6000 years ago, people already used cow’s milk in their nutrition – it was and has always been a staple food. Even today, cow’s milk enjoys great popularity and be it merely at breakfast in muesli, cereal or coffee.
Although milk is a natural food, doubts are growing as to whether cow’s milk is really as good as it is said to be and whether it can really be recommended without reservation. Some scientists point out that increased milk consumption can have an unfavorable effect on health. There are studies suggesting that milk can sometimes lead to obesity, increased tendency to develop acne, allergies, diabetes and also various cancers.
The valuable nutrients in milk
Cow’s milk is a complete food that contains all the important and necessary nutrients required for the development and intensive growth phase of babies and toddlers. It provides the body with energy in the form of lactose (milk sugar), with fat and protein – the most important building material for almost all body cells – as well as with numerous minerals and vitamins. It is above all its high calcium content that is positively emphasized to guarantee “strong bones”. And that’s why it is recommended for adults to consume milk and dairy products as often as possible to prevent osteoporosis.
Milk calcium for strong bones?
A publication by the scientists Walter Willett (epidemiologist) and David Ludwig (endocrinologist) from the Harvard T.H. Chan School of Public Health presented in Boston in 2020 contradicts the well-known theory that milk and its high level of calcium strengthen bones. According to their data, collected in Denmark and Sweden, the risk of bone fractures – with higher consumption of milk and dairy products – increased compared to countries such as China and Indonesia, where hardly any milk and dairy products are consumed.
Another study also showed the correlation between an increased risk of fracture in old age and frequent consumption of milk in childhood. The scientists explain these results as follows: calcium from food can only be stored in the bones in sufficient quantities if there are enough vitamin D and magnesium available; a fact which was not known for a long time.
Milk calcium and cancer
Despite these negative conclusions, the high level of calcium in milk presents benefits for one’s health. Scientists suppose that milk and dairy products can reduce the risk of colon cancer. This fact is based on the assumption that the calcium in milk is able to bind in the intestine and then eliminate harmful breakdown products of bile acids, which are suspected of promoting proliferation in the intestinal mucosa.
However, after evaluating international data, the World Cancer Research Fund also proved that milk may increase the risk of prostate cancer. This, however, was only observed in men who consumed extreme amounts of milk (1 liter) and dairy products (100 g of hard cheese) per day over a long period of time. The mechanism responsible for this correlation still has to be found.
The “bad” fats of milk
Fat is currently the most interesting object of study for science, of all the components of milk. About 70% of milk fat consists of saturated fatty acids, which have long been regarded critically because they are considered to be classic risk factors for arteriosclerosis and heart attack. However, according to new findings, milk fat is by no means as harmful as it was long thought to be. It is now believed that the cause of this is known, because the tiny droplets of fat are encased in a membrane that also consists of proteins and phosphorus. Obviously, milk fat seems to be particularly healthy when this structure is maintained. In an experiment, nutrition experts and scientists found that butter increases the concentration of LDL in the blood, whereas cream did not have this effect.
It is assumed that during the production of butter the membrane of the fat droplets is destroyed. This is because the milk must be centrifuged in order to extract the butterfat from the milk. This creates extremely strong centrifugal forces that destroy the structures.
Not all milk is the same
Nowadays, different types of cow’s milk are offered in the refrigerated shelves of supermarkets. Milk is almost always pasteurized (15-30 sec at 72°C). In addition to conventional heat treatment, researchers have developed other preservation methods that kill germs. The more rigorous the procedure, the more the milk changes.
Supermarkets currently sell mainly three heat-treated varieties, both conventional and organic:
- “traditionally produced” fresh milk (pasteurised, can be kept refrigerated for 10 days)
- “longer shelf life” (heated to 127°C for a few seconds, can be stored unopened for 3 weeks)
- “UHT milk” (heated to 135°C, can be stored unopened for up to 6 months)
Some of the vitamins are affected by the heat treatment. However, homogenisation has a much greater influence on the quality of milk. The milk is pressed under high pressure by means of closed-meshed filters. This finely spreads larger fat accumulations and prevents the milk from creaming. However, protein structures are also torn apart by this process. Some of these fragments cannot be broken down by the digestive enzymes and can therefore be a burden on the intestine.
Milk used for cheese production, yogurt and fermented dairy products is not homogenized.
Milk – a food, not a beverage
“The dose makes the poison” – using milk as a beverage is not recommended. For refreshment, the body primarily needs water and not additional calories. In many studies, three glasses of milk a day are already classified as “highly increased consumption” with possibly unhealthy consequences. This amount is quickly reached if you consume café latte, cocoa, milk shakes or muesli with milk several times a day.
Therefore, the German Nutrition Society (DGE) recommends consuming only 200 to 250 grams of milk and dairy products per day – provided there is no lactose intolerance or milk protein allergy.
What is Metabolic Balance’s position on milk?
For Metabolic Balance, too, cow’s milk in well-dosed quantities is a nutritionally high-quality food whose health aspects should not be underestimated. Our rule of “a different protein for every meal” also avoids excessive consumption, which could have an adverse effect. Cow’s milk should always have a fat content of at least 3. 5% – or even more (cow’s milk directly from the farm). It is also advisable to choose organic cow’s milk that has been processed as gently as possible.
Despite the various positive aspects, Metabolic Balance also takes into account the fact that many people in the world cannot tolerate cow’s milk. One of the reasons for this is that, due to genetic disposition, the enzyme lactase, which breaks down lactose, is not produced or is produced insufficiently in the intestine. The milk sugar enters the large intestine undigested and, on the one hand, dehydrates the intestinal mucosa, which leads to diarrhea, and on the other hand, is also decomposed by bacteria – among other things, carbon dioxide, hydrogen and methane are produced, which result in severe flatulence.
As an adequate substitute for cow’s milk, especially in order to absorb sufficient calcium, in addition to soybeans, tofu and fermented foods, numerous plant-based foods such as broccoli, green cabbage, Chinese cabbage, pak choi or legumes (pulses) and sweet potatoes are recommended.
- Milk and Health; Walter C. Willett, M.D., Dr.P.H., and David S. Ludwig, M.D., Ph.D; N Engl J Med 2020; 382:644-654 DOI: 10.1056/NEJMra1903547
- Milk Consumption During Teenage Years and Risk of Hip Fractures in Older Adults
- Diane Feskanich, ScD1; Heike A. Bischoff-Ferrari, MD, DrPH2,3; A. Lindsay Frazier, MD1,4; et al; JAMA Pediatr. 2014;168(1):54-60. doi:10.1001/jamapediatrics.2013.3821
- Calcium Intake and the Incidence of Forearm and Hip Fractures among Men William Owusu, Walter C. Willett, Diane Feskanich, Alberto Ascherio, Donna Spiegelman, Graham A. Colditz