High Fructose Corn Syrup: Dietary Friend, Foe or Fall Guy?

For quite some time, I have been thinking of  writing a piece about high-fructose corn syrup (HFCS).  HFCS consumption, mostly in soda drinks and highly processed foods, has grown steadily over the past 30-40 years and now represents a sizable percentage of both total carbohydrate and total calorie intake in the U.S.  HFCS has been both praised as a low cost nutrient and vilified as one of the primary causes of our obesity and diabetes epidemics.  A few weeks ago, I saw an ad on TV that was promoting HFCS as healthful “corn sugar,” implying that somehow that HFCS was a natural (and healthful) nutrient derived from corn.  Not surprisingly, the ad was produced by the Corn Refiner’s Association (CRA) and was clearly part of a PR campaign.  The ad was criticized by several food industry watch dogs, including the U.S. Food and Drug Administration (FDA) and  representatives from the sugar maker’s industry; accusing the CRA  of false advertising.

Here Comes The Judge

What got me to actually sit down at the computer and start writing was a recent news report in my local newspaper (the Columbia Daily Tribune, Friday, October 21, 2011, page 5B; columbiatribune.com).   U.S. District Court Judge Consuelo Marshall issued a ruling that a false advertising lawsuit filed by the sugar industry against the CRA could go forward.  The CRA had argued that the lawsuit should be dismissed because HFCS is equivalent to sugar in the way it is metabolized and that the lawsuit was “an attempt to stifle a national conversation about the merits of HFCS versus sugar.”  In addition, the CRA lawyers argued that educational campaigns from the CRA shouldn’t be considered advertising.  The judge dismissed those claims stating that the CRA’s educational campaigns constitute commercial speech and that the industry group is not insulated from federal false advertising regulations just because its “educational” statements relate to a public health issue.  I almost forgot to mention that the CRA had asked the FDA’s permission to use the term “corn sugar” rather than HFCS in both advertising and product labeling.  As far as I know, the FDA has not ruled on the request.  So, what is this all about?

What is HFCS anyway?

To understand what HFCS is and isn’t, we need to discuss a little basic chemistry.  Don’t be afraid, it’s not complicated.  To most people, the word “sugar” means good old table sugar, a sweet-tasting white crystalline substance called sucrose and which is composed of a molecule of glucose and a molecule of fructose.  Another word for sugar is saccharide.  So,  sucrose is a disaccharide; glucose and fructose are six-carbon monosacharides.  Another important disaccharide is lactose (milk sugar), which is composed of a molecule of glucose and a molecule of galactose.  Saccharides are a class of carbohydrates, molecules that are composed of carbon, hydrogen, and oxygen.  Carbohydrates, along with proteins and fats are the basic body building blocks.  Sugars can be composed of many monosaccharide molecules linked together, called polysaccharides, which are important storage forms of sugars in both animals and plants.  Although all sugars (by definition) are sweet, there is a large difference in the sweetness of individual sugars: fructose is the sweetest sugar, almost twice as sweet as glucose.

Sucrose comes mainly from sugar cane (60%) and from sugar beets (40%).  Sugar cane was first found in Papua New Guinea and was domesticated about 10,000 years ago.  The discovery of beet sugar was not until about 250 years ago.  The history of sugar is a fascinating one which has been chronicled by N Deerr in The History of Sugar (volumes 1 and 2, London, Chapman and Hill Ltd., 1949 v-258/1950 v-259-636).  An excellent summary of the subject was written by M. Gracey, N Kretchmer, and E. Rossi (A glimpse into the history of sugar, in: Sugars in Nutrition, Ed. M. Gracey, N. Kretchmer, and E. Rossi.  Nestle Nutrition Workshop Series, Vol 25; Nestec Ltd., Vevey/Raven Press, Ltd., N.Y., 1991).  I can assure you that HFCS is no more controversial than sugar itself, which has been considered by many historians to be most responsible for slavery (both in the U.S. and globally).

Anyway, for a variety of reasons, beginning in the 1970’s, HFCS was introduced as an ingredient in many processed foods.  HFCS is made from corn syrup, a liquid composed mostly of glucose molecules.  It is commercially available from a number of manufacturers, but perhaps, the best known form of corn syrup is Karo Syrup (ACH Food Companies, Inc.).  Corn syrup is made first by milling corn into corn starch, and then adding an enzyme, alpha-amylase, which breaks the starch into oligosaccharides (small chains of glucose molecules).  The next step is adding another enzyme, glucoamylase (also know as gamma-amylase) which results in a syrup consisting of only glucose molecules.  To make HFCS, the corn syrup is converted into fructose by another enzyme, D-xylose.  The manufacturing process results in HFCS with 90% fructose (HFCS 90) or 42% fructose (HFCS 42).  HFCS 90 is used to make HCFS 55, which is used to sweeten sodas and various sport drinks.  HFCS 42 is used in many processed foods including some yogurts, frozen desserts, breakfast cereals, and baked goods, and has about the same composition as sucrose.

