Food intolerances and food allergies
Digestive reactions to specific foods are incredibly common.
The majority are caused by a food intolerance rather than an actual food allergy but it’s easy to confuse the two.
A true food allergy affects the immune system and generates an instant, significant reaction.
A food intolerance tends to trigger a reaction within the digestive system so it may be delayed for hours or even days, often small amounts can be tolerated.
What is a true food allergy?
A true food allergy causes a reaction known as anaphylaxis.
Food allergy testing usually includes a skin prick test or blood test that measures allergen specific antibodies known as immunoglobulin E (IgE)
Even small amounts of the problem food will trigger immediate and possibly life-threatening symptoms and require urgent medical attention including:
Swelling of the mouth and face
Swelling or a closing of the throat
Difficulty swallowing and breathing
Skin rashes
Joint swelling
Allergies can be inherited and many appear during the first year of life.
Allergies are an overreaction of the body’s immune system to a protein in food as if it were toxic.
Allergies can also be caused by pollens, house dust, animals and moulds.
If you have a true food allergy you will likely need to avoid the offending foods for life.
What is a food intolerance?
Food intolerances occur when a food or beverage triggers issues with the digestive system but can also impact skin, cause headaches and other symptoms.
It can also be associated with irritable bowel syndrome (IBS).
Food intolerance can cause symptoms such as:
Excessive bloating
Excessive gas
Diarrhoea and/or constipation
Inflammation
Brain fog
Skin reactions
Migraines
Hives
An irritable bowel
Non-coeliac gluten sensitivity
Symptoms can be immediate or delayed. They are often non-specific and it’s hard to pinpoint what food is the cause.
The suspected problem food may not be a problem at all but simply a sign of an imbalance somewhere in the digestive system, including:
Digestive enzyme insufficiency
Delayed gastric emptying
Overgrowth of bacteria or yeast
Slow transit time
Protein maldigestion
Bile insufficiency
Chronic stress
Inflamed gut lining
Increased intestinal permeability (often called leaky gut)
How to deal with food intolerances
Many of these can be supported or resolved with professional guidance.
For example, lactose (the sugar naturally found in milk) intolerance is a deficiency in the digestive enzyme called lactase.
Supplementing lactase can be helpful in restoring balance so a person can comfortably digest milk again.
Usually, once you address and restore optimal gut function, you can go back to enjoying the perceived problematic foods.
Are foods intolerance tests helpful?
It can be tempting to turn to food intolerance testing for a quick fix but these tests are not scientifically validated and often a waste of money.
A food intolerance test usually involves a finger prick blood spot and measures the presence of IgG antibodies against food.
As you can see I’ve tested these myself and concluded they’re a waste of money.
The problem with these tests is that:
There’s a high risk of false positives and false negative results which means you might eliminate a food unnecessarily or keep eating a food that’s problematic for you
The issue with a food is not always a reaction to a protein (which IgG test measure). It might be the high fibre content or fermentable nature of the food causes gas and bloating which give you digestive symptoms.
If you have an underlying issue like slow transit time, constipation or bacterial overgrowth multiple foods will cause issues that won’t appear on tests. Again because they contribute towards gas formation in the small and large intestine.
You might not have antibodies to a food because you’ve been eliminating it for a while.
You can have raised IgG antibodies to a food and also not have any symptoms.
Intestinal permeability (leaky gut) and other digestive imbalances can also cause an increase in IgG antibodies so measuring IgG antibodies in our blood is not a reliable indicator of food tolerance.
The best way to tackle possible food intolerances
Elimination diets are the gold standard for identifying food that are problematic for your digestive system.
This involves removing specific foods are either known to cause uncomfortable symptoms or any foods you suspect maybe a trigger.
It’s helpful to aim to remove for around 30 days and reintroducing them at a later time.
Keeping a food diary is helpful for monitoring symptoms and to pinpoint trigger foods.
The following are helpful to test via an elimination diet:
Dairy
Wheat
Gluten
Yeast
Sugar
Nightshade vegetables
Eggs,
Seafood
Corn
Soy
If your symptoms still remain after removing the foods for 2–3 weeks, it is best to seek support.
If symptoms vastly improve during this time, it’s time to start the reintroduction phase which involves slowly bringing the eliminated foods one by one back into your diet.
Each food should be introduced one at a time, over three days, while monitoring for symptoms.
It’s helpful to avoid testing foods when eating out (as you won’t know all the ingredients) or using packaged food that contains multiple ingredients as it’s be hard to establish what causes a reaction if you experience one.
The entire process, including elimination, takes roughly 5–6 weeks and I’ve outlined how to do it in this article.
If you don’t find relief on the elimination diet then it’s unlikely to be a food intolerance that’s triggering your symptoms and it’s helpful to explore other possible imbalances in your digestive system with the support from a registered nutritionist.
You can contact me for a free 15 minute call to discuss further steps to fix your gut.
