Life-Cycle Studies: High-Fructose Corn Syrupby Ben Block on April 9, 2010
Corn was once a simple food, chewed off the cob. Now, with corn reinvented and transformed, it takes a chemist to recognize all its offspring. Among these is high-fructose corn syrup (a gooey sweetener used in soft drinks, meats, cheeses, and dozens more foods) that appeases confectionary cravings. But recent studies have raised concerns about the syrup by drawing links to obesity and other health effects.
High-fructose corn syrup (HFCS), also called isoglucose, is mainly a blend of two sugars, fructose and glucose. Soda and ice cream often blend 55 percent fructose and 45 percent glucose, while the HFCS used in canned fruits and condiments is generally a 42/48 percent mix (with other ingredients). White sugar is a 50/50 split.
In the United States, heavy corn subsidies and sugar-import barriers have made HFCS some 20 percent cheaper than sugar. The United States accounted for nearly 80 percent of global production in 2004 and U.S. consumers swallowed 58 pounds of the syrup per person last year in various products, according to the U.S. Department of Agriculture (USDA). Other producers include Japan, Argentina, the European Union, and China.
U.S. refineries discovered in the 1860s that mixing liquefied cornstarch with either acids or enzymes rearranges sugar molecules into a dextrose solution (a form of glucose). Chemists mixed dextrose with additional enzymes in the 1940s for the first batches of HFCS. The syrup was not quite as sweet as sugar itself until 1971, when a Japanese chemist's further tweaking perfected HFCS, according to the Corn Refiners Association.
The food industry began to replace cane and beet sugar with HFCS after sugar prices quadrupled in the 1970s, and a few years later soft-drink companies followed suit. The syrup's affordability in the United States has helped soda companies sell larger bottles and greatly expand consumption of the calorie-rich drinks.
As HFCS spreads to parts of the developing world, dietary concerns are convincing many U.S. consumers to avoid it. In response, a growing number of sweetened products are being reformulated with cane sugar.
Some claim that HFCS's global expansion and the parallel increase in obesity are linked. The concerned dietitians argue that, unlike glucose, which triggers appetite-suppressing signals in the body, fructose does not tell its eaters to stop. The theory remains unproven, but a growing body of literature has suggested the syrup may indeed counteract the satiation-hormone leptin. Conflicting research, supported by the American Beverage Institute, insists HFCS is no different than other sweeteners and is "safe in moderation."
The latest health concern stems from a recent Environmental Health study that found mercury in samples from two HFCS manufacturers. Chemicals mixed during production to stabilize pH may have contributed the toxic metal, the study said. The industry accuses the research of using "scant data of questionable quality."
The environmental impact of HFCS depends on how the corn is grown. Conventional farming practices use significant water resources, pesticides, and fertilizers, leading to widespread water pollution and nutrient-depleted soil. Corn production has also become a major contributor to climate change. In The Omnivore's Dilemma, author Michael Pollan estimates that between one-quarter and one-third gallons (about 1.0 to 1.25 liters) of oil are needed per bushel of corn to create the pesticides, fertilizers, and tractor gasoline, and to harvest, dry, and transport the corn. The U.S. high-fructose corn syrup industry used about 490 million bushels of corn last year, according to USDA.
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