Sept. 30, 2003 -- Introducing cereal into the diet too early or too late may trigger type 1 diabetes in children who are genetically predisposed to get the disease.
In two separate but similar studies, high-risk infants fed cereal products during the first three months of life were up to five times more likely than other high-risk babies to develop antibodies thought to cause type 1 diabetes. Neither study found early introduction of cow's milk to be linked to diabetes risk, however.
Researchers have long sought environmental triggers for type 1 diabetes -- events that are believed to cause the body's immune system to attack and destroy the pancreatic cells that make insulin. Early exposure to cow's milk has been implicated as a trigger in some studies, and a few have found breastfeeding to protect against the disease, but these associations have not held up in other studies.
Foods containing gluten can trigger the autoimmune disorder known as celiac disease, a gluten-sensitive digestive disorder. Celiac disease is usually seen first in infancy. The researchers say that some studies have also shown that by changing the introduction of gluten-containing foods, the risk of developing celiac disease can be changed.
This same food trigger has been associated in some studies with type 1 diabetes, and in one of the following studies the researchers looked at whether diet during the first year of life could modify the development of antibodies that lead to type 1 diabetes. Gluten-containing cereals in the second study included wheat, rye, barley, and oats.
Window of Exposure
The two new studies, reported in the Oct. 1 issue of TheJournal of the American Medical Association, included roughly 2,800 infants genetically predisposed to develop type 1 diabetes. The children were followed from birth and parents were questioned periodically about the foods the children ate.
Researchers conducting the study found that children at risk for type 1 diabetes who were exposed to cereals before the age of 3 months were at increased risk for developing the antibodies that lead to the development of type 1 diabetes, as were children introduced to cereals after the age of 7 months. The risk was roughly four times higher in high-risk infants fed cereal early and five times higher in the infants fed late. The study found no association between type 1 diabetes and cow's milk.
"This finding suggests a window of exposure to cereals outside which an increase of [type 1 diabetes] risk exists in susceptible children," the researchers wrote.
Lead researcher Jill Norris, MPH, PhD, tells WebMD that it is not clear why introducing cereals late presents a problem, but it may be that children tend to eat more of a newly introduced food when they are older because they are hungrier. Studies in children with gluten sensitivity suggest that this may play a role in the disorder as the second study suggests.
"It may be that the immune system, even in older babies, requires a gradual introduction of foods, and that introducing too much of a particular food at one time presents a problem," Norris says.
She adds that the best thing parents of at-risk children can do is follow the American Academy of Pediatrics infant feeding guidelines, which call for solid foods to be introduced between 4 and 6 months of age.
"I think many people may assume that waiting can't hurt, but this study suggests that it can, at least for high-risk populations," she says. "And it certainly doesn't appear to help."
Experts Urge Caution
The second newly reported study involved 1,610 German children at high risk for type 1 diabetes who were followed from birth to age 8. Researchers examined whether exposures to breast milk, cow's milk, solid foods, and gluten-containing foods such as cereals were associated with an increase in diabetes risk.
They found that babies fed cereal or other gluten-containing foods before the age of 3 months were five times as likely to develop the antibodies that lead to type 1 diabetes as children exposed to dietary gluten at 3 months or older. Early introduction of cow's milk was not found to increase risk.
"Certainly it does not appear from these studies that cow's milk is a risk factor for this group of children," researcher Ezio Bonifacio, PhD, tells WebMD. "But in our study all of the children had a mother or father with type 1 diabetes. It doesn't rule out the effect of cow's milk in children without a genetic predisposition."
In an editorial accompanying the studies, diabetes researcher's Mark Atkinson, PhD, and Edwin Gale, MD, urged clinicians and parents to use caution when interpreting the findings.
"It is clear that (these studies) do not present sufficient evidence to suggest that 'infant cereal causes diabetes,' and hopefully will not be misinterpreted as such by parents and the public," they wrote.
Atkinson tells WebMD that even after two decades of research, the environmental trigger or triggers for type 1 diabetes remain unidentified.
"I think these studies do put cereal at or near the top of the list of potential triggers, but we still have to look for other agents," he says. "I feel for the families of these children because every few years there is a new idea about what causes type 1 diabetes, and, so far, none of them has been proven [to be a cause]."