About Milk

Lots of discussions have been going on around milk and dairy products. Is milk good for the human body? Are vegans actually right, arguing that it is unnatural for humans, the only species among mammals, consuming the milk of other species? All of these questions and the general diversity among this topic led me to do some research around milk.

First of all, there are over 5600 species of mammals including humans, all of which start their life on a diet of milk. After several weeks or months depending on their kind, they will continue to nurture themselves only on plants, meat or both.

The Importance Of Lactation In Mammals

So why is lactation in mammals such an important mechanism in the early stage of their lives? One reason is probably the excellent way of transferring immunity from the mother to the offspring without being exposed to the vagaries of the environment. The early milk of many mammals including humans is very rich in antibodies. Feeding for youngsters becomes relatively effortless and their energy can be primarily channelled into their growth.

This leads to the second fact that makes lactation important. The organs, skeleton and digestive system of mammals have to first gradually develop until they are able to gather, masticate and digest the adult diet. That is, digestion in mammals has to reach a mature state before they get weaned off milk. In humans, the enzyme lactase cannot be produced in the early life of an infant. This is also often the reason why some humans that were not breastfed when newborn, are lactose intolerant in their adult life. As babies, they were fed immediately with cow’s milk which requires the enzyme lactase to be broken-down. Since their body was not yet ready to produce lactase, cow’s milk was very heavy for their immature stomach leading later on to sensitivities with dairy products.

According to science and environmental writer Shreya Dasgupta, breastfeeding is unique to mammals. Nevertheless, this does not mean that all characteristics are unique and the same among the different species. The growth of youngsters’ and its pace, their dependency on milk and its synthesis may vary significantly. In the very first days, milk is for the majority of the mammals fatty and as the infant matures the content of the milk changes and fat is substituted by other nutrients important to the youngster’s stage of growth. Bear cups, for example, weigh not more than a pound when born, are blind with no fur and their survival depends highly on their mother’s milk until they reach the 8th month of their life. If fed with another type of milk, with a poorer nutrient content they have little chance to survive. Human babies, however, weigh much more, their organs are much more developed when born and can live, though not ideally, on cow’s milk.

Going back to the argument often raised by vegans that milk consumption is unnatural for humans just because other mammals do not drink milk once mature is most probably a too general belief. It might sound silly, but my cat licks off the lid of a cottage cheese container but stays away from shredded carrot or coconut milk. It would be more appropriate to say that milk and other dairy product consumption is unethical rather than unnatural. Is it right to steal the milk of other animals and drink it or use it for our satisfaction while this is thought to be for calves? Nature has “programmed” mammals to produce milk only after giving birth and for a certain limit of time. So most probably, milk is not crucial nourishment for human health and life but vital for the growth of the calf. That is why my cat would never try any technic to milk a cow for his survival as he would do to catch a bird, but would for sure treat himself with milk if given to him effortlessly. Even within humans, individuals react differently to the same sort of food thus we often talk about bio-individuality. Some people are lactose intolerant and cannot consume any dairy products, others have sensitivities when eating too much of it while for others milk products appear not to be irritating at all. To understand better the reaction of the human body to milk and the several debates about whether it is good for our health, let’s first see the nutrition facts of milk. The focus will be on cow’s milk as it is the most common source for the majority of the dairy products consumed by humans.

Nutrition Facts Of Cow’s Milk

Cow’s milk is produced by the mammary glands of the mother cow and is the primary source of nutrition for calves before they are able to digest solid food. Milk contains high-quality protein, carbohydrates in the form of lactose, fatty acids and a wide range of vitamins, minerals and trace elements. Below table details, the nutrients included in 100 g of whole milk with 3.25% fat.

*Nutrition Facts: Whole milk, 3.25% fat – 100gr*
	Amount
Calories	61
Water	88 %
Protein	3.2 g
Carbs	5.1 g
Sugar	5.1 g
Fibre	0 g
Fat	3.3 g
Saturated	1.87 g
Monounsaturated	0.81 g
Polyunsaturated	0.2 g
Omega-3	0.08 g
Omega-6	0.12 g
Trans fat	~

Protein

Milk is very rich in high-quality protein as it includes both the insoluble protein casein as well as the soluble whey protein. These two types are considered an excellent source due to its good digestibility and variety of amino acids.

Casein accounts for 80% of the protein content of milk and consists of four subunits which together form the casein micelle. Casein micelle has a rich amino acid profile and is essential for the growth and development of infants as well as in muscle building. Casein is thus very popular among athletes forming a clot in the stomach which allows the slow breakdown of protein and supply of amino acid over several hours retaining body strength. Cheesemakers take also the advantage of the clotting features of casein by isolating the clot which forms the curd and is then further processed into cheese. Other important features of casein are its ability to increase the absorption of minerals, especially calcium and phosphorus as well as promoting lower blood pressure. Other known properties of casein are its ability to separate fat from milk.

