Separating Fact From Fiction.

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Is high fructose corn syrup "just-like-sugar?
No. The high fructose corn syrup industry advertises heavily to promote this misconception. In fact a review of fructose research helps us understand that HFCS is not just like sugar. Sugar, more formally known as sucrose, is a disaccharide of glucose and fructose chemically bound to one another in a one to one ratio. In sugar, the amount of glucose equals fructose. In high fructose corn syrup, there is no chemical bond between fructose and glucose. In HFCS, fructose levels are higher than glucose levels. How much higher depends on the HFCS formula used. Why is this important? Because the excess-free-fructose transports differently in the intestines than fructose paired in a one to one ratio with glucose. This difference is significant for people who for reasons that remain poorly understood, cannot properly absorb fructose. Researchers indicate that high levels of adults and children are fructose malabsorbers. At levels as low as 12.5 grams of fructose, 10% of adults showed signs of malabsorption including increased gas, abdominal pain, and gastrointestinal distress. Very little research has been done to assess the condition in children. What has been done suggests that children at are high risk of fructose malabsorption. No one has ever studied the condition beyond what is known to occur in the large intestines. What may be occuring in the small intestines of fructose malabsorbers given fructose's high reactivity remains unknown. The possibility exists that unabsorbed fructose may modify dietary proteins turning them into antigens capable of triggering an immune response. But this biochemical pathway remains untested and unresearched.
Can you be allergic to high fructose corn syrup?
Food allergies are caused by your body’s response to certain proteins in foods. During production and processing of high fructose corn syrup nearly all of the corn protein is removed. What remains is predominantly corn starch which undergoes conversion to glucose and fructose with the aid of numerous bacterial enzymes. The general lack of protein in high fructose corn syrup may be one of the reasons that case reports and anecdotal evidence linking high fructose corn syrup to asthma remains medically unrecognized and unresearched. However, when we consider the facts known about fructose, a totally different picture emerges about the role of fructose in activating the body's immune defenses. For example, fructose is known to be ten times more reactive than glucose and is known to interact with proteins (in the bloodstream of diabetics) and modify them into proteins capable of eliciting an immune response.

According to the biochemical hypothesis that links consumption of high fructose corn syrup to auto-immune reactivity and asthma, conditions in the small intestines of fructose malabsorbers may promote antigen formation. The exact mechanism proposed is the same as that which occurs in high fructose conditions in the blood stream of diabetics. What is thought to occur is a reaction between elevated fructose and dietary proteins known as the Maillard reaction. This reaction may result in dietary protein fragments becoming modified and digestion resistant. Once absorbed in the blood stream they may give rise to the auto-immune, respiratory distress, chronic bronchitis and asthma symptoms observed. Research is needed to test this hypothesis. The exact mechanisms that are responsible for the observed link between consumption of high fructose corn syrup and activation of the immune system remain unknown.

