DEAR DR. BLONZ: When my friends, also parents, discuss foods, the topic of simple carbs such as high-fructose corn syrup always seems to evoke universal scorn. I recall your concerns are more moderate but was hoping for some perspectives that I can share. -- F.P., Charlotte, North Carolina
DEAR F.P.: There are definite concerns related to excess consumption, but this tends to apply to fats, protein, vitamins and minerals, as well as the simple carbohydrates. The issue is when there’s an “excess.” The studies that examine these issues look at large populations, breaking them into levels of consumption from low to high. If the data show the group eating the most (of whatever is being studied) experiences significantly more of the health problem than the group eating the least, that component tends to be branded -- at least in the media and popular culture -- as causing the problem. It must be realized that this often is in population studies not designed to tell you what’s causing what (for more on this see b.link/studies77). Let’s now discuss high-fructose corn syrup (HFCS).
Fructose is a simple carbohydrate that’s about 1.4 times as sweet as glucose. Table sugar, also called sucrose, is a 1:1 mixture of glucose and fructose bound together. Honey has the same 1:1 ratio, but there, the glucose and fructose are separate. Honey tastes sweeter than sucrose because you can get the full benefit of the separate fructose's extra sweetness.
HFCS begins as starch, which is a long chain of glucose molecules bound together. Starch doesn’t have a sweet taste because the glucose is bound together. (This also explains why a cracker or piece of bread -- also mainly glucose -- is not sweet.)
In the making of HFCS, an enzyme gets mixed with the cornstarch that can break it into its glucose pieces. At this point, you have corn syrup -- which is sweet. Another enzyme then converts a portion of the glucose into fructose. The percentage will depend on the intended use. The typical HFCS is about 55% fructose (45% glucose), which makes it pretty close to honey in terms of sweetness.
Is HFCS innately unhealthful? One study in the respected 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 found no differences between HFCS, corn syrup and sucrose. Another study in a later issue of the same journal looked at the effects of beverages sweetened with HFCS, sucrose, fructose and glucose. That study reported no differences in several physiological measures, including 24-hour blood glucose, insulin and triglyceride levels.
Comparing HFCS to sucrose, 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 grams needed and 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 sweeteners, whether sucrose, HFCS or even honey, is the level of consumption. Also, keep in mind that any food that would use a high level of HFCS -- or any added sugar -- should only be a bit player, not a star, in an otherwise healthful diet. Don’t be afraid of the stuff; just don’t overdo it. Realize that processed food that adds excessive simple sugars will never equal fresh whole foods.
Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.