High-fructose Corn Syrup: Obesogenic Evil or Dietary Scapegoat, Part I

Today’s topic is probably one of my favorite topics, partly because it’s so controversial and partly because there is so much research behind it (epidemiological and lab-based), which makes it fun to draw conclusions. Over the years, high-fructose corn syrup has gained so much attention ever since its introduction into the food supply in the late 1960’s, largely in part to HFCS’s increased availability and consumption since that time, as well as similar rising trends in obesity. Many have tried to relate the two data sets to make the case that it is indeed HFCS that is causing this weight gain, but this just simply isn’t the case when you look at direct data from laboratory studies. Because this topic is so misconstrued and unfounded I will be devoting not one, but TWO articles to the topic of HFCS. Today will just be devoted to looking at the history behind HFCS, its introduction into the US food supply, and lastly, obesity trends, HFCS consumption trends (as well as total caloric intake trends) and the implications between the two. For part 2 I will delve into the more sciency articles and support why I believe HFCS is perfectly fine to consume. Let’s get to it, shall we?

HFCS: How it’s Made, and when it was introduced

HFCS is made by the isomerization of glucose to fructose in corn sugar. This is just a fancy way of saying that the glucose in corn syrup is flipped (via the enzyme isomerase) so that it becomes fructose. If you look up the chemical structure of the two monosaccharides you’ll notice they’re just mirror images of each other; seems safe enough. Many believe that because HFCS is largely in part a processed food then that makes it less healthy (or more harmful). In fact, if you want to really get into manufacturing processes I suggest you look up how normal sugar is processed and then make your case.

HFCS was first introduced into the food supply in 1967 as HFCS-42. As the ending number indicates, HFCS-42 is 42% fructose. Not until 1977 was HFCS-55 introduced, which is now the predominant version used (and is the sole sweetener used in soda). In total, HFCS (55 and 42) makes up about 42% of caloric sweetener availability in the United States [1], with the rest coming from sources such as sucrose (table sugar), honey, glucose, fructose, and other, less popular sweeteners.

HFCS composition

It’s commonly thought that HFCS is ‘high’ in fructose, which is actually far from the truth. First off, there is no definition for what high is, and second off, if we are using sucrose as the reference sweetener, than HFCS, on average, has about 5% more fructose. That’s not a whole hell of lot more, nor is it particularly ‘high’. Below I’ve provided a nice table so that you can visually see the similarities and differences between popular sweeteners and their contributions to fructose intake, because after all, that’s what it’s all about; fructose intake.

As you can see, HFCS is not really all that high in fructose, and in some cases, it’s actually quite ‘low’. The next thing you’ll recognize is that HFCS- 55 is not that different in composition from sucrose or honey, both of which humans have been consuming for quite some time now. So does this little bit of extra fructose REALLY make such a huge difference in terms of weight gain? Some seem to think so, while others (like myself) seem to think not.

Obesity Trends in the US: 1976-2010

It’s no secret that Americans are getting fatter. You’ve all seen the CDC color changing America that goes from a nice shade of blue to a deep orange and dark red country. If that’s not a symbol of our deteriorating health status, I don’t know what is. In fact, there was an article in the NY Times just the other day asserting that airlines will be increasing their seat sizes in order to accommodate larger passengers. Now, this is not something that hasn’t been done before (because it has with train seats), but it definitely symbolizes the severity of today’s weight status in America and proves that there is something going terribly wrong with our either our metabolic machinery or our lifestyles. I tend to thinks it’s a combination of both despite others trying to make causation out of correlation as you’ll see very shortly. Actually, I don’t think our metabolic machinery is messed up at all, but rather, we’re just abusing it.

So, without getting into too much detail, the prevalence of obesity has increased since 1976 (right around when HFCS made its way onto the scene) to the point where upwards of 68% of all Americans are either overweight or obese [2]. In terms of obesity alone, the most recent CDC data estimates over 33% of adults ages 20-74 with another 17% of children and adolescents ages 2-19 are obese [2, 3]. This wouldn’t be such a problem if obesity wasn’t related to diseases such as Type II Diabetes, cardiovascular disease, coronary heart disease, hypertension, various types of hyperlipidemias, and some forms of cancer, but unfortunately it is. Not to mention the draining costs of healthcare paid by innocent citizens like you and me. So why pin this all on one macronutrient in the spectrum of everyone’s dietary consumption and lifestyle choices? There must be some compelling data to make this assertion, right?

