Research Roundup: April/May 2018
The latest medical news for people with allergies and food sensitivities.
Food Allergies Increase in Adults
A new study found that food allergies are on the rise in adults as well as children. The increase is seen across all ethnic groups. About half of all food-allergic adults reported they developed one or more food allergies after age 18. Shellfish is the most common food allergy in adults, affecting an estimated 3.6 percent of adults in the United States. This is a 44 percent increase in prevalence from the rate recorded in 2004. The study also found that nut allergy in adults (now about 1.8 percent) has risen 260 percent since a 2008 estimate.
The research was presented at the American College of Allergy, Asthma & Immunology’s Annual Scientific Meeting.
Editor’s Note: For more about adult-onset food allergies, go to GlutenFreeAndMore.com/adult-onset.
Unexplained Anaphylaxis Linked to Meat Allergy
Researchers at the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, found that some unexplained cases of anaphylaxis can be blamed on the alpha-gal allergy, a meat allergy caused by tick bites. In the study, six of 70 patients with unexplained frequent anaphylaxis tested positive for alpha-gal allergy. All six had a history of tick bites.
The majority of alpha-gal allergy cases are clustered in the eastern part of the United States. The unusually long gap (4 to 6 hours) between allergen ingestion and allergic symptoms can make the alpha-gal allergy challenging to diagnose.
The study was published in Allergy.
Editor’s note: For an in-depth look at the alpha-gal allergy, turn to “Ask the Doctor,” our interview with alpha-gal allergy expert Scott Commins, MD, PhD, in this issue.
Improving Oral Immunotherapy Outcomes
Researchers at Stanford University School of Medicine report that the effectiveness of oral immunotherapy in children with multiple food allergies is improved with the addition of omalizumab (trade name Xolair).
In the study, over 80 percent of the children (ages 4 to 15) with multiple food allergies who received omalizumab while undergoing oral immunotherapy could safely eat 2-gram portions of at least two foods to which they were allergic, compared to only a third of the kids who received a placebo.
Omalizumab is an injectable antibody drug approved to treat moderate-to-severe allergic asthma. It blocks the activity of IgE, an immune system molecule that is central to an allergic reaction.Oral immunotherapy is an investigational treatment where very small but increasing dosages of an allergen are eaten over time under medical supervision. Neither oral immunotherapy nor omalizumab is currently approved for the treatment of food allergy.
The findings, part of a phase 2 study funded by the National Institute of Allergy and Infectious Diseases, were published in The Lancet, Gastroenterology & Hepatology.
An Easier Way to Detect Celiac Disease
Current blood tests that screen for celiac disease are not reliable for people who are eating gluten-free. This presents a problem for those who want to undergo a celiac test but are reluctant to give up their gluten-free diet.
Now researchers at Oslo University in Norway have developed a blood test that detects gluten-reactive T cells and can determine with a high level of accuracy whether or not someone has celiac disease even when a patient is regularly eating gluten. The test is not available commercially but researchers hope their study will “initiate commercial initiatives, along with more research.”
The study was published in Gastroenterology.
Celiac Disease & C. Diff Infection
In a large population-based study, a research team that included U.S. celiac experts Benjamin Lebwohl, MD, MS, and Peter H.R. Green, MD, examined the risk of people with celiac disease contracting Clostridium difficile infection (C. diff).
C. diff is a hard-to-treat bacterial infection that can cause diarrhea and potentially life-threatening colitis. It is often associated with recent antibiotic use and/or a healthcare facility stay. Seniors who are hospitalized or who live in long-term care facilities are the most vulnerable but C. diff rates have been increasing in healthy younger people.
Researchers found the risk of contracting C. diff was higher for those with celiac disease one to five years after diagnosis and highest in the first 12 months after diagnosis.
The study was published in The American Journal of Gastroenterology.
What’s Behind Gluten Sensitivity?
Researchers remain unclear about the precise mechanisms of non-celiac gluten sensitivity. There are currently no known biomarkers for the disorder. It is diagnosed after celiac disease and other disorders have been ruled out and the patient improves on a gluten-free diet.
In addition, researchers aren’t convinced that gluten is always the culprit behind non-celiac gluten sensitivity. Foods with gluten often contain fructans, a type of fermentable oligo-, di-, monosaccarides and polyols or FODMAP.
In a recent study, a team of researchers investigated the effect of gluten and fructans separately in patients with self-reported gluten sensitivity—and found that fructans alone induced symptoms. They concluded that intolerance to fructans (and other FODMAP foods) was more likely than gluten to induce symptoms, adding that fructan intolerance is unlikely the sole cause of non-celiac gluten sensitivity.
The study was published in Gastroenterology.