Within the last year, at least three studies were conducted with the goal of determining the relationship between the amount of gluten ingested and the risk of developing celiac disease. An important review of these studies, conducted by Jonas Ludvigsson and CDF Research Committee Member Benjamin Lebwohl, concluded that new clinical trials must be conducted on gluten intake and its effect on development of celiac disease before a recommendation for a new dietary strategy can be made. This is due to limitations of the studies that require more rigorous testing in order to make broadly applicable recommendations on the timing of the introduction and the amount of gluten in the diet.
In the latest study published in JAMA, researchers screened 424,788 newborn infants for HLA (a genetic predisposition to the development of celiac disease). Of these, 6,757 participated, representing 1.55% of the study population. The results of this study indicated each additional gram of gluten consumption per day was associated with a 50% increased risk of celiac disease in genetically predisposed children at age 3. However, because the results were based on such a small subset of the larger sample, the results may not be representative of the broader population.
The second study, published in the American Journal of Gastroenterology, examined data collected from 1,875 at-risk children between 1993 and 2017. Of these, 161 (8.6%) developed celiac disease autoimmunity (positive blood antibodies), and 85 (4.5%) developed celiac disease (biopsy-verified or persistently high blood antibodies). The researchers found the risk of celiac disease autoimmunity increased by 5% for each gram of gluten consumed between the ages of 1 and 2. The risk of later developing celiac disease/celiac disease autoimmunity was found to be strongest for an increased gluten intake at 1 year of age. However, these results were also based on a small subset (3.3%) of the larger sample, focusing only on genetically at-risk children. Because of this, these results should not be generalized to recommendations for children irrespective of genetic risk.
Lastly, the American Journal of Gastroenterology recently published a study examining the MoBa-cohort. Unlike the previous two studies, this study was population based and did not consider genetic risk (HLA). Of some 113,000 children initially enrolled, 67,608 were included in the study, 738 (1.1%) of whom were diagnosed with celiac disease. The researchers found that risk of celiac disease increased by 3% with each gram of extra gluten intake per day, with children who were introduced to gluten at 6 months of age or older having a significantly higher risk of celiac disease than those introduced at 4-6 months.
While the results of these three studies suggest that one extra slice of bread (about 2 grams of gluten) per day seems to be linked to a 20-50% increase in celiac disease, the limitations of these studies make it difficult to issue any recommendations as to when at-risk children should consume less gluten. Therefore, the authors of this review urge caution and agree with the authors of the first study that “A randomized clinical trial of different amounts of gluten during early childhood in genetically at-risk individuals would be warranted to confirm our findings.”
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