• Lucy Francis

Dairy Allergies vs. Intolerances

Updated: Sep 17, 2020

Found under the ‘dairy umbrella’ are the following substrates:

1. Casein and whey (dairy proteins)

2. Lactose (the sugar component within dairy)

Before we get started, dairy refers to milk and any food products made from milk… including cheese, quark, ice cream, cream, whey/casein protein powders, butter and yoghurts (eggs are not part of the dairy family!)


Dairy allergies and intolerances are separate issues, but the two get mixed up pretty frequently.

An allergy involves an IgE immune-mediated response where the body views dairy as a something to cause serious danger to health, creating a surge of anti-bodies against it, resulting in systemic inflammation such as itching, swelling, skin rashes/ hives, trouble breathing or wheezing and in severe cases anaphylaxis shock, which can be a life-threatening situation. Those who are allergic must avoid dairy completely (like you would a nut allergy or shellfish allergy).

The most common testing methods are skin-prick or blood tests; both looking for the presence of immunoglobulin E.


When we look at an intolerance, symptoms are connected to the digestive system and our natural differences in genetics, rather than involvement from the immune system.

Naturally, the activity of the lactase enzyme declines after weaning in around 70% of the population (the ability to break down lactose into glucose and galactose for digestion in the small intestine). Due to this, some of us may be unable to tolerate dairy in any quantity, or tolerate up to a certain amount before a range of unpleasant symptoms occur, some of which are:

  1. Excessive gas

  2. Bloating

  3. Bowel movement irregularities (constipation/diarrhoea)

  4. Abdominal pain

  5. Inflamed skin

  6. Neurological symptoms like brain fog

An intolerance should still be taken seriously as symptoms can affect the immune and endocrine/neuro-endocrine systems by other mechanisms.

Plenty of our digestive systems in the UK and predominantly those with Northern European ancestry (where climates have long supported dairy farming) are still able to digest lactose, due to the enzyme sustaining function from continued dairy consumption and gene expression consequently adapting – this is referred to as ‘lactase persistence’.

Is It Just Genetic?

So, despite our genetics largely determining how we process lactose (LCT gene), the health and integrity of the gut lining must equally be considered, and whether this has been compromised over time – i.e. an imbalance of gut flora due to heavy antibiotic use, sometimes a decline in beneficial lactobacillus strains following severe food poisoning, and of course certain health conditions which affect the small intestine. Each of these factors can have an impact on how the sugars and/or proteins within dairy are tolerated.

I Think I’m Intolerant, What Can I Do?

I’d advise always monitoring how you react after eating dairy products before making any cuts to your diet (as removing whole food groups is not sensible unless absolutely necessary) – dairy is a brilliant source of essential nutrients such as vitamin A, vitamin D, calcium and iodine (an important mineral often overseen), as well as being a complete protein source (aside from butter – butter has no protein, trace amounts of lactose and is pretty much entirely fat!)

Seeking professional guidance to help you implement an appropriate elimination diet over a period of time and/or provide methods of testing (such as IgE-antibody elevations, hydrogen/methane breath testing and possibly exploring genetics) would be the best solution if you suspect you are having a reaction. It’s vital to ensure the risk for a nutrient deficiency is avoided by sourcing sensible dietary alternatives.


Removing dairy in the diet is either a necessity due to allergy, or a decision to be made inline with your health/digestion abilities (or personal ethics).

It may be that someone with an intolerance can reduce dairy without cutting it completely in a ‘dose dependant’ manner… We get a variety of dairy products which have different nutritional compositions which can impact the body differently (hard/soft cheeses, yoghurts, milk, fermented forms, low fat/high fat compositions etc) and interestingly, the lactase enzyme can be found within some supermarket dairy products these days. There’s also the option to discuss with a nutrition professional about supplementing directly with a lactase enzyme if needed.

I hope you found this helpful!

If you are someone who does not include dairy in their diet and is in need of some ideas for dairy-free living, I’ve gathered a few of my recommendations for you in an upcoming post.

Lucy x







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