http://www.nature.com/nsu/040510/040510-5.html
Corn syrup linked to diabetes
Epidemic reflects rise in refined sugars.
12 May 2004
HELEN PEARSON
The startling rise in diabetes is perfectly mirrored by our mounting
consumption of refined carbohydrates, a new analysis reveals. The
study adds to evidence that sugary foods should be eschewed and that
public health advice to cut back on fat may have backfired.
Levels of obesity and late onset diabetes have risen slowly over the
last century and accelerated in the last 40 years. While the problem
is most acute in developed countries, there is evidence that rates are
starting to increase in developing countries too. Most experts agree
that worsening diets and increasingly inactive lifestyles are
responsible, but the exact cause is hard to pin down.
Simin Liu of the Harvard School of Public Health, Boston, and his
co-workers collected information on consumption and food composition
for the period between 1909 and 1997. They compared this with data on
disease incidence rates from the US Centers for Disease Control and
Prevention.
The climb in diabetes goes hand in hand with the rise in total calorie
intake, the team reports in the American Journal of Clinical
Nutrition1. This fits the idea that obesity places people at risk of
diabetes.
But when Liu broke down the figures into proteins, fats and
carbohydrates, a different picture emerged. Neither fat consumption
nor protein seem to be the root cause of the problem.
Instead, the diabetes rise best matches dropping fibre consumption and
escalating consumption of corn syrup, a ubiquitous sweetener in
today’s processed foods. "It is quite striking," says nutritional
scientist Cyril Kendall of the University of Toronto, Canada.
Foods high in refined carbohydrate, the argument goes, send blood
sugar soaring, requiring the pancreas to pump out insulin. Over time,
the body’s tissues become resistant to the excess insulin and
pancreatic cells wear out, resulting in diabetes.
Liu’s analysis does not prove that corn syrup caused the increase in
diabetes, experts are careful to point out. But the finding bolsters
the idea that this and other highly refined carbohydrates such as
white flour, white rice and sugar put people at risk of obesity and
diabetes.
That refined carbs are the culprits might seem obvious, but the idea
is at the centre of much controversy. In January this year, for
example, the World Health Organization released a draft road map for
tackling obesity, which among other targets pinpoints reductions in
sugary foods. The US government attempted to undermine these
recommendations, some claim, because of pressure from the food
industry.
Studies by Liu and others now make it harder to deny that excess sugar
is bad for our health. Epidemiological studies, which track people’s
health over time, have also shown that those who eat more refined
carbohydrates are at greater risk of developing diabetes "Together
they make a compelling case," says David Ludwig, a researcher also at
the Harvard School of Public Health.
Liu’s analysis also backs the argument that, since the 60s and 70s,
advice to the public to cut back on fat has misfired. Some experts say
such advice led food manufacturers simply to replace fats with
carbohydrates, which ultimately fuelled obesity rather than combating
it.
The study shows that the amount of corn syrup people ate started
rocketing at roughly the time the low-fat health message was being
broadcast. "Never before have people eaten so much highly refined
carbohydrates and led such a sedentary lifestyle," says Ludwig.
Many nutritionists now advocate a diet that avoids refined
carbohydrates in favour of wholegrain alternatives. They also promote
the choice of healthy fats, such as vegetable oils rather than animal
fats, as well as fruits, vegetables and frequent exercise.
But this message has yet to be accepted or incorporated into many
public health guidelines, says nutritionist Kendall. On top of this,
many people are confused by conflicting health messages, such as the
Atkins diet’s recommendation to spurn all carbohydrates. "We need to
rethink our approach to diet," Kendall says.
http://www.ajcn.org/cgi/content/abstract/79/5/774?maxtoshow=&HITS=10&…