High-fructose corn syrup (HFCS) – called isoglucose, maize syrup, or glucose-fructose syrup in the UK and glucose/fructose in Canada – comprises any of a group of corn syrups that has undergone enzymatic processing to convert its glucose into fructose and has then been mixed with pure corn syrup (100% glucose) to produce a desired sweetness. In the United States, consumer foods and products containing high-fructose corn syrup are typically using HFCS as a sugar substitute and it is ubiquitous in processed foods and beverages, including soft drinks, yogurt, industrial bread, cookies, salad dressing, and tomato soup. Critics of HFCS say it is "a toxic chemical concoction" which contributes to weight gain by affecting normal appetite functions. Many medical professionals dispute these claims and maintain that HFCS is comparable to table sugar. Studies by The American Medical Association suggest "it appears unlikely that HFCS contributes more to obesity or other conditions than sucrose" but calls for further independent research on the subject.
The most widely used varieties of high-fructose corn syrup are: HFCS 55 (mostly used in soft drinks), approximately 55% fructose and 45% glucose; and HFCS 42 (used in many foods and baked goods), approximately 42% fructose and 58% glucose. HFCS-90, approximately 90% fructose and 10% glucose, is used in small quantities for specialty applications, but primarily is used to blend with HFCS 42 to make HFCS 55.
|Nutritional value per 100 g (3.5 oz)|
|Energy||1,176 kJ (281 kcal)|
|Dietary fiber||0 g|
|Riboflavin (Vit. B2)||0.019 mg (1%)|
|Niacin (Vit. B3)||0 mg (0%)|
|Pantothenic acid (B5)||0.011 mg (0%)|
|Vitamin B6||0.024 mg (2%)|
|Folate (Vit. B9)||0 μg (0%)|
|Vitamin C||0 mg (0%)|
|Calcium||6 mg (1%)|
|Iron||0.42 mg (3%)|
|Magnesium||2 mg (1%)|
|Phosphorus||4 mg (1%)|
|Potassium||0 mg (0%)|
|Sodium||2 mg (0%)|
|Zinc||0.22 mg (2%)|
|Shown is for 100 g, roughly 5.25 tbsp.
Percentages are relative to US recommendations for adults.
Source: USDA Nutrient database
Cane sugar and beet sugar are both relatively pure sucrose. While the glucose and fructose, which are the two components of HFCS, are monosaccharides, sucrose is a disaccharide composed of glucose and fructose linked together with a relatively weak glycosidic bond. A molecule of sucrose (with a chemical formula of C12H22O11) can be broken down into a molecule of glucose (C6H12O6) plus a molecule of fructose (also C6H12O6 — an isomer of glucose) in a weakly acidic environment. Sucrose is broken down during digestion into fructose and glucose through hydrolysis by the enzyme sucrase, by which the body regulates the rate of sucrose breakdown. Without this regulation mechanism, the body has less control over the rate of sugar absorption into the bloodstream.
The fact that sucrose is composed of glucose and fructose units chemically bonded complicates the comparison between cane sugar and HFCS. Sucrose, glucose and fructose are unique, distinct molecules. Sucrose is broken down into its constituent monosaccharides – namely, fructose and glucose – in weakly acidic environments by a process called inversion. This same process occurs in the stomach and in the small intestine during the digestion of sucrose into fructose and glucose. People with sucrase deficiency cannot digest (break down) sucrose and thus exhibit sucrose intolerance.
It is argued that if the body actually does regulate sucrase production in order to regulate the hydrolysis of sucrose, then overconsuming sucrose should present the same symptoms as sucrose intolerance, as both situations would result in non-hydrolyzed sucrose in the large intestines.
Sucrose has approximately 4 kilocalories (kcal)—or 4 calories of food energy—per gram, while HFCS has approximately 3 kcal per gram. This is because HFCS contains roughly 25% water.
Honey is a mixture of different types of sugars, water, and small amounts of other compounds. Honey typically has a fructose/glucose ratio similar to HFCS 55, as well as containing some sucrose and other sugars. Like HFCS, honey contains water and has approximately 3 kcal per gram. Because of its similar sugar profile and lower price, HFCS has been used illegally to "stretch" honey. As a result, checks for adulteration no longer test for sugar but instead test for minute quantities of proteins that can be used to differentiate between HFCS and honey.
