Milk: understand everything in 2 min

For several years, there has been controversy about the positive health effects of milk consumption. There is an abundance of scientific literature on the relationship between milk and the onset, prevention or treatment of certain diseases. This is why it is important to make a critical and objective judgment. The statements below are intended to reflect current scientific data. Some elements of controversy, which are not supported by scientific research, are briefly presented taking into account the available literature on the subject.

Active ingredients and properties

Milk contains several vitamins and minerals, including calcium and vitamin D (added), which are essential for maintaining bone health . In addition, milk calcium may play a role in the prevention of various diseases such as cardiovascular disease , high blood pressure and obesity . Other bioactive compounds are present in milk and are also said to have health effects. This is the case with lactoferrin, a protein that plays a role in the fight against infections . It would also protect against certain types of cancer .

Cardiovascular illnesses. Milk, which contains saturated fatty acids and cholesterol, has long been suspected of causing cardiovascular disease. However, it also contains calcium. More and more studies confirm that the consumption of milk and calcium is not associated with cardiovascular disease and myocardial infarction ^1-4 . Low milk consumption has even been linked in some studies to an increased risk of cardiovascular disease ^5-6 . The amount of milk to consume to prevent cardiovascular disease has not been determined at this time, although the risks seem to increase for individuals who consume less than two servings of milk per day.

Blood lipids. In a recent study done in Quebec, the authors reported that high calcium intake from dairy products, including milk, was linked to a better profile of blood lipids ⁷ . Blood cholesterol is an important risk factor for cardiovascular disease. Consuming milk would maintain higher blood levels of HDL cholesterol (good cholesterol) ⁸ , which is believed to be a protective factor for cardiovascular disease. Milk fats are also associated with a composition of LDL cholesterol particles (bad cholesterol) ⁹ which would be less harmful for heart health.

High blood pressure. Epidemiological studies have shown that the calcium in milk can promote better blood pressure ¹⁰ . In addition, a daily consumption of three to four servings of milk combined with a diet rich in fruits and vegetables could lead to a decrease in blood pressure in individuals whose blood pressure is normal or slightly elevated ¹¹ .

Obesity. Studies show that milk calcium is associated with lower body weight ¹² , as well as a more favorable body mass index (BMI) ^13-14 . Low consumption of milk calcium is associated with greater adiposity ⁷ , particularly in women. According to some authors, milk has an anti-obesity effect ^15-16 and consuming at least three servings of milk per day could promote weight loss ¹⁷ . However, a recent study showed that a diet containing more than 800 mg of calcium per day from dairy products had no effect on weight loss ¹⁸. It is important to note that the benefits of calcium consumption on obesity are mainly seen in people who are initially low calcium consumers ⁷ .

Osteoporosis. Milk is recognized by many scientists as an important food for bone growth and health because it contains calcium and vitamin D. It is added to milk. Calcium and vitamin D are both important nutrients for preventing osteoporosis ¹⁹ . The consumption of milk during childhood and adolescence influences the size obtained during adolescence, but can also have greater repercussions in adulthood ^20-21 . Indeed, 45% of bone mass is formed during adolescence and during this intense period of growth, the consumption of milk and calcium influences the mineralization of bones ²² .

In addition, the consumption of milk and dairy products promotes better bone density, thus preventing osteoporosis ^21-23 . However, there is no consensus on whether milk calcium actually has a beneficial effect on osteoporosis. Studies have shown that certain types of fractures are more common in people who regularly consume dairy products and have rather high intakes of calcium ^24-25 . An American study, carried out over a 12-year period, showed that women aged 40 to 60 who consumed milk increased their risk of fractures ²⁶. Thus, it would seem that a significant consumption of proteins (mainly from animal sources) could be associated with an increase in calcium losses via the urinary tract, leading to a reduction in bone mass or an increase in fractures ²⁵ .

There is currently no consensus on the optimal amount of milk to consume in adulthood to prevent osteoporosis and to decrease the incidence of fractures in the elderly ^27-29 . However, the World Health Organization recommends consuming a minimum of 400 mg to 500 mg of calcium per day for people aged 50 and over who live in a country where the risk of fractures is greater ¹⁹ . In Canada, it is recommended to consume 1,000 mg to 1,300 mg of calcium per day depending on age, which is equivalent, for example, to two or three servings of dairy products ³⁰ . Drinking milk is suggested as it is an accessible way to get enough calcium and vitamin D ^21,31.

