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  • Writer's picturefranceswalker@thefoodinto


Updated: May 13

Do you react to dairy? Most people have heard of lactose intolerance but may not know that there is something else in milk that they could be reacting to.

Like all foods, milk is made from a combination of what we call MACRO nutrients (the main nutrients) which are:

· Protein

· Fat

· Carbohydrate.

Carbohydrates in milk

The carbohydrate in milk is LACTOSE which is also called the milk sugar.

If you react to lactose in cow’s milk then you are LACTOSE INTOLERANT.

Fat in milk

Regular milk has a 3.5% fat content and we call this full fat milk.

In line with consumer health demands, the fat is reduced to 2% for low fat milk and as low as .15% for skim milk.

Protein in milk

The protein in milk is the other macronutrient which can cause issues for sensitive babies, children and adults.

There is not just one protein in milk but quite a variety.

If you react to proteins in milk then you may have a MILK ALLERGY or a MILK INTOLERANCE.

In fact… you can react to both lactose and milk protein.

Let’s explore both these milk issues.

Do you have Lactose Intolerance?

Lactose is called milk sugar and is a DI-SACCHARIDE which is a fancy way of saying that lactose is made from two basic sugars which happen to be glucose and galactose.

LACTOSE = glucose + galactose.

Glucose and galactose are bonded together and this bond needs to be cut by a scissor-like enzyme to free the glucose and galactose.

This scissor-like enzyme is called LACTASE. Same as the enzymes added to foods to make it lactose free such as lactose free milk or lactose free yoghurt.

It is really important that lactose can be cut to free the glucose and galactose as we cannot absorb lactose across our gut wall- but we can easily absorb glucose and galactose.

If you don’t produce enough of the scissor enzyme (LACTASE) then the lactose in the dairy food will not be broken down so cannot be absorbed into the body.

INSTEAD….lactose stays in the gut and being so very small will attract water to whoosh into the gut.

Not only is water drawn into the gut but the lactose travels through the gut in large amounts and makes it to the large intestine part where we have the most gut microbes.

These microbes LOVE lactose and they will very rapidly ferment the lactose which results in loads of gas such as hydrogen, methane and carbon dioxide being produced in a short period of time.

The extra gas and the extra water can stretch our gut wall and trigger the stretch receptors in the gut wall. The receptors send a message to our brain which is interpreted as pain.

30 minutes to 4 hours of eating or drinking a lactose rich food or drink may result in a speedy exit to the bathroom accompanied by:

· Bloating

· Mushy to watery diarrhoea that can be very frequent

· Excessive and quite smelly gut gas

The classic Lactose Intolerance symptoms.

How lactose intolerant you are depends on how much LACTASE enzyme your body is programmed to produce.

We speak of a SPECTRUM of lactose intolerance from mild to severe. BUT- we all produce at least some LACTASE. Symptoms tend not to occur until there is less than 50% of lactase activity. It takes a lot of reduced production of lactase before we feel the pain!

Babies produce a lot of LACTASE and indeed it is very rare for babies to be lactose intolerant, because being able to digest human milk is incredibly important for their survival.

Babies (and adults) can get short lived lactose intolerance due to something else upsetting the gut but once the issue is ironed out, the LACTASE enzyme can do its job again.

It is perfectly natural to produce less LACTASE as we get older – as per our evolutionary blue print, as we transition from milk to food for our nutrition.

However, some very distant ancestral forebears somewhere in Northern Europe developed a mutation that allowed the LACTASE enzyme to continue into adulthood. This meant they could rely on a nutritional food source - milk from the animals they farmed and thus have a greater chance of surviving and passing on this mutation to the following generations.

Modern humans evolved from these groups have the ability to digest lactose, while around the world, 2/3 of the human population have not retained the ability to produce LACTASE as they become adults.

Managing Lactose Intolerance

If you suspect you have lactose intolerance then you can trial a reduced lactose diet to see if your gut symptoms improve.

Choosing a reduced lactose diet can be easily achieved via choosing the dairy lactose-free alternatives that are readily available such as lactose-free milk and lactose-free yoghurt or yoghurts that are naturally low in yoghurt such as traditional Greek yoghurts.

Cheese is made from the casein fraction of milk (we will discuss that in the protein section) which is lower in lactose.

If cheese is not ripened (for example ricotta, cream cheese, marscapone, quark, cottege cheese): then itb will contain some lactose.

Most cheeses (85%): are ripened which reduces the remd.aining lactose which is converted to lactic acid.


Keeping some lactose in the diet

It is good to keep lactose in your diet at an amount that your body can manage.

