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Are Food Allergies linked to IBS?

A small-scale but revealing study shows that more than 50% of IBS patients were found sensitised to one or more foods without displaying typical allergy-type symptoms (1). Whilst the general medical opinion about the association between food allergens aggravating IBS symptoms is inconclusive, this associated aspect of gut dysfunction could well uncover a potential link to persistent long-term symptoms of bloating and related pain, particularly where symptoms may not be easily identified to offending foods.

One of the problems in associating gut symptoms with a food immune-generated reactions is the time delay between food consumption and immune response and the variability of symptoms, which may or may not be associated with an immune response. This is why food-elimination diets can be problematic.

Immune-triggered food reactions generally fall into two categories: A food allergy involves an immunoglobulin IgE antibody, and food hypersensitivities display a slightly different class of antibody known as IgG.

Many people associate an allergy IgE response with the full-scale and systemic (body-wide) immediate type reactions of:

· An itchy sensation inside the mouth, throat, or ears

· A raised, itchy red rash known as urticaria or hives

· Swelling of the face, around the eyes, lips, tongue, and roof of the mouth

These symptoms are usually immediate and noticeable. However, there is a delayed response version of the IgE immune reaction, which takes longer to manifest into symptoms, from 24 hours to 72 hours after consuming the food. These are known as IgE-independent, delayed (cell-mediated) immune reactions (2) and can include the more typical allergy reactions mentioned above but can also be seen behind the following more subtle symptoms:

  • An increase in pulse rate after eating

  • Hives as an immediate or delayed reaction

  • Anxiety

  • Difficulty speaking or swallowing

  • Dizziness or feelings of light-headedness and changes in blood pressure

  • Flushing of the face

  • Food cravings

  • Sinus congestion

  • Stomach cramps, nausea, vomiting or diarrhoea

  • Fatigue following specific foods

  • Bladder incontinence

  • Puffiness anywhere in the body

  • Repetitive coughing

IgG-mediated food hypersensitivities can also present symptoms as delayed reactions and can differ in their nature:

  • Allergic Rhinitis, sinus problems

  • Anxiety, depression, brain fog,

  • Asthma can be seen with both IgE and IgG antibodies

  • Bed-wetting in children

  • Constipation

  • Ear, nose and throat infections

  • Eczema can be seen with both IgE and IgG antibodies

  • Fatigue

  • Gut pain and IBS-type symptoms

  • Irritability

  • Headaches, migraines

  • Joint pain

  • Sleep problems (insomnia, snoring)

Both types of food reactions develop due to changes in the digestive system and exist in a large group of those suffering from IBS-type symptoms. When the offending IgE or IgG-triggering foods are eliminated, a significant improvement is seen in IBS symptoms, including pain severity, pain frequency, bloating severity and settled bowel habits (2).

Why do food hypersensitivities occur?

It is estimated that up to 20% (3) of the global population develops gastrointestinal symptoms after eating a meal, but the underlying reactions leading to food-induced abdominal pain are not fully understood by the scientific community.

However, a recent study has confirmed that clear inks exist connecting gut bacterial infections and immune responses that lead to the production of dietary-antigen-specific IgE (allergy) antibodies, which are contained in the intestine (4). This study showed that patients with IBS given typical food antigens of gluten, wheat, soy, and milk developed local oedema in the gut (swelling) and food-induced abdominal pain. The study underpins that gut pain and bloating can be caused by food-triggering IgE immune responses, which are localised to the gut region. It challenges the original understanding that IgE reactions were generally presented systemically across the body.

To put this into perspective, some background information may be helpful.

Food hypersensitivities are an overreaction of the immune system. The immune system, designed to provide protection, comprises the various white blood cells and mucous membranes throughout the body, especially the digestive system. An allergy starts developing within the immune system long before symptoms appear. Immune responses occur in a disrupted intestinal environment, often going unnoticed for several years. Changes happen in the normal intestinal flora (bacteria), typically seen after a gut infection, a course of antibiotics, or a prolonged stressful period. The gut lining houses a particular tissue that produces immune cells; it also plays host to cooperative bacteria, which help process food into the body. When infection or antibiotics alter intestinal flora, the absorptive ability of the intestinal membranes can become impaired and can result in nutrient deficits.

Alongside food hypersensitivity, two co-existing gut conditions are often present – Hypochloridria and Digestive Enzyme Insufficiency:

Hypochlorhydria is the reduced intensity of stomach acid, which is thought to start a sequence of events creating an environment which triggers food hypersensitivity.

Digestive Enzyme Insufficiency occurs in the small intestine, causing maldigestion of carbohydrates, fats, and proteins.

It is believed that large undigested food particles (a consequence of hypochlorhydria and digestive enzyme insufficiency) cause alternations to the gut flora by positively encouraging the growth of destructive bacteria. Over time, these large food proteins enter the blood system, where they become recognised as foreign and trigger threat signals. The immune system creates antibodies to attack and remove the foreign invader, starting the cycle of food hypersensitivity symptoms.

Author: Christine Lewis, nutritionist and specialist in gut health and gut-associated conditions.

If you experience persistent IBS symptoms of pain and bloating or notice any of the above-mentioned symptoms, ruling out food allergens is a sensible next step.

Henley Nutrition can help you identify food hypersensitivities and provide the appropriate IgE and IgG testing. A consultation can help highlight symptoms relating to hypochloridria and digestive enzyme deficiency and start the recovery programme.

Call Henley Nutrition on 07831 120423 or visit

This information is not designed to replace advice from your Doctor.

See the full Blog series of gut articles:


2. Choung R, Talley N. (2006) Food Allergy and Intolerance in IBS



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