Whey fills in the rest 20% of the milk protein content. It is essential due to its branched-chain amino acids, leucine, isoleucine and valine. The main whey proteins are b-lactoglobulin which is not well studied and a-lactoglobulin which is important in the synthesis of lactose. Like casein, whey is excellent for the growth and maintenance of muscles and it decreases blood pressure. Other beneficial health effects are its ability to improve mood during periods of stress as well as its disease resistance factors.

Carbs

Carbohydrates in milk constitute around 5% and are in the form of a simple sugar called lactose. Lactose is composed of one molecule glucose and one galactose which are broken down with the help of the enzyme lactase in the digestive system.

Fat

Whole unprocessed milk straight from the cow is 4% fat but commercial milk varies based on the type. It is one of the most complex natural fats, containing about 400 types of fatty acids with 70% being saturated. Polyunsaturated fats constitute around 2.3% of the total fat in milk while the rest are monounsaturated. Trans fats are naturally included in milk, in small amounts and have some health benefits unlike the trans fats found in processed foods. CLA (conjugated linoleic acid) is one of those trans fats positively associated with weight loss, the delay of type II diabetes and atherosclerosis, while also modulating the immune system and improving bone mineralization.

Vitamins and Minerals

Milk is considered one of the most nutritious foods on the planet containing in particularly large amounts some of the most essential vitamins and minerals for the human being: B12, B2, calcium and phosphorus. That is also why for Ayurveda, one of the world’s oldest holistic healing systems, milk is so precious. According to Ayurveda milk nourishes body and mind (Ojas), has a cooling effect and is the most balancing and enlivening (sattvic) food in the universe. Due to its sattvic quality, milk satisfies hunger and thirst while also soothing pain and irritation caused by diseases. Latest studies prove that indeed milk is a balanced source of calcium and phosphorus, two of the most critical minerals for bone health. The optimal calcium to phosphorus ratio is currently placed between 2:1 and 1:1 with the latter being also the proportion in cow’s milk. Calcium in milk is why many people associate milk with strong bones or the agent to battle osteoporosis.

Indeed a 99% of calcium in the human body is stored in the bones and teeth while the rest is found in the blood and tissues. The body gets the calcium it needs from foods that contain calcium or by pulling it from the bones. Ideally, the “borrowed” calcium will be replaced at a later stage but this will not happen by simply eating more calcium. Calcium absorption is quite complex and often it ends up being excreted in the feces or the urine. Kidneys also control calcium blood levels in the blood and kidney stones may also be build due to high or improper ways of consuming calcium. Calcium is better absorbed with amino acids and vitamin D while other minerals such as magnesium and potassium play also an important role in healthy bones.

Osteoporosis

Bones are living tissues which are constantly broken down and built up in a process called remodelling. In healthy individuals, bone production exceeds bone destruction up to around age 30. After that, destruction exceeds production.

Osteoporosis is the weakening of bones caused by an imbalance between bone building and destruction. Preventing osteoporosis especially in adulthood requires good sources of calcium, good nutritional habits, regular physical activity and a diet that promotes healthy gastrointestinal function. Drinking just a lot of milk on a daily basis will not do the job. Despite the debates surrounding milk and calcium, it is clear that calcium is a key factor in reducing the risk of osteoporosis. To ensure that the population gets enough calcium, the National Academy of Science (NAS) recommends the below intake levels:

1000 milligrams per day for adults between the age of 19 and 50
1200 milligrams per day for adults between over the age of 50
1000 milligrams per day for pregnant or lactating women.

Calcium and Bone Strength

The healthiest amount of dietary calcium has not yet been established as studies of long duration are required. In some of Harvard long term studies, though the importance of calcium for bone strength is not a question, there are doubts on the value of consuming the large recommended amounts suggested by NAS.

Individuals who drank one glass or less of milk per week were at no greater risk of breaking a hip or forearm than those who drank two or more glasses per week. Also, results from trials that compared calcium supplements with a placebo showed that supplements did not protect against fractures of bones. Some studies revealed that calcium supplements taken without vitamin D increased the risk of hip breaks. Additional results showed that in countries such as India or Peru where the average daily calcium intake is lower than that of American adults had less incidence of bone fractures due to higher levels of physical activity and greater exposure to sunlight. Another interesting study was that conducted in the 1960s during the Apollo space missions which showed that astronauts lost calcium during their space travel due to the lack of ultraviolet light exposure but also the lost forces of gravity. That is why weight-bearing activities such as jogging and weight training are also important for maintaining strong bones. Evidence of other studies showed that vitamin K found mainly in vegetables plays also an important role in calcium regulation. Low levels of vitamin K are linked with low bone density.

Results from the Framingham Osteoporosis Study suggest that caffeine promotes calcium excretion in urine. People who drink a lot of coffee or soft drinks like coca cola on a regular basis have weaker bones than those who consume it less frequently or at all. Soft drinks are also very high in phosphorous which might be an additional factor that affects the essential dietary balance between calcium and phosphorous. There are also links between high amounts of protein consumption and weak bones. The human body releases acids to digest protein which then needs to be neutralized by drawing calcium from the bones.