Diabetes. Early consumption of cow’s milk in infants may contribute to the development of type 1 diabetes in children with a family history of diabetes, although the mechanisms involved are unclear . ³³ According to some authors, the physiological response is caused by an autoimmune response to bovine serum albumin, resulting in the destruction of pancreatic beta cells manufacturer insulin ³⁴ . Breastfeeding is therefore recommended for infants. However, milk consumption could decrease the incidence of type 2 diabetes in adults. As reported in a recent study ³⁵consuming two to three servings of milk a day could lower the risk of type 2 diabetes.

Cancer. Milk contains calcium, added vitamin D, lactoferrin, and conjugated linoleic acid, four compounds that are thought to inhibit the formation of cancer in animals ^36-37 . In humans, the role of milk in the development of cancer has not been clearly demonstrated. Milk has a protective effect against certain types of cancer such as colon cancer ³⁶ and does not contribute to breast cancer ³⁸ . It may also play a role in prostate cancer ³⁹ . Since the results of the studies are inconclusive, for the moment, there are no official recommendations concerning the consumption of milk in connection with cancer.

Other properties

Most important nutrients

See the meaning of the nutrient source classification symbols

 Calcium. Milk is an excellent source of calcium. This mineral is by far the most abundant in the body. Calcium is mainly stored in the bones, of which it is an integral part. It contributes to the formation of bones and teeth, as well as to the maintenance of their health. Calcium also plays an essential role in blood clotting, maintenance of blood pressure and contraction of muscles, including the heart.

 Phosphorus. Milk is an excellent source of phosphorus (see our fact sheet on Phosphorus nutrients ). Phosphorus is the second most abundant mineral in the body after calcium. This mineral plays an essential role in the formation and maintenance of healthy bones and teeth. In addition, it participates among other things in the growth and regeneration of tissues, helps to keep the blood pH at normal and is one of the constituents of cell membranes.

 Vitamin B2. Milk is an excellent source of vitamin B2, a vitamin also known as riboflavin . Like vitamin B1, it plays a role in the energy metabolism of all cells. In addition, it contributes to tissue growth and repair, hormone production and the formation of red blood cells.

 Vitamin B12. Milk is an excellent source of vitamin B12. This vitamin works together with folic acid (vitamin B9) to make red blood cells in the blood. It also participates in the maintenance of nerve cells and cells that make bone tissue.

 Vitamin D. Milk is an excellent source of vitamin D. Vitamin D is closely linked to the health of bones and teeth, making calcium and phosphorus available in the blood, among other things for the growth of bone structure. Vitamin D also plays a role in cell growth, including cells in the immune system. Note that vitamin D is added to milk.

 Selenium. 1% and 3.25% milk are good sources of selenium, while skim and 2% milk are only sources. This mineral works with one of the main antioxidant enzymes, thus preventing the formation of free radicals in the body. It also helps to convert thyroid hormones to their active form.

 Pantothenic acid. (Vitamin B5). Milk is a good source of pantothenic acid. It is part of a key coenzyme in the energy use of the food we eat. It also participates in several stages of the synthesis of steroid hormones, neurotransmitters and hemoglobin.

 Vitamin A. Skim milks, 1% and 2% are good sources of vitamin A, while 3.25% milk is only one source. Vitamin A is one of the most versatile vitamins, playing a role in several body functions. This vitamin promotes, among other things, the growth of bones and teeth. It keeps the skin healthy and protects against infections. In addition, it plays an antioxidant role and promotes good vision, especially in the dark.

Source  : Health Canada. Canadian Nutrient File , 2005.

Precautions

Pasteurized milk and raw milk

The pasteurization , heat treatment, provides a healthy milk by extending the shelf . Pasteurizing milk can control bacterial contamination, destroy pathogens, and eliminate certain enzymes that produce unpleasant flavors. Due to their nature and their physical and chemical properties, the nutrients present in raw milk are sensitive to heat treatments. Thus, pasteurization decreases the content of vitamins B1, B12 and C – a loss of about 10%. However, it has no effect on other vitamins such as A, D and B2 ⁴⁰ . Pasteurization has no effect on the amount of protein, fat, lactose and minerals present in milk ^40-41. In addition, a study has shown that there is no difference in protein digestibility between raw milk and pasteurized milk ⁴¹ . Milk intended for consumption must be pasteurized.

