What causes SIBO and why it’s so hard to treat

Learn the symptoms of SIBO, and how to treat the types of SIBO so that it’s gone for good..

What is Leaky Gut?

What is Leaky Gut, how to recognise it, and how can you heal it?

How to heal your gut using food, lifestyle and supplements

How to heal your gut using diet, supporting gut bacteria and digestion, and removing imbalances.

Improve your Digestion through the Digestive Dominoes Principles

Improve your digestion without changing your diet

Food sensitivities: Why you react, and how to identify your trigger foods

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.

  1. Immune system mediated – antibodies and inflammation in response to particular foods
  2. Digestive tract mediated – e.g. enzyme dysfunction such as a lactase deficiency which results in an inability to break down lactose, found in dairy
  3. Gut fermentation mediated – high FODMAP foods may lead to a worsening of symptoms. Read about the Low FODMAP diet here.
  4. 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.

Immune Tolerance

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’s role includes actively suppressing our reaction to things we don’t need to react to.

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.

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, and up to 3 months). After this period, foods are re-introduced systematically, every two or four 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. How long you avoid the trigger foods before re-introducing them, and how often you re-introduce them will depend on the severity of your symptoms.

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. Other options include the Functional Medicine elimination diet and the Autoimmune Paleo diet, but both of these diets eliminate more than these 8 foods and so are more limiting in what you can eat.

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.

Ultimately, my goal when I work with clients is to get them on the least restrictive and simplest diet possible that has the biggest impact on their health and vitality. It can be beneficial to work with a practitioner as the foods that need to be eliminated varies from person to person, as does how the duration the food re-introduction phase – it can be quite overwhelming with support!

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.

I recommend food sensitivity testing that measures the response of your immune system to foods (through a blood sample). It’s important that the test measures the IgG antibody reaction and also something call Compliment which measures actual tissue damage.  By measuring both IgG and Compliment simultaneously, we get a much clearer signal of activation of the immune system, giving more accurate results than other IgG food tests that only measure IgG. To find out about or order the food sensitivity testing I recommend, see here.

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, I take a deep dive into what you can do to reduce food sensitivities and improve your oral tolerance.

If you have any questions, I’m always happy to help so please get in touch. To know more about how you can work with me, you can find out more here.

Stephen Ward Headshot Image


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.

Food Sensitivities: Heal your gut and enjoy food again

In the first article in this series, I introduced you to some of the concepts behind food sensitivities, and how test for your current food sensitivities accurately using lab testing and/or elimination diet. I say current food sensitivities as these reactions to foods are by no means set in stone. By improving the health of your gut and the functioning of your immune system, it is possible to re-gain tolerance to foods and no longer react to them. This article is all about the nutritional strategies to achieve this.

But first, a reality check!

Let’s check in with our expectations before we get started Is regaining tolerance to all the foods you struggle with now even possible? The answer to this question my friends, is my favourite answer of ‘it depends..’

It depends on the person and it also depends on the food.

Something I tell my clients in clinic, is that I can’t say for certain how long it will take you to achieve results, until we get started. Only then can we see how you personally are responding to interventions.. Once we’ve started, we will then have a better idea of what we are working with. Remember, everyone is different!

But in general, it can be much more difficult, or not possible, to regain tolerance to the ‘top allergens’ such as gluten, and easier with foods like eggs and dairy. After working on improving your gut health, it may be that you can eat these foods without issue, or it may be that it only allows you to cheat occasionally and then have only mild symptoms. This varies from person to person!

The Functional Medicine approach

Are you eating like a bird to control your symptoms?

That’s not good for your health or your well-being!

If you have developed reactions to a wide array of foods, avoiding all these foods doesn’t do anything to resolve the underlying causes of your gut issues –  your immune system and gut bacteria will still be dysregulated; In time, this can lead to worsening of food sensitivities, auto-immunity and chemical sensitivities. Eating a more and more restricted diet isn’t the answer and is a path you don’t want to go down..

The question is not how do you avoid all the foods you react to 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.

The approach I recommend follows a number of steps, which importantly includes addressing the root causes of your loss of tolerance to foods (or to the environment as in the case of chemical sensitivities):

  1. Identify the foods that you are reacting to through an elimination diet and / or lab testing (see my first article in the series for details on how to identify these foods)
  2. Whilst working to improve the health of your gut (step 3), temporarily remove the foods from your diet that provoke the biggest reactions. This removes the ongoing source of inflammation, so that you are not ‘pouring more fuel to the fire’.
  3. Improve the reactivity of your immune system by addressing the root causes of your gut issues and fixing an overly leaky gut 
  4. Reintroduce foods one at a time, re-establishing diet containing a wide range of foods. Working towards eating a diverse range of foods is key to regaining oral tolerance.
  5. Consider re-testing or monitor symptoms

In this article, we are going to focus on step 3 which is the step where we address your root causes of your food sensitivities.

