In recent years, dairy has developed a bad rep. Why? A surging increase in cases of self-reported food allergy or intolerance, with milk and dairy topping the list.
The rise in a self-reported dairy intolerant has come hand-in-hand with the upsurge of totally unqualified, self-proclaimed fitness ‘models’, ‘bloggers’ and ‘insta-nutritionists’. And they’ve been encouraging their followers to boycott certain food groups based on, well, utter nonsense.
Sadly, for cheese-lovers, dairy is often front and centre of their dietary ‘recommendations’.
So, is dairy a problem? Let’s take a look at what the science really says.
Dairy Intolerant vs. allergic reactions
Before we all descend into mass milk panic, we need to separate food allergies from food intolerances. The two are very different.
A food allergy is a reaction involving the immune system, for example an anaphylactic response to eating nuts. The reaction is immediate and it doesn’t matter how much of the food you eat, even trace amounts can trigger a response. Not very pleasant.
A dairy intolerant, however, doesn’t involve the immune system and is usually down to a an enzyme deficiency or a pharmacological reaction (i.e. running to the bathroom after too much caffeine). The responses don’t often occur every time a food is consumed, aren’t immediate and often depend on how much of the food you eat. Dairy intolerant is common – and an example of what differentiates an intolerance from an allergy. The issue is a deficiency in the lactase enzyme, used to digest lactose (the sugars found in milk), not an immune response.
Cow’s milk allergy is a common allergy in children and most food allergies involving the immune system – the most common being eggs, milk, peanuts, tree nuts, wheat, fish, and shellfish – develop in early childhood.
However, most children grow out of cow’s milk allergy, gaining tolerance to the food as they get older. Ergo, if you’re getting symptoms immediately after enjoying a lovely glass of milk, you should do two things. Firstly, rule out a true immune-system mediated allergy with your doctor.
Secondly, get an actual dairy intolerant test (like a hydrogen breath test) from your doctor to determine whether you are, in fact, dairy intolerant instead.
What’s interesting is that dairy intolerant doesn’t mean the downfall for dairy overall. Fermented dairy products, like yoghurts, often have sugars modified by fermentation or – in the case of cheeses – can be predominantly protein and fat. And researchers found that some lactose intolerant people can tolerate cheeses and yogurts. That’s a welcome relief. On top of this, lactose-free milk is widely available.
Let’s talk dairy intolerant
So, milk allergy and dairy intolerant are both diagnosable conditions.
This is important because, as more and more of us banish dairy from our diets, one fact stands out. As self-reported ‘intolerance’ has increased, medically diagnosed allergy or intolerance hasn’t – over a 10-year period. Two studies indicate the reasons for this are largely psychosocial.
The first study was a survey of raw milk drinkers that asked why they drink raw milk over pasteurised milk. Apart from some environmental (and entirely valid) reasons, almost 60% said they thought it was healthier and easier to digest. Matching the increase in self-reported dairy intolerance, however, only 3% had been diagnosed as dairy intolerant by a doctor. Hmm.
Like any good scientific survey, this generated a research question: Does pasteurisation make commercial milk harder to digest than raw milk?
Well, a group of researchers from Stanford University decided to find out. They gathered a group of lactose intolerance ‘self-reporters’ and then tested which ones were actually dairy intolerant. The group then drank either whole organic raw milk for eight days or whole organic pasteurised milk, with whole soy milk serving as the non-dairy control. The results? Interestingly, by day eight, there was no difference – both milks produced the same response. That suggests raw milk – unaltered and still containing bacterial enzymes that supposedly aid digestion – doesn’t reduce the symptoms of lactose intolerance.
So – we’ve got people reporting food intolerance to commercial milk and also self-reporting tolerance to raw milk.
Yet the evidence above shows no difference in symptoms between the two, in subjects with diagnosed lactose intolerance. That suggests many self-perceived intolerances to dairy are psychosomatic, which is supported by evidence that many who self-report dairy intolerance show no clinical signs of lactose malabsorption.
