The MOH guide to food allergies and intolerances
…and why they both matter
Our food plays a massive role in our overall health, it contributes to our weight, our energy, our cardiac and mental health and to a very large extent…our physical health. In clinical practice it seems the extent to which this is true, is sorely underestimated. Many chronic health conditions can be triggered and/or influenced by unidentified and untreated food intolerances. Asthma, arthritis, diabetes, depression…all have good evidence for dietary factors playing a key role.
But what is a food intolerance?
Bodily reactions to foods are common, but most relate to food intolerances rather than actual allergies. Food intolerances often cause some of the same symptoms as a food allergy, so people frequently blur the two. They are in fact different things.
A true food allergy causes an immune response that affects several organs or systems in the body, and these can range from minor skin or bowel irritations through to severe or life-threatening complications.
Allergies occur when an over-reactive immune system produces proteins (called IgE antibodies) against substances in the environment that are otherwise harmless — pollens, house dust mites, moulds, animal hair (dander), or in this case, specific food proteins. Food allergy is mainly a problem of infants, toddlers and young children but new food allergies can arise in adult life, usually with crustaceans and other more exotic foods that are not commonly eaten in childhood.
In adults, a single food such as peanut or shellfish is usually involved, but children are commonly allergic to two or three foods, sometimes more. The most common ones are peanut, egg, milk, other nuts, seafoods and / or sesame. Fortunately, many children grow out of their egg and milk allergies before they reach school age, or during the early school years, but allergies to nuts and seafoods more commonly persist. Wheat, sesame and soy can also cause allergies, but these tend to be milder and more transient.
If you have a reaction to any particular food, always see your GP to determine whether you have a food intolerance or a food allergy. They are different and the difference matters. If you are found to have a food allergy, you may be at risk of anaphylaxis, a life-threatening allergic reaction, even if your past reactions have been quite mild. Your GP will also educate you on how to recognise the warning signs of a more severe allergic reaction and instruct you on what to do if and when one occurs. You may need to carry an EpiPen – an emergency epinephrine shot for emergency self-treatment.
So back to intolerances…
By contrast, food intolerance reactions are generally less acute, less serious and often limited to digestive problems. This doesn’t mean we should ignore then though; it just means that they’re slower to create health issues. But they do create health issues.
If you have a food intolerance, you may be able to eat small amounts of the offending food from time to time without issue. You may also be able to prevent or limit reactions. For example, if you have lactose intolerance, you may be able to drink lactose-free milk or take lactase enzyme pills (Lactease) to aid digestion.
Common causes of food intolerance include:
- Irritable bowel syndrome – This chronic condition presents much as the name implies, with frequent irritation of the bowel leading to cramping, constipation and diarrhea. It’s thought to be a hypersensitivity disorder where benign substances are setting off protective nervous system responses that really aren’t necessary.
- Sensitivity to food additives. For example, sulfites used to preserve dried fruit, canned goods and wine can trigger asthma attacks in sensitive people. MSG, aspartame and nitrates also fall into this category and can cause gastric distress, diarrhoea, hives and irritability or insomnia.
- Lack of the enzymes required to completely digest a food. Lactose intolerance is a very common example, but a lack of alcohol dehydrogenase is another example. These enzymes really only effect one substance but broader pancreatic insufficiency can also occur secondary to other bowel conditions such as Celiac or Chron’s disease; and this may result in an inability to breakdown a wide variety of foods.
- Chronic stress can lead to intestinal hypersensitivity. We don’t really understand exactly how this plays out, but we know that chronic stress can lead to an exaggerated inflammatory response in many tissues and the gut is no different. This tends to create an IBS-type hypersensitivity that can make us reactive to a number of foods.
- Coeliac disease. This chronic digestive condition is triggered by eating gluten, a protein found in wheat and handful of other grains. Coeliac disease has some features of a food allergy because it is a primary immune dysfunction. Symptoms can include gastrointestinal symptoms as well as joint pain and headaches. Unlike allergies, people with coeliac disease are not at risk of anaphylaxis.
You are what you eat
The old saying ‘you are what you eat’ is true but it’s only part true… in actual fact you are what you eat and absorb. And, there are many factors that influence our ability to actually digest and absorb nutrients. Undiagnosed or unheeded food intolerances are a very common cause of chronic gut dysfunction that leads to poor absorption and results in nutrient deficiencies. They likely also contribute to the chronic inflammatory responses we think contribute to cardiovascular disease, depression and osteoarthritis.
If you have any of the following recurring symptoms, then you may be suffering from food intolerance.
Common Symptoms of Food Intolerance’s
- Abdominal Pain, Belching or Bloating after meals
- Diarrhoea, Constipation or Flatulence
- Nausea, Stomach cramps or Indigestion
- Inability to control weight
- Irritable Bowel Syndrome
- Muscle and Joint Pain & Swelling
- Anxiety, Depression & Mood swings
- Difficulty concentrating
- Insomnia, Fatigue & exhaustion
- Drowsiness or Lethargy
- Asthma or Persistent cough
- Sinusitis, nasal discharge & Snoring
- Skin disorders
- Low immunity – frequent colds & infections
What to do about Food Intolerances
Understanding the difference between intolerance and other types of food reaction is an important starting point because the approach to dealing with them is quite different. Unlike allergies and coeliac disease, which are immune reactions to food proteins, intolerances don’t tend to involve the immune system at all. They are triggered by food chemicals which cause reactions by irritating nerve endings in different parts of the body, in much the same way that certain drugs can cause side-effects in sensitive people.
Skin prick tests or blood tests (radioallergosorbent test or RAST) that can detect IgE antibodies in people with allergies are of no real value in the diagnosis of intolerances. The chemicals involved in intolerances are often found in many different foods, so the approach involves identifying them and reducing your intake of whole groups of foods that contain the same offending substances. This means that the first best step is often to work with a dietitian or nutritionist who can help you identify what substances you might be sensitive to. They really are best placed to help you understand how capsicums and potatoes are related or avocados and bananas – Relationships between various foods aren’t always apparent to the rest of us.
Once you have identified the chemicals involved you can start limiting or avoiding them, and start improving your health. Down the track your dietitian or nutritionist may be able to help you reintroduce them.