Pregnant women often face the daunting task of navigating a vast number of potential concerns and recommendations — regarding their diet, physical activity, prenatal medical care, and of course caring for a child after giving birth. And now, the results of a new study add one more item to the list of potential worries: gluten intake during pregnancy and its impact on a child’s Type 1 diabetes risk.
Gluten is a protein found in the family of grains that includes wheat, barley, and rye. It must be avoided entirely by people with celiac disease, an autoimmune condition in which the body’s immune system attacks the intestine when gluten is consumed. But it has long been suspected that gluten can have negative health effects in people without celiac disease, including those who have trouble digesting grains containing the protein.
And while the link between gluten consumption and developing celiac disease has been explored in previous studies, only lately have researchers begun to explore a connection between gluten and Type 1 diabetes.
Finding a pattern
For the latest study, published in September 2018 in the journal BMJ, researchers looked at data from the Danish National Birth Cohort, a wide-ranging data-collection study that took on pregnant women as new participants between 1996 and 2002.
A total of 70,188 participants from the wider study filled out a food frequency questionnaire during their pregnancy. For the current study on gluten and diabetes, researchers excluded the data from women whose pregnancies ended in miscarriage, abortion, or stillbirth, or whose questionnaires indicated impossibly high or low food intake. This left 63,529 women and 67,565 pregnancies.
During each pregnancy, participants’ average gluten intake was found to be 13 grams per day, based on their dietary questionnaires. Among individuals, gluten intake ranged from less than 7 to more than 20 grams per day.
During a follow-up period that lasted until 2016, the study also tracked the health status of children whose mothers were part of the study. The average length of this follow-up period for each child was 15.6 years, during which 0.37 percent of the children developed Type 1 diabetes.
By looking at the gluten intake during pregnancy of women whose children either did or didn’t go on to develop diabetes, the researchers calculated that there was a proportional increase in diabetes risk for every 10 grams of gluten a woman consumed daily. In fact, the children of participants with the highest daily gluten intake (at least 20 grams) were twice as likely to develop diabetes as those of participants with the lowest daily intake (less than 7 grams).
What do the results mean regarding gluten during pregnancy?
The results of this study don’t directly show that a mother’s gluten intake during pregnancy affects her child’s diabetes risk. There could be other factors at work. For example, it’s possible that women who consume more gluten also have different lifestyle habits in other ways, such as a different diet generally, different exercise habits, or different levels of stress — the list of potential differences is endless.
That’s why to find a causal link between gluten and diabetes, a different type of study would be needed — one that randomly assigns women a strictly controlled level of gluten to consume during their pregnancy, then looks at outcomes in their children.
Such a study would be much more difficult and expensive to perform, and it could also introduce a new problem: Women who agree to sign up for such a study might not be representative of the general population. Still, data from a study like this could help confirm or cast doubt on the current study’s findings.
And while gluten is presumed to be the dietary cause of the increased diabetes risk the study found, it’s just one component of certain grains in the diet. There are good reasons to assume that gluten is the culprit based on how it interacts with the digestive system, but it’s possible that any substance — or combination or substances — found in gluten-containing grains could be responsible for any observed outcomes unless a study involves adding different levels of pure gluten to its participants’ diets.
So while pregnant women might understandably view gluten with caution in light of the current study, it’s worth keeping the study’s limitations in mind. It’s also wise to consider that reducing or eliminating gluten could have unintended consequences, such as a lower intake of potentially important nutrients.
As always, it’s important to talk with your doctor if you’re considering making any major changes to your diet, especially during pregnancy.