Straight Talk About High-Fructose Corn Syrup: What it is and What it Ain’t. – Research Review
White JS. Straight talk about high-fructose corn syrup: what it is and what it ain’t. Am J Clin Nutr. 2008 Dec;88(6):1716S-1721S.Click here to read Links
High-fructose corn syrup (HFCS) is a fructose-glucose liquid sweetener alternative to sucrose (common table sugar) first introduced to the food and beverage industry in the 1970s. It is not meaningfully different in composition or metabolism from other fructose-glucose sweeteners like sucrose, honey, and fruit juice concentrates. HFCS was widely embraced by food formulators, and its use grew between the mid-1970s and mid-1990s, principally as a replacement for sucrose. This was primarily because of its sweetness comparable with that of sucrose, improved stability and functionality, and ease of use. Although HFCS use today is nearly equivalent to sucrose use in the United States, we live in a decidedly sucrose-sweetened world: >90% of the nutritive sweetener used worldwide is sucrose. Here I review the history, composition, availability, and characteristics of HFCS in a factual manner to clarify common misunderstandings that have been a source of confusion to health professionals and the general public alike. In particular, I evaluate the strength of the popular hypothesis that HFCS is uniquely responsible for obesity. Although examples of pure fructose causing metabolic upset at high concentrations abound, especially when fed as the sole carbohydrate source, there is no evidence that the common fructose-glucose sweeteners do the same. Thus, studies using extreme carbohydrate diets may be useful for probing biochemical pathways, but they have no relevance to the human diet or to current consumption. I conclude that the HFCS-obesity hypothesis is supported neither in the United States nor worldwide.
I think it’s just human nature, people seem to have a need to find a single enemy that is the cause of all woes under the sun. The one that causes obesity, diabetes, and all manners of health problems. Nutritionally, I’ve watched the enemy change over the years. In the 80’s it was dietary fat, which was blamed for all the problems of humanity. During the 90’s, things started to shift and carbohydrates became the enemy. About the same time, trans-fatty acids became the one thing that people MUST NOT EAT or they would seemingly drop dead nearly instantly.
And now, as we enter 2009, if there is a single nutrient that is blamed for everything that is wrong in the world, it is high-fructose corn syrup (HFCS). Much of this started with a 2004 paper by Bray where he correlated changes in HFCS intake with changes in obesity, suggesting that it was the increase in HFCS intake that was driving obesity. This was taken, as usual, far out of context into the popular realm of magazines, newspapers and tv soundbites.
Nowhere is this more prevalent than in the athletic/bodybuilding and fat loss arena where people are simply losing their ever-loving minds over anything with HFCS. Any food that dare list high-fructose corn syrup on its label (even if the total quantity is obviously miniscule) is immediately deemed to be evil, a destroyer of not only one’s physique but a corrupter of children, a direct line to Satan himself. Ok, maybe I’m exaggerating but not by much.
This paper addresses this idea, by looking at the hypothesis that somehow HFCS is uniquely obesity or health-problem causing beyond simply being a source of calories. The author states that several assumptions must be found to be true to accept this idea as fact. They are:
- HFCS and sucrose are significantly different
- HFCS must be uniquely obesity-promoting
- HFCS must be predictive of US obesity
- HFCS must be predictive of global obesity
- Eliminating HFCS from the food supply must significantly reduce obesity
I won’t detail in full every one of his arguments; the punch line of course is that none of these actually turn out to be true. Yes, HFCS and foods containing them often contribute a large number of calories to the diet and clearly that alone causes problems; but there is nothing special about HFCS to warrant the fear about it that many seem to have developed.
What is HFCS and Is it Really Different than Sucrose?
Historically, HFCS was developed back in the 50’s as an alternative to cane sugar for food preparations. The reasons why HFCS is superior for foods than cane sugar isn’t really that relevant; sufficed to say that HFCS is more stable and has replaced your basic cane sugar/sucrose in a lot of foods.
Now, a lot of the silliness, especially in the fitness world about HFCS probably comes out of two things. The first is a generally anti-fructose, anti-fruit idea that started about 30 years ago with John Parillo. Fruit is considered forbidden on a diet; nevermind that it helps a LOT of people with hunger (liver glycogen status is one of many signals to the brain) and seems to do something good for thyroid status for many people.
The second is a general confusion about what HFCS actually is, the problem is with the name, the ‘high-fructose’ part of it suggests to people that HFCS is much higher in fructose content that it actually is. However this is not the case as the chart below shows. The percentage of either fructose or glucose is shown for each of the types of sugars (HFCS-42, HFCS-55, Corn Syrup, Pure Fructose, Pure Sucrose, Invert Sugar, Honey).
|HFCS-42||HFCS-55||Corn Syrup||Fructose||Sucrose||Invert Sugar||Honey|
As the chart clearly shows, HFCS-42 is only 42% fructose, lower than sucrose, invert sugar or honey (which is often considered a ‘healthy’ sugar, at least in the hippie subculture). HFCS-55 is 55% fructose which is only slightly more fructose than the other sugars. It’s worth noting that there are products such as HFCS-80 and 90 which contain 80 and 90% fructose but they aren’t used widely commercially.
