High-fructose corn syrup is a sweetener made by converting a portion of the high glucose content of cornstarch into fructose, or fruit sugar. It is also known as glucose-fructose, isoglucose, and glucose-fructose syrup. Fructose is metabolized differently than other sugars; it is processed immediately in the liver for storage as fat and thereby has been suggested to contribute to weight gain and the development of obesity-related chronic disease.
High-fructose corn syrup is used as a sweetener in manufactured foods and beverages, most often in place of common granulated table sugar (sucrose), a refined product of sugar cane. Sometimes it is also used illegally to stretch the honey content in jarred honey or honey-containing products. In food manufacturing, high-fructose corn syrup is considered easier to handle than granulated sugar and it is also a less expensive ingredient than regular sugar.
Beekeepers also use undiluted high-fructose corn syrup as a nectar substitute for honeybees when blossoms are scarce or absent altogether. Bees dehydrate plant nectar to produce honey. The nectar contains only small amounts of sugar and trace amounts of proteins and other nutrients. Fructose solutions have higher amounts of sugar, fewer nutrients, and contain hydroxymethylfurfural, a chemical formed by dehydration of sugars, which tends to increase in the presence of heat. It is shown in studies to be toxic to rats and mice and can be toxic to honeybees when consumed at high concentrations.
Although corn syrup has been manufactured since the mid-1800s, the modern corn syrup evolved when scientists in an industrial research institute in Japan discovered how to produce a heat-stable enzyme (xylose isomerase) from yeast between 1965 and 1970. Using that technology as a basis, glucose isomerase enzyme was used to convert the glucose content of corn into fructose, giving rise to high-fructose corn syrup. After the Food and Drug Administration (FDA) classified high-fructose corn syrup as GRAS (generally recognized as safe) in 1976, the product was introduced as a replacement for sucrose, or table sugar, in manufactured foods. Since then it has been used consistently in the United States as an added sugar to sweeten soft drinks and food products, including breads, cereals, baked goods, and processed foods of all kinds.
The production of high-fructose corn syrup begins with milling corn to produce cornstarch and then using an acid-enzyme technique to acidify the cornstarch solution. Carbohydrates in the solution are then broken down by the acid-enzyme, converting the sugars obtained into fructose. During the process, xylose isomerase enzyme derived from the fermentation of bacteria turns the sugars into about 52% pure glucose and 42% fructose. Several types of high-fructose are available to manufacturers, identified by the percentage of fructose content found with water and glucose.
Research results have indicated that consumption of added sugar in food products and beverages contributes to obesity, and high-fructose corn syrup is the most commonly added sugar, particularly in the United States where subsidies of U.S. corn have kept the cost of corn products low and attractive to manufacturers. The use of added sugars, primarily high-fructose corn syrup, rose by 25% in the 1970s, and obesity began increasing at the same time. Although obesity held constant at about 15% in the 1960s and 1970s, after that, obesity rates increased markedly, rising to 35% in the 1980s among all ages, even older adults. Concerns grew in the United States about the health effects of high-fructose corn syrup after researchers demonstrated links between high-fructose consumption and increased lipids such as triglycerides and low-density lipoproteins (the so-called “bad” cholesterol) in the blood and increased weight. As concerns increased among health organizations and the public, the food industry and corn companies tried to change the product's name to “corn sugar,” but the FDA did not allow the change on food labels. Many manufacturers have returned to using cane sugar in their food products, and some companies have emphasized in their packaging and labeling that their products do not contain high-fructose corn syrup.
Basic biochemistry reveals the differences between cane sugar and high-fructose corn syrup. The cane sugar commonly known as table sugar is sucrose, which comprises two sugar molecules, glucose and fructose, bound together in equal amounts. It is broken down by enzymes in the digestive tract into separate molecules of glucose and fructose that are absorbed into the bloodstream and distributed throughout the body. The glucose and fructose concentrations in high-fructose corn syrup are not equal; they appear unbound in a ratio of 55:45. Because glucose and fructose are not chemically bound as in cane sugar, digestion is not required and the sugars are absorbed rapidly into the bloodstream. Fructose is processed immediately by the liver, triggering lipogenesis, which is the production and storage of cholesterol and triglycerides, the primary cause of fatty liver disease. At the same time, rapid absorption of glucose increases production of the body's fat hormone, insulin. These two biochemical responses to high-fructose corn syrup disrupt the body's metabolism, increase appetite, deplete energy metabolism at the cellular level, and trigger inflammation, which may lead to weight gain, diabetes, heart disease, and other chronic conditions. Clearly, more human studies are needed to clarify the possible contribution of high-fructose corn syrup to weight gain and metabolic changes.
