Page 48 - Spring2009

increase in obesity and HFCS consumption in insulin and leptin concentrations and increased triglyceride levels in
the U.S., and a number of columnists publicized women. (Although published in a major medical journal, this study does
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his theory that, calorie for calorie, HFCS is more not appear in a Medline search.)
likely to cause weight gain than sugar. According to Bray: “Because insulin and leptin act as key afferent
The Bray paper provides an explanation for signals in the regulation of food intake and body weight, this suggests that
the mechanism whereby fructose would be more dietary fructose may contribute to increased energy intake and weight
fattening. Sugar is a disaccharide that breaks gain.” 6
down into two monosaccharides—glucose and There is another difference between fructose and glucose metabolism.
fructose—in the intestinal tract. After absorp- Glucose enters the cells through the action of insulin; fructose enters the
tion, fructose must pass through the liver. Small cells through the action of something called a Glut-5 transporter, which
amounts of fructose added to glucose in the does not depend on insulin. This transporter is absent from pancreatic
diet increase the production of glycogen (stored B-cells and the brain, which indicates limited entry of fructose into these
sugar) and reduce the release of glucose into the tissues. Glucose provides “satiety” signals to the brain that fructose cannot
bloodstream, an outcome that is theoretically provide because it is not transported into the brain.
helpful to those suffering from type 2 diabetes. Once inside the cells, fructose facilitates the formation of triglycerides
However, large amounts of fructose in the diet more efficiently than does glucose. Bray references a study by Bantle and
rapidly turn into fatty acids—a process called others in which a diet containing 17 percent fructose (very typical of today’s
“de novo lipogenesis”—which are then stored as consumer), caused a highly significant increase of 32 percent triglyceride
fat or released into the bloodstream as triglycer- levels in the blood in male subjects, although not in female subjects. 7
ides. Bray also discusses the fact that sweetened beverages in general, as
Small amounts of L-fructose—the type of compared to sweeteners added to solid foods, have a greater tendency to
fructose that human beings have traditionally cause weight gain, citing a randomized, double-blind European study by
consumed in fruit—can actually be beneficial to Rabin and others, which found that drinking calorically sweetened bev-
diabetics because L-fructose does not stimulate erages resulted in greater weight gain over the ten-week study than did
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insulin secretion. However, research indicates drinking diet drinks. Since the beverages in this study were sweetened
that insulin concentrations in the central nervous with sucrose, Bray called for a second randomized controlled study to
system have a direct inhibitory effect on food compare sucrose- and HFCS-sweetened beverages.
intake—when insulin secretions increase, food
consumption declines. Furthermore, insulin INDUSTRY RESPONSE
increases release of leptin, a hormone that also But instead of support for such a study, the industry has responded
inhibits food intake. Individuals who are ge- with a wallop of damage control in the form of a report by the Center for
netically unable to produce leptin are massively Food, Nutrition and Agriculture Policy. The study was supported by a
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obese; low leptin concentrations are associated gift from British sweetener company, Tate & Lyle, Inc.
with increased hunger and gains in body fat. The magnitude of the deleterious effects of fructose varies depend-
Thus, to the extent that fructose inhibits ing on such factors as age, sex, baseline glucose, insulin, triglyceride
insulin and leptin levels, one would expect an concentrations, the presence of insulin resistance, and the amount of
increase in food intake in a diet that includes dietary fructose consumed. Some people are more sensitive to fructose
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HFCS. Bray cites a 2002 study by Teff and oth- than others. They include hypertensive, hyperinsulinemic, hypertriglyc-
ers, published in Diabetes, in which consumption eridemic, non-insulin dependent diabetic people, people with functional
of high-fructose meals reduced 24-hour plasma bowel disease and postmenopausal women. The expert panel was able
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A RETURN TO SUGAR?

A recent Wall Street Journal article (January 11, 2006) reports that many outfits are importing Coca-Cola from Mexico
into the U.S., not because Mexican Coke is cheaper (it’s actually more expensive), but because in Mexico it is made with
sugar, which many consumers prefer. By one estimate, such imports have eroded up to 25 percent of total U.S. sales.
Pepsi and Coke are testing demand with Kosher-for-Passover versions of the soft drinks containing sugar rather than HFCS.
(Corn is one of the grains forbidden in Passover.) According to one report, Pepsi and Mountain Dew will test consumer
preferences with sodas made from sugar for a limited time starting in April, and Snapple has made a permanent switch
from HFCS to sugar (webstv.com, February 23, 2009).
46 Wise Traditions SPRING 2009