People with celiac disease have an increased risk for certain types of cancer, research has shown. But do people with non-celiac gluten sensitivity also carry a higher risk of cancer? Here's what we know (and don't know).
Research into gluten sensitivity is in its infancy in fact, clinicians haven't yet coalesced around a definition of the condition, and there's still no accepted way to diagnose it. Therefore, few studies have looked specifically at the risk of cancer in people determined to be gluten-sensitive.
In addition, the two main studies that have been done conflict with each other: one shows an increased risk of certain types of cancer, while the other shows no overall increased risk. It's possible that the discrepancy comes from the study methods (each study used a different definition for gluten sensitivity), but it's clear that any questions about gluten sensitivity and cancer risk haven't yet been answered.
Study: Higher Cancer Deaths Overall in Gluten-Sensitive Individuals
In a large medical trial conducted in Ireland, researchers found more deaths from cancer plus more deaths from all causes in people they defined as sensitive to gluten.
The researchers looked at cancer rates in people deemed "gluten sensitive," which they defined as someone who had a positive AGA-IgA or AGA-IgG blood test (meaning their immune systems were reacting to gluten), but negative results on the EMA-IgA blood test, which is specific to the type of intestinal damage found in celiac disease. (The AGA-IgA and AGA-IgG blood tests indicate the presence of antibodies against the gluten protein, but cannot determine if there's intestinal damage.)
Cancer rates in the gluten-sensitive population were higher than normal, but that doesn't tell the whole story: men in the group had a significantly higher-than-normal risk for all cancers, while women had a lower risk overall, apparently because of a lower risk of breast cancer. It's not clear why women with gluten sensitivity may have a lower-than-average risk of breast cancer, but it may result from overall immune system dysfunction, the authors wrote.
There weren't enough people included in the study to tease out associations with other specific types of cancer, with the exception of non-Hodgkin lymphoma the risk of non-Hodgkin lymphoma seemed to be elevated in people with gluten sensitivity, and there was a significant increased risk of death from lymphoma in people with the condition, the study found.
Finally, overall deaths, and deaths specifically from cancer, were increased in people with non-celiac gluten sensitivity — but again, it's not clear why. The researchers recommended more studies to determine if the cause is gluten sensitivity itself or some other condition.
Second Study Finds No Increased Risk for Cancer
Researchers in Sweden, meanwhile, searched medical records to find how many people with celiac disease, intestinal inflammation (a condition that can precede celiac disease) and latent celiac disease (not considered to be full-blown celiac disease requiring a gluten-free diet) had gastrointestinal cancer, including cancer of the pharynx, esophagus, stomach, small intestine, colon, rectum, liver or pancreas.
The study found that the risk of gastrointestinal cancer in all three groups those with celiac disease, latent celiac disease and intestinal inflammation was increased in the first year after diagnosis in all three conditions, but not in the years afterward. The authors noted that the first-year increase in cancer rates could be due in part to the fact that the cancer was causing symptoms that ultimately led to another diagnosis.
"Although one might argue that the reduced risk of gastrointestinal cancer in celiac disease beyond the first year of follow-up is due to a gluten-free diet, this is unlikely because a similar pattern was also seen in inflammation and latent celiac disease. In Sweden, patients with inflammation and latent celiac disease have traditionally not received a gluten-free diet," the researchers wrote.
Bottom Line: We Don't Know Enough Yet to Know
So what does this tell us about the risk of cancer in people with gluten sensitivity?
Unfortunately, not much. It appears possible that non-celiac gluten sensitivity may increase your risk of cancer. However, not enough research has been done to determine whether or not this is true ... or whether following a strict gluten-free diet can reduce your risks of the condition, as it may do with celiac disease.
Anderson L.A. et al. Malignancy and mortality in a population-based cohort of patients with coeliac disease or "gluten sensitivity". World Journal of Gastroenterology. 2007 Jan 7;13(1):146-51.
Elfström P. et al. Low risk of gastrointestinal cancer among patients with celiac disease, inflammation, or latent celiac disease. Clinical Gastroenterology and Hepatology. 2012 Jan;10(1):30-6. doi: 10.1016/j.cgh.2011.06.029. Epub 2011 Jun 30.
Gao Y. et al. Increased risk for non-Hodgkin lymphoma in individuals with celiac disease and a potential familial association. Gastroenterology. 2009 Jan;136(1):91-8. doi: 10.1053/j.gastro.2008.09.031. Epub 2008 Sep 25.
Hoggan R. Considering wheat, rye, and barley proteins as aids to carcinogens. Medical Hypotheses. 1997 Sep;49(3):285-8.