London - Eating lots of gluten in pregnancy doubles the risk of having a child with Type 1 diabetes, research suggests.
A study of 63 500 women found that the more gluten they ate during pregnancy, the higher the chance that their child would develop the condition by the age of 16.
The researchers, from Denmark, Iceland and the US, stressed that they had not proved the link and that more studies were needed before women should alter their diets.
But if confirmed, it would radically change the way medics think about Type 1 diabetes.
The autoimmune disease results in the body being unable produce its own insulin, stopping proper regulation of blood sugar.
Unlike the Type 2 form of diabetes, Type 1 has nothing to do with lifestyle and is irreversible.
Until now scientists have thought of Type 1 diabetes as an unavoidable condition that has more to do with genetics than any environmental factor.
So the idea that a mother’s behaviour may contribute to its development is controversial.
The scientists, writing in the British Medical Journal, stressed that their findings are tentative.
The team, led by the Statens Serum Institute in Copenhagen, said: "The safety of substituting gluten-containing foods for other foods and nutrients should be investigated as well as the possibility of obtaining a larger effect by adherence to a completely gluten-free diet."
Gluten is found in wheat, rye and barley and gives food a chewy texture and elasticity during the baking process. The scientists are not sure why this would trigger Type 1 diabetes, but believe gluten may provoke inflammation in the metabolic system.
They stressed that the results – which included women across Denmark – were modest.
The 10 percent of women who consumed the most gluten – about 20g a day, the equivalent of 13 slices of bread – were twice as likely to have a child with Type 1 diabetes compared with the 10 percent who ate the least, about 7g.
The absolute risks, however, remained small, with only 0.52 percent of women with the highest consumption having a child with Type 1 diabetes.