Food can be a minefield!
Food provides the building blocks for life, can act as medicine, and is associated with celebrations and our most memorable times, sharing with family and friends.
Yet, food can also be a source of fear and confusion, ill-health, and toxicity in the body. We can spiral into a hole of poor gut health and inflammation, reacting to more and more to foods, still not knowing exactly which foods are triggering us. Some people then end up eating a severely restricted diet and become afraid of food in general.
Common digestive symptoms include bloating, wind and diarrhea. We may not have yet connected the dots between what we eat and seemingly unrelated symptoms such as migraines, joint pain, eczema, fatigue or sinus congestion, and mood disturbances.
Adverse food reactions fall into four causal categories.
- Immune system mediated – antibodies and inflammation in response to particular foods
- Digestive tract mediated – e.g. enzyme dysfunction such as a lactase deficiency which results in an inability to break down lactose, found in dairy
- Gut fermentation mediated – high FODMAP foods may lead to a worsening of symptoms. Read about the Low FODMAP diet here.
- Something else in the food e.g. salicylates, oxalates, sulfur, histamine, lectins
This article will explain how immune-system mediated over-reactivity comes about, and how to identify which foods are may be affecting you. My aim is help you understand the reasoning behind the interventions I suggest in my second article (released in the next week or so) on lessening these reactions.
A huge proportion of our immune system lives within the lining of the Gastro-Intestinal (GI) tract. The immune cells that line our GI tract have two critical jobs:
1) Defend us from potentially harmful ‘pathogens’ in our guts (e.g. bacteria or viruses that are a threat)
2) To not react to food that we eat, and the bacteria in our gut. The immune system should actively suppresses a reaction to these.
It turns out that most of the time, the role of the immune system is actually NOT to respond to things. It should only react when there actually is a real threat. This concept of an appropriate response to our food and environment is called Oral Tolerance. Oral intolerance normally develops through a baby’s contact with their parents and breastfeeding. The first 1000 days of life are therefore very important in establishing immunity in general.
If we lose oral tolerance, we can start reacting to foods that we eat, and often we also develop increased intestinal permeability (leaky gut), inflammation, and digestive discomfort. This may progress to the stage where our immune system starts targeting our own tissues and organs (auto-immunity). And so it’s important to work on improving gut health not just to reduce food sensitivities themselves, but also to prevent progression of an auto-immune process.
Leaky Gut and Loss or Oral Tolerance
Increased intestinal permeability, commonly known as leaky gut, can be a contributing factor to loss of oral tolerance, but it isn’t the only mechanism involved in food sensitivities!
With a leaky gut, larger molecules, such as undigested food particles, toxins and micro-organisms, can enter the bloodstream through gaps, called tight junctions, between the cells that make up the gut lining.
The immune system doesn’t recognise these foreign molecules, raises the alarm that an invader is present, and then makes antibodies specific to these molecules. If those macro-molecules are gluten, your body will make antibodies to gluten. If it’s dairy, your body will make antibodies to dairy. A loss of oral tolerance to that food is developing..
A leaky gut can also be associated with a general loss of tolerance to a range of foods. In which case, you may find yourself reacting to more and more foods.
Then the question is not how do you avoid those foods but how do you calm the over-reactivity of the immune system in your gut, as well as heal leaky gut. The goal here is to reduce the hyper-reactivity to a whole range of foods, rather than focus on tolerance or avoidance of individual foods. We will cover this later in this article.
Dendritic Sampling Cells
Dendritic cells are a type of immune cell that sample the environment inside the gut (the gut lumen), providing an inflammatory signal to the rest of the immune system if they find something which they deem to be a threat. It’s vital therefore that they aren’t over-reactive (like Donald Trump on Twitter!).
So dendritic cells can initiate an inflammatory response to foods in the absence of leaky gut! This is important as it means even fixing a leaky gut, doesn’t necessarily mean the inflammatory response in our gut will develop normal tolerance. It may take extra work to support the Dendritic cells and T-Reg cells in our gut, as well as the spleen and liver!
One of the ways our dendritic cells are protected from over-activation by the contents of our gut is through a natural layer of mucus that lines our gut. This mucus contains a protective antibody called secretory IgA (SIgA). SIgA also take some of the pressure off dendritic cells by surrounding bacteria, viruses, and problematic proteins.
