[Previous Months][Date Index][Thread Index][Join - Register][Login]
[Message Prev][Message Next][Thread Prev][Thread Next]
[IP] Pregnancy and Beyond ...Wheat Protein Pinpointed in Pioneering Diabetes Study
The text of an article in the 'Ottawa Citizen', February 5, 2003, p.1
and 2 followed by the Journal of Biological Chemistry reference abstract.
Ottawa researcher links diet, childhood diabetes. Wheat protein
pinpointed in pioneering study. by Tom Spears.
"For years the medical textbooks all agreed on one thing: Type 1
diabetes, the kind that strikes in childhood, is not caused by a
This didn't make life easier for Fraser Scott, an Ottawa medical
researcher looking for things in our diet that do cause the disease.
How do you ask for funding to investigate a connection that doesn't
This makes his team's discovery a little sweeter. They have just
published findings in the 'Journal of Biological Chemistry' that show a
protein in wheat appears to cause some children's immune systems to
attack the wrong target, damaging their body's own cells and causing
Dr. Scott first got the idea when he worked at Health Canada in the
early 1980s. He was experimenting with a strain of lab mice bred to
develop diabetes easily. But when he put the mice on a restricted diet
he noticed something odd.
Mouse after mouse stayed healthy, showing no signs of diabetes.
At first he suspected that someone had sold him a batch of dud mice.
But he tried again with with more mice and got the same result.
Maybe diet is important after all he concluded. Wheat seemed a possible
candidate: children with Type 1 diabetes (once called juvenile
diabetes) often have celiac disease, an inability to digest wheat. He
decided to have a closer look at wheat.
Dr. Scott, Amanda MacFarlane and Karolina Burghardt at the Ottawa Health
Research Institute and colleagues at the University of Ottawa and in
Finland have isolated one protein in wheat that appears to cause the
trouble. They scanned through one million candidate proteins from
wheat, narrowing the field first to three that caused reactions in the
immune system, and finally one that is linked to damage in the islets,
parts of the pancreas that produce insulin, which helps the cells break
down sugar. Diabetes occurs when the pancreas loses the ability to
"To put it in the simplest terms, some individuals have an abnormal
immune system," he says. A proper immune system should attack germs in
our food, but not the proteins, of which we eat untold thousands, every
But when the immune system goes off course and starts attacking the
proteins in wheat, he suspects that it keeps going on its destructive
course and starts attacking the insulin-producing cells in the pancreas
as well. Somehow he believes, wheat has mobilized these disease
fighting cells into full-scale attack mode - but against the wrong
These destructive cells in the immune system "are just sitting there
until something stimulates them," Dr. Scott says. Then they expand,
migrate to the pancreas, and cause a long period of inflammation that
ultimately kills the beta cell," the cell that makes insulin. Other
infections may also play a role, possibly making this immune attack
In his lab, one wheat protein called GlB1 caused blood from people and
rats to "light up" in an immune reaction. That appears to clinch the
link with diabetes.
If his findings hold up, this will be the first protein in food shown to
cause at least some diabetes. (The disease also has genetic causes but
isn't purely genetic: If one identical twin has it, chances are only
about 30 per cent that the other twin will have it, despite having all
the same genes.)
The team hasn't made the type of discovery that will create new drugs.
But they do see some uses for the findings.
It's possible they believe that exposing babies to the wheat protein at
an early age, when the immune system is still learning what's an enemy,
can "teach" the immune system not to react to wheat later in life.
Another possibility is that people with family histories of diabetes may
want to avoid wheat, "but that's a really grim diet," Dr. Scott said.
His co-author, Illimar Altossar, who teaches food biochemistry in the
medical school at the University of Ottawa has started making "knockout"
varieties of the wheat they used, removing just the one protein linked
to diabetes. He wants to see whether rats fed the knockout variety will
still develop diabetes.
Wheat blends thousands of proteins, he said, "to make all the magical
things we know in baking: the dough, the aroma, the mystique of bread,
the baguette in a bicycle pannier. It's a very, very complex matrix."
Looking for wheat varieties that don't have the problem protein "is the
first thing we have to do," he also added. Food scientists may also
decide to engineer or breed a wheat variety without that protein.
1: J Biol Chem 2003 Jan 3;278(1):54-63
A type 1 diabetes-related protein from wheat (Triticum aestivum). cDNA
a wheat storage globulin, Glb1, linked to islet damage.
MacFarlane AJ, Burghardt KM, Kelly J, Simell T, Simell O, Altosaar I,
Ottawa Health Research Institute, Ottawa, Ontario K1H 8L6, Canada.
The development of autoimmune type 1 diabetes involves complex
among several genes and environmental agents. Human patients with type 1
diabetes show an unusually high frequency of wheat gluten-sensitive
T-cell response to wheat proteins is increased in some patients, and high
concentrations of wheat antibodies in blood have been reported. In both
models of spontaneous type 1 diabetes, the BioBreeding (BB) rat and
diabetic mouse, at least half of the cases are diet-related. In studies
rats fed defined semipurified diets, wheat gluten was the most potent
diabetes-inducing protein source. A major limitation in understanding
or other dietary antigens affect type 1 diabetes has been the difficulty
identifying specific diabetes-related dietary proteins. To address this
we probed a wheat cDNA expression library with polyclonal IgG antibodies
diabetic BB rats. Three clones were identified, and the intensity of
binding to one of them, WP5212, was strongly associated with pancreatic
inflammation and damage. The WP5212 putative protein has high amino acid
sequence homology with a wheat storage globulin, Glb1. Serum IgG
diabetic rats and humans recognized low molecular mass (33-46 kDa) wheat
proteins. Furthermore, antibodies to Glb1 protein were found in serum
diabetic patients but not in age-, sex-, and HLA-DQ-matched controls.
raises the possibility that in some individuals, type 1 diabetes may be
by wheat proteins. Also, it provides a first candidate wheat protein
that is not
only antigenic in diabetic rats and human patients but is also closely
with the autoimmune attack in the pancreas.
PMID: 12409286 [PubMed - in process]
for HELP or to subscribe/unsubscribe, contact: