Almost every one of us started our journey in this world by sipping mother’s milk…
The history of human consumption of milk spans millennia. Today, in some enterprises with a scent of the Soviet Union inside, it is still issued as harmful, while many health organizations, both local and global, emphasize the health benefits of regular consumption of dairy products.
At the same time, scientists are not idle. The longer the world exists, the more time they have to research everything and anything. A significant part of the scientific community, often represented by unrecognized loners, is currently sounding the alarm, warning of the exceptional harm of milk and recommending avoiding its consumption.
There are rumors that milk contains hormones, antibiotics, and that the human body is not adapted to digest it, and that the widespread distribution of dairy products is a result of marketing funded by the multibillion-dollar dairy industry.
The situation is very similar to that which has developed around another very controversial product – soy.
Today, it is reliably known that its distribution in Western countries is lobbied at the state level, and the product itself combines both beneficial and very harmful properties for human health.
In this article, we have gathered some interesting facts about the benefits and harms of cow’s milk for the human body.
Main thoughts:
Humans are the only animals that consume milk in adulthood, and moreover – the milk of other animals
Scientific research on the benefits of milk for bone health is very controversial
Pregnant cows’ milk may contain 20-30 times more of the female sex hormone estrogen
How natural is it for humans to drink milk?
Typically, the search for truth about the benefits and harms of milk for health begins with contemplating how natural its consumption is for humans.
And it must be acknowledged that there is some common sense in the assertion that it is unnatural.
Humans are the only animals that continue to drink milk in adulthood and the only animals that consume milk from other animals.
This is either a mysterious mistake that no brilliant mind has managed to critically contemplate throughout time, or a wonderful illustration of human ingenuity, which has once again subjugated nature to its interests.
But what about cats (see the reader’s comment at the bottom of the page)? These lovely creatures would not drink milk if… humans did not pour it for them. Their fondness for the white liquid undoubtedly indicates its nutritional value.
The biological purpose of milk is to ensure the growth of animal offspring. From this perspective, it is a super-food, packed with all the necessary ingredients: vitamins and minerals, quality protein, carbohydrates and fats, antioxidants and… hormones.
Humans are the only animals that consume milk in adulthood, and that is milk from other animals…
Cow’s milk is intended for the growth of calves; definitely, an adult human is not a calf and does not need to grow.
I will immediately preempt a question from bodybuilder athletes working on gaining muscle mass: they also do NOT need to grow.
The increase in muscle mass, which they have chosen as their life goal, is simply a desire to excel and stand out, which has no reasonable justification from the perspective of life necessity.
I think no one will argue that consuming milk as an adult is not very natural, as it contradicts the basic laws of nature.
Nevertheless, the fact remains: humans have been milking cows for thousands of years, dairy products form the basis of the diet for most of humanity, and milk protein is the foundation of the entire sports nutrition industry.
From a common-sense perspective, consuming milk as an adult is unnatural or is a wonderful illustration of human ingenuity.
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A large portion of the world’s population is unable to digest milk. Lactose intolerance
Lactose is a type of carbohydrate found in milk.
To digest it, a special digestive enzyme called lactase is required. It is produced in the body of almost every child, allowing them to absorb breast milk.
Approximately 75% of people worldwide lose the ability to break down milk lactose 1. In medical terms, this phenomenon is called “lactose intolerance.”
Interestingly, lactose intolerance has a clear geographical dependence 2: entire regions on the world map are highlighted where it is extremely common (Africa, Asia, South America); in others, it is very rare (Russia, North America, Europe, Australia).
It is evident that in countries with good milk digestibility, livestock farming is well developed, and dairy products have been consumed for centuries.
Lactose intolerance manifests as vomiting, diarrhea, nausea, and other digestive disorders after consuming milk. Often, fermented dairy products (yogurt, kefir) do not cause digestive issues for people with lactose intolerance 3.
Geographical dependence of lactose intolerance 2 (the darker the blue color, the higher the percentage of the population unable to digest lactose)
What does it all mean?
The fact that 75% of the Earth’s population is unable to digest milk is indirect evidence that this product and its derivatives are not intended for human consumption.
But how can we explain that 25% of people do not experience problems with the digestion of dairy products?
Some scientific studies suggest that over a long period of milk consumption in these countries, there has been a genetic adaptation of the body to digest it, which has maintained lactase production throughout life 4.
Approximately 75% of adults on Earth have lactose intolerance. This indirectly indicates the harm of milk to the human body.
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1 Benefits of Milk
Milk is one of the most nutrient-dense foods
Dairy products are rightly positioned as some of the most beneficial for humans.
Milk contains complete protein, fatty acids, vitamins and minerals, and biologically active substances.
In one cup of milk 5 there are:
- 8 g of high-quality combined protein with a complete amino acid profile, which combines proteins with different absorption rates (“fast” + “slow”, see types of protein);
- 8 g of fat;
- 13 g of carbohydrates;
- 146 calories;
- calcium – 276 mg (28% of the daily value);
- vitamin D – 24% of the daily value;
- vitamin B2 (riboflavin) – 26% of the daily value;
- vitamin B12 – 18% of the daily value;
- potassium – 10% of the daily value;
- phosphorus – 22% of the daily value.
- vitamin A, vitamin B1 and B6, selenium, zinc, and magnesium.
This is a lion’s share of what is necessary for the health of the human body.
Of course, not all dairy products are the same. The set of nutrients in its composition significantly depends on what the cows are fed (grass, hay, grains, artificial feeds), the conditions in which they are kept (stall or free-range), and the stage of lactation or pregnancy the cow is in 5.
If it seems that all this is very relative, look at the following example.
Let’s take, for example, fat in milk. What associations come to mind? Something very harmful to heart and vascular health, the consumption of which should be minimized, and the ideal to strive for is low-fat dairy products.
In reality, milk fat is very complex in its composition and includes about 400 (!) different types of fatty acids, many of which are biologically active and beneficial for human health 5.
Cows that are kept in free-range conditions on pastures produce milk that contains significantly more incredibly beneficial omega-3 fatty acids (by 62%)6 and CLA (conjugated linoleic acid) (2-5 times), which has fat-burning properties 7, as well as fat-soluble vitamins.
Note: the fattier the milk, the more fat-soluble vitamins and omega-3 it contains. And the benefits of non-fat milk are lower from this perspective.
As for the “harmful to health” saturated fats, their content in milk is minimal in summer when cows are pastured, and maximum in winter 5.
But let’s not forget that this only applies to milk from organic cows raised in natural conditions.
Milk and dairy products are rich in nutrients, making them almost ideal food. The benefits of milk from cows raised on pastures are significantly higher
So, from the perspective of ingredients, milk is an ideal product.
Enough to raise a healthy and strong calf or… a big and strong bodybuilder.
However, just as a drop of tar can spoil a barrel of honey, all the benefits of the ingredients in milk that are good for humans can be overshadowed by the harmful substances it contains (read on).
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The benefits of milk protein
One of the most important beneficial properties of milk is that it is a source of high-quality protein, 80% of which is casein and 20% is whey protein. Both types of protein are the foundation of the entire sports nutrition industry.
Casein protein is a slow protein with a complete amino acid profile, which is often recommended in bodybuilding to be taken at night for muscle mass gain.
Considering the benefits of protein for weight loss, casein often becomes the type of sports protein used for this purpose by those who are losing weight.
Casein has many other beneficial properties, which are discussed in detail here.
However, there is one important caveat. It is essential to distinguish between casein from milk and casein as a type of sports nutrition. There is a significant difference between them.
Sports casein is the result of harsh technological processing, and there is evidence confirming the exceptional harm to human health of such casein.
Whey protein is undoubtedly the most popular of all types of proteins in sports and bodybuilding, possessing numerous beneficial properties for both health and muscle mass gain.
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Milk protein is the source of the two most popular proteins in sports nutrition – casein and whey protein
2 The questionable benefits of milk
The questionable benefits of calcium from dairy products for bone health
Everyone has known since childhood that milk is one of the best sources of calcium – the main component of bones.
The relationship between milk consumption levels and bone health seems quite logical.
Leading health organizations recommend consuming 2-3 servings of dairy products per day to meet the daily calcium requirement 9,10.
However, scientific research on the benefits of calcium from cow’s milk for bones is very controversial.
Some of them point to an interesting fact: the prevalence of osteoporosis is often lower in countries where the consumption of dairy products is low; and conversely, in many countries where a lot of dairy products are consumed, osteoporosis is very common 38.
If this is illustrated on a map, a very clear correlation can be seen: in regions where lactose intolerance is prevalent, i.e., less dairy products are consumed, the incidence of hip fractures – one of the main indicators of bone strength – is lower.
The frequency of hip fractures in countries around the world: red – high; orange – medium; green – low 38
A possible explanation is the predominance in the diet of other calcium-rich foods: green leafy vegetables, tofu, legumes, nuts and seeds, fish, and seaweed.
Individual scientific studies question the existence of a relationship between calcium intake and bone strength 39, while a large statistical analysis of dietary habits of over 100,000 people in Sweden indicates that consuming dairy products in large quantities (more than three servings a day) increases the risk of mortality and the likelihood of bone fractures 40.
At the same time, a large number of studies indicate that the consumption of dairy products positively affects bone density, reducing the risk of fractures and osteoporosis 11-15.
What could explain such contradictions?
It’s a complex question.
Perhaps the reason lies in other foods or low physical activity, which, alongside the consumption of dairy products, negatively impacts bone health.
Or it could be in the component composition of the dairy products themselves. After all, it is no secret that the milk most of us drink is far from organic, and we can only guess how much its producer cares about the health of its consumers.
Calcium is not the only ingredient in milk that determines bone health. In addition to it, protein, phosphorus, potassium, and vitamin K2 play important roles, while excessive consumption of vitamin A, in cases where dairy products are fortified with it, is a factor that increases bone fragility 37.
Scientific research on the benefits of milk for bone health is very contradictory
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Benefits/harms of milk in diabetes and.. obesity
This again concerns the difference between full-fat and low-fat dairy products.
As paradoxical as it sounds, some scientific studies indicate that the consumption of FULL-FAT dairy products is not a factor that increases the risk of obesity and may even reduce it, as well as the risk of diabetes and other metabolic diseases 16-19.
All these effects are explained by the content of palmitoleic acid in milk fat. From this perspective, full-fat dairy products may be more beneficial.
But even here, everything is ambiguous. Other studies discuss the benefits of LOW-fat dairy products for reducing the risk of diabetes 20,21.
It seems that both types work.
This contradiction is not surprising, as diabetes is a complex multifactorial disease, and it is difficult to attribute its occurrence to the consumption or non-consumption of any single product.
Scientific research questions the existence of a relationship between the consumption of full-fat dairy products and obesity, as well as the risk of diabetes and other metabolic diseases
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Benefits/harms of milk for heart and vascular health
“Saturated fats found in fatty dairy products are harmful to heart and vascular health, as they increase the risk of atherosclerosis, heart attack, and stroke” – one of the pillars of dietetics, which serves as the basis for recommending the consumption of non-fat dairy products.
However, recent scientific studies indicate that there is NO correlation between the consumption of saturated fats and cardiovascular diseases 22-24. We have already touched on this issue when discussing another myth about the harm of cholesterol in chicken eggs.
Some studies emphasize the existence of a positive correlation between the consumption of dairy products and a reduction in blood pressure, and thus a lower risk of stroke and heart attack 29,30.
So how can we explain the popularity of the claim about the harm of fatty dairy products and the benefits of non-fat ones? And the statistical epidemiological data that label saturated fats, including those found in dairy products, as one of the culprits of the epidemic of cardiovascular diseases and deaths 25,26?
One possible reason has been mentioned several times above: the significant difference between milk from cows raised on pastures in natural free-range conditions and those kept in captivity.
For example, it is known that in Australia, cows are kept on pastures. Long-term observations by scientists of thousands of Australians indicate that the consumption of milk with normal fat content reduces the risk of cardiovascular diseases by 69% 27. (No health benefits of non-fat dairy products are noted here either.)
Why?
One probable reason could be a higher content of vitamin K2 in such milk 28, which is beneficial for vascular health by preventing the formation of calcium-induced blood clots 8. But this is just a hypothesis.
The question requires further research.
Scientific studies on the benefits and harms of cow’s milk for cardiovascular health are contradictory. The conditions in which cows are kept are of great importance: organic milk may be beneficial.
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3 Harm of milk
Hormones in cow’s milk
Does cow’s milk contain hormones?
Yes. Even organic.
In addition to them, laboratory analysis of dairy products may show the presence of antibiotics, pesticides, and some other contaminants.
Hormones are naturally present in milk, and their concentration depends on the stage of pregnancy or lactation of the cow. Additionally, some farms administer hormones to animals to increase milk production 42. Finally, when consuming milk, the production of certain hormones is stimulated in the human body.
There is little good in all of this…
Estrogen
Estrogen is a female sex hormone, and an excess level of it in the blood is associated with an increased risk of breast cancer in women and prostate cancer in men 37.
In the milk of pregnant cows, the level of estrogen is 20-30 times higher than that of those nursing their calves 37!
How dangerous is estrogen-rich milk for human health?
Experiments on mice indicate that when consuming food with estrogen content 100 times higher than that in the milk of pregnant cows, the level of estrogen in their blood does not increase at all.
This is explained by the fact that estrogen is destroyed during digestion, just like testosterone.
By the way, this is precisely why in bodybuilding, testosterone and other anabolic steroids are usually administered via injections rather than taken orally.
And although mice are not humans, and it is unclear how milk consumption affects estrogen levels in human blood, it is important to keep in mind that even a slight regular increase in estrogen levels in the blood can pose serious health risks.
This topic is thoroughly explored with numerous illustrations from the animal and human worlds in the material on the dangers of soy using the example of phytoestrogens.
Milk from pregnant cows may contain 20-30 times more of the female sex hormone estrogen
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Growth Hormone
On many farms today, cows are administered growth hormone (somatotropin) to increase milk production 37.
As with estrogen, when it enters the gastrointestinal tract, most of it is broken down into peptides, chains of amino acids, just like during the digestion of proteins (the structures of protein and hormone molecules are very similar).
The concentrations that could theoretically enter the bloodstream are not harmful to humans.
The growth hormone is naturally synthesized in the human body and is responsible for the growth and regeneration of organs and tissues. In bodybuilding, the growth hormone is used by athletes to stimulate muscle mass growth and primarily acts by enhancing the secretion of another hormone – IGF-1.
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IGF-1
During the digestion and absorption of milk and dairy products, the production of certain hormones is stimulated in the human body. This primarily refers to IGF-1 – insulin-like growth factor.
This circumstance has its pros and cons.
For those engaged in bodybuilding with the goal of increasing muscle mass, IGF-1 can be beneficial as it stimulates muscle mass growth and accelerates recovery after training 31.
That’s all about the pros. Now for the cons.
For the health of the human body, the balance between various hormones is very important. Its disruption
Dairy products can both contain hormones and stimulate their natural production in the human body. This has advantages for athletes in bodybuilding, but at the same time, they can increase the risk of cancer.
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Antibiotics, pesticides, and toxins in cow’s milk
Due to the unnaturally high milk production, cows often suffer from mastitis or inflammation of the mammary glands. Antibiotics are used to treat this, some of which inevitably end up in the milk 41.
Pesticides, polychlorinated biphenyls (PCBs), dioxins – these are a few examples of contaminants that may be present in milk 41,43 and are a characteristic consequence of the industrial and agricultural revolutions.
These chemicals are strong toxins and pose serious harm to human health.
They are not excreted from the body and tend to accumulate, and when a certain concentration is reached, they negatively affect the immune, reproductive, and central nervous systems and increase the risk of cancer 44.
Among other possible contaminants are melamine and the carcinogenic toxin aflatoxin, which milk is “enriched” with during production 45,46.
Melamine is often used in the production of plastic containers; it is harmful to the kidneys and urinary tract due to its high nitrogen content.
There was a time when unscrupulous sports nutrition manufacturers deliberately used it in sports proteins, which allowed them to reduce costs at the expense of significant harm to the kidneys. See our material Quality protein: common quality issues of sports proteins, laboratory analysis results, how to check it yourself.
Chemical impurities in milk are all the more dangerous as they are not destroyed during pasteurization.
Laboratory tests detect the presence of antibiotics, pesticides, and strong toxins in milk, which can accumulate in the body and pose serious harm to human health.
Conclusion
There is no definitive answer to the question of the benefits and harms of milk for the human body.
From a compositional standpoint, it is a fairly valuable product, packed with numerous beneficial substances sufficient to grow a weak calf into a powerful bull.
At the same time, the beneficial properties of milk seem to significantly depend on the conditions in which cows are kept and what they are fed. Milk obtained industrially is less beneficial and can indeed contain hormones, antibiotics, and numerous chemical contaminants.
The harm to the body from hormones is not obvious: most of them are destroyed in the digestive tract, however, there is a possibility that even small concentrations can be dangerous with regular consumption.
