Food allergies are on the rise. In the United States, it is now estimated that more than 10 percent of the adult population is allergic to peanuts, shellfish, dairy products, or some other food. In the UK, over the past three decades, hospital admissions for food allergies have increased fivefold. Fortunately, we are building the arsenal to reverse this trend so that one day such potentially fatal reactions will become a thing of the past.
Immunoglobulins E or IgE
The most common types of food allergies are triggered by antibodies that we make called immunoglobulins E or IgE. These antibodies were discovered in the mid-1960s and started an era of allergy research that is still going strong today. The initial findings have given rise to thousands of studies that paint a complex picture of how allergies work, suggesting ways to prevent and treat them.
When a person has a food allergy, IgE is involved in triggering a response when the immune system comes in contact with that food. Essentially, the body sees this part of your meal as an enemy, releasing histamine and other inflammatory chemicals in an attempt to manage it. This causes symptoms ranging from itching and sneezing to wheezing and anaphylactic shock. The result can be anything from a slight inconvenience to death.
We haven’t yet figured out why the body sometimes sees harmless substances this way, but we now know a lot more about how to prevent this process from happening in the first place.
Prevention is better than cure
The old adage “prevention is better than cure” holds true for food allergies. My colleagues and I use the so-called six D’s as a guide to preventative measures in childhood: diet, dirt, dogs, dry skin, detergents, and vitamin D. Studies have shown that people have a lower risk of developing an allergy when, as young people, they eat a diverse diet and often do so, have healthy levels of vitamin D, live in a house with a dog, avoid dry skin, and are exposed to dirt, which allows them to develop a good microbiome. The use of harsh detergents has also been associated with an increase in IgE.
There is also some evidence to suggest that when children eat potentially allergenic foods early in life, it causes the immune system to accept them.
Obviously, for many people with food allergies, such early prevention is no longer an option. However, other approaches are emerging.
Most of the interventions we currently use target the immune system in an attempt to retrain its response to allergens. One technique, known as allergen immunotherapy, involves slowly increasing exposure to a problematic food. By starting with very small doses, the body seems to be able to retrain itself so that it no longer sees it as a threat. People with reactions to peanuts, eggs, milk, or even multiple foods have been successful in using this method. However, immunotherapy requires regular exposure to allergens, which can lead to side effects.
There are also anti-IgE drugs that can block the antibodies involved and raise your threshold for a particular allergen before it makes you sick. These can be especially helpful when used with allergen immunotherapy to help people become immune to bothersome ingredients.
Another option is allergy shots. These work by reshaping the body’s immune response to a particular food so that it does not end in illness. One example is a vaccine that has been used to help people with allergies to peanuts.
As we gain more evidence and experience with each of these approaches, we move closer to being able to treat all food allergies. Many of us around the world are aiming to forge a new era, in which this scourge is a thing of the past.