Is high fructose corn
syrup making us fat?
The Center for Media Research reported this week that nearly 25 percent of adults diet more than four weeks a year, making this activity more popular than hunting, fishing, skiing or golf. And yet, obesity is still on the rise. It is no wonder that researchers are looking under every rock to understand what happened to the health and weight of Americans over the last 30 years. One of the latest culprits being implicated is the sugar fructose when found in a sweetener called high-fructose corn syrup, HFCS.
Question: What is fructose and what is high-fructose corn syrup?
Answer: Fructose, also called fruit sugar, is naturally present in most fruits and in honey. Common "sugar" (sucrose) made from sugar cane and sugar beets is half fructose and half glucose bound together.
Corn does not contain fructose. But through processing, the starch from corn can be converted into glucose and then to fructose. The result is HFCS, which is about half glucose and half fructose.
Q: How does it differ from common table sugar?
A: HFCS is less expensive to produce and about 1.2 times sweeter than sugar. Both sweeteners contain glucose and fructose sugar units. Consequently, once sugar and HFCS end up in the intestine, there is little difference in the amounts of fructose and glucose available to the body.
Q: Why might HFCS be contributing to obesity?
A: Between 1975 and 1985, HFCS almost completely replaced the use of sugar in foods in this country. This is still the case. As the use of HFCS increased, so did the prevalence of obesity.
Researchers are concerned because fructose does not stimulate satiety signals to the brain as much as glucose does, so we may tend to consume more high-fructose sweets before we feel full. Also, under some conditions, the liver tends to make slightly more fat from fructose than from glucose.
Other researchers doubt these concerns and point out any problem with higher fructose intake would likely be due to the fact that Americans are eating more sugars of all types. Also, fruits and fruit juices that are naturally high in fructose are consistently associated with health benefits.
Q: So how does HFCS really rank compared to other likely causes of the obesity epidemic?
A: Compared to increased portion sizes and increased use of vegetable oils, HFCS is likely a rather small contributor.
Other factors that likely play a much greater role are decreased physical activity, cutting physical education in schools and other things that keep us off our feet, such as the TV remote, personal computers and video games.
As with so many health issues, it comes to balance. Keeping added sugar at lower levels can benefit the diet. But just switching from a high intake of HFCS to some other sugar is not going to make any individual or nation become thin.
See the Columnists
section for some past articles.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S. are
nutritionists in the Department of Human Nutrition, Food and Animal
Sciences, College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Services and prepares
the nutritional analyses marked with an asterisk in this section.