This is because the lactose will promote healthy bacteria to take up residence in your gut.

These bacteria will in fact break down some lactose which in turn means you will be able to manage more lactose in your diet over time.

If you are avoiding lactose, try and introduce 30- 60mls of lactose containing milk and gradually build up over time to help your gut to adapt.

Full fat milk may be better tolerated than lower fat milks.

Do you react to Dairy Protein?

Do you react to lactose-free milk or cheese such as tasty cheese that contains no or minimal lactose?

If so, you may have an allergy or intolerance to cow’s milk protein.

The proteins in cow’s milk are of 2 main types: the CAESIN proteins or the WHEY proteins.

We all know the nursery rhyme:

“Little Miss Muffet sat on her tuffet eating her curds and whey..”

Caesin Proteins

The curds are the CAESIN proteins and there are 7 different main casein proteins.

One of these Casein proteins (Beta-casein) is the protein that can be A1 or A2 depending on whether the cow comes from an ancestral herd which had this mutation.

Whey Proteins

The WHEY proteins are the other group of proteins and there are 5 different ones.

If you react to dairy proteins, you could be reacting to any of these proteins either in isolation or a combination.

On top of this, you may be reacting to the 3D SHAPE of the protein or to the SEQUENCE of the AMINO ACIDS in sections of the protein.

If you are reacting only to the shape then anything that changes that shape, for example baking milk, may mean that you may be able to tolerate the milk in that form.

If you react to the amino acid sequence then breaking down the 3D structure as a result of processing or high temperatures will not improve your tolerance as the amino acid sequence of the protein that you react to has not changed.

Milk protein reactions can be serious allergies which we call IgE allergies and these allergies are potentially dangerous due to carrying a risk of anaphylaxis.

If you feel you have an IgE allergy to cow's milk protein then see your Medical Doctor and be prepared to completely avoid dairy foods.

Otherwise, less serious reactions can be called delayed allergies (or non IgE allergies) or milk protein intolerance. It does not matter what they are called as they are managed in the same way- reducing the amount of dairy protein to a level that can be tolerated without causing symptoms.

Common Dairy Issues

Symptoms of cow's milk protein intolerance vary hugely and can affect many systems of the body including our guts.

Common symptoms can include:

  • Gut symptoms: constipation or diarrhoea

  • Skin issues: acne or rashes or hives or flare of eczema

  • Mood changes

  • Upper airway congestion/sinus

  • Headaches

  • Muscle and joint pain

  • Loss of concentration/ brain fogginess

DAIRY exclusion and Nutritioanl Impacts

If you suspect cow's milk intolerance, it is important not just to avoid dairy foods but to replace the lost nutrients such as calcium, protein, phosphorus, zinc, magnesium and vitamin A to promote future health and minimise risk of osteoporosis.

It can be dangerous to provide plant milks other than soy milk as a main milk for babies, toddlers and children.

Seek a Dietitian for a baby or child following a dairy free diet.

What is your Dairy Issue?

If going lactose-free solves your issues then you are in luck! Just choose lactose-free dairy alternatives but over time try and include some lactose slowly promote healthy bacteria in your gut.

If you react to lactose-free dairy foods or have a range of symptoms beyond the gut, then dairy protein allergy or intolerance may be in play. Replacing a whole food group such as dairy can make a big dent in your nutrition. This is magnified if it is a child or a toddler.

It is best to seek a medical doctor is you suspect allergies or a qualified Dietitian well versed in food intolerance to maximise your nutrition going forward.


Deng Y, Misselwitz B, Dai N, Fox M. Lactose Intolerance in Adults: Biological Mechanism and Dietary Management. Nutrients. 2015;7(9):8020-8035. Published 2015 Sep 18. doi:10.3390/nu7095380

Verduci E, D'Elios S, Cerrato L, et al. Cow's Milk Substitutes for Children: Nutritional Aspects of Milk from Different Mammalian Species, Special Formula and Plant-Based Beverages. Nutrients. 2019;11(8):1739. Published 2019 Jul 27. doi:10.3390/nu11081739

Venter C, Groetch M, Netting M, Meyer R. A patient-specific approach to develop an exclusion diet to manage food allergy in infants and children. Clin Exp Allergy. 2018;48(2):121-137. doi:10.1111/cea.13087

Villa, C., Costa, J., Oliveira, M.B.P. and Mafra, I. Bovine Milk Allergens: A Comprehensive Review. Comp Rev Fs & Food Safety. 2018;17:137-164. doi:10.1111/1541-4337.12318

Updated July 2020


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