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Demystifying Food Intolerances and Allergies

In the realm of dietary concerns, the spotlight often shines brightly on nut allergies due to their potential life-threatening nature. However, beyond this well-known peril, food allergies remain a topic that isn't always taken as seriously as it deserves. Part of the issue may stem from a lack of awareness about the symptoms to watch for. Additionally, some individuals tend to use the terms "food allergy" and "food intolerance" interchangeably, contributing to the confusion. Today, I'm here to shed light on both these aspects and provide you with insights on what to do if you suspect certain foods don't sit well with you.


A genuine food allergy is an abnormal response triggered by the body's immune system when it encounters a specific food. This reaction can range from mild to severe, even life-threatening in some cases (known as anaphylaxis).

The immune system responds by producing IgE antibodies, mistakenly interpreting the food as a threat. This immune reaction can be localised, affecting specific areas like the digestive system or skin, or it can become a full-body event. In extreme cases, widespread inflammation and swelling, referred to as anaphylaxis, can occur, posing a deadly risk. Notably, food allergy reactions often manifest swiftly, typically within moments or shortly after consuming even a small quantity of the problematic food.

Common Symptoms of Food Allergies:

- Tingling or itching in the mouth

- Hives, itching, or eczema

- Swelling of the lips, face, tongue, throat, or other body parts

- Wheezing, nasal congestion, or breathing difficulties

- Abdominal pain, diarrhoea, nausea, or vomiting

- Dizziness, light-headedness, or fainting

For those experiencing severe allergic reactions (anaphylaxis), immediate action is vital as it can be life-threatening:

- Constriction and tightening of the airways

- Swollen throat or the feeling of a lump in the throat, making breathing difficult

- Shock with a significant drop in blood pressure

- Rapid pulse

If diagnosed with a food allergy, strict avoidance of the allergenic food is essential. The immune system retains a memory of its response, similar to how it remembers a vaccine's effects. This means even a tiny amount of the suspect food can trigger an immune system overreaction.

Food allergy testing is available through your GP or private clinics.

Clinical Insights:

Interestingly, if you experience typical allergy symptoms like itchy eyes or swelling, but allergy tests show no problematic foods, the issue might reside in your gut. Specific gut microbes can stimulate the production of high levels of IgE antibodies, the same antibodies linked to food allergies. Surprisingly, conventional medicine often overlooks this potential cause of allergy-like symptoms.


Food intolerance differs significantly, as it induces low-grade inflammation throughout the body and results in less dramatic but diverse symptoms. These may include:

- Stubborn weight that refuses to budge

- Uncomfortable bloating

- Recurring migraines

- Persistent headaches

- Frequent coughing

- Chronic runny nose

- Itchy or excessively waxy ears

- Stomach discomfort

- Irritable bowel symptoms (bloating, cramping, diarrhoea, constipation, or alternating bowel patterns)

- Hives

- Lingering fatigue

- Asthma

- Joint pain (arthritis)

- Chronic nasal congestion

- Ear infections

- Skin conditions like eczema

- Sinusitis

- Urticaria (hives)

Underlying Causes of Food Intolerance

Leaky Gut: Food intolerances may stem from a condition known as leaky gut or intestinal permeability. This involves damage to the intestinal lining, allowing undigested food proteins to enter the bloodstream and trigger the immune system, leading to intolerance symptoms. Addressing the root causes of leaky gut is essential to prevent developing intolerances to additional foods, and many find that they can reintroduce foods once they have healed the gut lining.

Imbalances of the Microbiome: Certain harmful bacteria, yeasts, and parasites can harm the gut lining, contributing to leaky gut and immune system interactions. Beneficial bacteria also play a crucial role in maintaining mucosal linings and reducing inflammation, making microbiome imbalances a potential source of food sensitivities and intolerances.

Low Digestive Function: Difficulty digesting specific foods, such as dairy, fructose, or food high in histamines, can result from low digestive function. Inadequate production of the correct digestive enzymes can hinder the breakdown of particular substances, such as lactose in milk.

Non-Celiac Gluten Sensitivity: Some individuals react to gluten, yet standard coeliac tests yield negative results. This condition, known as non-celiac gluten sensitivity, mirrors the symptoms of coeliac disease and wheat intolerance. Although the exact causes remain unclear, it's believed that the immune system still plays a role.

Understanding FODMAPs:

FODMAPs, an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, represent specific carbohydrates found in various foods like onions, garlic, mushrooms, apples, lentils, rye, and milk. Poor absorption of these sugars causes them to traverse the small intestine and enter the colon, where bacteria ferment them, producing gas. This gas can stretch the sensitive bowel, causing bloating, gas, and pain.

It's essential to note that FODMAP-rich foods are not inherently unhealthy; they serve as vital nourishment for the large intestine's bacteria. If following a low FODMAP diet alleviates symptoms, it may indicate a condition called Small Intestinal Bacterial Overgrowth (SIBO), where bacteria in the small intestines feed on these fermentable fibres. SIBO should be addressed, and the low FODMAP diet isn't meant as a long-term solution.

Suspect an intolerance?

Elimination Diets:

An elimination diet involves systematically excluding and then reintroducing different foods to identify allergies, intolerances, or sensitivities. This approach can help pinpoint problematic foods and ease the burden on the digestive system while you address gut health, microbiome balance, and digestion.

Testing for Allergies and Intolerances:

While food allergy testing is available through your GP or privately, food intolerance testing typically requires private testing. At-home finger prick tests examine specific antibodies in your blood, revealing immune system reactions to foods. However, it's crucial to look beyond intolerance tests and consider the root cause. Stool tests can provide valuable insights into gut health, microbiome imbalances, inflammation markers, and digestive enzyme production.

A Personalized Path Forward:

Remember that a one-size-fits-all approach doesn't apply when it comes to health conditions. We are all unique, and uncovering what's ailing you is essential. The journey to improvement often involves addressing various factors, so don't hesitate to reach out for guidance.

Connect with me:

If you're interested in exploring testing or seeking support, feel free to contact me for a free digestive health review. Email link [your contact email] to arrange a call. Join our IBSand Digestive Health Facebook Group to learn more about potential causes of your symptoms.

Click here to join the supportive group:

Fixing your digestion isn’t as hard as you think. I can help you.

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