Milk is a nutrient-rich white liquid that is produced by the mammary glands of mammals. Humans began consuming milk regularly during the Neolithic Revolution several thousand years ago through the domestication of cattle. Subsequently, milk products such as cheeses and curds were produced by curdling milk protein, and butter was made from milk fat.
Although milk and dairy products are a traditional part of many cultures and have been consumed for several thousand years, unfortunately milk (especially cow's milk) and other dairy products are shrouded in many superstitions, myths and untruths, some of which have persisted among humans for centuries! Let's take a look together to see how these myths really are.
❌ 1. "Milk and dairy products create mucus."
This widespread myth dates back to the Middle Ages, specifically from the Jewish physician Moses Maimonides, who stated in his 12th century treatise on the treatment of asthma that milk increases mucus production in the airways. Today, however, we are living in the 21st century and, thanks to many studies, we know that milk does not increase mucus production and that it is not even necessary to avoid it if you suffer from asthma or cystic fibrosis.
This myth of congestion has probably persisted for so long due to the consistency of milk and dairy products, which can feel like mucus. More recent studies have also confirmed the paradoxical phenomenon that an increased feeling of constipation after consuming dairy products or milk is subjectively reported by people who truly believe this myth, even though increased mucus production does not objectively occur (this is the so-called "nocebo effect", the opposite of the placebo effect).
❌ 2. "Milk is indigestible for an adult."
Milk serves as the primary source of nutrients for mammalian babies after birth, including humans, and because of this we have the highest activity of the enzyme lactase after birth, which helps us digest milk sugar (lactose). Lactase enzyme activity naturally decreases over the course of life, but sometime between 5000 and 10,000 BC a mutation occurred that ensures the enzyme is maintained into adulthood, allowing us to digest lactose later in life. Thus, humans have adapted to milk intake throughout history, because for individuals who had no difficulty digesting it, milk was a significant advantage in times of scarcity of other foods. This so-called 'lactase persistence' is particularly widespread among the inhabitants of north-western Europe.
Even in the UK, about 75% of the population has the allele for the preservation of this enzyme in adulthood, and therefore the vast majority of the UK population has no problem digesting lactose and drinking milk even in later life. At the same time, it is true that lactase deficiency in adulthood varies widely regionally, and while in Denmark only about 4% of adults are affected (i.e. 96% of the adult population has no problem drinking milk), in Thailand the figure is as high as 97%. Also, the vast majority of African Americans and Indians are lactose intolerant in adulthood. But this is simply not the case for indigenous European populations.
❌ 3. "Calcium, which is found in milk and dairy products, is not well utilised by the body, and consumption of milk and dairy products causes osteoporosis."
Other myths include the claim that calcium from milk is not well utilised by the human body, or even that milk contributes to osteoporosis, or 'thinning of the bones'. If we look at the relevant scientific studies, we find that, on the contrary, compared to most plant sources, calcium from milk is very well utilized and milk also contains other substances (casein phosphopeptides, lactose, vitamin D with excellent bioavailability, etc.) that promote its absorption and retention in the body. In fact, we absorb approximately 30-35% of all calcium from milk, making milk one of the most important sources of this mineral in our diet. In comparison, the absorption of calcium by the human body from spinach is only around 5%.
The osteoporosis claim is not true either, of course, because milk, on the contrary, promotes bone mineralisation, reduces the activity of osteoclasts (i.e. cells that break down bone mass) and also supplies the body with necessary micronutrients such as vitamin D or the aforementioned calcium. Thus, consuming MILK actually works AGAINST osteoporosis, promoting the health of our bones and the proper development of the skeleton.
❌4. "Man is the only mammal that drinks the milk of other mammals."
According to the opponents of milk, drinking it is unnatural because no other mammal on Earth usually drinks the milk of other species. This reasoning is flawed for three basic reasons. First, according to this logic, we should not be allowed to fly planes, to operate on the sick, use the internet, and perhaps not have higher brain functions. Second, other mammals don't drink the milk of other mammals in the wild simply because NO OTHER MAMMAL HAS DOMESTICATED OTHER MAMMALS. If other animals had that option in the wild, they would certainly consume the milk of other mammals, just as the consumption of eggs of other species is widespread in the wild.
This is not the prerogative of man, but the search for and consumption of reptile, bird, or oviparous mammal eggs by other species is extremely widespread in nature because it is a rich and welcome source of easily obtainable nutrients. This includes great apes such as orangutans collecting bird eggs in trees. And third, this claim is simply FALSE, and anyone can verify on YouTube that e.g. abandoned cubs consume the milk of other mammals (e.g. tiger cubs from a female), adult cats consume domestic cow's milk, etc. And tiger cubs do not grow up to be dogs by consuming dog milk, just as a house cat or a human does not grow up to be a cow by consuming cow milk.
❌ 5. "Hormones in cow's milk are bad for us and cause cancer."
It is true that cow's milk contains bovine hormones and growth factors that are important for the growth and development of the calf. However, if we look at their harmfulness, nothing of the kind has been shown in humans. This is because bovine hormones are peptide in nature (e.g. bGH), so in the process of digestion they are broken down by our digestive enzymes into smaller fragments (oligopeptides or single amino acids) which lose their original biological activity. In addition, hormones are found in milk only in minimal concentrations, and when milk that has been heat-treated by pasteurisation is consumed, there is about a 90% reduction of these hormones due to the high temperature.
As for the growth factor IGF-1, which is sometimes associated with an increased incidence of certain types of cancer (e.g. prostate), it is true that bovine IGF-1 is more resistant and has an identical structure to human IGF-1, but even so, milk contains only minimal amounts of it, which have no biological effects in our bodies. In fact, the concentration of IGF-1 in milk is about 100 times lower than in our blood, because IGF-1 is also naturally produced in our liver, for example. If this minimal concentration had biological effects, bodybuilders and other athletes would not consume anything else. In addition, in the European Union, unlike the USA, growth promoters (hormones) are not allowed to be used in livestock, so that on average the milk of European cows contains less IGF-1 than in the USA.
If we set aside all these myths and look at the benefits of drinking milk, we find that we have been consuming this nutrient-dense food (yes, it really is a food) for several thousand years, and over the course of our evolution, many populations have adapted to milk intake (even into adulthood). This is because it is a complex food that contains all three essential macronutrients (protein with high biological value, carbohydrates and fat), a complex spectrum of vitamins (except vitamin C), minerals, led by the highly usable calcium, and many other beneficial substances such as lecithin or MBP (milk basic protein).
Sour (or fermented) dairy products such as yoghurt, acidophilus milks and especially kefir, which contain health-promoting lactic acid bacteria such as bifidobacteria and lactobacilli (so-called probiotics), are also of great importance in healthy and sports nutrition. These have a positive effect on the composition and proper function of the gut microbiome and promote the renewal of the intestinal epithelium. Milk and dairy products can therefore undoubtedly be classed as a healthy food, and if we do not have health problems with their consumption (for example, milk allergy or lactose intolerance), there is no reason to avoid them because of the above myths.
Literature
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