High Fructose Corn Syrup Emerges as Possible Obesity Culprit
For years I’ve been saying that sugar is essentially toxic. Americans consume added sugars in unnaturally high amounts, and they’re highly unhealthy. But what about the type of sugar? For years, there’s been a debate about the potential role of fructose—and high fructose corn syrup (HFCS) in particular—in the growing obesity, diabetes and heart disease epidemics in the industrialized world. Defenders (such as the soft drink industry) claim the body doesn't differentiate among different types of sugar, so we shouldn’t worry about all the industrial HFCS being added to any and every type of packaged food and drink over the past half century.
But others have pointed out that HFCS supplies somewhat more fructose that table sugar (sucrose), and that fructose does, in fact, affect the body differently than other sugars. Now researchers at Harvard Medical School say that certain individuals may be more sensitive to fructose than others, with the result that the simple sugar causes overstimulation of a hormone directly linked to fat metabolism in the body.
The research suggests that consuming fructose may be more harmful for some people than others, because some people react so dramatically to fructose in the diet.
Table sugar consists of a molecule of glucose and a molecule of fructose. Glucose is taken up by cells for fuel in the presence of insulin. But fructose must be metabolized by the liver. The new research shows that among some people, fructose triggers a sharp, consistent increase in a hormone that plays a role in fat metabolism. Among some people, fructose caused a four-fold increase in levels of the hormone.
Alarmingly, fructose caused the sharpest increases among people who were already obese. But even some lean people were especially susceptible to the negative effects of fructose from HFCS. Ironically, the hormone, called fibroblast growth factor 21, or FGF21, is believed to prompt fat cells to burn fat for energy. This should be a good thing. But fructose appears to cause dramatic increases, prompting cells to become desensitized to its effects, much as diabetic patients’ cells become insensitive to the effects of another important hormone, insulin.
HFCS does not occur naturally; it’s a byproduct of the corn industry. Perhaps now we can put aside the debate about the dangers of this unnatural “natural” sweetener. While no added sugars are good for you, this latest research indicates that HFCS is a ticking bomb for some of us. If you haven’t stopped drinking sweetened soft drinks yet, now’s a great time to start. By the way, fructose from fresh fruit does not appear to affect the body in the way that added fructose does, perhaps because fruit also contains fiber, which slows the metabolism of fructose.
Harvard Medical School. Harvard Health Publications. Available at: http://www.health.harvard.edu/blog/is-fructose-bad-for-you-201104262425