More than a leaky gut diet..

Whilst addressing an overly leaky gut is important part of reducing food sensitivities, it is not the only thing! Healing a leaky gut alone does not reduce the inflammatory response to foods. We need to support our T-Reg and our dendritic cells in order to switch off the inflammatory messaging in our gut (revisit the first article on this series for a detailed recap on this). Any ongoing sources of inflammation will need to be addressed to reduce inflammation. These potentially include

  • Bacterial overgrowth or gut dysbiosis (an imbalance of bacteria in the gut)
  • Yeast overgrowth (e.g. Candida) or SIFO
  • Pathogenic bacteria or Protozoa (parasites)
  • Small intestinal bacterial overgrowth (SIBO)
  • Auto-immunity including IBD
  • High stress or extreme exercise can also be triggers

You may want to refer to my article on the 4 steps to restore gut health to get you started with these issues. Realistically, you will need to work with a practitioner, such as myself, to identify and treat these gut issues.

Dendritic 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 overly-reactive (like Donald Trump on Twitter!).

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!

dendritic cells sample antigens from the gut lumen

A key process in the loss of oral tolerance is the development of over reactivity in dendritic cells. These long armed cells sample the contents of the gut, and determine whether the immune system should respond to the proteins they find. We can balance the function of dendritic cells by

  1. Digest your food well
  2. Increasing protective secretory IgA

Digest your food well

If foods arrives in our gut, through our mouth and stomach, and hasn’t been appropriately broken down, it is more likely to activate our dendritic cells, and the immune system.

So how do you ensure foods are appropriately digested?

Well, digestion starts when we think about food, when we see and smell something appealing. Then our hormonal and nervous system trigger the release of stomach acid (hydrochlocic acid – hcl) and digestive enzymes, and blood flow (i.e. energy) is redirect to digestion. This happens best when we eat and are relaxed, at ease, and particular when eating in a social situation. Taking a few deep breaths before eating, using 4-7-8 breathing for example, can help to move our body to a relaxed state, and directing energy towards digestion.

It’s also vital that we chew our food really well before swallowing it, usually around 20 to 30 times. A useful image to keep in mind is that food should not be recognisable as the original food by the time we have chewed it and then swallowed it. One yourself indication that you aren’t doing this well, as recognisable food in your stool! I have a short course on optimising your digestive processes that is a great way to focus in on these fundamental requirements for gut health.

If, after focusing on eating your food in a relaxed state and chewing your food well, you still have the signs of low stomach acid, supplementing with HCL and high quality, broad spectrum digestive enzymes may be needed whilst you work on improving your gut health.

Secretory IgA (SIgA)

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 immunoglobulin called secretory IgA (SIgA). The intestinal cells produce about 2-3g of SIgA every day and production tends to peak in childhood and start to declines with old age.

Many people think of mucus as being mainly in the nose and sinuses, but there is actually much more in the gut. This sticky mucus lining of the gut protects against gastro-intestinal pathogens like bacteria, viruses, fungi, toxins and food particles.

Essentially, SIgA antibodies bind themselves to the nasties, trapping them in mucus and stopping them from reaching the gut lining, and so SIgA protects our dendritic cells from over activation

These antibodies also ‘tag’ foods as acceptable by the body, suggesting why SIgA is an important part in maintaining tolerance to foods and avoiding progressive food reactions. 

Low SIgA is common in people with adrenal fatigue or who are combating an infection of some sort, particularly a Candida overgrowth. Signs of low SIgA can include cracked dry lips and skin, eczema, psoriasis, acne, chronic infections and accutane or steroid use. SIgA levels can be tested as part of a stool test such as GI Map or GI 360.

In most cases, you can think of the infection as dragging the SIgA down. The bacteria, yeast, or viral overgrowth (or all three – eek!) may need to be resolved and adrenal and thyroid issues addressed (are you constantly under emotional and psychological stress?), and detoxification pathways supported in order to see a change in SIgA.

In other more simple cases, I see a boost in SIgA from nutritional strategies that focus on pre and probiotics (including Sacchromyces Boulardi) with targeted minerals, vitamins and fatty acids. We know Vitamin A and D, Zinc and glutamine support SIgA and so it makes sense to optimise or supplement these nutrients.  

