Is milk good or bad? Can it be part of a healthy and balanced diet or should it be limited? As we will see, milk can be an interesting food for children but should be limited in adulthood. But let's try to understand better.
Milk during childhood
Milk of animal origin and its derivatives have always been considered nutritious and well balanced foods. Milk is the first food in mammals, it contains all the nutrients needed by the calf to grow and develop, such as vitamins, like vitamins A and E, group B, including vitamin B12, mineral salts, such as calcium, zinc, magnesium and selenium, proteins, fatty acids (Górska-Warsewicz et al, Nutrients, 2019). And as milk helps the calf to grow, this drink is also useful for the child, ensuring all the energy and nutrients necessary for growth, development and for the formation of bone mass (Pereira et al, Nutrition, 2014). Therefore, as far as childhood is concerned, the consumption of milk is certainly beneficial. Problems and disputes arise, however, regarding the consumption of milk in adulthood.
Milk in adulthood
For a long time it was believed that milk was an essential ingredient in human nutrition, even for adults. For example, it was claimed that high milk consumption could reduce the risk of type 2 diabetes and obesity. However, scientific research has not observed this link (Bergholdt et al, Am J Clin Nutr, 2015). As for the connection between milk and cellular degeneration, the action of this drink is controversial. Researches have observed a protective role of milk with regard to the development of colon tumors while the situation is different for hormone dependent tumors. Although the topic is still much debated and not all scientists agree, it seems that high consumption of milk and dairy products may increase the risk of prostate, ovarian and endometrial cancer (Jerayaman et al, BMJ Open, 2019). Attention must also be paid when it comes to bone health. In fact, it has been observed, especially in women, that low milk consumption in childhood increases the risk of fractures in adulthood. However, this protective effect disappears when one grows, indeed, the opposite is observed. In particular, in adults, a high consumption of milk, at least three glasses a day, is associated with a high risk of bone fractures due to the action of D-galactose, a sugar that is formed in the body following the digestion of lactose. (Michaelsson et al, BMJ, 2014 - Kalkwarf et al, Am J Clin Nutr, 2003). D galactose triggers aging processes, increases the action of free radicals, reduces the response of the immune system, promotes neurodegeneration and inflammation processes (Michaelsson et al, BMJ, 2014). So, what emerges from these studies is that, for those who want it and do not have allergies, intolerances or a predisposition to acne, as we will see better in the next paragraph, drinking milk is not to be avoided but care must be taken in order to not overdo it.
Milk and acne
Scientific studies have observed that the consumption of milk can worsen acne due to the hormones contained in milk. These hormones, it is believed, can influence the release of endogenous hormones produced by the body and the increase of sebum produced by the sebaceous glands (Melnik et al, Exp Dermatol, 2009 - Adebamowo et al, J Am Acad Dermatol, 2008).
Lactose intolerance and allergy to milk proteins
Lactose intolerance and allergy to milk proteins are conditions that can occur. However, these are two different conditions. In fact, allergy to milk proteins tends to appear in 2-3% of young children and is an immune response to some proteins present in milk, such as caseins. In case of known allergy to milk proteins, the doctor will advise to eliminate milk from the diet. This allergy tends to disappear with age and is rare in adults, where lactose intolerance is more common. Lactose intolerance is different from allergy to milk proteins, it is frequently observed in adults and is due to a deficiency in the intestine of the lactase enzyme. Problems digesting lactose are estimated to be found in nearly 75% of the world's population. In case of intolerance it is not necessary to completely eliminate milk and its derivatives but it is possible, if you like and wish, to take it in limited quantities, which in any case is recommended to all given the considerations of the previous paragraphs (Haug et al, Lipids Health Dis, 2007).