How bad is high-fructose corn syrup?

Q. You are the voice of reason. What do you think of high-fructose corn syrup? Is it worse for us than regular sugar?

R.F., Walnut Creek, Calif.

A. Human biochemistry is a tapestry of interwoven chemical reactions. The foods we eat in our diet can have different effects depending on how much we eat, the other foods consumed during the day, and the circumstances under which a particular food is consumed. Eating is not complicated, but how a particular component affects the body is not always straightforward.

I bring this up because there are definite issues related to the excess consumption of certain foods, whether they are carbohydrates, fats, protein, vitamins or minerals. The idea of balance may seem boring, but it holds considerable sway over our life and well-being.

Consider the sweeteners: Fructose is about 1.4 times as sweet as glucose. Sucrose (table sugar) is a 1:1 mixture of glucose and fructose, and the two are bound together in the sucrose molecule. Interestingly enough, honey is also a 1:1 blend, but in this case, the glucose and fructose are not bound together. Honey tastes sweeter than sucrose because you can get the full benefit of fructose's extra sweetness.

Corn syrup starts as corn "starch," which is a long chain of glucose molecules bound together. The first step in making the corn syrup is separating the individual glucose molecules, and this is done using an enzyme. It is a process similar to what goes into our digestive system when we eat starch. The next step uses a specialized enzyme that converts glucose into fructose. Not all the glucose gets converted, and the percentage of fructose in the final product depends on its intended use. The typical corn syrup you find at the store is about 55 percent fructose (45 percent glucose), which is similar to honey. It is called a "high" fructose corn syrup (HFCS) because standard corn syrup is mostly glucose.

A study in the July 2007 issue of the American Journal of Clinical Nutrition looked at whether HFCS might not satisfy like other sweeteners, which could then lead to excess consumption (and an increased risk of obesity), but it found no differences between the corn syrup and sucrose. In the same journal in May 2008, there is a look at the effects of beverages sweetened with HFCS, sucrose, fructose and glucose. The study reported no differences in a number of physiological measures, including 24-hour blood glucose, insulin and triglyceride levels.

With an HFCS you get more sweetness per unit weight. It is also less expensive than cane or beet sugar, which explains why it's found in so many processed foods. Using a sweeter sweetener means fewer calories for the equivalent level of sweetness. HFCS is simply another sweetener, and I consider it to be no worse than regular sugar. The issue with a sweetener, whether it is sucrose, HFCS or even honey, relates to the level of consumption. The foods in which high levels of this sweetener are used are not the types that should overwhelm our diets, anyway.

Don't be afraid of the stuff as having some dark effect on the body; just don't overdo it. It's that simple.

• Ed Blonz, Ph.D., is a nutrition scientist and the author of "Power Nutrition." Write him at: "On Nutrition," Ed Blonz, c/o Newspaper Enterprise Association, 200 Madison Ave., New York, NY 10016 or ed@blonz.com. Due to the volume of mail, personal replies cannot be provided.