Food Allergy, Intolerance and Sensitivity

These terms get banded around quite a bit in my field, and I feel the average person doesn’t quite understand the subtle differences between them. Hopefully I can help clear up a bit of the confusion below.

What is a Food ALLERGY?
This is a reaction involving the immune system, and typically involving a class of antibodies known as IgE antibodies. These sneaky chaps rush in FAST so reactions are often very quick (seconds – minutes) and can be very acute and severe. Think anaphylaxis (where the body has become acutely hypersensitive to an antigen). These reactions can be life threatening, and can be very unpleasant.

Common food allergens include peanuts (as well as many other nuts), shellfish, milk, eggs, oranges, wheat, fish and soya.

Sadly IgE antibodies have a LIFE LONG memory meaning you need to avoid these foods for life if you have a food allergy. Reactions can get worse the more you are exposed to the food as they recognise the food faster and can mount bigger responses. Not fun.

These are often diagnosed in childhood (but can be adulthood), can have a genetic link (if a family member has one) and are usually determined by a blood test for IgE antibodies, or a patch test for skin based allergens.

What is a Food INTOLERANCE?An intolerance is not an immune response. Food intolerance occurs when one or more of the following occur:

  • your body lacks a particular enzyme to digest nutrients
  • nutrients are too abundant to be digested completely
  • a particular nutrient cannot be digested properly

Symptoms are usually exclusively gastrointestinal (occur in the gut) and be secondary to sugar fermentation by the bacteria in the gut, leading to the production of gas, which may cause bloating, abdominal pain, diarrhoea and/or constipation.

Common examples include lactose intolerance, or intolerance to excess fermentable oligo, disacchararides, monosaccharides and polyols (FODMAPs) or lactulose.

I typically see people who are INTOLERANT to dairy, gluten and often legumes as the body cannot break them down well in the small intestine and this causes a range of digestive symptoms. Often temporary removal of a hard to digest food can allow the body to digest more efficiently. Once enzyme levels and beneficial bacteria levels are restored these can usually be successfully reintroduced.

So… INTOLERANCE is not life threatening or as severe as an ALLERGY. However the symptoms can be very distressing and reduce a person’t quality of life severely. The good news is they can often be resolved, or reduced.

What is a Food SENSITIVITY?
Lastly we have food sensitivities. Now these (like food allergy’s) ARE immune responses. Just not as severe as a food allergy, and involving different antibodies, normally IgG and IgA.

Now these antibodies are slower to respond, rather than seconds-minutes they may respond hours-days later. Symptoms can be very varied – skin itching and rashes, tightness in the chest, headaches and migraines, digestive symptoms, spots, wheezing, tiredness and fatigue, stubborn weight loss (caused by ongoing immune mediated inflammation) amongst loads of others.

Because the symptoms are so varied, and can come on a completely different time to when the food was ingested it can be really hard to pin these sensitivities down. On the positive side these antibodies do not have a life long memory, and foods may be removed – the gut and immune system supported – and the foods may be reintroduced without causing problems.

I say may as this isn’t always the case. A rotation diet and strict elimination and challenge of the foods is the gold standard. But this is pretty darn hard to adhere to all the time.

There are laboratory tests available to look at food sensitivities which can make the process of removal quite a bit easier.

One last note is that you can have an allergy, sensitivity and intolerance to the same food, or different ones for all!

For example:
You might have a milk allergy, lactose intolerance and a sensitivity to milk and yoghurt. Basically dairy is off your menu!
Or you might have a nut allergy, gluten intolerance and a sensitivity to yeast and strawberries. So total nut avoidance, potential temporary gluten avoidance and gut repair, and 3-6 month removal of yeast and strawberries before retrying.

Interesting?! If you think you might be suffering with a problematic food, do fill out my short client intake form if you would like to work with me.