By Aga Lemieszewska
According to a survey conducted by Allergy UK in 2009, 45% of adults in the UK suspect they might be sensitive to some of the foods they eat. As practitioners, that’s a percentage that captures our attention!
Hidden food sensitivities may play a role in the development and progression of numerous chronic conditions, from gut related disorders, through to autoimmunity, and neurological disease. Sadly, chronic disease is on the rise, and we need all the tools we can get to stop this alarming trend. This is where IgG testing and IgG guided elimination diets can be a very useful addition to your clinical toolbox.
Defining Food (Hyper)Sensitivity
Before we have a closer look at the role of food sensitivities in chronic disease, it’s important to understand what food sensitivity is. Although the terms food allergy, food (hyper)sensitivity and intolerance are often used interchangeably, they mean different things.
Food allergy is a reaction mediated by immunoglobulin E (IgE), which manifests with mild to severe symptoms (anaphylaxis) that develop minutes to hours after consuming the offending food. Because the reaction tends to be immediate, most people with allergies know and avoid their trigger foods.
Histamine is the main chemical mediator of allergic reactions, an itchy or swollen lips/tongue/throat, stuffy nose, skin reactions (rashes), stomach pain, and diarrhoea are some of the typical symptoms. Food allergy is a lifelong condition and even trace amounts of the allergen can trigger a reaction.
Food (hyper)sensitivity is a reaction mediated by immunoglobulin G (IgG), which develops more slowly and manifests with signs and symptoms within 8–72 h after ingestion of the offending food. Food sensitivities can be hard to identify because the symptoms develop with a delay and often lack the classic ‘allergic’ characteristics (such as itchiness or swelling). Unlike in an allergy, small amounts of trigger foods can be tolerated, and it is possible to reintroduce larger quantities once the immune system has been rebalanced and the gut lining healed.
Not all reactions to food are mediated by immunoglobulins. Food intolerances can result from genetically determined enzyme deficiencies. For instance, lactose intolerance is caused by the absence/decreased activity of the enzymes lactase, while histamine intolerance is linked to decreased diamine oxidase (DAO).
Food Sensitivities, Leaky Gut, Inflammation, and Chronic Disease
Etiological studies suggest that diseases such as migraine, asthma, dermatitis and irritable bowel syndrome, as well as other chronic conditions, may be related to adverse food reactions (food sensitivities). These food sensitivities, as per the definition above, are characterized by increased levels of food-specific IgGs in serum.
The basic theory behind the generation of increased levels of IgG antibodies to foods is intestinal hyper-permeability (leaky gut). The immune system in the gut is meant to remain unresponsive to the foods that we eat (immune tolerance), while mounting an appropriate response to the pathogens introduced with the food.
In order for this to happen, the intestinal epithelium and the intestinal mucosal lining need to stay intact. Any breach of the epithelial and mucosal barriers can lead to a decreased nutrient absorption and an increased exposure to environmental toxins and, what’s crucial here, partially digested food molecules. When these incompletely digested food molecules leak into the bloodstream, an immune reaction is triggered, and IgG antibodies are produced. The IgG’s attach to the food molecules in the bloodstream and form immune complexes. These large immune complexes trigger the complement pathways leading to inflammation.
In short, increased intestinal hyper-permeability leading to IgG generation activates the inflammatory pathways leading to low grade chronic systemic inflammation.
The role of on-going inflammation in chronic disease has become indisputable (Furman, 2019) and, needless to say, addressing inflammatory drivers, including hidden food sensitivities, is foundational to the management of chronic disease in clinical practice.
What’s the Evidence?
In 2007 5,286 individuals reporting a wide range of chronic medical conditions were recruited into a study on the efficacy of Elimination Diets based on food‐specific IgG test results (Hardman, 2007). The study found that:
- 75.8 per cent of people who followed the diet rigorously experienced an improvement in their condition.
- Those who reported more than one condition seemed to benefit the most.
- The beneficial effects were noticeable within 3 weeks.
- Symptom relief varied by body system – digestive symptoms like irritable bowel syndrome and psychological symptoms like anxiety and depression showed the most improvement.
- 92.3 per cent of those who reported a significant symptom relief noticed a return of symptoms on reintroduction of the offending foods.
Commenting on the study, Dr Nigel Abraham, the Scientific Director at CNSLab, points out that a longer period of elimination (3 to 6 months) is necessary in order to be able to successfully reintroduce a trigger food. High levels of IgG antibodies can serve as a marker of increased intestinal permeability. This means that for best results, the elimination period should incorporate a gut healing protocol to restore the integrity of the gut lining.
As for research on specific conditions, IgG guided elimination diets appear to benefit those with irritable bowel syndrome, inflammatory bowel disease, migraine, arthritis, obesity, and neurological conditions, including depression, schizophrenia, and autism. Despite being very different from one another, all of these conditions seem to share a common thread – low grade systemic inflammation, leaky gut and the presence of food-specific IgG immune complexes.
Elimination-reintroduction diets are frequently used by nutritional therapists to ‘unmask’ hidden food sensitivities. More personalised diets, based on IgG test results, could be an easier and perhaps a more effective intervention.
When it comes to testing, it’s key to understand that here are 4 types of IgG4 antibodies. IgG4 is a very unique, peculiar entity, not linked to food sensitivities. Its function is to block IgEs, found in true allergies, to help prevent severe reactions. In simple terms, IgG4 reflects tolerance. This means that food sensitivity tests ultimately look for IgG1 to IgG3, not IgG4. Currently, all commercially available tests measure all IgGs, including IgG4. Does that influence the total result? Not really, as the IgG4 component under normal circumstances represents only around 5% of the total count.
To learn more, visit the ANP Education Hub in the members’ area and watch the webinar on food sensitivities with Dr Nigel Abraham and Caroline Peyton.
For more resources, visit the Cambridge Nutritional Sciences website – https://www.cnslab.co.uk
CNSLabs will be exhibiting at the 2022 ANP Summit offering generous discounts on their services.
Atkinson, W. et al. (2004), Food elimination based on IgG antibodies in irritable bowel syndrome: a randomised controlled trial. Gut, 53(10):1459-64.
Cambridge Nutritional Sciences (2022), Allergy vs. Intolerance – https://www.cnslab.co.uk/blogs/food-intolerance-1
Drisko, J. et al. (2006), Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics. The Journal of the American College of Nutrition 25(6):514-22.
Furman, D. et al. (2019), Chronic inflammation in the etiology of disease across the life span. Nature Medicine, 25(12):1822-1832.
Gaby, A.R. (1998), The role of hidden food allergy/intolerance in chronic disease. Alternative Medicine Review, 3(2):90-100.
Hardman, G. & Hart, G. (2007), Dietary advice based on food‐specific IgG results. Nutrition & Food Science, 37(1):16-23.
Ostrowska, L. et al. (2021), IGg food antibody guided elimination-rotation diet was more efective than FODMAP diet and control diet in the treatment of women with mixed IBS-Results from an open label study. Journal of Clinical Medicine, 10(19):4317.