The reason I list the results from all of these studies which are more linked to calcium and bone strength rather than milk as such, is to highlight first that it is very difficult to isolate milk and its effect on the human body since the majority of the human population consume other foods, have plenty of good or bad habits and are exposed to several environmental factors. Consequently, this leads to the second point: there are so many features that are important to maintaining strong bones all linked to the lifestyle we choose to follow. Consuming milk based on the recommendation suggested by NAS for example while at the same time drinking large amounts of coffee, avoiding salads and vegetables and staying away from any physical activity will not save us from osteoporosis. Besides, milk and dairy products are not the only sources of calcium, some vegetables (such as broccoli, cauliflower), legumes (such as chickpeas, soybeans), nuts (such as almonds, Brazil nuts) and seeds (such as sunflowers, sesame) are excellent providers of calcium.

Milk As A Source Of Calcium

Keeping these in mind lets go back to milk, since there are some additional facts that need to be considered if consuming it as a source of calcium. Milk is high in saturated fats which is a risk factor for heart disease. This is mostly relevant for people with cholesterol and atherosclerosis issues. In a Harvard study, men who drank two or more glasses of milk a day were almost twice as likely to develop prostate cancer as those who didn’t consume milk at all. Other studies have found a correlation between high levels of galactose and ovarian cancer. Although there was no association between overall milk or dairy products and ovarian cancer, some researchers believe that the modern industrial milk production practices have changed the milk’s hormone composition in ways that could increase the risk of ovarian and other hormone-related cancers. Homogenization is possibly the biggest concern in milk which is correlated with the increase in cardiovascular disease and probably also ovarian and prostate cancer.

Homogenization

Homogenization is the mechanical process where milk fat is converted into small globules through the use of high pressure and prevents the cream from rising to the top when it sits. Many argue that this process does not affect the quality of the milk as it does not require additives. However it does not only change the size of the fat globules, also the fat and protein molecules are rearranged which could alter how they act in the human body. By reducing the size of the protein molecule, protein cannot be absorbed and passes through the body undigested contributing to weight gain, heart and artery issues. Homogenization is advantageous for large-scale dairy farms because milk gets a longer shelf life, it is more appealing as the fat does not “swim” in the surface of the milk bottle and the most important, milk from different herbs can be mixed without any issues. Many types of homogenized milk contain also hormones which increase the risk of cancer.

Ayrvedic Guidelines

Ayurvedic guidelines suggest to choose fresh, organic, unpasteurized, un-homogenized whole milk. Raw milk is the best option which stays away of all these processes that denature milk. It is recommended to boil raw milk and drink it warm. Due to its high amounts of lactose, water can be added to make it lighter and easier to digest. To support digestion, Ayurveda suggests also to add a pinch of spices such as ginger, clove, saffron, cardamom or cinnamon. Milk should be treated as a meal itself and if combined with other food types, these should be grains. Milk with salt or combined with anything sour like fruits, or eaten together with other animal products (i.e. fish, cheese) should be avoided.

Until research can progress with its findings and provide concrete and accurate evidence about milk and its effects on the human body, some of the best practices that we can follow to protect ourselves from poor quality milk and milk and its association to cancer and heart issues are:

Listen to our body and test whether milk feels good or causes digestion issues, allergies or has other negative effects.
Follow as much as possible the ayurvedic guidelines in respect to food combinations.
Choose high quality milk. That is fresh, organic, unpasteurized, un-homogenized, whole raw milk.
Go for milk produced by farms that care about animals, treat them well and understand their rights.
Respect nature and calves and their mothers. Avoid dairy products from large farms that focus on mass production, low production costs and high return.
Consume moderate amounts of milk and dairy products and rely on other sources such as legumes, vegetables, nuts and seeds to acquire calcium and support your bone strength.
Exercise on a regular basis and get some sunlight exposure.
Let balance be an attitude in your life with everything: your diet, habits, work, …

Bibliography

Haas, Elson M. Levin, B. (2006). Staying Healthy with Nutrition

Schneider, A. (2018). Milch im Ayurveda

Smolin. Grosvenor. Gurfinkel. (2015). Nutrition Science and Applications

http://www.slate.com/blogs/wild_things/2015/10/09/lactation_in_mammals_humans_whales_seals_bats_and_echidnas.html?via=gdpr-consent

https://www.medicalnewstoday.com/articles/273451.php

https://www.medicalnewstoday.com/articles/296564.php?sr

http://www.bbc.com/earth/story/20150725-breastfeeding-has-ancient-origins

https://www.healthline.com/nutrition/foods/milk#section1

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429457/

http://edenayurveda.com/142/

https://www.livestrong.com/article/450275-the-balance-of-calcium-phosphate/