Testing IgG-mediated antibodies to identify food intolerances is a subject that has been much debated in both the scientific and the nutrition communities over the years – this is an emerging field that is still being researched and, while there are studies supporting the use of food intolerance tests, there are also others suggest interpreting the results with caution, and to avoid making dietary changes based on food intolerance results alone. In this blog I will present eight groundbreaking studies and papers that have transformed our understanding of food intolerance and their impact on various disorders and diseases.
IgG-mediated food intolerances are associated with delayed reactions – symptoms such as eczema, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and migraines, occurring hours or days after consumption of a trigger food.
Lactose intolerance x eczema?
In 1986, a small study explored the presence of IgG antibodies in patients with milk intolerance, and a link was proposed between the presence of the IgG4 subclass of antibodies, and milk protein intolerance in individuals with eczema. This groundbreaking conclusion was supported in 2023, when a review of 59 IgE and IgG studies concluded that IgG antibodies to cow’s milk proteins are commonly found in both adults and children with eczema, rhinitis, reflux, skin rashes, constipation.
What Does IBS and Allergies Have In Common?
In 2003, the first study to explore the possibility of a link between the presence of IgG antibodies and irritable bowel syndrome was published stating a positive connection between IgG-based elimination diets and IBS symptoms. In 2010, The American Society for Parenteral and Enteral Nutrition published a paper reviewing 28 studies covering IgE and IgG antibodies and concluded that while IgG antibody testing for food intolerances may be controversial, elimination diets that were based on IgG test results result in significant improvement in symptoms for individuals with irritable bowel syndrome.
What’s The Difference Between Crohn’s Disease And Intolerances
In 2010, a double-blind cross-over trial found that stool frequency in individuals with Crohn’s disease increased when they ate foods to which they had IgG-mediated food intolerances, and decreased when they avoided those foods. A double-blind cross-over study uses the participants themselves as a control, to increase validity of the results.
Do IBD Sufferers Experience The Same Reactions?
In 2018, the efficancy of the medication Infliximab was explored in a study of 301 individuals with IBD who also showed positive IgG results to a selection of foods (corn, rice, tomato, egg, milk, wheat, cod, soya). It was noted that this medication was effective in suppressing the immune response in individuals with Crohn’s disease by reducing inflammation in the intestines and promoting mucosal healing, resulting in reduced IgG antibodies. The study concluded that testing IgG antibodies in individuals with IBD may support diagnosis and management of the disease.
Could This Reduce Migraines?
In 2021, Test Your Intolerance published an observational study, exploring the link between IgG-mediated food intolerances and migraine symptoms. While the study was small, it showed a positive link between IgG antibodies and migraine symptoms and suggests that the study should be expanded to incorporate a larger cohort of participants for a longer period of time, to confirm their findings.
Celebrating An Ever Growing Industry
As the discussion around IgG testing for food intolerances evolves, these studies and reviews highlight the potential benefits of elimination diets tailored to IgG-mediated food intolerances. It’s important to interpret food intolerance results as part of a broad diagnostic approach, considering additional factors such as lifestyle and environment influences. Ongoing research will continue to refine our understanding and help guide the interpretation of IgG antibody test results.
