The science behind the headlines

MULTIMEDIA coverage of the results of two studies presented at an American Heart Association meeting in Chicago this September was widespread because they linked the sweetener, High Fructose Corn Syrup (HFCS), to hypertension. These reports while certainly sounding 搇ike something we should be concerned about" require a second look 揳t the science and you can decide how concerned you should be" the group Asian Food Information Centre (AFIC) has commented. AFIC cites one such a reports from the Straits Times (Singapore), September 24 edition, where the article starts with the observation: 揂 diet high in a form of sugar found in sweetened soft drinks and junk food raises blood pressure among men厰 and goes on to say, “The findings provide the latest evidence of ties between sugarrich diets and health problems that have prompted some experts to call for a tax on sugary soft drinks." Traditional table sugar consumers are all familiar with is pure sucrose, which is a chemical combination of two smaller sugars, glucose and fructose. HFCS, a sweetener commonly added to beverages and foods in the USA in place of sucrose, is made up of about the same amounts of glucose and fructose in a mixture that is not chemically combined. “There have been two recent reviews on HFCS and obesity. The first of these was released in April 2007 (“High Fructose Corn Syrup - Everything you wanted to know and were afraid to ask" Experimental Biology Annual Conference). A second review undertaken by the University of Maryland Center for Food, Nutrition and Agriculture Policy (CFNAP) was published in August 2007. The conclusion reached by both of the reviews is that HFCS and sucrose are chemically similar and that they are metabolized by the body in a similar manner," AFIC said. The reviews looked at the increase in HFCS use in the US food supply. As it was used to replace sucrose, the intake of sucrose fell at the same time. While the combined intake of sucrose and HFCS increased, so too did available energy from fats, oils and grain products. The overall contribution of calorie-contributing sweeteners (sucrose, fructose, honey etc) to total calorie intake in the US has not changed significantly over the last few decades. What has happened is that the total number of calories consumed in the USA has risen while the levels of physical activity have declined. This imbalance in energy intake versus energy expenditure is what is thought to have caused the obesity epidemic. And the excess calories have come from multiple sources - not just HFCS. The reason these reviews were important is because of the confusion caused by studies that look at the effects of people eating fructose alone, rather than as a part of the usual mixture with glucose. This fact, plus the fact that the amounts eaten were much more than most people would consume called the conclusions of those studies into question. Pure fructose and HFCS are not the same A lot of the misunderstanding in this area appears to stem from the confusion between studies using pure fructose and those using HFCS. Fructose is found naturally in fruits, honey, some vegetables, sugar cane and beets.

The confusion is caused by studies that look at the effects of people eating fructose alone, rather than as a part of the usual mixture with glucose

Fructose appears to affect appetite and fullness in a different way to other sugars and it was hypothesized that this effect may increase the risk of obesity. Studies using very high doses of pure fructose (not HFCS) show that fructose appears to lower the levels of the hormones insulin and leptin, (both of which are associateNike Odyssey React