Acne may not be the only problem caused by eating
large quantities of highly refined starches. Such
diets have also been blamed for causing
short-sightedness and contributing to adult onset
diabetes.
 
Plague of pimples blamed on bread
 
 
09:50 05 December 02
 
Exclusive from New Scientist Print Edition
 
Eating too much refined bread and cereal, rather than
chocolate and greasy foods, may be the culprit behind
the pimples that plague many a youngster.

That is the theory of a team led by Loren Cordain, an
evolutionary biologist at Colorado State University in
Fort Collins. Highly processed breads and cereals are
easily digested. The resulting flood of sugars makes
the body produce high levels of insulin and
insulin-like growth factor (IGF-1).

This in turn leads to an excess of male hormones.
These encourage pores in the skin to ooze large
amounts of sebum, the greasy goop that acne-promoting
bacteria love. IGF-1 also encourages skin cells called
keratinocytes to multiply, a hallmark of acne, the
team say in a paper that will appear in the December
issue of Archives of Dermatology.

An Australian team will soon test the theory by
putting 60 teenage boys with acne on a
low-carbohydrate diet for three months to see if it
makes a difference.


Anecdotal evidence


"There's lots of anecdotal evidence," says Neil Mann,
the nutrition researcher at RMIT University in
Melbourne who will oversee the study. "Dermatologists
will tell you they have put patients on
low-carbohydrate diets and seen improvements. This
will be the first controlled study."

Up to 60 per cent of 12-year-olds and 95 per cent of
18-year-olds in modern societies suffer from acne, and
for a few the zits persist into middle age. Yet acne
is almost unknown in subsistence societies such as the
Kitava islanders in Papua New Guinea and the Ache of
the Amazon.

"The only foods available to these populations are
minimally processed foods," Cordain points out. "They
don't know refined sugars or refined grains." The
Inuit people of Alaska also used to be acne-free, but
pimples arrived along with a Western diet.

Easy access


This could be because modern breads are made from more
finely ground flour, and cereals are manufactured
using high-pressure processes that disrupt the grains'
protein structures with air bubbles, in either case
giving digestive enzymes easy access to the starch.
The pancreas responds to speedy digestion by gushing
out truckloads of insulin.

Evidence suggests a link between insulin or IGF-1 and
acne. Many women with acne overproduce insulin and
IGF-1. When IGF-1 was used to treat people with a
condition called Laron syndrome, they experienced a
spike in male hormones, followed by acne. And the
insulin-blunting drug metformin has been found to curb
acne in women with polycystic ovary syndrome, a
condition in which too much insulin is secreted.

Acne may not be the only problem caused by eating
large quantities of highly refined starches. Such
diets have also been blamed for causing
short-sightedness and contributing to adult onset
diabetes.
 
 
Douglas Fox