The raw milk is freshly drawn milk from the udder of the lactating cow. It has not undergone heat treatments, homogenization and skimming. It retains all the properties that nature has attributed to it ⁴² . These natural factors include well-known nutrients such as proteins, vitamins and calcium, but also antimicrobial agents and immunological factors. Although some people claim that the consumption of raw milk by farmers and their immediate families does not have a negative impact on health, ⁴² there is no scientific study to confirm this fact. It should be noted that since 1991, the sale of raw milk has been strictly prohibitedin Canada by the Food and Drug Regulations. Raw milk is an environment conducive to the proliferation of pathogenic microorganisms dangerous to human health. In addition, Health Canada has recently reported in Ontario cases of E coli contamination that may be related to the consumption of raw milk. It is allowed to use raw milk for cheese production, because raw milk retains its natural flora and allows the production of various high-end products. However, the cheese must be kept at a certain temperature for a minimum of 60 days before being consumed.

Food allergy

Along with peanuts, eggs and seafood, milk is one of the main causes of food allergies. Cow’s milk allergy is one of the most frequent clinical syndromes encountered in young children, ranging from 1% to 5% according to studies ⁴³ . This high frequency would be related to children with a family history of allergy, as well as the too early introduction of cow’s milk in the diet of infants ³⁴. However, allergies to milk decrease after the age of three and almost disappear during adolescence. It is mainly the proteins present in milk which are responsible for allergic reactions, mainly caseins and beta-lactoglobulin. Breast milk, on the other hand, does not contain beta-lactoglobulin ³⁴ . The classic manifestations of milk allergy are digestive disorders (diarrhea, vomiting, cramps and pain), respiratory disorders (bronchitis, asthma) and skin problems (eczema).

Lactose intolerance

Many people are intolerant to milk because they don’t produce enough lactase, an enzyme (beta-galactosidase) found in the gut that helps digest milk sugar called lactose. Lactose intolerance is characterized by various symptoms such as bloating, gas and diarrhea.

People who are lactose intolerant may decide to avoid or consume milk by adding a few drops of enzyme (commercially sold) which makes lactose more digestible. It should be noted that individuals who suffer from lactose intolerance usually tolerate yogurt well because it contains little lactose.

When did human beings realize that they could take cow’s milk for their own ends without endangering the life of their little one? First of all, it was necessary to domesticate the imposing auroch and, through the game of selection, reduce its size and attenuate its aggressive character so as to be able to approach the female without too much risk. This domestication would have occurred 7000 years or 8000 years ago, in the south of Asia. Unless one had first consumed the milk of the goat, which one had domesticated 1000 or 2000 years before on the Iranian plate.

However, as it corrupts quickly as soon as it comes into contact with air, milk as it has been universally consumed only very recently in history, unlike its by-products – cheese , the butter , the yogurt and other fermented milk – which store better and are appreciated for millennia. Not until the XIX ^th  century and the onset of rapid transport, especially the train, so that the milk is produced and sold widely. Then, in the XX ^th century, producers will find themselves with significant surpluses, which will encourage them to promote dairy products, supported by health authorities. This will give milk definitively its status as an essential daily food, both for adults and for children.

Previously, it was mainly consumed by peasants, and especially by the elderly, the sick and children. In the countryside, it was not uncommon to see a child suckling from the udder of a cow or a goat. Until the XIX ^th  century, we will keep in children’s hospitals in France goats and even donkeys, in order to treat sick children.

The need to supply milk to a city population increasingly distant from the countryside, and in the midst of a population explosion, will bring about major changes in the way in which this eminently perishable food is treated. In the first half of the XX ^th  century, pasteurization , to counter the risk of transmission of TB from cows to humans become mandatory in Canada and twenty US states. Then comes homogenizationand, when fats of animal origin become a subject of health concern, the systematic separation in the factory of milk and its cream to recombine them according to specific proportions, namely 3.25%, 2%, 1%, with the exception of skimmed milk which should only contain 0.1% cream. Other industrial processes, such as evaporation , dehydration , extraction , to name the least complex, will make it possible to create a whole range of products from this simple food.

These processes will serve not only the retail market, but also the food industry which makes great use of it, in particular for the emulsifying, foaming, gelling, browning or dispersion properties of its proteins. There is also an increasing use of sterilization (carried out at a higher temperature than pasteurization) and ultrafiltration to eliminate pathogenic germs that resist pasteurization.

Pasteurized or raw?

From the moment we wanted to impose the pasteurization of milk, voices were raised to oppose it. In the years 1920 to 1930, when it became common practice, the majority of the population was also against it, because it was believed that it had the effect of destroying a good part of the nutrients, even the vital force, of milk.

This debate continues today, even within the scientific community, where doctors and nutritionists question this process, which is universally used today. Not only is he accused of modifying milk proteins and destroying part of its vitamins, as well as the useful bacteria and enzymes necessary for its digestion and assimilation, but it is suspected to be the cause of some modern diseases which incidence is constantly increasing, in particular allergies, dental caries, colic in infants, growth problems in children, osteoporosis, arthritis, heart disease and cancer . In addition, by destroying the useful bacteria whose milk is naturally rich, it would actually contribute to the proliferation of harmful bacteria downstream of the process. There is also opposition to homogenization which, by causing the release of an enzyme, xanthine oxidase, would have harmful effects on human health.

