|
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
| 