The consumption share of high-fructose corn syrup worldwide shows the United States ahead by far at 55%. Mexico is second with 13% and China third with 11%. All other countries have lower consumption. Per person consumption of high-fructose corn syrup in the United States was at its peak in 2000 at 62.5 lb. (28.3 kg) per person. This declined to 42.5 lb. (19.3 kg) per person in 2012, but the consumption of refined sugar cane products and beet sugar increased to 39 lb. (17.7 kg) per person in response to health concerns about high-fructose corn syrup. In 2014, consumption of high-fructose corn syrup was estimated to be 41.4 lb. (18.8 kg) per person, and production in the United States was 8.37 thousand tons (7.59 thousand metric tons) in 2016.
A production quota was established for high-fructose corn syrup in the European Union (EU) in 2005, keeping annual usage at 303 thousand tons (275 thousand metric tons) compared to prior annual use of cane sugar in manufactured foods and beverages of more than 18 million tons (16.3 million metric tons). The per person consumption in the EU is not known or unavailable, and it also is not known whether declining consumption of high-fructose corn syrup is having an impact on obesity rates.
Production of high-fructose corn syrup is highest in the United States, and large amounts were exported to Mexico and other countries in 2012, according to statements made by the U.S. Department of Agriculture Economic Research Service. Use of the product has increased globally but is consumed mainly in U.S.produced soft drinks. Many countries still do not use it in manufactured food products.
In the United States, high-fructose corn syrup is added as a sweetener to a wide range of foods and to most popular soft drinks, tonic, iced tea and coffee beverages, fruit drinks, sweetened milk beverages, and flavored water. It is found most often in low quality foods that lack essential nutrients but are rich in fats, salt, and chemical additives. Among sweetened foods, high-fructose corn syrup is found most often in breads, cereals, baked goods, and dairy desserts such as ice cream and frozen yogurt. Many popular packaged foods that may not be thought of as sweetened, including salad dressings, stuffing mixes, nutrition bars, crackers, cottage cheese, yogurt, macaroni and cheese, baked beans, tomato paste, jarred tomato sauce, applesauce, sweet pickles, relish, and more, are also sweetened with high-fructose corn syrup. Some flavored cough syrups also contain high-fructose corn syrup.
The World Health Organization announced in 2015 that its recommended intake of added sugar for adults and children was less than 10% of total daily calories consumed (total energy intake) and that further reduction to below 5%, equivalent to about six teaspoons a day or 25 grams, provided even greater health benefits.
The American Heart Association (AHA) recommends that adults limit their sugar intake to not more than 100 calories per day (about 6 tsp. or 24 g) for women and 150 calories a day (about 9 tsp. or 36 g) for men. The AHA does not distinguish between sugar sources, emphasizing that all sugars contribute to overconsumption of dietary sugar. Any type of syrup or an ingredient ending in “ose” such as dextrose or maltose is a sugar. The AHA advises that individuals track their intake of added sugar carefully, being sure to remember that each gram of sugar has four calories and each teaspoon holds four grams of sugar or 16 calories. When a food label lists 20 grams of sugar, it is equal to 5 teaspoons of sugar or about 80 calories. Cane syrup and rice syrup in natural foods are also added sugars. According to the AHA, overall intake of sugar is the issue and moderation is the key to sugar consumption.
Consumption of high-fructose corn syrup varies between countries because of the range of products in which it is used. For example, although the United States uses high-fructose corn syrup routinely to sweeten soft drinks and beverages such as tonic water or fruit-flavored drinks, beverages in Mexico, Europe, and Asia are primarily sweetened with sugar. Nevertheless, high-fructose corn syrup has been implicated, perhaps more than other sugars, as a factor in the development of health issues such as obesity, type 2 diabetes, and related metabolic disorders. Nutritionists have reported that high-calorie sweeteners, especially when consumed regularly in beverages, tend to increase total calorie consumption, which is believed to contribute to the obesity epidemic in the United States. A global study of per capita usage of high-fructose corn syrup among 200 countries, using a database from the U.S. Food and Agricultural Organization, showed no significant differences in body mass index (BMI), calorie intake, or total sugar intake among people in countries that used high-fructose corn syrup compared to those in countries that did not, but markers of diabetes and diabetes prevalence were significantly higher in countries using high-fructose corn syrup compared to those that did not. Thus, countries with higher availability of high-fructose corn syrup had a higher prevalence of diabetes.
The FDA classifies high-fructose corn syrup as “generally safe for human consumption.” The Code of Federal Regulations (CFR 184.1866) states that common forms of high-fructose corn syrup contain either 42% or 55% fructose, represented in food industry labeling as HFCS42 and HFCS55. The FDA states that it has no evidence that there are differences in safety between foods containing HFCS42 and HFCS55 and foods containing similar amounts of sweeteners with approximately equal glucose and fructose content.