How much sucrose and HFCS do Americans actually consume?

You may find it hard to believe, but since 1970, U.S. consumption of HFCS has risen from zero to about 40 lbs/yr/person.  At the same time, consumption of sucrose has decreased from about 70 lbs per person to about 40 lbs per person.  Net (total) sugar consumption has risen from about 80 lbs/yr to about 100-120 lbs/yr.  Thus, virtually all of the increase in total sugar consumption is the result of increased consumption of HFCS in its various forms.  But, the ratio of fructose to glucose intake has remained about the same over time

Why is HFCS so widely-used?

The development of HFCS was to a great extent the result of political and economic circumstrances.  Cane sugar quotas in the U.S. have kept the price of can sugar high while corn subsidies have made growing corn relatively inexpensive.  The bottom line is that it is cheaper to make HFCS than to process cane sugar.  It is also important to note that HFCS has some desirable qualities; It mixes well with foods and keeps foods moist.

How is HFCS metabolized?

Remember that HFCS and sucrose are composed of glucose and fructose molecules.  It is the fructose that most experts have focused on as a possible health culprit, beyond the fact that sugar in the form of glucose, sucrose or fructose add calories to the diet- about 4 calories/gram consumed.  Metabolism of glucose is relatively simple.  Glucose can be used by all cells in the body for energy, it can be stored in the form of glycogen (long chains of glucose molecules, much like starch, and used as a building block for polysaccharides).  Fructose, on the other hand, is taken up mainly by the liver and can be converted into glucose, glycogen, triglycerides  and some fatty acids.  It is the role of fructose in fat metabolism that has generated the most controversy.  There are considerable data in both animal and humans that consumption of large amounts of fructose raise triglyceride levels and increase insulin levels, promoting insulin resistance.  Does fructose promote cardiovascular disease?  Does fructose promote the development of diabetes mellitus? Does high fructose intake stress the liver?  These are just some of the questions that have been raised about dietary consumption of fructose, and by extension, consumption of HFCS.

Is HFCS metabolized differently than sucrose derived from cane and beet sugars?

There is considerable controversy whether HFCS has unique properties such that it is metabolized differently than sucrose derived from cane or beet sugar.  In my opinion, there are no credible data to show that HFCS and sucrose are metabolized differently or that the fructose in HFCS is any different than frucose in sucrose or fructose in fruits, honey, maple sugar, agave syrup or brown rice.

So, what’s the problem?

In my opinion, the problem is that we in the U.S. consume far more calories than we need and many of those calories come from foods containing various sugars, including HFCS.  The latest data show that Americans currently consume, on average,  about 120 lbs of sugar a year which works out to be almost 40 teaspoons of sugar every day.  It’s extraordinary.  We have twin epidemics of obesity and diabetes mellitus and plenty of cardiovascular disease to go around.  We don’t need to single out a single food or food additive (i.e., HFCS) as the reason for our many ills; there is plenty of blame to go around, including our fondness for inactivity.  But, it is clear that if we curb our sugar intake, we will benefit.  I am neither defending or condemning the use of HFCS in foods.  I seriously doubt that if tomorrow, the use of HFCS in foods and drinks were banned, it would have any impact on the prevalence of obesity, diabetes or heart disease.  We  will still eat too much (including an extraordinary amount of the various sugars) and exercise too little.

If you find this subject interesting, I urge you to read an article by Mary Franz (“High-fructose corn syrup: what’s the fuss about?,” published in Diabetes Self-Management, May/June 2011, pages 33-37) and an article by Gary Taubes (“Is sugar toxic?,” published in the New York times Magazine, April 17, 2011).  The Taubes article discusses the highly controversial views of Robet Lustig, a physician from the University of California San Francisco.  Don’t miss the Lustig video on You-Tube which is a lecture he gave in 2009 entitled “Sugar: the bitter truth.”  I’m not saying whether I agree or disagree with Lustig’s views, but………..

Finally, what about calling HFCS corn sugar?  In my opinion, it’s clearly false advertising.  Why don’t the corn growers just call HFCS something like “sugar derived from corn?”  Or, maybe, just continue to call it HFCS?

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