A short history of dairy consumption
Humans have been involved in dairying practices for around 10,000 years (1). Early dairy farmers saw the opportunity to convert uncultivated, dry grassland into an energy and nutrient-rich food. Prior to this, our hunter-gatherer ancestors were exposed to milk curds in the stomachs of young mammals that were hunted. This would have been a cheese like substance that would have been consumed on an opportunistic basis.
Dairy in our modern world
Dairy production is one of the biggest sectors in our commercial food system. The use of high-yield breeds of cattle has become common place, with a resulting change in the protein make up of our milk. Other processes used in modern dairy production include pasteurisation, including ultra-high temperature pasteurisation to produce UHT milk. Homogenisation is a process used to distribute the fat droplets evenly throughout the milk. We reduce the fat content, add some vitamins, put into plastic containers and transport it across the country in trucks. Sometimes we even dry it down into a powder, which we add to bread and other processed foods. Strangely enough, often we don't even realise that what we are eating has dairy in it at all! Does the dairy we consume now even resemble the structure or quantity that was consumed by our ancestors?
A note on dairy allergy
Classical allergies to dairy are IGE-mediated immune reactions to one of the proteins present. These reactions can potentially be sudden and severe, and are outside the scope of this article concerning intolerances. Diagnosis is usually made in babies and young infants, with symptoms that can include hives, eczema, diarrhoea, vomiting, swelling and breathing difficulties. If you suspect your child has this type of reaction see your general practitioner for further information regarding diagnosis and management. Around 2% of Australian infants are allergic to dairy, with most of these outgrowing their reaction by 4 years of age (2).
What are the forms of dairy intolerance?
While an intolerance to dairy is not as urgent to identify as an allergy, it can still produce very real symptoms and discomfort for the individual in question. Intolerances can be triggered by other parts of our immune system, including IGG mediated reactions. They can be delayed reactions that are difficult to assess and manage. These are often associated with poor digestive function and increased intestinal permeability. The category of dairy intolerances can also involve mechanical reactions within the digestive system, such as in the case of lactose intolerance discussed below.
What is lactose intolerance?
Lactose is a milk sugar occurring naturally in milk and some other dairy products to varying degrees. In mammals, the quantity of lactase (the enzyme that digests lactose) decreases after weaning. Insufficient lactase produces symptoms including bloating, cramping, diarrhoea, gurgling noises, flatulence and nausea. Up to 70% of the adult population is thought to be lactose intolerant, with the lowest incidence in Northern European descendants (approximately 5%) who have a long cultural history of fermented dairy intake. Culinary traditions have also evolved to allow the reduction of lactose content in dairy, such as in the case of yoghurt and cheese.
There are many other variables which decide whether a person will have symptoms of this condition. These include the amount of lactose consumed, other components of the meal, characteristics of the individuals digestive system and the presence of infection or inflammation. Research shows that live yoghurt increases lactose digestion, as a result of an enzyme released by the good bacteria present in response to digestive secretions. Yoghurt that was then pasteurised after fermentation did not offer the same support as the live yoghurt. It's also important to note, that acidophillus-rich milk also did not produce the same actions as the live yoghurt either (3). This suggests that despite the presence of a moderate amount of lactose in most yoghurts, it could offer digestive benefits to those with lactose intolerance that is superior to some probiotic supplementations.
What about A2 dairy?
Cow's milk contains two main forms of the beta-casein protein, commonly referred to as A1 and A2. Casein is the protein in dairy that is most frequently involved in allergy and intolerances. Consumption of A1 dairy (in 'regular' dairy) is associated with the production of a casomorphin compound which can induce inflammation in the gastrointestinal tract. A 2016 study concluded that replacing A1 beta-casein with A2 beta-casein reduced the post-dairy discomfort symptoms experienced by a group of individuals with self-reported intolerance to cow's milk or lactose. A1 beta-casein (in 'regular' dairy) consumption was also associated with a slower transit time, and avoidance of this protein could play a role in constipation for some individuals. A surprising result of this study was that A1 beta-casein (in 'regular' dairy) was also associated with decreased cognitive performance, in terms of both speed and accuracy. To me, this is yet another reminder of the ability of our food choices and digestive function to affect the activities of nervous system and brain (4). This outcome suggests that a trial of A2 dairy is certainly warranted in individuals who suspect they react to milk proteins or lactose.
What about whey protein?
Whey is another protein found in dairy. While it is possible to have an intolerance reaction to this protein, it is much less likely. Whey is the clear liquid that you often see on top of your yoghurt, and also the base of many protein powders. If you do tolerate this dairy product, you might be surprised to find out it has many health benefits to offer you. I suggest you source it in the most natural way you can, from yoghurt if tolerated, or a pure whey protein isolate (WPI) which should be additive free. Whey contains the immune supporting compounds lactoferrin and immunoglobulins, which are useful in a range of bacterial and viral conditions. Research has shown whey protein to be beneficial for a range of therapeutic applications, including improving stress tolerance, reducing digestive inflammation, healthy weight maintenance and increasing exercise tolerance (5).
What are the best dairy choices?
Dairy provides some nutrients that are often difficult to source in our modern diet, including vitamin D and K. These are both fat-soluble vitamins, which is why I recommend the consumption of a moderate amount of whole dairy products as tolerated. I recommend organic or grass-fed dairy, which has been shown to have a higher omega- 3 content than milk produced by conventional farming methods. I recommend A2 dairy as a trial if you don't tolerate 'regular' dairy well. Keep in mind that some organic brands farm jersey cows which produce A2 milk also (but most likely won't be certified as A1 protein free). The quantity and forms of dairy you consume will also be influenced by other health conditions you have, including high cholesterol.
I would recommend the following dairy products as being the most nutritionally dense and useful to most diets. They are in the order of the easiest to most difficult to tolerate for most people.
- Ghee (recipe here)
- Whey protein isolate
- Home made yoghurt (recipe here)
- Commercial yoghurt
- Milk (small quantities)
What can I do if I think I have a dairy intolerance?
Lactose intolerance can be diagnosed through a hydrogen breath test. It can also be tested through an elimination challenge. Keep in mind that lactose-free dairy and hard cheeses are very low lactose. Dairy protein intolerance may require an elimination challenge, to determine your level of tolerance. Research suggests that individuals on a dairy-restricted diet are more likely to have an overall reduced intake of calcium. This was associated with an increase in hypertension and diabetes in one trial (6). This highlights the importance of including the broadest range of food groups and nutrients in your diet that you can tolerate.
As a general rule, I prefer to be inclusive with the diet I recommend to my clients rather than exclusive. There are times when I recommend a two-six week dairy free trial to clarify the role dairy might play in my client's symptoms. This should always be done with the support of a health professional to ensure your diet is nutritionally balanced at all times. The aim is always to work towards better digestive function to broaden the range of foods that your digestive system tolerates.
Putting dairy intolerance into perspective
Humans are very adaptable, and if there is a food source on offer then chances are we can utilise it so some degree. However, hopefully you can see that the question of wether dairy is an ideal food source for you is not such a black and white question. This will depend on your genetic make up, cultural background, digestive system and the dairy choices you opt for. We are all individuals, and really why would our tolerance to dairy products be any different. If you would like help identifying or managing a dairy intolerance consider an appointment at the clinic to discuss your situation further, more information here.
This blog post is for your general information and is not intended to be medical advice. Please see your qualified healthcare professional for more information on the safe treatment of your specific health conditions.