Is there a dairy intolerance test?
Just quickly, it’d be silly not to mention ‘food intolerance tests’. You know the ones. I’ll keep this brief: barely any evidence supports the use of these tests for diagnosing a food intolerance, and the European Academy of Allergy and Clinical Immunology has advised against their use too. Save your money.
If not lactose intolerance, then what? The A1 vs. A2 debate
So why do you feel rough after demolishing the dairy?
Given that self-reported symptoms aren’t matching up to diagnosed lactose intolerance, some now think the difference in protein between the milk of different breeds of cow is an issue.
The theory relates to a genetic mutation that naturally occurred in European cows – a.k.a Holstein cows – leading to a variant of the protein produced in cow’s milk, called A1-beta casein. On the other hand, African, Asian, Jersey or Guernsey cows – they didn’t get the mutation – produce another variant known as A2-beta casein. That creates one serious international cow competition. Anyway…
Some research suggests (and this gets a bit technical) when we digest A1 milk, we produce an opioid as a product of A1-casein breakdown.
It’s this opioid that causes gastrointestinal symptoms. A trial in China, a country with lots of lactose intolerance, found people consuming mixed A1/A2 milk had more symptoms than those consuming A2 milk alone. However, the symptoms were mainly significant in those with dairy intolerant, which is difficult to differentiate given that the lactose, not the protein, may have been the culprit.
Another trial comparing an exclusive A1 milk to an A2 milk found no significant difference in symptoms, except in those with self-reported (not diagnosed) lactose intolerance.
Overall, the A1 vs. A2 debate is difficult to justify because of limitations in the studies and the greater chance of subjects with dairy intolerant seeing symptoms. Let’s move on.
Is eating dairy healthy?
Traditionally, whole-milk dairy products – as foods containing saturated fats – have been ousted by low-fat dairy options because of the link between saturated fat and cardiovascular disease. However, nutrition has recently begun focusing more on foods and less on individual nutrients. So, while the evidence still supports that eating high levels of saturated fat (through lots of animal fat) is strongly associated with heart disease, this shift in focus has found something else that’s rather interesting. Whole-milk dairy is not associated with cardiovascular disease or obesity risk.
One reason for this may be calcium, found readily available in dairy products – eating lots of it reduces blood pressure, in turn reducing heart disease risk. However, one of the interesting things to note here is that the protective benefit of consuming dairy is observed with whole milk dairy – a.k.a naughty “full-fat’, the good stuff. Though this goes against standard public health recommendations to choose low-fat dairy produce, the shift in focus to particular foods over nutrients has revealed the fat composition of milk has certain properties that are beneficial to health.
This doesn’t mean low-fat dairy produce is suddenly out, in fact the opposite. Low-fat dairy foods, like Greek yoghurts or cottage cheese, are higher in protein. Milk-derived proteins appear to have important roles to play in protecting against obesity and low-fat dairy consumption is closely associated with a lower risk of obesity. There is an important take-home message here because, right now in nutrition, there is far too much black and white thinking. There are benefits to low-fat dairy and there are benefits to whole-milk dairy.
Tasty dairy brownie points
There are more health benefits for dairy stacking up.
Dairy fat contains short-chain fatty acids, which bacteria in the human gut use for energy and for repopulating the gut with beneficial bacteria. These short-chain fatty acids are also less of a problem for heart health, as they don’t affect blood cholesterol as much as longer-chain fatty acids do, like the ones found in beef.
Dairy is also a fortified source of vitamin D and, together with calcium and a high protein content, these are all nutrients associated with the lower risk of metabolic disease. This might explain why eating dairy foods is significantly linked with a lower risk of obesity.
All of this has resulted in a reappraisal of the health benefits of dairy, and whole-milk produce, in particular.
The evidence overall suggests dairy can help to maintain lower body weight and reduce the risk of heart disease. Remember, nutrition isn’t a zero-sum game: including a mix of whole-milk and low-fat dairy produce can offer a broad set of health benefits.
