Research Roundup: August/September 2017
The latest medical news for people with allergies and food sensitivities.
Celiac & Anorexia
Swedish researchers have confirmed an association between celiac disease and anorexia nervosa, a disorder that causes disturbance in the way people view their body weight, prompting unhealthy fear of weight gain. Anorexia typically affects girls during adolescence and young adulthood, although it can occur in men too. Genetic susceptibility may play a role. Recent genome-wide studies of anorexia indicate the condition shares genetic regions with type 1 diabetes and other autoimmune disorders. The dietary restrictions associated with the gluten-free diet might prompt disturbed eating patterns in susceptible young women, researchers suggested.
Published in the journal Pediatrics, the study of about 18,000 Swedish women diagnosed with celiac disease showed a link between celiac and anorexia both before and after celiac diagnosis. “This bidirectional association warrants attention in the initial medical assessment and follow-up of these conditions,” researchers said.
Common Virus Can Prompt Celiac
Infection with reovirus, a common but otherwise harmless virus, can trigger an immune system response to gluten that leads to celiac disease, according to a new study by researchers at the University of Chicago and the University of Pittsburgh School of Medicine. The team studied two different strains of reoviruses in mice. Both strains triggered an immune response that protected the mice against infection. However, the animals infected with one strain (TL1) also showed altered immune responses in the gut. After being infected with TL1, susceptible mice lost their oral tolerance to gluten.
The researchers also found that celiac patients have higher levels of reovirus antibodies than those who don’t have celiac.
“This study clearly shows that a virus that is not clinically symptomatic can still do bad things to the immune system and set the stage for an autoimmune disorder, and for celiac disease in particular,” said the study’s senior author Bana Jabri, MD, PhD, director of research at the University of Chicago Celiac Disease Center.
The study was published in Science.
Digestive Disease Week (DDW), the annual convention of gastroenterologists and other medical specialists, was held this year in Chicago in May. Here are some highlights of the research presented there.
Celiac Testing Methods
Many people start a gluten-free diet before they’re officially tested for celiac disease. This can later skew an accurate diagnosis, as a patient must be consuming gluten for celiac blood tests to be effective. Researchers from ImmusanT, a lab that’s working to develop the Nexvax2 vaccine for celiac disease, looked at changes in circulating levels of cytokines (proteins secreted by specific immune cells) in celiac disease volunteers on a gluten-free diet. They found that when these individuals consumed gluten, they showed elevated levels of IL-2 and IL-8 cytokines within two to four hours after ingestion. Measurement of these cytokines following a gluten challenge may help identify celiac disease in those already on a gluten-free diet, the researchers said.
Antibody blood tests, such as the tTG test, are often poor predictors of intestinal healing in those with celiac disease. About a third of celiac patients with normal antibody test results actually show tissue damage on a biopsy. Researchers at the Mayo Clinic reported that combining antibody blood tests (tTG and DGP) with tests for intestinal fatty acid binding proteins (I-FABP), a marker of mucosal damage, can be useful in assessing intestinal healing in cases where celiac disease antibody tests are only moderately elevated.
Doctors find it difficult to assess their celiac patients’ true adherence to the gluten-free diet. Argentinian researchers reported that gluten immunogenic peptides (GIP) detected in stool and urine may help physicians identify whether patients have consumed gluten within 48 to 72 hours after ingestion. These tests could be used in conjunction with other tests to assess whether a patient is inadvertently consuming gluten.
Celiac & Associated Conditions
Researchers in Dublin looked into the co-existence of other immune-mediated conditions in people with celiac disease. They found that about 30 percent of celiacs are likely to have an additional autoimmune condition. The most prevalent are thyroid disease (almost 64 percent), type 1 diabetes (about 12 percent), psoriasis (almost 9 percent), inflammatory bowel disease (6 percent) and rheumatoid arthritis (5 percent).
Researchers at the Mayo Clinic looked at gender-based differences in people with celiac disease, including the rate of associated autoimmune diseases. Their study examined stored serum from a community-based sample of people age 18 to 49 living in a Minnesota county. Concurrent autoimmune diseases were recorded in almost 20 percent of the females and almost 25 percent of the males. Depression was more than twice as common in females (almost 28 percent) than males (about 10 percent).
Persistent Villous Atrophy
Some celiac patients continue to have symptoms and intestinal villous atrophy despite being on a gluten-free diet. A multi-site study looked into the causes and found that, in a small percentage of people, villous atrophy was associated with use of proton-pump inhibitors (PPIs, a type of reflux medication), non-steroidal anti-inflammatory drugs (NSAIDs) or selective serotonin reuptake inhibitors (SSRIs, a type of antidepressant medication). Researchers concluded that the majority of symptomatic celiacs in the study did not have active disease. They recommended further study on the impact of PPIs, NSAIDs and SSRIs on mucosal healing in celiac disease.
In separate presentations at DDW, various researchers pointed to other factors that can contribute to ongoing villous atrophy, including rotavirus, HIV infection, cow’s milk protein enteropathy, certain medications (such as olmesartan, a blood pressure medicine), giardiasis (a parasitic infection), Crohn’s disease, H. pylori infection and bacterial overgrowth.
ATIs in Wheat
Many people with non-celiac gluten sensitivity may actually be reacting to other components in wheat, not to gluten. A multi-site study examined amylase trypsin inhibitors (ATIs, pest-resistant molecules that play a role in grain maturation) and found that ATIs in wheat can initiate innate immunity in celiac disease and promote symptoms in those with non-celiac wheat sensitivity.
In a separate study, some of these researchers identified and tested bacterial strains with a capacity to degrade ATIs and reduce their immune stimulatory activity. They found that certain Lactobacillus strains have the capacity to change the inflammatory effects of ATIs. Supplementation with these Lactobacillus strains may help gluten- and wheat-related disorders, they concluded. More research is needed.
Quality of Life
Various studies at DDW examined quality-of-life indicators for those with celiac disease on the gluten-free diet. Research presented by the Celiac Disease Center at Columbia University revealed that the cost of gluten-free products is 183 percent more expensive than their wheat-based counterparts. Researchers reported that availability of gluten-free products in traditional grocery stores has increased, while online availability has dropped.
Another study from Columbia University showed that almost half (46 percent) of patients with biopsy-diagnosed celiac disease have a positive depression screen. Researchers found a moderate correlation between more severe celiac disease symptoms and depression. They recommended that physicians consider depression screening for their patients with persistent celiac symptoms.
Researchers from Columbia University also found that celiac teens and adults with the highest adherence to the gluten-free diet had significantly lower quality-of-life scores than those with the lowest adherence. Roughly a third of individuals with celiac disease had dysphoria (unhappiness, dissatisfaction) stemming from worry about cross-contamination (adults 28 percent, teens 37 percent), dislike of being so vigilant and asking constant questions about their food (adults 28 percent, teens 27 percent), distrust of restaurant menus leading to extensive planning (adults 36 percent, teens 30 percent), and constant educating of uninformed or dismissive waiters (adults 26 percent, teens 20 percent). Researchers concluded that hypervigilance can have an adverse effect on quality of life.
“Research is needed to determine the best level of dietary adherence that can both avoid intestinal damage and long-term complications, yet maximize quality of life and energy levels,” they wrote.