The process by which HFCS is produced was first developed by Richard O. Marshall and Earl P. Kooi in 1957. The industrial production process was refined by Dr. Y. Takasaki at Agency of Industrial Science and Technology of Ministry of International Trade and Industry of Japan in 1965–1970. HFCS was rapidly introduced to many processed foods and soft drinks in the U.S. from about 1975 to 1985.
High-fructose corn syrup is produced by milling corn to produce corn starch, then processing that starch to yield corn syrup, which is almost entirely glucose, and then adding enzymes that change most of the glucose into fructose. The resulting syrup (after enzyme conversion) contains approximately 90% fructose and is HFCS 90. To make the other common forms of HFCS (HFCS 55 and HFCS 42) the HFCS 90 is mixed with 100% glucose corn syrup in the appropriate ratios to form the desired HFCS. The enzyme process that changes the 100% glucose corn syrup into HFCS 90 is as follows:
While inexpensive alpha-amylase and glucoamylase are added directly to the slurry and used only once, the more costly glucose-isomerase is packed into columns and the sugar mixture is then passed over it, allowing it to be used repeatedly until it loses its activity. This 42–43% fructose glucose mixture is then subjected to a liquid chromatography step, where the fructose is enriched to about 90%. The 90% fructose is then back-blended with 42% fructose to achieve a 55% fructose final product. Most manufacturers use carbon absorption for impurity removal. Numerous filtration, ion-exchange and evaporation steps are also part of the overall process.
The units of measurement for sugars including HFCS are degrees Brix (symbol °Bx). Brix is a measurement of the mass ratio of dissolved sugars to water in a liquid. A 25 °Bx solution has 25 grams of sugar per 100 grams of solution (25% w/w). Or, to put it another way, there are 25 grams of sugar and 75 grams of water in the 100 grams of solution. The Brix measurement was introduced by Antoine Brix.
When an infrared Brix sensor is used, it measures the vibrational frequency of the high-fructose corn syrup molecules, giving a Brix degrees measurement. This will not be the same measurement as Brix degrees using a density or refractive index measurement, because it will specifically measure dissolved sugar concentration instead of all dissolved solids. When a refractometer is used, it is correct to report the result as "refractometric dried substance" (RDS). One might speak of a liquid as being 20 °Bx RDS. This is a measure of percent by weight of total dried solids and, although not technically the same as Brix degrees determined through an infrared method, renders an accurate measurement of sucrose content, since the majority of dried solids are in fact sucrose. The advent of in-line infrared Brix measurement sensors have made measuring the amount of dissolved HFCS in products economical using a direct measurement. It also gives the possibility of a direct volume/volume measurement.
Recently, an isotopic method for quantifying sweeteners derived from corn and sugar cane was developed by which permits measurement of corn syrup- and cane sugar-derived sweeteners in humans, thus allowing dietary assessment of the intake of these substances relative to total intake.
A system of sugar tariffs and sugar quotas imposed in 1977 in the United States significantly increased the cost of imported sugar and U.S. producers sought cheaper sources. High-fructose corn syrup, derived from corn, is more economical because the domestic U.S. and Canadian prices of sugar are twice the global price  and the price of corn is kept low through government subsidies paid to growers. HFCS became an attractive substitute, and is preferred over cane sugar among the vast majority of American food and beverage manufacturers. Soft drink makers such as Coca-Cola and Pepsi use sugar in other nations, but switched to HFCS in the U.S. in 1984. Large corporations, such as Archer Daniels Midland, lobby for the continuation of government corn subsidies.
Other countries, including Mexico, typically use sugar in soft drinks. Some Americans seek out Mexican Coca-Cola in ethnic groceries, because they prefer the taste compared to Coke made with HFCS. Kosher for Passover Coca-Cola sold in the U.S. around the Jewish holiday also uses sucrose rather than HFCS and is also highly sought after by people who prefer the original taste.
