Above: Peanuts (Wikimedia Commons/Aney)
Peanuts are a nutritious and healthy snack filled with proteins, vitamins, and essential oils. But for one in every two hundred Canadians, eating a peanut can have terrifying results. In fact, studies suggest that peanut allergies may be on the rise. Fortunately, scientists are working on ways to make life better for allergy sufferers and their families by preventing the immune system from overreacting to peanuts.
Fast fact: The average person digests 30 kilograms of protein every year. An allergic reaction starts when your body encounters an allergen (something you’re allergic to) through ingestion (swallowing), inhalation (breathing), or skin contact. When your immune system encounters what it thinks is a dangerous and/or foreign substance, it mounts an immune response. In some extreme cases, simply being around someone eating a peanut butter and jam sandwich can be enough to trigger a reaction in someone allergic to peanuts.
The result of an allergic reaction can be diarrhea, an itchy rash, or a swollen throat. The immune system actually thinks it’s doing the body a huge favour by trying to eliminate the foreign peanut. That’s what the immune system does: it protects the body against everything that shouldn’t be there.
So why do some people’s bodies think that peanuts are dangerous? In fact, your body considers all the foods that you eat to be foreign. After all, it produces none of the meat, vegetables, seeds, or fruit you ingest. So the better question might be: Why aren’t you allergic to all foods?
This is where your amazing intestines come in to play. Like nowhere else in your body, the immune system in the intestine can tolerate foods and even protect against unwanted over-reactions through a process called oral tolerance.
Fast fact: The lining of the small intestine is estimated to have an area of about 300 square metres.Oral tolerance depends on a very special type of immune cell called T regulatory cells. Normally, your body produces these cells to prevent autoimmunity, a situation where your immune system attacks your own cells and tissues. Similarly, the T regulatory cells in your small intestine can recognize food that you’ve eaten and stop other immune cells in the body from treating it as foreign. In other words, the creation of T regulatory cells in your small intestine can permanently keep your immune system from over-reacting to the food you eat.
So what if allergy sufferers could generate enough T regulatory cells by simply eating the foods they’re allergic to? This is exactly what a group of researchers from Cambridge University are currently studying. They fed 39 children with pre-existing peanut allergies small amounts of peanut flour. After a year, 91% of the participants could tolerate eating five peanuts a day with no allergic reaction. Basically, after gradually eating more and more peanut flour, they developed a tolerance, which is also called desensitization.
This potential treatment is not quite a cure for allergies, but it stops all of the really awful side effects of an allergic reaction. And although much more research remains to be done, it offers new hope for all the peanut allergies sufferers in the world.
Anagnostou K et al. 2014. Assessing the efficacy of oral immunotherapy for the desensitisation of peanut allergy in children (STOP II): a phase 2 randomised controlled trial. The Lancet. 383(9925):1297-1304. Ben-Shoshan M, et al. 2010. A population-based study on peanut, tree nut, fish, shellfish, and sesame allergy prevalence in Canada. Journal of Allergy and Clinical Immunology. 125(6):1327-35. Branum AM, Lukacs SL. 2009. Food Allergy Among Children in the United States. Pediatrics. 124(6):1549-1555. Weiner HL, da Cunha AP, Quintana F, Wu H. 2011. Oral tolerance. Immunological Reviews. 241(1):241-259.