What's the deal with High Fructose Corn Syrup?
- Apr 29, 2016
- 4 min read
What is High Fructose Corn Syrup (HFCS)?
HFCS is a liquid sweetener alternative to sucrose (aka table sugar) that is used in many foods and beverages today. It was first developed in the 1960’s to be used in foods and beverages because it was more stable in acidic environments. It is easier to transport and simple to add. It’s derived from corn, so it is more renewable, abundant, and cheaper than cane sugar. The United States funds farmers to grow crops such as wheat, soybeans, and corn. Due to this subsidy, corn is cheap and so HFCS is cheaper to produce making foods that contain this cheaper to buy for consumers.
When corn starch is broken down into its individual glucose (simple sugar) molecules, the end result is corn syrup. To make HFCS, enzymes are added to the corn syrup to convert some of the glucose to fructose ("fruit sugar" - another simple sugar) and break chemical bonds. HFCS comes in 2 main forms: HFCS-42 and HFCS-55. The number indicates the percent of fructose in the syrup (42% and 55%). The remaining carbohydrates are free glucose and some small glucose chains. HFCS-42 is mainly used in processed foods, cereals, baked goods, and some beverages. HFCS-55 is mostly used in soft drinks.
How is HFCS different from regular sugar?
Sucrose, or table sugar, is 50% glucose and 50% fructose bonded together. So, as you can see, not all HFCS has more fructose in it than sucrose. HFCS is called “high fructose” because it contains more fructose than corn syrup, which is 100% glucose. The name is definitely a misnomer in some sense. The primary differences between table sugar and HFCS are that HFCS contains water and there is no chemical bond between the glucose and fructose in HFCS like in sucrose.
It is commonly believed that HFCS is sweeter than sucrose, but it is actually slightly less sweet. HFCS also provides the same number of calories per gram that other sugars do.
How is HFCS metabolized and absorbed in the body?
Since HFCS contains fructose and glucose, it is important to consider both metabolic pathways. Fructose metabolism is different from glucose metabolism in 2 major ways. Firstly, fructose is rapidly taken up by the liver and bypasses steps that glucose takes to be broken down into energy. Second, there are different enzymes that act on fructose and glucose in their initial metabolism.
(Rippe J, Angelopoulos T, Adv Nutr, 2013. Fig 2)
Simply put, this image shows the different pathways that fructose and glucose take in the body, but ultimately, they plug into the same path. These differences could theoretically lead to different effects of fructose compared to glucose. Studies have shown that glucose causes higher spikes in blood sugar and insulin levels as well as increases in other hormones like leptin as well as more suppression of the hormone ghrelin than fructose does. However, this is examining pure glucose vs. pure fructose. Both HFCS and sucrose are a combination of the two. Other studies indicate that when this is repeated with HFCS and sucrose, these differences disappeared. The primary concern with fructose is that large amounts may overwhelm the system and as it does not trigger the insulin response in the same way, and lead to a host of other problems. More research is needed in this area.
Does HFCS cause obesity?
There is a hypothesis that are presented in 2004 that asserts that HFCS consumption is heavily associated with the rising obesity rates in the nation. This study looked at the increasing HFCS use and the rising obesity rates and stated that the increased use of HFCS contributed to the rising obesity rates. However, the studies did not examine rising caloric intake or other added macronutrients. Data from the US Department of Agriculture shows that overall calorie intake had increased 24%. And, although total caloric sweetener consumption has increased since 1970, sucrose remains the primary sugar consumed by Americans and is the leading source of fructose in our diets. The overall trend shows that, added sugar use, as a percent of total calories per day, has slightly decreased over the 35 year period that the study had originally looked at. Simply to say that the rising use of HFCS over this 35 year period from the 70’s to 2000’s caused the increased obesity epidemic is not entirely accurate. Both may have increased but this does not indicate that one caused the other.
There have been some studies in rats that show that HFCS may cause increased obesity rates. However, as with many animal studies, it is difficult to shift those findings over to humans. A more recent study in 2012 found that HFCS has the same effect on weight as sucrose does. Multiple other studies have also shown that the idea that HFCS is different from sucrose in causing obesity, may not be accurate. These findings caused the American Medical Association and the Academy of Nutrition and Dietetics to issue statements saying that there are no major differences between HFCS and sucrose and their likelihood of causing obesity. Of course, more studies are needed in this area to look at greater long term effects.
However, as with any sugar source, consuming too much sugar, relative to one's calorie requirements, will cause the body to take the excess and store it as fat. The most recent 2015-2020 Dietary Guidelines for Americans recommends to limit one's intake of added sugars, including HFCS and sucrose. So, excess calories from any sweetener or food can cause weight gain. Moderation really is the key to a healthy diet. Even HFCS, in moderation, can fit into most diets without causing harm.
(Cover image from Precision Nutrition website)
Resources:
1) White J. "Straight talk about high-fructose corn syrup: what it is and what it ain't 1'2'3'4." Am J Clin Nutr. 2008; 88(6): 17165-17215. doi: 10.3945/ajcn.2008.25825B
2) Kalley L, Shelnutt K. "Facts About HFCS - High Fructose Corn Syrup." UF IFAS Extension. Published May 2010. Updated July 2013. https://edis.ifas.ufl.edu/pdffiles/FY/FY115500.pdf. Accessed April 29, 2016.
3) "High Fructose Corn Syrup: Questions and Answers." U.S. Food and Drug Administration website. Updated November 5, 2014. http://www.fda.gov/Food/IngredientsPackagingLabeling/FoodAdditivesIngredients/ucm324856.htm. Accessed April 29, 2016.
4) Parker H. "A sweet problem: Princeton researchers find that high-fructose corn syrup prompts considerably more weight gain." Princeton University website. Published March 22, 2010. http://www.princeton.edu/main/news/archive/S26/91/22K07/. Accessed April 29, 2016.
5) Rippe J, Angelopoulos T. "Sucrose, HIgh-Fructose Corn Syrup, and Fructose, Their Metabolism and Potential Health Effects: What Do We Really Know?." Adv Nutr. 2013; 4: 236-245. doi 10.3945/112.002824
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