The average American consumed approximately 37.8 lb (17.1 kg) of HFCS in 2008, versus 46.7 lb (21.2 kg) of sucrose. In countries where HFCS is not used or rarely used, sucrose consumption per person may be higher than in the USA; sucrose consumption per person from various locations is shown below (2002):
Of course, in terms of total sugars consumed, the figures from countries where HFCS is not used should be compared to the sum of the sucrose and HFCS figures from countries where HFCS consumption is significant.
In the European Union (EU), HFCS, known as isoglucose or glucose-fructose syrup:, is subject to a production quota. In 2005, this quota was set at 303,000 tons; in comparison, the EU produced an average of 18.6 million tons of sugar annually between 1999 and 2001. Therefore, wide scale replacement of sugar has not occurred in the EU.
Critics of HFCS point out a correlation between increased usage of HFCS in foods and obesity rates in the United States over three decades. Some allege that HFCS is in itself more detrimental to health than table sugar (sucrose); others claim that the low cost of HFCS encourages overconsumption of sugars. The Corn Refiners Association has launched an aggressive advertising campaign to counter these criticisms, claiming that high-fructose corn syrup "is natural" and "has the same natural sweeteners as table sugar". Both sides point to studies in peer reviewed journals that allegedly support their point of view.
Elliot et al. implicate increased consumption of fructose (due primarily to the increased consumption of sugars but also partly due to the slightly higher fructose content of HFCS as compared to sucrose) in obesity and insulin resistance. Chi-Tang Ho et al. found that soft drinks sweetened with HFCS are up to 10 times richer in harmful carbonyl compounds, such as methylglyoxal, than a diet soft drink control, and claimed that sucrose does not have the same tendency to produce these compounds. Carbonyl compounds are elevated in people with diabetes and are blamed for causing diabetic complications such as foot ulcers and eye and nerve damage.
A study in mice suggests that consumption of a fructose solution (not HFCS) increases obesity when compared with a sucrose solution. Large quantities of fructose stimulate the liver to produce triglycerides, promotes glycation of proteins and induces insulin resistance.
A 2008 study in humans analyzed the circulating levels of glucose, insulin, leptin, ghrelin, and triacylglycerol during a 24 hour period after consuming drinks containing HFCS or sucrose. The researchers concluded that the consumption of HFCS or sucrose did not yield differing metabolic effects.
In a 2007 study, rats were fed a diet high in fat and HFCS and kept relatively sedentary for 16 weeks in an attempt to emulate the diet and lifestyle of many Americans. The rats were not forced to eat, but were able to eat as much as they wanted; they consumed a large amount of food, and the researcher, Dr. Tetri, stated that there is evidence that fructose suppresses the sensation of fullness. Within four weeks, the rats showed early signs of fatty liver disease and type II diabetes. An equivalent diet using sucrose instead of HFCS was not tested.
Shapiro et al. fed rats a high-fructose diet for six months and compared them to rats that had been fed a fructose-free diet. Although the rats that had consumed high levels of fructose showed no change in weight, when compared to the rats that had consumed a fructose-free diet, levels of leptin in the blood of rats fed a high-fructose diet indicated the development of leptin resistance. When the rats were switched to a high-fat diet, the leptin-resistant rats, those fed a high-fructose diet, gained more weight than those who had not developed the resistance and had been fed a fructose-free diet.
Several studies funded by Tate & Lyle, a large corn refiner, the American Beverage Institute and the Corn Refiners Association, have defended HFCS. Forshee et al. concluded "that HFCS does not appear to contribute to overweight and obesity any differently than do other energy sources." Melanson et al. (2006), studied the effects of HFCS and sucrose sweetened drinks on blood glucose, insulin, leptin, and ghrelin levels. They found no significant differences in any of these parameters. Monsivais et al. (2007) compared the effects of isocaloric servings of colas sweetened with HFCS 42, HFCS 55, sucrose, and aspartame on satiety and subsequent energy intake. They found that all of the drinks with caloric sweeteners produced similar satiety responses, and had the same effects on subsequent energy intake.
