To Your Health

Q. Is high-fructose corn syrup really worse for us than other sweeteners? I heard on TV that it makes us gain weight more rapidly than even regular sugar.

A. Table sugar or sucrose is familiar to consumers as the granular sugar we dip out of the sugar bowl. It is extracted from sugar cane or sugar beets but is not directly absorbed from our intestinal tract. Enzymes in our intestines break table sugar down to glucose and fructose. High-fructose corn syrup contains the same two sugars as table sugar, glucose and fructose, but it is made from less expensive cornstarch. To make HFCS, commercially available enzymes are used to convert cornstarch to glucose, and then another enzyme is used to convert glucose to fructose. Some glucose is mixed with the fructose to yield a blend of about 55% fructose to 42% glucose (with small amounts of a few other sugars). This blend is nearly the same as table sugar, but since fructose tastes sweeter than glucose, the mix is a little sweeter than table sugar.

For food manufacturers HFCS has advantages over table sugar: It tastes sweeter, costs less, and as a liquid the syrup is easier to blend into soft drinks and other beverages.

Little wonder that use of HFCS is increasing. Until about 1970, table sugar accounted for almost all the sweetener used in America. Today, HFCS is the leader, with over 50% of the sweetener market.

However, some scientists noticed that the increase of obesity in America parallels the increased use of HFCS and began to wonder if there is a connection. The known effects of dietary fructose suggest that increased consumption might lead to changes in the insulin response that could result in weight gain. There is evidence from animal studies that combining high consumption of pure fructose with copper and chromium deficiency results in a shortened life span, but attempts to directly link HFCS consumption alone with obesity have failed. HFCS is not pure fructose, and in spite of the efforts of HFCS opponents, research done with pure fructose does not apply to HFCS.

The increased consumption of added sugars is the more noticeable cause of obesity. There is only a small difference in the amount of fructose in HFCS and table sugar, but the amount of sugar added to processed food has increased over 30% in the years since HFCS was introduced. Several recent studies show that the consumption of large amounts of soft drinks is associated with increased risk for obesity. Teenagers in particular consume two to three times as much added sugar as adults, mostly in the form of soft drinks, though it is still unproven whether the HFCS in soft drinks is the reason for increased teen obesity.

The new "Dietary Guidelines for Americans" distinguish between added sugars and the sugars occurring naturally in foods, and recommends restricting added sugars to 25% of total daily calories. The World Health Organization is stricter still, recommending restriction to 10%. For most Americans that is approximately the amount found in one soft drink.

America's obesity problem is a complex issue that involves many factors. The most likely offenders – increased calorie consumption and a lack of physical activity – are easy to overlook in the rush to pin the blame on a recent addition to our menu. Experts agree that the best way to combat obesity is by matching energy intake with energy use.