T-Reg Cells

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 launch a response of activation or tolerance. We need healthy T-Reg cells in order to distinguish between friend and foe and to not launch an overly zealous response to food. If a response is initiated, B cells within the immune system start to create antibodies to the proteins found in that food. This overactive immune response is a large part of what we experience as food sensitivities.

The good news is that we can support out T-Reg cells through nutrition and lifestyle. So, a key focus in our approach is to enhance the ability of our T-reg cells to distinguish pathogens. 

Short chain fatty acids (SCFAs) and Fibre

One of the best interventions we can make to support out T-Reg cells is to feed them more fibre. Fibre comes from plant based foods and so I recommend eating a diverse range of vegetables and berries, and to constantly switch the vegetables that you eat. This supports a diverse range of healthy gut bacteria, which in turn, metabolise plant material to make SCFAs. SCFAs help regulate T-Reg cells and reduce inflammation.

This is why I ask my clients to not eat only the same well-tolerated foods over and over again, even if test results show that they react to certain vegetables. Of course, if you have a noticeable reaction to a particular food, you probably want to remove it from your diet whilst you are working on repairing your gut. But it really is crucial, that you work on expanding your diet, eating new foods. It is only by doing this that you can regain tolerance to a wide range of foods.

If you tolerate FODMAPs, hummus and stewed apples are particularly good sources of fibre for the gut. Supplemental fibre choices (again if tolerated) include FOS, inulin, psylium, oat bran, beta-glucans, resistance starch,  and arabinogalactin. If you can’t tolerate fibre right now, due to SIBO or IBS, you can also add to your natural SCFA production with supplemental SCFAs, such as Butyrate.

Vitamin D is also critical to dendritic and T_Reg cell function, and helping prevent leaky gut. Test your levels to ensure they are optimal.

Bisphenol A (BPA), typically found in plastics, has been identified as a risk factor in the development of food allergy and food intolerances. A study in 2014, found that childhood exposure to BPA was linked to food intolerances later in life (this study was in rats, but is likely also applicable to humans). BPA is thought to play a role in auto-immunity, PCOS, suppressing tolerance to foods and the environment e.g. multiple chemical senitivities.

BPA is contained in certain plastics, fire retardants, receipts, fast foods, canned food liners and drinks, plastic drink bottles and food containers. Also, you should be aware that other plastics may also have a negative impact on our health – we only now just starting to study the impact of these other forms of plastic on our health..

Liver and spleen

Studies have shown that individuals with liver disease are four to six times more likely to develop an intolerance to gluten, and Celiac disease (the autoimmune reaction to dietary gluten). Our livers can launch an overly zealous reaction to foods in the same way that the immune system in our guts can. If you have food sensitivities and your liver enzymes are raised, you should always work towards restoring the health of your liver as well as your gut.

Leaky Gut

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!

Mechanism of Intestinal Permeability

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.

Healing an overly leak gut needs a three pronged approach, a lot of which we have already covered:

  1. Support SCFA production through pre and probiotics and fermented foods (see above)
  2. Support SIgA production (see above)
  3. Supporting the mucosal lining

Supporting the gut lining

You should always start by working on lifestyle factors, such as good sleep and managing stress. Stress and extreme exercise can lead to a leaky gut, and associated issues. 

The foods I tend to recommend for repairing the gut lining include:

  • 30ml Aloe Vera juice daily
  • 250ml Cabbage juice daily (rich in glutamine)
  • 200ml Bone broth daily
  • 500ml of strong homemade ginger tea daily 

Helpful supplements include Zinc Carnosine, L-Glutamine, Butyrate, Vitamin A and D, Colostrum, Flavonoids, and omega 3s.

Food Re-introduction

After you have done the work needed to improve your gut health (and yes, it is work – unfortunately, there isn’t a magic bullet I know of for this), any foods that were removed from the diet are re-introduced systematically. Typically, foods are re-introduced every two or four days whilst keeping a close eye on your symptoms for a reaction to the food. In that way, we can identify which foods you are still reacting to, and may need to continue to limit. How long you avoid the trigger foods before re-introducing them, and how often you re-introduce them will depend on the severity of your symptoms.


At the end of the day, the aim is to have you eating, enjoying, and tolerating a wide range of foods, particularly plant based foods that provide the fibre for our gut bacteria, but how you get these is a journey which varies from person to person. It’s easy to become overwhelmed and confused by all the information and options, and so I do recommend working with a practitioner, such as myself, through all these steps. Let me know if I can be any help. You may also be interested in the food sensitivity testing service, we offer.