In some European countries, as well as in 28 American states, the sale of raw milk is authorized under certain conditions. However, the health authorities are clearly against it and the trend is, on the contrary, towards a tightening of the legislation in this regard.

Milk from goats and other mammals

Although, in developed countries, the cow is by far the animal most commonly raised for milk production, it is the goat that feeds the largest number of people on the planet, especially in Asia and in Africa, where 80% of all goat farms are found. In the West, its milk enjoys the reputation of some people for being healthier and more digestible than that of the cow.

The females of other species have been and, in some cases, are still put to use in various places of the world: camel in Arabia, Central Asia and Africa, buffalo (or buffalo) in Asia and to a lesser extent in Europe , sheep in the Middle East, yak in the Himalayas, zebu in certain parts of Asia, reindeer in the Lapps, donkey in Europe and in the Near and Middle East.

Choose well

Always check the expiration date on the packaging.

Culinary dishes

• In morning cereals, hot or cold.
• To suppress hunger in the middle of the afternoon or afternoon, take a glass of milk.
• Mix with eggs, sugar and vanilla for making eggnog, with fresh or frozen fruit for milkshake, or with melted chocolate, honey, cinnamon and nutmeg .
• In soups, creams, soups: cauliflower, pumpkin, parsnip, tomato, seafood.
• In the flans, omelettes, quiches, soufflés, sweet desserts, French toast, pancakes, waffles, dough, etc.
• In cakes and puddings, especially rice pudding.
• In fruit mosses.
• In salty or sweet sauces. Indispensable in the making of béchamel.
• Meat or fish can be poached in milk seasoned with salt, pepper and herbs or spices. Liver and kidneys are frequently cooked this way.
• In macaroni and cheese or other baked pasta dishes.
• In pranks.
• It can be incorporated into salad dressings.
• In veal, chicken or beef casseroles à la Stroganov.

We also use the skin of milkin the kitchen. To prepare it, pour two liters of milk into a wide-bottomed pan, heat gently until it boils, no more than five minutes. Remove from heat and let stand 24 hours in the fridge. It will then be enough, using a skimmer, to lift the skin which will have formed on the surface of the milk. To prepare larger quantities in a short time, put the pan in a hot oven and remove the skin that has formed as soon as it starts to brown. Reserve it. Repeat as many times as you need skins for the recipe. Most often, they are made into cakes: the same quantity of skins, sugar and flour is needed. Mix and place by spoonfuls on a buttered baking sheet. Bake in the oven at medium temperature for 5 to 10 minutes or until the edges are golden.

• Refrigerator  : pasteurized milk, one week. Sterilized milk or UHT, up to three months until it is started. Once started, consume it in the following days. The skin of milk can be kept for 48 hours.
• Freezer  : if necessary, it can be kept in the freezer for six months.

The meadow is the natural pantry of herbivores, which have a quadruple stomach allowing them to digest the cellulose fibers of grass and hay, or even the bark and stems of shrubs, as it is case for goat. However, modern so-called above-ground farming methods are making less and less room for this type of food, in favor of soy and corn concentrates, and corn silage, materials that promote rapid fattening of animals and greater milk production, but which have important consequences for their health.

For example, it is estimated that, before domestication, the cow produced on average 1,000 liters of milk per year. Once domesticated, this production rose to 4,000 liters. Today, the Holstein breed, which is gaining ground around the world, can produce 12,000 to 24,000 liters per year, and we continue to look for ways to increase these yields.

As for the composition of its milk, it differs notably from that of a cow raised on the grass. Even when it is not treated with bovine somatotropin, the genetically engineered hormone that has been the subject of so much controversy, the content of growth hormone in its milk is significantly higher due to a higher great stimulation of the pituitary gland. In addition, his milk contains much less omega-3 fatty acids and conjugated linoleic acid.

Finally, the accumulation of manure in above-ground farms is such that it poses a real headache for farmers, who are required to comply with certain environmental standards. The solution? Cut down the trees and transform the forests into cornfields, on which manure is spread so that we can get rid of these surpluses with impunity.

In Europe as in North America, this management model is increasingly questioned. We advocate the return to pasture and to less degenerate dairy breeds than Holstein, notably Jersey , Guernsey and Canadian , a small cow from Normandy who has acclimatized well in Quebec and whose milk is delicious.