In the past few decades, instances of gluten intolerance and celiac disease—a condition where your small intestine is overly sensitive to gluten, making it difficult to digest food—have soared. Celiac disease is four-times more common today than it was about 60 years ago, according to a Mayo Clinic study published in the American Journal of Gastroenterology. It begs the question: What's changed?
Turns out, while celiac disease is largely determined by genetics and your exposure to gluten, there are some heavy-hitting environmental factors that could have influenced your susceptibility in the early stages of life. More specifically, when you were born, the season you were born in, and where, geographically, you grew up for the first 15 years of life can explain if and when you were diagnosed with the disorder, according to new research published in the Archives of Disease in Childhood.
Two of the main culprits, the researchers found: Viral infections and vitamin D.
These moving parts may seem disjointed and unrelated. But they're not—not when you piece the puzzle together.
To examine the risk of developing childhood celiac disease, researchers conducted a long-term study of nearly 2 million children, all of whom were under the age of 15, born in Sweden between 1991 and 2009. In all, 6,569 of these children were diagnosed with celiac disease; and the common denominators were particularly telling... and interesting.
The risk of celiac disease was about 10 percent greater among children born in spring (March-May), summer (June-August), and autumn (September-November) than it was among those born in winter (December-February). Spring babies were more at risk for being diagnosed before the age of 2, while boys and girls born in summer or autumn were at increased risk for being diagnosed after the age of 2. There's some fine print, though. These findings differed depending on region.
The risk of celiac disease was highest among children born in the south where the sunlight in spring and summer is most intense compared to the risk for children born in the north where springs are colder and summers shorter.
Date of Birth
The year children were born was categorized into three periods: 1991-1996, when there was an epidemic of new cases; 1997-2002 which followed the epidemic; and 2003-2009 when the epidemic of celiac disease had dwindled.
- Kids born in 1991-1996 were at increased risk of being diagnosed with celiac disease if they were born during the spring.
- Children born in 1997-2002 were at increased risk if born during the summer and autumn.
- Boys and girls born in 2003-2009 were at increased risk if born in the autumn.
Despite all time periods and seasons, the risk of celiac disease was consistently higher among girls than boys.
Why Does This Make a Difference?
Researchers stress no absolute conclusions can be made about cause and effect, but they do believe infections and vitamin D both play a part.
"One hypothesis for increased [celiac disease] risk and spring/summer birth is that those infants are more likely to be weaned and introduced to gluten during autumn/winter, a time characterised by exposure to seasonal viral infections," the researchers said in a press release. Viral infections can change your intestinal bacteria and increase the permeability of the cells lining your gut. This can prompt the development of celiac disease since the immune reaction is characterized by damaging inflammation in the small intestine lining whenever you eat gluten.
In the particular example of Sweden, the researchers note yearly epidemics of any virus or flu start in the south of the country and move north, which might also explain the association.
What's more, low levels of vitamin D have also been linked to immune related diseases (like multiple sclerosis, inflammatory bowel disease, and type 1 diabetes).
"A remaining possible link to sunlight and vitamin D is that pregnant women who give birth in spring have the lowest levels of vitamin D during late gestation when important programming and development of the fetal immune system takes place," the researchers add.
What Does This Mean for You?
If you know you have celiac disease, eat foods that are naturally gluten-free, like rice, sweet potato, quinoa, buckwheat, even popcorn. Get most of your carbs from whole grains so you can save the extra calories from sugar and fat typically found in pre-made gluten-free products; you'll save money and get the natural source of vitamins B and E, calcium, iron, magnesium, zinc, potassium, fiber, protein, carbohydrates, and unsaturated fats.
If you believe you have an allergy or sensitivity to gluten, get the proper blood work done to see if your reactions are severe, treatable, and/or manageable before diagnosing yourself. It may help to take a 2-week break from gluten to see if you feel better and stop experiencing non-celiac wheat sensitivity symptoms like abdominal pain, bloating, and headaches.
If you don't have a sensitivity or intolerance, don't eat gluten-free foods—especially if you're an athlete. Research has shown gluten-free diets don't improve performance or gastrointestinal issues in people without a sensitivity.