One much-publicized 2004 study found an association between obesity and high HFCS consumption, especially from soft drinks. However, this study provided only correlative data. One of the study coauthors, Dr. Barry M. Popkin, is quoted in the New York Times as saying, "I don't think there should be a perception that high-fructose corn syrup has caused obesity until we know more." In the same article, Walter Willett, chair of the nutrition department of the Harvard School of Public Health, is quoted as saying, "There's no substantial evidence to support the idea that high-fructose corn syrup is somehow responsible for obesity .... If there was no high-fructose corn syrup, I don't think we would see a change in anything important." Willett also recommends drinking water over soft drinks containing sugars or high-fructose corn syrup.
A pilot study reported that some high-fructose corn syrup manufactured in the U.S. in 2005 contained trace amounts of mercury. The mercury appeared to come from sodium hydroxide and hydrochloric acid, two chemicals used in the manufacture of high-fructose corn syrup. This mixture used to produce HFCS may have come from plants also specializing in industrial chlorine chlor-alkali using the mercury cell Castner-Kellner process, and may contain traces of mercury if this specific process is utilized. Mercury concentrations in the samples testing positive ranged from 0.012 μg/g to 0.570 μg/g (micrograms per gram). Nine of the twenty samples tested did contain measurable amounts of mercury.
A March 18, 2010 Duke University Medical Center study found that "increased consumption of high fructose corn syrup was associated with scarring in the liver, or fibrosis, among patients with Non-alcoholic fatty liver disease (NAFLD)."  NAFLD is not uncommon in the United States, affecting almost 1/3 of the adult population.
In the United States, high-fructose corn syrup has become a sucrose replacement for honey bees. In 2009, a study by Leblanc et al. found that at temperatures above 45 °C (113 °F) HFCS rapidly begins to form hydroxymethylfurfural, which is toxic to the honeybees being fed HFCS.
In May 2006, the Center for Science in the Public Interest (CSPI) threatened to file a lawsuit against Cadbury Schweppes for labeling 7 Up as "All Natural" or "100% Natural", despite the presence of high-fructose corn syrup. The U.S. Food and Drug Administration (FDA) has no general definition of "natural"; however, FDA regulations define "natural flavoring" to include products of vegetables. In April 2008, an FDA employee was quoted in an article suggesting that the agency had changed its opinion on HFCS. However, this was not the official position of the agency. The FDA subsequently issued a clarification stating that the agency does not object to labeling HFCS as "natural." The CSPI also claim that HFCS is not a “natural” ingredient due to the high level of processing and the use of at least one genetically modified (GMO) enzyme required to produce it. On January 12, 2007, Cadbury Schweppes agreed to stop calling 7 Up "All Natural". They now label it "100% Natural Flavors".
In September 2008, the Corn Refiners Association launched a series of United States television advertisements that claim that HFCS "is made from corn", "is natural" (changed from previously-stated "doesn't have artificial ingredients"), "has the same calories as sugar or honey", "is nutritionally the same as sugar", and "is fine in moderation", in an attempt to keep consumers from boycotting HFCS. The ads feature actors portraying roles in upbeat domestic situations with sugary foods, with one actor disparaging a food's HFCS content but being unable to explain why, and another actor rebuking the comments with these claims. Finally, the ads each plug the Corn Refiners Association website. As HFCS is a controversial topic, parodies and criticisms of the ads have appeared on YouTube.
A March 21, 2009 New York Times article said that some food companies and restaurants were using sugar in their product as a selling point, in order to attract customers who prefer not to consume high-fructose corn syrup. As one example, the article cited Jason’s Deli, a chain of delis with 200 restaurants in 27 states. The chain had replaced high-fructose corn syrup with sugar in everything except a few soft drinks. Daniel Helfman, a spokesman for the deli chain, was quoted as saying, "Part of this is a huge rebellion against HFCS... but part of it is taste."
PepsiCo recently put forth a "throwback" version of Mountain Dew and Pepsi-Cola, designed to taste the same as these drinks did in the 1960s and 1970s. One aspect of the formulation is that sugar is used instead of HFCS. PepsiCo stated that HFCS and sugar are "essentially the same" and that the only reason HFCS was eschewed was in order to accurately reflect the taste of the past. Dr. Pepper also released a "heritage" version of Dr. Pepper Soda in 2009 that was made to the original formula and used cane sugar instead of HFCS.