The 2015–2020 Dietary Guidelines for Americans recommends limiting consumption of all added sugars, but does not distinguish between them, and the FDA supports this recommendation. In addition, the FDA has no firm definition of the word “natural” used in the labeling and advertising of products containing high-fructose corn syrup. When the “all natural” claim by Snapple Beverage Company for its Snapple Iced Tea product, which is sweetened with high-fructose corn syrup, was challenged by campaigners against high-fructose corn syrup in 2009, the use of “natural” was upheld in the U.S. District Court for the Southern District of New York after consulting with the FDA. Nevertheless, the company introduced a natural line of tea drinks brewed with cane sugar and promoted it with a major national advertising campaign. Also, in 2009, PepsiCo introduced three new sodas sweetened with cane sugar and beet sugar (Pepsi Natural, Pepsi Throwback, and Mountain Dew Throwback).
In the European Union, high-fructose corn syrup, known as isoglucose or glucose-fructose syrup, is restricted by a production quota but is available to manufacturers in limited quantities as a food additive. The European Union has ruled that food and drink manufacturers can claim health benefits of sweetened products if more than 30% of glucose and sucrose are replaced with fructose. This has been met with harsh criticism by obesity experts who explain that fructose is metabolized differently; it is processed immediately in the liver for storage as fat. Therefore they suggest that it can contribute to the development of obesity-related chronic diseases.
Animal studies have shown interactions between high-fructose corn syrup and the absorption of various minerals in the body. As with any food additive, it is important to check with a healthcare provider to be sure any medications will not interact unfavourably with high-fructose corn syrup and to find out if this sweetener should be eliminated from the diet.
Duyff, Roberta Larson. American Dietetic Association Complete Food and Nutrition Guide. 5th ed. Boston, MA: Houghton Mifflin Harcourt, 2017.
Healey, Justin, ed. Sugar Consumption. 15th ed. Thirroul, Australia: Spinney, 2017.
Roberts, Elizabeth. Sugar Counter for Health: The Smart Person's Guide to Hidden Sugars. New York: Souvenir, 2016.
U.S. Department of Agriculture. Dietary Guidelines for Americans, 2015–2020. 8th ed. Washington, DC: U.S. Government Printing Office, 2015.
Campos, V. C., and Tappy, Luc. “Physiological Handling of Dietary Fructose-Containing Sugars: Implications For Health.” International Journal of Obesity 40 (March 2016): S6–11.
DeChristopher, L. R., J. Uribarri, and K. L. Tucker. “Intake of High-Fructose Corn Syrup Sweetened Soft Drinks, Fruit Drinks and Apple Juice Is Associated with Prev
alent Arthritis in U.S. Adults Aged 20–30 Years.” Nutrition & Diabetes 6, no. 3 (March 7, 2016): e199.
Goran, Michael I., Stanley J. Ulijaszek, and Emily E. Ventura. “High-Fructose Corn Syrup and Diabetes Prevalence: A Global Perspective.” Global Public Health 8, no. 1 (January 2013): 55–64.
Rippe, James M., and T. J. Angelopoulos. “Added Sugars and Risk Factors for Obesity, Diabetes and Heart Disease.” International Journal of Obesity 40 (March 2016): S22–7.
American Heart Association (AHA). “Added Sugars.” Heart.org . http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Added-Sugars_UCM_305858_Article.jsp (accessed May 19, 2018).
Dufault, Renee. “High Fructose Corn Syrup.” Food Ingredient and Health Research Institute. http://www.foodingredient.info/ingredientsofconcern/highfructosecornsyrup.htm (accessed May 19, 2018).
Zeratsky, Katherine. “Nutrition and Healthy Eating: What Is High-Fructose Corn Syrup? What Are the Health Concerns?” Mayo Clinic. http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expertanswers/high-fructose-corn-syrup.faq-20058201 (accessed May 19, 2018).
American Diabetes Association, 2451 Crystal Dr., Ste. 900, Arlington, VA, 22202, (800) 342-2383, AskADA@diabetes.org, http://www.diabetes.org .
American Heart Association, 7272 Greenville Ave., Dallas, TX, 75231, (888) 242-8883, firstname.lastname@example.org, https://www.onlineaha.org .
Food and Nutrition Information Center, National Agricultural Library, 10301 Baltimore Ave., Beltsville, MD, 20705, (301) 504-5755, Fax: (301) 504-7042, fnic@ars. usda.gov, https://www.nal.usda.gov/fnic .
International Food Information Council Foundation, 1100 Connecticut Ave. NW, Ste. 430, Washington, DC, 20036, (202) 296-6540, email@example.com, http://www.foodinsight.org .
L. Lee Culvert