HFCS Consumption Trends: 1967-2010

Coincidentally (and conveniently), HFCS consumption closely mimics obesity trends over the past 40 years, causing many to assume HFCS has played a significant role in obesity’s increase by disproportionally driving up caloric intake [4]. Today, HFCS consumption has increased greater than 100-fold since the 1970’s and contributes to ~132kcals/day/person (~19g fructose) [4]. Using the United States Department of Agriculture data set [1] we can see that HFCS availability (not consumption) went from 0g/day to about 92g/day in 2000, while total caloric sweeteners increased from 166g/day to 218g/day. However, since 1999 (when HFCS consumption peaked), there has been a steady decline in HFCS consumption [5] while obesity rates continued to rise [1, 2]. It should also be noted that, within the same time frame, total calories increased nearly 25% from about 2,170kcals in 1970 to 2,700kcals in 2005 [6]. Yea, it was HFCS and not the extra 530kcals a day that were causing people to gain weight! And, in actuality, HFCS consumption, as a percentage of total kcals, actually decreased over time, meaning, that as our caloric intake increased, HFCS decreased as part of that intake while other macronutrients like fats and flour/cereal products increased [5]. Simply put, HFCS did not drive up caloric intake, but rather other foods such as flour/cereal products and fats did.

HFCS Intake by Quintiles

The rest of what I will present today really sets the stage for where the studies which support HFCS causing obesity fall apart, wherein I’ll pick up again next week. Simply put, it’s from this information that makes the research relevant or not, and I will explain why. Judging from the data presented by the CSFII and USDA charts and interpreted by Bray et al. [4, 6-7], the lowest 20% of HFCS consumers only take in about 2% of their total energy (kcals) as HFCS, while the highest 20% take in about 11% of total energy as HFCS. On average, about 7% of the Nation’s total energy intake comes from HFCS. This, however, is based on the average 2,000kcal diet. Remember earlier that I said caloric intake increased by 24% since 1970 and is hovering around 2,700kcals. This REALLY makes consumption of highest quintile (these are the top 20% of people who consume HFCS), only about 8% and the National average about 5%. By using the recommended 2,000kcal diet instead of actual caloric intake, Bray and colleagues make HFCS consumption artificially high. This misrepresents the data and does a disservice to science. I would ask you to keep in mind these numbers, because a lot of what we will look at next week is based on research that administers either HFCS of fructose in doses that exceed the highest 20% of US consumption!!! So before I get ahead of myself let’s wrap up what I’ve gone over so far today.

Summary

In summary, energy from added sugars, namely HFCS, is higher now than it was in 1970, but it increased at a slower rate than that of other macronutrients in proportion to our total caloric intake. Also, availability of HFCS has also been on the decline since 1999 yet obesity prevalence still continued to rise. Finally, total energy has not been driven up disproportionally by HFCS, but rather the diet as a whole. Simply stated; we’re eating more of EVERYTHING.

I hope so far you’re on the same page as me and can see that even though HFCS consumption has increased over the years, it is nothing compared to overall caloric intake which is a MUCH better indicator of weight gain. Next week I hope to show you why all the studies that paint HFCS as bad are virtually irrelevant to normal consumption patterns and even some research that suggests higher fructose intake might even be beneficial.

References

1. Puttnam, JJ, Allshouse, JE. Food consumption, prices and expenditures: 1976-97. United States Department of Agriculture Research Service statistical bulletin no. 965, April 1999. Washington DC; US Government Printing Office, 1999.

2. Flegal, KM, Carroll, MD, Ogden, CL, Curtin, LR. Prevalence and Trends in Obesity Among US Adults, 1999-2008. The Journal of the American Medical Association. 2010;303(3):235-241.

3. Odgen, CL, Carroll, MD. Prevalence of Obesity Among Children and Adolescents: United States, Trends 1963-1965 through 2007-2008. Center for Disease Control and Prevention. 2010.

4. Bray GA., Nielson, SJ., Popkin, BM. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. The American Journal of Clinical Nutrition. 2004;79:537-43.

5. Economic Research Service, USDA. Loss-Adjusted Food Availability Data. Updated Feb 27, 2009.

6. White, JS. Misconceptions about high-fructose corn syrup: is it uniquely responsible for obesity, reactive dicarbonyl compounds, and advanced glycation endproducts? The Journal of Nutrition. 2009;139:1219-27.

7. Tippet, KS, Cypel, YS. Design and operation: the Continuing Survey of Food Intakes by Individuals and the Diet and Health Knowledge Survey, 1994-96. Continuing Survey of Food Intakes by Individuals 1994-96, Nationwide Food Surveys report no. 96-1. Beltsville, MD: US Department of Agriculture, Agriculture Research Service, 1998.

8. United States Department of Agriculture, Agriculture Research Service. Design and Operation: the Continuing Survey of Food Intakes by Individuals and the Diet and Health Knowledge Survey 1994-196 and 1998. Beltsville, MD: US Department of Agriculture, Agriculture Research Service, 2000.