Wheat Gluten Linked to Type 1 Diabetes
People who develop type 1 diabetes have
a genetic predisposition to the disease that is triggered by some,
as yet unknown, environmental factor.
"It's known that people have
a genetic predisposition. But there's something which triggers
it that is environmental, and it's still not clear what that is,"
says Antony Horton, scientific program manager at the Juvenile
Diabetes Research Foundation in New York City.
Quite a bit of controversy among
researchers has centered on whether this trigger might be the
protein in cow's milk or wheat gluten, the concentrated form of
the protein contained in wheat flour that's sometimes used in
Two studies appearing in the Oct.
1 issue of the Journal of the American Medical Association
seem to point the finger at the latter. But some diabetes
experts say that conclusion may be premature.
The authors of the first study
did blood tests and collected detailed diet information on 1,183
American infants considered to be at risk for type 1 diabetes.
The data revealed that infants
who were susceptible to diabetes -- because of a family history
or genetic makeup -- and who were fed cereal before they were
4 months old or after the age of 6 months, had a higher risk of
developing antibodies to the islet cells of the pancreas.
These islet cells are responsible
for producing insulin, the hormone that ushers glucose into individual
cells. The immune systems of people with type 1 diabetes -- formerly
called juvenile onset diabetes -- mistakenly attack these islet
cells so they are no longer functional. Autoantibodies to the
islet cells are often present for years before the islet cells
themselves are destroyed. This is called islet autoimmunity (IA).
Specifically, those children who
were fed cereals both with and without gluten before 4 months
of age had a four times greater risk for IA, and those who were
first fed cereal at 7 months or older had a five times increased
risk, the study found. Both of these groups were compared to children
in the 4- to 6-month age range, which is when U.S. pediatricians
generally recommend introducing solid foods, especially cereals.
The authors also found that introducing
cereals while the child was still breast-feeding reduced the risk
of IA. No association was found between IA and cow's milk.
The authors of the second study,
based in Germany, followed 1,610 newborns of parents with type
1 diabetes to see if timing of exposure to breast milk, milk formula,
solid foods or gluten-containing foods was associated with a greater
risk of developing antibodies to islet cells.
This time, early introduction of
gluten-containing foods was found to be a risk factor for IA.
Babies who ate gluten before the age of 3 months had a fivefold
higher risk for developing the autoantibodies, compared with those
who ate gluten after 3 months of age.
One weakness of both studies was
that they based their conclusions on the development of autoantibodies,
not on the development of diabetes.
"The more autoantibodies you
develop, the stronger the indication that you will likely develop
diabetes. But some people can have antibodies all their lives
and never develop diabetes," Horton says.
The study authors feel the research
results are bringing the world closer to some much-needed answers
about what causes type 1 diabetes. Others aren't so sure.
"We are closer to knowing
what is causing type 1 diabetes," says Jill Norris, lead
author of the first study and an associate professor of preventive
medicine at the University of Colorado Health Sciences Center
in Denver. "Certainly, [these studies] highlight the point
that there is something in the infant diet that is important and
whether it's strictly timing or some combination of timing and
dose, we haven't entirely sorted [it] out."
Other experts urge caution in interpreting
the study results.
The two studies, writes Mark Atkinson,
a professor of pathology at the University of Florida and author
of an accompanying editorial in the journal, "do not present
sufficient evidence to suggest that 'infant cereal causes diabetes,'
and hopefully will not be misinterpreted as such by parents and
Adds Horton: "These studies
are not wholly conclusive. There's a controversy in the literature
which has not been ironed out and this study doesn't iron it out.
This is just an interesting observation but it's still not a strong
support of the actual candidate being wheat gluten."
About 17 million people in the
United States have diabetes, according to the American Diabetes
Association. Of those 17 million, about 5 percent to 10 percent
have type 1.
In type 1 diabetes, the body's
inability to produce insulin requires people to inject insulin
daily to survive and to keep their levels of glucose -- blood
sugar -- under control. If glucose levels get too high, it increases
the risk of complications such as blindness or kidney problems.
For more on type 1 diabetes, visit
Diabetes Research Foundation or the American
Reference Source 101