Does high fructose corn syrup cause diabetes and obesity?
Data pouring out of the scientific research community suggests that there is increasing evidence supporting the claim that HFCS contributes to hypertension, dyslipidemia, elevated blood lipids, and insulin resistance. All are hallmarks of metabolic syndrome. Experimental data also indicates that weight gain associated with consumption of high fructose corn syrup is abdominally concentrated as compared to weight gain associated with sugar which is broadly distributed throughout the body. In 2013 researchers at Yale University found that fructose does not turn on satiety centers in your brain as does glucose. So if you eat foods containing more fructose than glucose [HFCS], the switch that controls apetite and signals the feeling of being full and satisfied never gets turned on. In other words, on a high fructose [HFCS] diet you will tend to eat more.
Should I worry about fructose?
This question appears in the FAQs of "sweetsurprise", a website sponsored by the high fructose corn syrup industry association. In their answer they suggest that there is nothing to worry about and that the ratio of fructose in the American diet today is not higher than it was 30 years ago. The problem with this response is that 30 years ago the preferred sweetener was sucrose and we have already seen that sucrose has an equal ratio of fructose and glucose. This is not the case with high fructose corn syrup which contains elevated excess-free-fructose. Excess-free-fructose at levels as low as 12.5 grams is a problem for those who cannot properly absorb it. Independent laboratories have analyzed soda containing high fructose corn syrup and found that the formula used contains 65% fructose and 35% glucose. This is not the 55% fructose formula that the industry reports as being its defacto standard. The 240 calories in a 20 oz. bottle of cola is from 65 grams of sugar - in the U.S. this is all from HFCS. In a 65/35 formula, 19.5g is unpaired fructose (i.e. excess free fructose). This is alarming given that studies show that 30% of otherwise healthy adults test positive with a 25g challenge of fructose in excess of glucose. Scant research has been done to understand the health effects of fructose malabsorption in children.
Is high fructose corn syrup a safe ingredient?
The answer to this question is being heatedly debated. It is the job of the FDA to certify foods as safe for consumption. In 1983, the FDA certified high fructose corn syrup as a “Generally Recognized as Safe” (known as GRAS status) food. Despite data from studies suggesting high rates of fructose malabsorption in the general population, and a general lack of research regarding fructose malabsorption in children, the FDA reaffirmed that ruling in 1996. Fructositis.org is sponsoring a petition directed to the commissioner of the FDA requesting that the FDA revisit their decision to provide GRAS status to high fructose corn syrup. The pressure for them to revisit this decision is building. This pressure is building because of the steady flow of research linking it to metabolic syndrome. It should also be building because the FDA gave high fructose corn syrup "GRAS" certification despite the need for further research into the incidence, prevalence and consequences of fructose malabsorption particularly in children, and the need for research into reports linking it to auto-immune reactivity, chronic bronchitis, airway hyper-reactivity, airway mucus hypersecretion and asthma.
What about claims that high fructose corn syrup is metabolized by the body in the same way as table sugar, honey and many fruits?
The high fructose corn syrup industry as reported in their association website "sweetsurprise" suggests that "the body metabolizes these sugars in the same way and that these simple sugars are absorbed into the blood stream in similar ways." A focus by the corn refiners on fructose metabolism to the exclusion of absorption and transport routes is misleading and self serving. Research tells us that excess-free-fructose as occurs in HFCS is absorbed into the body via a different transport route than does equivalent pairs of glucose and fructose. Scientific researchers report that excess-free-fructose transports via an intestinal transporter named GLUT5 whereas "paired" glucose and fructose transport via GLUT2. Why is this important? For reasons that are not well understood 10% to 30% of adults cannot adequately absorb excess-free-fructose as occurs in high fructose corn syrup. Very little research has been done to assess the condition in children. The little research that has been done suggests the rates are higher in children and in fact may be as high as 44%, particularly in children under age 4. How this has remained off the radar is unclear. It is time to redirect the national conversation from fructose metabolism to execess-free-fructose transport, malabsorption, and reactivity in the gastrointestinal tract. Researchers haven't found any "misspellings" in the GLUT5 genes of people testing positive for fructose malabsorption. As such, they speculate that for reasons unknown, fructose malabsorbers have low levels of GLUT5 transporters that may be responsible for the condition.

It is thought that fructose malabsorption is a condition that underlies the link between high fructose corn syrup and auto-immune reactivity, chronic respiratory distress and asthma. Lastly, very few natural foods contain fructose to glucose in ratios consistent with what independent laboratories have found when analyzing high fructose corn syrup containing foods. Apples, watermelons, and pears are notable exceptions. But we generally don't eat the amounts of these natural foods to reach the doses scientists observed as triggering fructose malabsorption symptoms. For example, to consume 30 grams daily of excess-free-fructose you would need to eat about 8 - 10 apples or a twelve pound watermelon per day. How likely is that? Not likely.

Is high fructose corn syrup unnatural?
Research into the processing of corn into corn syrup and high fructose corn syrup tells us that corn syrup and high fructose corn syrup are the products of corn that has undergone a high degree of processing. Corn starch is enzymatically modified to HFCS through a number of processing steps using bacterial enzymes. Through a wet milling process the proteins are removed and the remaining starch is converted to glucose and then to fructose. In the final step, HFCS 42 is combined with HFCS 90 to yield HFCS 55.

In 2008, a team of researchers at Rutgers State University of New Jersey found high levels of highly reactive intermediate products of the Maillard reaction known as dicarbonyl compounds in all non-diet carbonated beverages they tested (Tan, Wang, Lo, Sang, and Ho, 2008). These compounds are known to interact with proteins or peptide fragments to form what researchers refer to as advanced glycation end-products (AGEs) and their presence has been found to be elevated in the blood stream of diabetics as compared to non-diabetics. More and more evidence indicates that the increase in reactive dicarbonyl intermediates is a consequence of hyperglycemia in diabetes. Dicarbonyl stress leads to increased modification of proteins, followed by oxidant stress and tissue damage (Tan, Wang, Lo, Sang, and Ho, 2008). These bio-molecules are thought to contribute to the development of diabetes mellitus and its complications. For example, damage by the contaminants found in the soda to low-density lipoproteins (LDL - "the bad cholesterol") through a reaction referred to as glycation causes a fourfold increase in the formation of plaques in the lining of arteries (Rabbani et al., 2011). In experiments by Tan et al., of all non-diet sodas tested, they were able to identify high fructose corn syrup as the major source of methylglyoxal (MG), a well characterized, highly reactive dicarbonyl of the Maillard reaction (Tan, Wang, Lo, Sang, and Ho, 2008).

What is fructose malabsorption?
Fructose malabsorption is a medically recognized disease. What we know so far is that in individuals suffering from fructose malabsorption, some percentage of the fructose that is consumed never gets absorbed by the gut. The disease is characterized by a deficiency in the fructose transporters of the small intestine, the major site of nutrient absorption in the gastrointestinal tract (GI). Fructose transporter deficiency leads to greater amounts of unabsorbed fructose in the large intestine which provides increased substrate for gut bacterial fermentation. The physiological consequences of fructose malabsorption involve increased gases including hydrogen, carbon dioxide and methane. The abnormal increase in hydrogen is detectable with the hydrogen breath test. A number of other symptoms are possible involving changes in GI motility, function, and decreased tryptophan, folic acid, and zinc in the blood. According to our present knowledge of the disease, no other symptoms are described as being associated with this disease. The possibility that elevated fructose in the small intestines results in reactivity between fructose and dietary proteins remains unresearched. The possibility that unabsorbed fructose may contribute to the formation of digestion resistant protein fragments capable of eliciting an auto-immune response remains to be tested and researched.
I have heard that fructose is metabolised primarily by the liver. What is the significance of this?
The liver has been identified as the primary site of the majority of dietary fructose metabolism. Fatty liver disease has been reported to be a risk factor for individuals consuming large amounts of fructose. A focus by the corn refiners association on the "sameness" of fructose metabolism, whether it originates from high fructose corn syrup or sugar appears self serving. This skewed focus has come at the expense of further research into the role of fructose malabsorption in chronic disease and auto-immune reactivity. Yes, the cellular mechanisms of metabolism of fructose are the same whether the fructose being metabolised originates from high fructose corn syrup or sugar. But the better question may in fact be, "why haven't we paid closer attention to the scientific data on fructose malabsorption rates in the general population?" And why have we not researched its impact in children? Sugar [sucrose] is made of equal amounts of glucose and fructose that transport together. There is no excess-free-fructose in sugar. This is likely the reason why fructose malabsorbers do not exhibit symptoms of fructose malabsorption when consuming sugar, but do exhibit symptoms of malabsorption including gas, bloating, and abdominal pain when consuming fructose in excess of glucose as occurs with HFCS. As detailed above, data suggest that at levels as low as 12.5 grams of fructose, 10% of otherwise healthy adults exhibit symptoms of malabsorption. At 25 grams, 30% of adults are malabsorbers.