.
By contrast, reactive carbonyls are not present in table sugar because its fructose and glucose components are “bound” and chemically stable.
Reactive carbonyls are elevated in the blood of individuals with diabetes and are linked to the health complications of diabetes. It is estimated that a single can of soda contains about five times the concentration of reactive carbonyls than the concentration found in the blood of an adult person with diabetes.
fructose also does not contain any enzymes, vitamins or minerals so it takes these micronutrients from your body while it assimilates itself for use. Unbound fructose, found in large quantities in HFCS, can interfere with your heart's use of minerals such as magnesium, copper and chromium. ... and is almost always made from genetically modified corn
Chart on ratio in several sweeteners Fructose Glucose Sucrose Other sugars
Granulated sugar 0 0 100 0
Brown sugar 1 1 97 1
HFCS-42 42 53 0 5
HFCS-55 55 41 0 4
HFCS-90 90 5 0 5
Honey 50 44 1 5
Maple syrup 1 4 95 0
Molasses 23 21 53 3
Corn syrup 0 35 0 0