Is Milk the Devil?

Is Milk the Devil? 

The answer to this question is - it really, really depends.

Thanks Anna, that's "very helpful"  😕

I know, I'm sorry - but as you've heard me say before, the name of the game, once again, is nuance. So here goes...

Dairy is one of those controversial topics and if you are confused about whether or not it should be part of your diet, you are not alone. As a child you were probably told to drink your milk so you can grow big and have healthy bones. Nowadays, the internet is full of health experts claiming that dairy is bad. Plant "milks" and plant yoghurt and cheese alternatives are lining the shelves of even the smallest supermarket.

So who is right? Your grandma or the internet?

In a way, both of them. But lets zoom in.

What we know is good about milk

If you think about it, milk is actually a superfood. It's one of those rare foods that contains everything needed to sustain life - proteins, carbohydrates, fats, minerals, vitamins and WATER! It provides both calories and hydration. 

The protein in milk contains all essential amino acids  - these are the building blocks of proteins that our body cannot live without but also cannot make itself.

Milk contains a special type of sugar, lactose, which is unique to milk. Lactose has a glycemic index of 46 (compared to glucose whose glycemic index is 100). This means that it will not cause a big spike in your blood sugar - unlike other sugars, such as the regular table sugar (sucrose) which has a glycemic index of 65.  

Milk is also a source of some very special fats. It contains certain natural trans fats which - unlike artificial trans fats that really are the devil - have unique health benefits. Trans-palmitoleic acid and conjugated linoleic acid, the natural trans fats in dairy have been associated with healthier levels of blood cholesterol, inflammatory markers and insulin levels and have been shown to reduce the risk of heart disease, cancer, and diabetes. Butyrate, a short chain fatty acid found in milk, has strong anti-inflammatory properties and provides energy to the cells lining the colon. 

As far as vitamins go, the fat in milk is a good source of fat soluble vitamins, A, K2 and even some vitamin D. The vitamin A in milk is in a form your body can use directly - unlike the vitamin A in plants which comes in the form of beta carotene and which the body needs to work hard to convert to a form it can use. 

Milk also contains several B vitamins, including B12 without which red blood cells cannot be made, DNA cannot be synthesised and our neurons cannot function properly. B12 is only available in animal products, thus dairy is an important source of it for vegetarians. 

One cannot, of course, forget the minerals, of which calcium is the star. Your grandma was onto something, because when you drink milk you absorb about 30-40% of the calcium from it. The same is not true for calcium that comes from plants. For example, when you eat spinach, due to the oxalates it contains, you absorb only about 5% of its calcium. You would need to eat about 16 cups of spinach to get the same bioavailable calcium that you get from one glass of milk. The story is similar for other vegetables, even those with good bioavailable calcium, like the cruciferous family that is low in oxalates. You would need to eat A LOT of cabbage and broccoli to obtain enough calcium to cover your daily needs.

The objections to milk

How many times have you heard the argument: "milk is the perfect food ... for baby cows. No animal drinks milk after the age of weaning". Well, this is true for about the first 18 months of your life or so. Milk from a different animal is absolutely not suitable for human babies due to its different chemical composition. Cow milk, for example, has too much protein and too little lactose compared to human milk. The same way you do not give small babies steak, beans, honey, or whatever else their tiny bodies are not yet ready for, you are not going to give them milk from another animal. However, after the age of 18 months or so, this argument falls apart. There are reasons to avoid milk - which we will address below - but this is not one of them! 

Throughout our evolutionary history we have adapted to our environment so we can get the best out of the resources that surround us and ensure our own survival. We have processed foods so that we can digest them and preserve them - no other animal uses fire to cook its food, no other animal processes grains and seeds into flour which they can turn into bread and easily digest, no other animal uses fermentation and other techniques to preserve its food. I will not go on about what else we do now that our ancestors did not do 2 million years ago and that other animals do not do. I believe you get the idea.

There are communities of humans in Africa and Asia that still, to this very day, rely on milk and its derivatives for the majority of their nutrient and energy needs. In areas of the world that are mountainous and inhospitable, humans have found a way to survive by living together with animals. The animals turn plants, inedible to humans, into nutrient dense food in the form of milk. Dairy also forms part of the Mediterranean diet, seen as one the healthiest in the world.  

But what if I cannot digest milk?

You probably don't care if the Maasai in Kenya or the yak herders in the Himalayas eat dairy for breakfast, lunch and dinner if your own body does not agree with milk.

It is very true, that many people today cannot digest milk. Genetics plays a role, but that's not the whole story.

When it comes to the inability to consume dairy - some people do have a true allergy to the proteins in milk (beta-lactobulin, gamma-globulin, alpha-lactalbumin and casein). However, a true allergy to milk protein is quite rare (affecting about 3% of children) and most do generally grow out of it by age 5 or so. So only 1% of adults are affected by this. 

What is much more common in an intolerance to lactose (the sugar in milk). This is where your genetic lottery matters. About 10,000 years ago some humans domesticated animals and also developed the ability to digest their milk well into adulthood. These populations maintained the ability to produce the enzyme lactase (which can break down lactose into its component parts: glucose and galactose) beyond their childhood years. This only happened in some parts of the world - and while it spread somewhat - still today a good part of the earth's population is either unable to digest lactose in adulthood or has varying degrees of trouble doing so. 

If your ancestors came from northern or central Europe you have a very good chance of being able to enjoy your glass milk into your old age. If, however, you are of East Asian, or sub-Saharan African origin you might as well forget about it. Everyone else, is somewhere in between. 

Regional lactose malabsorption prevalence and country estimates in Asia and Oceania, the Middle East and northern Africa, America, Europe, and sub-Saharan Africa 

Data Source: Christian Løvold Storhaug, Svein Kjetil Fosse, and Lars T Fadnes, "Country, Regional, and Global Estimates for Lactose Malabsorption in Adults: A Systematic Review and Meta-Analysis," thelancet.com, Oct. 1, 2017

The problem with technology

However, genetics is not the be all and end all. There are many people today who do not tolerate milk and genetics is not the main reason. In our attempt to make milk and its by products safe, more tasty and increase their shelf life milk undergoes a significant amount of processing. There are various degrees of processing but -

the more milk is processed the less easily digestible it becomes, the lower its nutrient value and the higher the amount of toxic by products.

Loss of the good stuff

Milk, in its raw form, contains enzymes, such as lactase, which aid with its digestion. These enzymes are destroyed by heat. As soon as milk is heated its digestibility is decreased. The other things lost with heat is certain B vitamins and vitamin C. This decrease in digestibility and nutrient density happens to some extent already when milk is pasteurised - i.e heated to 72 degrees for 20 seconds. However, pasteurised milk is expensive because its shelf life is short and it requires constant refrigeration. 

To extend shelf life, milk is heated even more. Sterilised milk is heated to 115 - 120 degrees for 2o minutes and UHT (Ultra High Temperature) milk is heated to a 140 - 150 degrees for a few seconds. This process kills everything alive - bacteria but also enzymes and reduces the content of heat sensitive vitamins significantly. While it increases shelf life to > 3 months, without the need for refrigeration, it comes at a certain cost. 

The Maillard reaction 

Other than the loss of enzymes and vitamins, heating milk leads to what is known as the Maillard reaction - its a chemical reaction that takes place when proteins and sugars are heated together. In milk the amino acids that make up the milk proteins (in particular lysine), react with the sugar lactose and the result is in something called CML (carboxymethyline) which is a type of AGE - Advance Glycated End-product.  

The Maillard reaction is not unique to milk. In fact you have seen it multiple times with your own eyes. Every time you fry, toast or barbeque something and it brows, that's the Maillard reaction right there! It also happens inside our own body. In fact, that's one way diabetes is diagnosed! The Hemoglobin a1c (Hba1c) is what your doctor will measure to see what percentage of your hemoglobin (the protein that makes your blood red) has glucose literally stuck to it. As red blood cells have a lifespan of a few months, by seeing how many of them have glucose stuck to them we can figure out what our average blood sugar has been in the preceding months. (I find that super cool!). A high hemoglobin a1c is not good news, because sugar stuck to things in the body is not good news. And consuming AGEs in our food does nothing good either.

Over time, AGEs accumulate, leading to inflammation, chronic disease, and accelerated aging.

Middle aged women with high levels of AGEs in their blood were found to be twice as likely to die from heart disease, even if they were not overweight and did not have diabetes. AGEs cause damage everywhere they go. They accelerate inflammation, atherosclerosis and damage the kidneys. They alter the structural quality of blood vessels, bone, muscle, and other tissues through cross-linking with collagen. Due to their ability to cross-link with collagen, AGEs quite literally age us - they cause the skin to lose elasticity, which shows up as fine lines and wrinkles.

Our body has systems in place to deal with a certain amount of AGEs. The problem starts when over time, the amount of AGEs we ingest or make internally exceeds our body's capacity to deal with them. So as a matter of course, we should all try to minimise how many AGEs we put into our body - that's one thing that is in our control.

Homogenisation

The other thing that happens to milk before it reaches your supermarket shelf is that it gets homogenised.  Milk is squeezed through microscopic pores or tubes at very high pressure so that the fat molecules break down into tiny droplets that can then stay dispersed throughout the milk, and not than rise to the top. Homogenisation is what gives milk its familiar rich, white color and smooth texture. It is almost impossible to find milk on a supermarket shelf that has not been homogenised.

Fat molecules in raw milk are quite complex structures. Fat and water are not friends, so in order for fat to move around in a watery medium, it needs to be enveloped by a membrane that is friendly with water. Fat molecules in raw milk have a very elaborate and complex membrane structure. Homogenisation completely destroys this membrane. The much smaller fat molecules now have a much larger total surface area that needs to be covered with something in order to move through the watery medium that is milk. That "something" is proteins, mainly casein and whey, that come and stick to the fat molecules. At the same time, things that made up the original fat membrane get released into the watery medium - one of them, an enzyme called xanthine oxidase, starts doing its job of converting things to uric acid (known for its role in gout) and causes a good amount of oxidative stress in the process.

After homogenisation milk becomes quite a different product. Its matrix has been changed from how nature originally designed it. The tiny fat molecules, covered with proteins, enter the blood stream in this new form much faster and the body has to figure out what they are and what to do with them. 

While homogenisation has been the standard in milk processing for over 100 years now, there are not many studies on its effect on human health. Is the body able to recognise this different structure or will it treat it as foreign and send its defences to attack it? What is the impact of this faster entry of milk proteins and fat into the blood stream? Is this the optimal way to consume milk? I don't know. What we do know is that messing with the matrix of a food, departing from its original molecular form, changing the way its nutrients interact together, also changes the way it is digested and the effect it has in our body. We do this all the time in the case of ultra processed food - and there, for sure, its never a good thing. If one is to err on the side of caution it may be prudent to consume milk in a format as close as possible to its original structure - without compromising safety.

Getting the best, minimising the worst

Does this mean that we should all buy a cow and drink raw milk?  

No - but here is how you can optimise and decide what is best for YOU in the world YOU live in.

• Minimise your consumption of UHT milk - we can all do with less AGEs in our life.
• Avoid store bought flavoured, chocolate, condensed milk - its dessert. Not something you or your kids should be relying on to get nutrients from.
• Prefer fresh, pasteurised milk. If possible organic (and if you are in the US - grass fed). Its more expensive but you are going for quality over quantity and you are voting with your €/$/£. The nutrient density of your milk is closely linked to what the cows ate and what kind of life they had. Chose a company that respects the animals. Usually (but not always) organic is also synonymous with better animal welfare, more nutrient density and less exposure to toxic substances that do not belong in your body.
• If you can find a local farm (or one that delivers to you), buy their raw milk and heat it up at home, you are a rock star!  More and more farms sell direct to consumers these days. It may require you to get a bit out of your comfort zone to investigate this option. Don't be put off by the process. All you need is a pot, a simple food thermometer and some glass jars to store the milk. Just heat the milk to 72 degrees Celsius for 20 seconds and, once it cools a bit, put it in the fridge. The cream will rise to the top so you can chose to remove it (or use it in your coffee or cooking). This extra bit of effort is well worth it - you are getting milk which is more nutrient dense (vitamins get lost the longer milk sits on a shelf) and which is not homogenised. 

Finally, figure out what your lactose tolerance actually is. Just because some health expert, somewhere said that dairy is bad, it does not mean it is bad for you and it does not mean that you cannot optimise the way you consume it. If your body is not making the enzyme lactase to break down the lactose in milk, you will know. Lactose will not be broken down into glucose and galactose and it reach your large intestine intact. There, it will act like a kind of prebiotic, i.e. food for your gut bugs. You may be lucky and have bugs that can deal with it without giving you too much trouble - or you may not. In that case it will be "fireworks" in there - and not in a good way. If this is you, you may still be able to get the benefits of dairy by having milk in a fermented form, like yoghurt or kefir - since the bacteria will have done part of the lactose digesting work for you. You may not be able to tolerate store bought milk or yoghurt (lactose is often added by the manufacturer), but you may be able to tolerate farm bought milk and home made yoghurt. Also, remember that lactose is in the watery part of milk. So the harder the cheese, the less lactose it has. Butter has virtually none and ghee has zero.

So the moral of this is story is -

Milk is not the devil - it can be a fantastic, nutrient dense food, if you have the genes to digest it and if you choose to consume it in a form that has undergone as little processing and time on the shelf as possible.