Physical reactions to foods are common. While food allergies account for some of these reactions, the majority are caused by a food intolerance (also known as food sensitivity). The symptoms for both are similar, which can cause confusion.

With a food allergy, your immune system wrongly acts as if a certain food is dangerous and produces antibodies to try to neutralise it. Chemicals such as histamine entering your bloodstream during this episode can result in a wave of symptoms that may affect different organs around the body. These symptoms can vary greatly, from mild irritation to symptoms that are severe or even life-threatening.

Generally caused – we think – by your body’s inability to break down or digest certain foods or ingredients, food intolerances do not involve your immune system and are generally less serious than allergies. While some symptoms occur immediately after eating others may take a few hours to materialise. This delay can make it difficult to pinpoint the source of sensitivity, leading many intolerances to go undiagnosed.


What are the symptoms of a food intolerance?

While many food intolerances affect the digestive system, the impacted region and the precise symptoms vary greatly between people, as well as the different foods and ingredients involved. Here are some of the more common symptoms to look out for.

Digestive Issues

Digestive issues are by far the most common symptom of intolerance. The most reported symptoms being:

  • Bloated after eating
  • Abdominal pain
  • Acid reflux
  • Diarrhoea
  • Difficulty losing weight
  • Excessive gas

Skin issues

Life with dry, bumpy and itchy skin can be a challenge, and identifying the cause is often difficult. There are many potential causes for skin issues, food intolerance being one of them.

  • Acne

Psychological issues

A little-known fact: the gut produces 90% of the body’s serotonin (known as the happy hormone). So, it’s not surprising that the food you eat may have a direct impact on your mood.

  • Fatigue
  • Depression
  • Anxiety
  • Hyperactivity
  • Rapid heartbeat


Common causes of food intolerance

Each of us comes with our own unique physiology, making it difficult to generalise where food intolerances are concerned. Nevertheless, research and experience point us in the direction of the usual suspects, starting with those below.

  1. Lack of enzymes

Enzymes play a key role in the digestive process, allowing us to break down our food into a form we can assimilate and to optimally absorb important nutrients. If certain enzymes are missing or lacking, your digestion may be compromised.

The most common example is probably lactose intolerance. Owing to reduced level of the lactase enzyme, sufferers have difficulty breaking down and absorbing lactose, a sugar found in milk and other dairy products.

  1. Natural chemicals

Certain foods contain chemicals that have a toxic effect on humans, causing digestive disruption. Undercooked beans, for instance, contain aflatoxins whereas fully cooked beans do not. This partly explains why people may react to certain foods on some occasions, and other times not.

  1. Amines

Amines are produced by bacteria during storage and fermentation and therefore found in foods such as fish that haven’t been stored properly. They include histamine, a bodily chemical produced by the digestive, nervous and immune systems, and which is frequently associated with food-related intolerances.

For most people, histamine is easily metabolised and excreted. Some people, however, cannot break it down (because of impaired enzymes in charge of its break down) properly, causing a build-up in the body. Those who are particularly sensitive may experience symptoms that are similar to anaphylaxis (a strong allergic reaction).

  1. Salicylates

Present in many foods, salicylates (derivatives of salicylic acid) are natural chemicals produced by plants as a natural defence against environmental stressors like insects, bacteria and disease. Due to their anti-inflammatory properties, foods with high levels of salicylates have been found to protect against diseases such as colorectal cancer.

Salicylates can be found in processed foods, as well as in most plant-sourced foods, including most fruits and vegetables, herbs, mint flavourings, tomato sauce, coffee, honey, nuts and flavour additives.

  1. Individual intolerances

For reasons unknown, certain substances trigger sensitivities in certain people but not others. The common culprits include

  • Sulfites, found in red wine and some medications
  • Artificial sweeteners, such as aspartame, found in many fizzy drinks
  • Monosodium glutamate (MSG), used as a flavour enhancer in many foods
  • Colouring and preservatives, such as tartrazine dye and benzoates


How to manage a food intolerance

The most effective way to deal with intolerance is simply to eliminate the offending substance from your diet. Sometimes, the body can tolerate the food if it’s avoided for a period of time, then reintroduced in small amounts. If you’re struggling to pinpoint the root of your symptoms, or you suspect you’re reacting to a particular food, then a food intolerance test can help you join the dots.

Most importantly, if you’re concerned by any of the symptoms you’re experiencing, then a visit to your GP is always advisable. And always seek advice from a specialist doctor or nutritional therapist before eliminating certain foods or reintroducing them to your diet.

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