Over the last year and a half, Genetic Literacy Project has done an excellent job covering how and why groups opposed to GMO crops have latched onto the phenomenon of non-celiac gluten sensitivity (NCGS) and attempted to link it to GMOs in the diet. There is no connection.
“There has been no scientific evidence put forward for a GMO/celiac disease link that is supported by the CFD Medical Advisory Board,” said Marilyn Geller, CEO of the Celiac Disease Foundation.
Geller was responding to a claim by anti-GMO activist Jeffery Smith that GMO food, particularly Bt corn, could explain the observed increase in NCGS over the last several years. Smith’s claim is well rebutted in the GLP article and its cited sources, so there’s no need to rehash that here, but during 2014 there were more developments related to NCGS. As another Genetic Literacy post summed up six weeks ago, avoidance of gluten appears to be just a fad, medically necessary only in “rare cases”.
Those rare cases mean celiac disease. That’s because the more the NCGS issue is investigated, the more it seems to be not a real condition. As PBS Nova recently reported, unless you have celiac disease gluten sensitivity is probably just in your head.
While I agree with the literal meaning of the that headline, we must remember that people believe they have NCGS because they do feel symptoms in connection with eating food that contain gluten. By dismissing people’s symptoms as psychological, we don’t win those people over or help them with very real symptons. Although only about one percent of people have celiac disease, approximately 18 percent of people seek or buy gluten free food products. It’s an extreme statistic, but it’s very likely many of the people who eat gluten free, or feel better eating that way, they do have some non celiac condition with gastrointestinal symptoms. As of several months ago, the science suggests that what they have is not NCGS, however.
Studies over the last two years have revealed that many “cases” of NCGS are self-diagnosed, and that often proper testing was not conduced to determine whether the individual suffered from celiac disease. Diagnosing celiac disease requires a biopsy of the small intestine, and the study also suggests a common situation associated with failure to have such a biopsy: the individual was diagnosed by an alternative health care provider, not an M.D.
What’s really going on here is a growing awareness that grainy foods eaten in high quantities cause gastrointestinal symptoms, particularly gas, bloating and diarrhea. In medicine, this is called irritable bowel syndrome (IBS). Unlike celiac disease, which involves reaction by immune cells called T-lymphocytes that see gluten as an invading substance, leading to inflammation in the intestinal wall, IBS is not an immune condition.
It’s not a sensitivity, because the word sensitivity also implies the immune system. Instead, it’s intolerance. Specifically, over the past three years or so many patients with IBS symptoms diagnosed as NCGS have an intolerance to fermentable, oligo-, di-, and mono-saccharides and polyols (FODMAPs). These are different classes of carbohydrate entities and people vary in their ability to digest them. FODMAPs are in grainy and beany foods, and have always been there.
Their presence has not increased in recent history, but people have been eating more complex carbohydrates while also becoming more aware of their symptoms. Unlike celiac disease, which (if the individual continues eating gluten) can strip off the intestinal lining, causing not only malnutrition but putting the person at risk for cancer and other serious medical conditions, FODMAP intolerance is not dangerous. It’s just uncomfortable.
Depending on which component of the FODMAP bothers the individual, it can be controlled by taking supplemental digestive enzymes. For instance, one type of FODMAP (a type of “D” or disaccharide) is the sugar lactose. Taking the enzyme lactase can take care of this problem for such individuals. In another case, people with the condition may simply have to limit, not eliminate entirely, their consumption of grainy foods. As with any medical condition, the situation can be complex, and so the discussion should be appropriately nuanced.
David Warmflash is an astrobiologist, physician, and science writer. Follow @CosmicEvolution to read what he is saying on Twitter.