Consumption of various sweeteners has risen in the United States from an estimated 113 pounds per person in 1966 to 147 pounds in 2001, according to the U.S. Department of Agriculture (USDA).
The increase has raised some concern among nutrition experts, as echoed by the World Health Organization’s (WHO) recent recommendation to limit intake of added sugars in the diet to no more than 10 percent of daily calories, a recommendation that is much more strict than those of U.S. groups.
Along with the change in the amount of sugar consumed, the type of sweeteners consumed has also changed--a transition that may be playing a role in weight gain.
In 1966, refined sugar, known as sucrose, was the most commonly used sweetener, accounting for 86 percent of all sweeteners. Currently, sweeteners made from corn are most common, accounting for 55 percent of sweeteners on the market and bringing in $4.5 billion in annual sales. The rise in corn sweeteners stems largely from the steady growth of high-fructose corn syrup, which increased from zero consumption in 1966 to 62.6 pounds per person in 2001.
Among the leading products containing high-fructose corn syrup are soft drinks and fruit beverages, although cookies, gum, jams, jellies and baked goods also contain the syrup.
High-fructose corn syrup is made from corn starch and contains similar amounts of both fructose and glucose. Sucrose, on the other hand, is a larger sugar molecule that is metabolized in the intestine into glucose and fructose.
The syrup is easier to blend into beverages and tastes sweeter than refined sugar, allowing food manufacturers to use less. Also, the price of high-fructose corn syrup dropped slightly in the 1980s, leading to huge savings for the food industry.
However, while the switch made sense economically, fructose is absorbed differently than other sugars, which may have nutritional consequences. When glucose is consumed, it increases production of insulin, which enables sugar in the blood to be transported into cells where it can be used for energy. It also increases production of leptin, a hormone that helps regulate appetite and fat storage, and suppresses production of ghrelin, a hormone made by the stomach that helps regulate food intake. Because of this reaction, it has been suggested that after eating glucose, hunger declines.
Fructose, however, doesn't stimulate insulin secretion or increase leptin production or suppress production of ghrelin. Therefore, researchers suggest that consuming a lot of fructose, similar to consuming a lot of fat, may contribute to weight gain.
Additionally, fructose is converted into the chemical backbone of trigylcerides more efficiently than glucose, and elevated levels of trigylcerides are linked to an increased risk of heart disease. One study found that fructose produced significantly higher blood levels of triglycerides in men, although not in women, leading researchers to say that diets high in fructose may be undesirable, especially for men.
Further, fructose may alter the magnesium balance in the body, leading to an acceleration of bone loss, according to a USDA study.
Researchers have also examined evidence from multiple studies and concluded that large quantities of fructose from a variety of sources, such as table sugar and high-fructose corn syrup, induce insulin resistance, impair glucose tolerance, produce high levels of insulin, boost a dangerous type of fat in the blood and cause high blood pressure in animals.
However, other scientists question whether high-fructose corn syrup acts differently in the body than table sugar and say that using one over the other wouldn’t make much difference.
Many nutrition experts say that it makes sense to follow the WHO’s sugar recommendation, although food industry groups note that there are many factors contributing to the nation’s obesity epidemic and evidence has not shown that high-fructose corn syrup is a contributing factor.
Washington Post March 11, 2003; Page HE01