WEDNESDAY, May 18, 2005 (HealthDay News) -- New parents with a family history of either celiac disease or type 1 diabetes should be very careful about when they introduce wheat into their baby's diet, a new study suggests.
Researchers found that if wheat was introduced before 3 months of age or after 7 months, the risk of developing celiac disease was increased compared to babies who had their first taste of wheat when they were between 4 and 6 months old.
"Children fed wheat, barley or rye cereals in the first three months had a fivefold increased risk [for developing celiac disease] compared to children who didn't have those cereals until they were 4 to 6 months old," said study co-author Jill Norris, head of the section of epidemiology and community health at the University of Colorado at Denver and Health Sciences Center.
"Children who had cereals after 6 months had a small increase -- about a twofold increased risk," Norris said.
Norris and her colleagues published their findings in the May 18 issue of the Journal of the American Medical Association.
Celiac disease is an autoimmune disorder that causes the body to perceive gluten, a protein substance found in wheat, rye and barley, as harmful. As a result, the small intestine becomes damaged from the immune system's ongoing assault on gluten. Eventually, the small intestine becomes so damaged it can no longer process nutrients from other foods, and serious nutritional deficits can occur.
The disease is inherited and researchers have identified several genes associated with celiac disease autoimmunity. Not everyone with the gene defects, however, develops celiac disease.
All of the children in the study had known genetic defects that put them at greater risk of developing the disease, and Norris was quick to point out that because all of the children in her study were at increased risk to begin with, these findings do not apply to the general population of newborns.
Another important issue this study wasn't able to address is whether the early -- or late -- introduction of gluten into the diet contributed to the development of celiac disease, or simply accelerated the appearance of the illness, Norris said.
Between 1994 and 2004, Norris and her colleagues identified 1,560 newborns from the Denver area at increased risk of celiac disease, either because they carried a genetic mutation associated with celiac disease or had a first-degree relative with type 1 diabetes. The genetic defects associated with celiac disease are the same as those for type 1 diabetes, so a family history of type 1 diabetes is also a risk factor for celiac disease, Norris explained.
The investigators tracked health outcomes in each of the babies for an average of five years, interviewing parents, checking each child's blood for signs of celiac disease, and monitoring the youngsters' diets.
Fifty-one children developed celiac disease during the study, the researchers report. Children fed products containing gluten before they were 3 months old faced more than a fivefold increase in risk for the illness, while children first fed gluten products during their seventh month or later were at a slightly less than twofold increased risk of the disease, compared to babies fed gluten between 4 and 6 months.
Norris said the researchers weren't able to learn exactly why early and late wheat introduction was associated with the development of celiac disease, but she suspects that young babies' digestive systems are too immature to process gluten, a complex protein. This may cause some gluten to cross into the bloodstream, where the immune system would start to attack it.
And, in the case of those introduced to wheat later, Norris said they may simply be getting exposed to more gluten at once because older babies take in much larger amounts of food per meal than newborns.
While calling the trial a "welcome study, and the first to suggest that timing [of first wheat ingestion] may be a risk factor," Dr. Richard Farrell, an assistant professor of medicine at Harvard Medical School, said these findings must also be interpreted with caution.
"Only three infants actually exposed to gluten before four months developed celiac disease," noted Farrell, who wrote an accompanying editorial in the same issue of the journal. He said a much larger study needs to be done to corroborate the findings.
"As the editorial author said, this study leaves 'too many questions' unanswered," added Angela Kurtz, a pediatric nutritionist from New York University Medical Center.
Kurtz said previous research has shown a protective effect from breast milk, and she pointed out that this study did not address the potential effects breast-feeding might have on the development of celiac disease.
She recommends breast-feeding children exclusively until they reach 6 months of age. Then, when babies start eating solid food, Kurtz recommends starting with rice cereals, or fruits or vegetables.
"Hold off on wheat, rye and barley, and when you do introduce them, only give small amounts once a day," she said.
Both Norris and Farrell said the results of this study are far too preliminary to recommend any changes to the current feeding guidelines, which suggest beginning solid foods at 4 to 6 months of age.
To learn more about celiac disease, visit the Celiac Disease Foundation.