Wednesday, January 1, 2014

Children of the Corn (Syrup): Is High Fructose Corn Syrup Actually Worse Than Sugar?

          In the United States, high fructose corn syrup (HFCS) is often used as a sweetener in place of cane sugar in both food and beverages.  Many consumers are concerned about the relative health effects of HFCS compared to sugar, and the increased consumption of HFCS in western nations such as the US is associated with a greater prevalence of poor health outcomes such as type II diabetes.  This concern has caused a recent campaign to replace HFCS with cane sugar in popular foods and beverages, such as the increase in popularity of HFCS-free Mexican Coke.  As with Genetically Modified Organisms, health fears over HFCS have created an irrational fervor among the general public, even among educated individuals.  I have therefore attempted to provide a (mostly) unbiased, rational summary of existing data on the subject to promote better-educated personal decisions on dietary choices.

General Background on HFCS
The chemical process for creating HFCS was first invented in 1957 and was later optimized for industrial scale production by Dr. Yoshiyuki Takasaki in the late 1960s-1970.  HFCS is now the leading sweetener (and #1 source of calories) in the US due to many factors, including tariffs on foreign sugar, subsidies to corn farmers, and industrial benefits of its liquid state.  HFCS is produced by isolating glucose-rich corn syrup and  enzymatically converting some of the glucose into fructose. Two primary types of HFCS exist: HFCS-42 (42% fructose/53% glucose) and HFCS-55 (55% fructose/42% glucose).  HFCS-55 is typically used in soft drinks and other beverages, while HFCS-42 is often used in processed foods and baked goods.  It is important to note that despite the name, HFCS in both forms maintains close to a 50% ratio of fructose, similar to that in sucrose (with glucose) and honey (with dextrose).  Fructose and glucose exist independently together in solution as HFCS while sucrose contains covalently linked glucose and fructose molecules that are only separated upon metabolism.

Research Studies
          One of the most cited studies suggesting a relationship between HFCS consumption and negative health outcomes was published by Bray et al in 2004, which stated that “the increased use of HFCS in the United States mirrors the rapid increase in obesity”.  The study also claimed that fructose is metabolized differently than glucose, leading to increased fat production in the liver and reduced insulin release.  Additionally, reduced insulin levels decrease secretion of leptin (in agreement with another paper), which induces satiety and restricts hunger.  In strong criticism of these conclusions was a sternly worded report debunking the association between obesity and HFCS.  The report argued that increased overall caloric intake is more likely the cause of increasing obesity rates, evidenced by the fact that HFCS use in the US has actually remained stable over the past 15 years despite ever increasing obesity rates, while the ratio of HFCS consumption does not actually correlate with obesity worldwide (Figure 1).

(John White, Am J Clin Nutr 2008)