Did you know that 70 percent of your body’s immunity is in your digestive tract?  It’s no surprise, then, that digestive wellness has a profound impact on how your body reacts to the foods you eat, including the initiation of allergies.

What is an Allergy?
An allergic reaction occurs when an irritant, called an antigen, causes your immune system to release antibodies.  These immunoglobulins (Ig) come in several types and serve different purposes.  The two most commonly associated with digestive immunity are IgE and IgG (Bauman, 2013c).

IgE is responsible for the reaction in true allergies, the kind where you eat a food and immediately experience symptoms.  These types of food allergies are rare, affecting only 0.3-7.5 percent of children and 1-2 percent of adults in the US.  Eight of the most common foods that trigger these allergies are milk, soy, peanuts, tree nuts, wheat, eggs, fish and shellfish.

Delayed allergies, also called delayed hypersensitivity reactions, primarily involve IgG and don’t give you symptoms for hours or even days after eating an allergenic food.  These sensitivities affect an estimated 10-20 percent of people and can cause many of the same reactions associated with other allergies including stuffy or runny nose, watery eyes, sneezing, rashes and hives (Lipski, 2012).

How does eating food wind up giving you allergy symptoms?  It’s all thanks to a collection of cells called gut associated lymphoid tissue, or GALT, that monitors everything that passes through your digestive tract.  Special cells within the GALT “test” the food particles and other substances that come in and trigger appropriate reactions such as eliminating pathogenic bacteria. However, there are times when your body doesn’t properly break food down.  The resulting large molecules, usually proteins, aren’t recognized by the GALT and often provoke immune reactions (Bauman, 2013c; Lipski 2012).

Dysbiosis & Leaky Gut Syndrome
More than 100 trillion beneficial (“good”) bacteria in your large intestine aid the GALT in supporting digestive immunity (Bauman, 2012; Bauman 2013a) by preventing the growth and spread of pathogenic (“bad”) bacteria.  Any imbalance of good-to-bad bacteria is known as dysbiosis and can be caused by a number of factors including poor diet (Bauman, 2013a).

Digestive inflammation from too many “bad” bacteria or any other source can lead to a condition called leaky gut syndrome (Bauman, 2013b) in which the normally tight barrier between cells in your small intestine becomes damaged, allowing large molecules of partially digested food to pass through.  The immune system attacks these molecules as if they were invaders, producing symptoms elsewhere in the body  (Lipski, 2012).

Identifying Allergens & Supporting Digestive Health
Although there are comprehensive allergy tests available, an elimination diet followed by a provocative food challenge is still considered the best way to determine reactivity.  This process involves removing suspected allergenic foods for a period of two to four weeks before carefully reintroducing them one at a time to see how the body responds. (Bauman, 2012).

Once suspected foods have been identified, a program known as 4R can help heal digestive damage.  The 4R protocol involves (Bauman, 2013a):

  • Removing reactive foods
  • Replacing supportive nutrients
  • Reinoculating with beneficial bacteria through supplements and fermented foods as well as supporting their growth with prebiotics and probiotics
  • Repairing the system with a diet low in processed foods and high in fruits, vegetables, whole grains, nuts, seeds and legumes

Maintaining the health of your digestive tract can go a long way toward clearing up irritating allergy symptoms.  When you eat well and digest well, you give your body the tools it needs to respond appropriately to all forms of potential invaders.

Bauman, E., Friedlander, J. (2013). NC102 Digestive physiology. Foundations of Nutrition. Penngrove, CA: Bauman College

Bauman, E., Friedlander, J. (2013). NC204 Gastrointestinal health. Therapeutic Nutrition Part I. Penngrove, CA: Bauman College

Bauman, E., Friedlander, J. (2013). NC207 Nutritional assessment. Therapeutic Nutrition Part II. Penngrove, CA: Bauman College

Bauman, E. NC102.2 Small intestine & large intestine [PowerPoint slides]. Retrieved from Bauman College:

Lipski, E. (2012). Digestive Wellness (4th ed.). McGraw-Hill

Writer Theresa “Sam” Houghton is a freelance writer and foodie who believes in the power of a whole-foods, plant-based, oil-free diet for lifelong health.  She holds a Certificate in Plant-Based Nutrition from eCornell and the T. Colin Campbell Foundation and is currently enrolled in the Nutrition Consultant Distance Learning program through Bauman College.  Sam blogs about food, recipes and health over at QuantumVegan.com.