An overgrowth of yeast, such as Candida in the intestine, aswell as other bacterial and viral overgrowths, psychological and emotional stress, and immune suppressants can all decrease the amount of protective SiGA and this has the potential to allow over-reactivity of our dendritic cells, and an inflammatory response to food.
It’s important that you chew food well, and have adequate stomach acid and digestive enzymes as partially digested food can also over-activate the dendritic cells
Regulatory T-Cells (T-Regs)
Dendritic cells surround foreign proteins and transport them to the lymphatic system. There, they present the protein to T-Reg cells. It is the T-Reg cells that determine whether the immune response should be one of activation or tolerance. If a response is initiated, B cells within the immune system start to create antibodies to that protein.
The good news is that we can support out T-Reg cells through nutrition and lifestyle. I’ll cover this and what else we can do to reduce food sensitivities in my next article in this series.
Testing for Food Sensitivities
The first step you should take when working to lessen food sensitivities is to temporarily remove trigger foods from your diet. We can then work to improve your overall gut health so that you are better able to tolerate foods without an exagerated immune response. But how do you know all the foods that you are reacting to?
One of the best ways to identify food sensitivities is an elimination diet. An elimination diet involves removing all suspect foods, that may be triggering the immune system, for a limited time (at least 3 to 4 weeks). After this period, foods are re-introduced systematically, every two or three days whilst keeping a close eye on your symptoms for a reaction to the food. In that way, we can identify which foods that you are react to.
Whereas lab testing only tests how certain parts of the immune system (such as IgG) respond to foods, an elimination diet paints the picture of how the body as a whole responds to the food. This is important as there may be other causes of a reaction other than just IgG antibody reactions.
Eight common foods that are often temporarily eliminated by someone suspecting food sensitivities are dairy products, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat and soy containing foods.
An elimination diet like this can be empowering but it is also restrictive, mentally challenging and time-consuming. An elimination diet, combined with IgG food reactivity lab-testing, provides the most complete view of food sensitivities. If a strict elimination diet is not possible for a person, then lab-testing alone is still a valuable option.
IgE – Allergic Reactions
In this article, I’m not going to go into detail around allergic IgE mediated, but I am going to focus on IgG food sensitivities. The difference between the two is IgE symptoms develop within a couple of minutes to one or two hours after eating a food and include symptoms such as hives, congestion or swelling of the throat. If you suspect a true allergic reaction to a food, please speak to your GP or contact me for further details on lab testing as I’m not going to focus on true allergies in this article. It is also possible to reduce the severity of IgE reactions, but not typically get rid of them, through nutritional support and Functional Medicine.
IgG Food Reactivity Lab-Testing
IgG antibodies tend to be associated with food sensitivities, and are produced from 3 to 72 hours after a food is eaten. At low levels, IgG antibodies are protective and their production is expected but at higher levels, they are associated with inflammation and typical IBS type symptoms. An IgG-mediated reaction to a food may not be noticed until more than 24 hours after eating a food, and remain in the body for weeks after a reaction is triggered, making identification of food sensitivities difficult without an elimination diet or lab testing.
There are many versions of IgG antibody testing to foods, and this diversity of testing can make choosing the right test confusing and overwhelming. Interpretation also benefits from professional help as the key to real improvement is not to only identify and remove trigger foods from the diet, but also support the gut and immune system so that it’s not so reactive. Our intention should always be to eat as varied and nutrient-rich diet as possible.
The food sensitivity test I recommend is by Dunwoody Labs. It is probably the most clinically relevant as it tests over 90 foods against a single blood sample for the production of IgG antibodies and also something call Compliment (Immune Complex containing C3d (IC-C3d)). By measuring both IgG and IC-C3d simultaneously, we get a much clearer signal of activation of the immune system, giving much more accurate results than other IgG food tests that only measure IgG.
It is however important to note that some people, that have a severely impaired immune system, may not be capable of launching an immune response to trigger foods. In which case, IgG food sensitivity testing would be essentially useless.
How to Reduce Food Sensitivities
In the second article in this series (which will be coming in the next few weeks), I’ll take a deep dive into what you can do to reduce food sensitivities and improve your oral tolerance.
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Stephen Ward (MSc) is trained in assessing the root cause of chronic health issues through Functional Medicine.
He uses nutrition, lifestyle changes, and nutraceuticals (targeted supplements) to help you achieve your goals and improve your health.