The point being that despite it’s name, HFCS is actually no higher in fructose than many other sugars such as sucrose (table sugar), invert sugar or honey. The ‘high-fructose moniker’ is simply a poor choice of names but HFCS will not provide any greater amount of fructose to the diet than those other sugars.
Additionally, despite Bray’s assertion that increases in HFCS corrleates with increases in obesity, the paper points out that he looked at the relationship in isolation. During the time that HFCS intake was going up, daily food intake was also increasing, by about 500 calories per day from 1980 to the year 2000.
Additionally, intake data shows that total sugar intake did not increase over that time frame, and as HFCS intake was going up, sucrose intake was going down; leading to no change in overall sugar intake. Rather, what people were eating more of was grains and dietary fat. There is simply no basis to conclude that increasing HFCS intake has any correlation with rising rates of obesity.
Additionally, while it is often claimed that HFCS is sweeter than sucrose (with that being argued that HFCS will increase intake of itself), this is also untrue. While pure crystalline fructose IS sweeter than sucrose, HFCS is identical in sweetness. Increasing use of HFCS in the US food supply did not increase the relative sweetness of those foods.
Of course, the caloric value for HFCS and sucrose is identical at 4 calories/gram. In that sucrose appears to have been swapped out for HFCS in a more or less 1:1 ratio, there is no reason to believe that HFCS intake is increasing caloric intake outside of simply being a source of calories.
Finally, the paper looks at the issue of absorption and metabolism of sucrose vs. HFCS. While fructose is metabolized differently than glucose (in terms of the transporters used and how it is handled in the liver), keep in mind that HFCS is only about half-fructose, just like sucrose. Fructose malabsorption is a problem, mind you, but only when large amounts of fructose by-itself is consumed, this does not apply to HFCS.
Quoting from the paper:
Sucrose, HFCS, invert sugar, honey an many fruits and juices deliver the same sugars in the same ratios to the same tissues within the same time frame to the same metabolic pathways. Thus…it makes essentially no metabolic difference which one is used.
So, again, while HFCS is certainly a source of calories (and many HFCS containing foods are easily overconsumed), there is nothing special about HFCS that makes it uniquely problematic. Fruit juice or a sucrose containing soda would function identically in the body.
Is HFCS Uniquely Obesity Promoting?
Much of the concern over HFCS has to do with the fructose content as stated above; and a lot of very silly studies have come out recently showing that massive intakes of fructose by itself are problematic in terms of health or obesity.
One that is making the rounds now showed that feeding rats a 60% fructose diet for 6 months caused leptin resistance. But let’s be realistic. For someone on a 3000 calorie/day diet that would be the equivalent of 450 grams of pure fructose per day. Every day. For six straight months. This simply has no relevance to any real human diet.
As the paper states:
A pure fructose diet is surely a poor model for HFCS, because HFCS has equivalent amounts of glucose. Because no one would eat a pure fructose diet, such experimentation must be recognized as highly artificial and highly prejudicial and not at all appropriate to HFCS.
Rather, diets examining sucrose intake make a much more appropriate model for HFCS. Not much has been done comparing HFCS to sucrose but what has been shows no metabolic difference between the two; exactly what would be expected due the fact that they have nearly identical composition.
Does HFCS predict either US or Global Obesity?
In a word, no. While Bray’s original analysis suggested a correlation between increasing HFCS intake and US obesity, that relationship no longer holds. Despite reduced HFCS intake in the last few years, obesity continues to increase. Simply, HFCS cannot explain the continuous rise in US obesity.
Moving to the global arena, there is simply no relationship between HFCS intake and obesity rates with the two countries showing the highest rates of obesity showing the lowest intake of HFCS.
Will Eliminating HFCS from the Food Supply Affect Obesity?
You can probably guess the answer which is no. Given that HFCS and sucrose are nearly identical in composition, given that HFCS has replaced sucrose intake in the human diet over the past 30 years, given that they are handled metabolically identically, given that they have the identical caloric value, replacing HFCS with sucrose will simply have no effect on anything. Except perhaps to raise prices since sucrose is higher than HFCS.
The paper concludes, as you might imagine, by reiterating the points I’ve made above. HFCS is in no way unique amount sugars, with a composition identical to sucrose as well as the supposedly ‘healthy’ honey. Increased caloric intake since the 1970’s is the driver for increased obesity, with no relationship with HFCS intake per se.
In that all fructose-glucose solutions (whether HFCS, sucrose or honey) are metabolized in exactly the same fashion in the body, there is simply no reason to think that HFCS per se is particularly obesity promoting outside of being a caloric source.
Now, since I know some people will mis-interpret this piece, I want to be clear: the paper is not saying that people can or should be consuming HFCS in massive amounts. Many HFCS containing foods contain massive numbers of calories.
This is especially true of sweetened sodas and it’s interesting to note that a good bit of data suggests that such drinks can be consumed in massive amounts without signalling the body about their caloric content; but this has more ot do with their fluid nature than their composition.
What I’m getting at with this research review is that the near insane over-reaction and concern to any food containing any amount of HFCS among certain groups. Folks on forums are throwing out the baby with the bathwater under the gross misunderstanding that HFCS per se is a unique evil which it clearly isn’t. Within the context of a calorically controlled diet, there is no reson to believe it will have any differential impact beyond every other sugar that has ever been used.
So stop freaking out.