Is dairy good for gut health?
When we talk about ‘dairy’, we’re obviously not simply talking about milk; the food group is diverse and includes foods that are products of fermentation, like yoghurts, fermented milk, and glorious cheeses. These foods contain bacteria beneficial to the human gut, dairy being one of the few food groups that provides this.
Changes to bacteria in the gut can be a key feature of many conditions, like inflammatory bowel conditions, obesity and metabolic disease. Eating yoghurt, a food enriched with probiotic bacteria, reduces levels of potentially pathogenic bacteria, like E.coli and H.Pylori. On top of this, research has shown that probiotic-rich yogurts can relieve symptoms in those with lactose intolerance and irritable bowel syndrome.
What’s more interesting is the recent research on the role that gut bacteria plays in mental health, given the now well-established links between the gut-brain axis. Research has shown fermented milk influences brain activity in a manner which corresponds to improved cognition. In a study of healthy women, without any gut or psychiatric symptoms, researchers found that consuming 250g/d of a probiotic-enriched yogurt, over four weeks, led to changes in brain activity in the regions that control emotion and sensation.
While research into the human gut microbiome remains in its early days, one thing that can be said is that the composition of gut bacteria plays a significant role. And that’s in both gastrointestinal and neurological health, with emerging data on metabolic health. Keeping your gut happy is a step to better health – time to go get some fermented dairy produce, things like yogurt or kefir to you and me.
Dairy-fuelled muscle growth
What about making ‘gainz’ at the gym, can dairy help there?
Recent research has shown muscle protein synthesis (MPS) is most strongly triggered by the amino acid leucine, a dose of 2g leucine resulting in maximal stimulation. Okay – but how does that relate to a pint of milk? Dairy proteins, particularly whey, are a rich dietary source of leucine and therefore might contribute to increasing MPS. In a study comparing 500ml low-fat milk vs. 500ml soy milk, the low-fat milk significantly increased leucine concentrations in the body.
However, dairy proteins are typically 80% casein, a slow-digesting protein, and 20% whey, a rapidly digesting protein. The different absorption rates lead not only to a higher leucine response but to more sustained MPS in the hours following a meal. This is a positive attribute of dairy proteins, specifically with eating casein-rich protein before bed as it leads to more sustained MPS overnight while you sleep.
So, what else? Dairy proteins, as a dietary source, also contain higher levels of essential amino acids than many other food groups. Due to the rapid absorption and maximal stimulation of MPS from whey, low-fat milk products are ideal for activating MPS right after training. On the other hand, casein-rich proteins like cottage cheese and/or Greek yogurt are great for maintaining MPS during extended periods of time without eating, like overnight.
The dairy verdict
I’ve found any attempts to present positive findings about dairy are often met with comments about ‘industry funding’ or some other cynical guff. These criticisms are largely divorced from the reality of the evidence. While there are certainly some research gaps to fill regarding allergies in adulthood, the idea of blanket exclusion of an entire food group (poor old dairy) is based more in the realm of ideology than evidence.
This isn’t merely my opinion – a recent review of all the evidence relating to dairy found that, consistent with all of the above, dairy protects against many chronic diseases, is a nutritionally dense food and contributes significantly to keeping us fit and healthy. On top of this, plant milk ‘alternatives’ – a rising trend pulling along an ever-increasing bandwagon – simply can’t be considered true alternatives. They are entirely different to milk, are often nutritionally bereft and there is no evidence to support their adequacy as an alternative.
All the evidence supports dairy as a health-promoting, nutrient-dense food group. It comes in many forms, and can be consumed in a variety of ways. And if you really think you have issues, please have these ruled out medically so you’re not guessing in the dark. Assuming you’re not dairy intolerant and don’t have a cow’s milk allergy, there is really no evidence to support the boycotting of dairy for health or nutrition. Now, where’s that milkshake?