Milk is a highly nutritious fluid that forms in the udder of dairy cows, designed to support the newborn calf during the first months of life.
A wide variety of food products are made from cow's milk, such as cheese, cream, butter and yogurt.
These foods are known as dairy products or dairy products, and they are an important part of the modern diet.
The nutritional composition of milk is highly complex and contains almost all the nutrients that the human body needs.
The following table contains detailed information about the nutrients in the milk (1).
|Omega 3||0.08 Sun|
Keep in mind that many dairy products are fortified with vitamins, including D and A.
Milk is a rich source of protein (1).
It has approximately 1 g of protein in each liquid ounce (30.5 g), or 7.7 g in each cup (244 g).
The proteins in milk can be divided into two groups according to their solubility in water.
Insoluble milk proteins are called casein, while soluble proteins are known as whey proteins.
These two groups of milk proteins are considered to be of excellent quality, with a high proportion of essential amino acids and good digestibility.
Bottom line: Milk is a very good source of high quality proteins, which can be divided into two categories, casein and whey proteins.
Casein forms the majority (80%) of the proteins in milk.
Casein is actually a family of different proteins and the most abundant is called alpha-casein.
An important property of casein is its ability to increase the absorption of minerals, such as calcium and phosphorus (2).
Casein can also promote lower blood pressure levels (3, 4).
Bottom line: Most of the proteins in milk are classified as casein, which has a number of health benefits.
Whey is another family of proteins, which represents 20% of the protein content in milk.
The serum is particularly rich in branched chain amino acids (BCAA), such as leucine, isoleucine and valine.
It consists of many types of soluble proteins with different properties.
Whey proteins have been associated with many beneficial effects on health, such as lowering blood pressure (5) and improving mood during periods of stress (6).
The consumption of whey protein is excellent for the growth and maintenance of muscles. As a result, it is a popular supplement among athletes and bodybuilders.
Bottom line: Whey proteins are one of the two main families of milk proteins. In addition to being good for muscle growth and maintenance, they can lower blood pressure and improve mood.
The whole milk, directly from the cow, is around 4% fat.
In many countries, the marketing of milk is based primarily on the fat content. In the USA UU., Whole milk has 3.25% fat, while low-fat milk has 2% fat and low-fat milk has 1%.
Milk fat is one of the most complex natural fats, since it contains around 400 different types of fatty acids (7).
Whole milk is very high in saturated fat. About 70% of the fatty acids in milk are saturated.
Polyunsaturated fats are present in minimal amounts. They constitute about 2.3% of the total fat content.
The monounsaturated fats constitute the rest, approximately 28% of the total fat content.
Bottom line: Unprocessed milk has 4% fat, but the content of commercial milk varies depending on the type. Milk fat is mainly composed of saturated fats.
Trans Ruminant Fats
Trans fats are found naturally in dairy products.
In contrast to trans fats found in processed foods, trans fats from dairy products, also called trans fats from ruminants, are generally considered to have beneficial health effects.
Milk contains small amounts of trans fats, such as vaccine acid and conjugated linoleic acid or CLA (7).
CLA has attracted considerable attention due to its various health benefits (8, 9, 10).
However, large doses of CLA through supplements can have detrimental effects on metabolism (11, 12, 13).
Bottom line: Milk contains small amounts of trans fat from ruminants. Conjugated linoleic acid (CLA) is the most studied and has been linked to several health benefits.
Carbohydrates in milk are mainly in the form of a simple sugar called lactose, which makes up about 5% of the milk's weight.
In the digestive system, lactose is broken down into glucose and galactose. These are absorbed into the bloodstream and galactose is converted into glucose in the liver.
Some people lack the enzyme needed to break down lactose. This condition is called lactose intolerance.
Bottom line: Carbohydrates make up about 5% of milk, most of which is lactose (milk sugar), which many people are intolerant.
Vitamins and minerals
Milk contains all the vitamins and minerals necessary to maintain growth and development in the young calf during the first months of life.
It also contains almost all the nutrients that humans need, making it one of the most nutritious foods on the planet.
The following vitamins and minerals are found in particularly large amounts in milk:
- B12 vitamin: This essential vitamin is only found in foods of animal origin (14) and milk is very high in B12 (1).
- Calcium: Milk is not only one of the best dietary sources of calcium, but the calcium found in milk is also easily absorbed (15).
- Riboflavin: One of the B vitamins, also called vitamin B2. Dairy products are the largest source of riboflavin in the Western diet (16).
- Match: Dairy products are a good source of phosphorus, a mineral that plays an essential role in many biological processes.
Milk Enrichment with Vitamin D
Enrichment, also called fortification, is the process of adding minerals or vitamins to food products.
As a public health strategy, the enrichment of dairy products with vitamin D is common and even mandatory in some countries (17).
In the United States, a cup of milk enriched with vitamin D (244 g) may contain 65% of the recommended daily amount of vitamin D (18).
Bottom line: Milk is an excellent source of many vitamins and minerals, such as vitamin B12, calcium, riboflavin and phosphorus. It is often enriched with other vitamins, especially vitamin D.
More than 50 different hormones are naturally present in cow's milk.
These hormones are important for the development of the newborn calf (19).
With the exception of insulin-like growth factor 1 (IGF-1), cow's milk hormones have no known effects in humans.
IGF-1 is also found in human breast milk and is the only hormone that is known to be absorbed from cow's milk. It is involved in growth and regeneration (20).
Bovine growth hormone is another hormone naturally present in milk in small amounts. It is only biologically active in cows and has no effect on humans.
Bottom line: Milk contains a wide variety of hormones that promote the development of the newborn calf. Only one of them, insulin-like growth factor 1 (IGF-1), is active in humans.
Bone health and osteoporosis
Osteoporosis, a condition characterized by a decrease in bone density, is the main risk factor for bone fractures in the elderly.
One of the functions of cow's milk is to promote the growth and development of bones in the young calf.
Cow's milk seems to have similar effects in adult humans and has been associated with higher bone density (15).
The high content of calcium and proteins in milk are the two main factors responsible for this effect (21).
Bottom line: Being a rich source of calcium, milk can promote a higher bone mineral density, reducing the risk of osteoporosis.
Other health benefits of milk
Milk is one of the most nutritious foods you can find.
It has been widely studied and appears to have several important health benefits.
Abnormally high blood pressure, also called hypertension, is an important risk factor for cardiovascular disease.
Dairy products have been linked to a lower risk of hypertension (22, 23).
It is believed that this is due to the unique combination of calcium, potassium and magnesium found in milk (24, 25).
Other factors may also be involved in milk, such as the peptides formed during the digestion of casein, the main class of protein in milk (3, 4).
Bottom line: Milk and dairy products have been linked to the reduction of blood pressure.
Lactose, also called milk sugar, is the main carbohydrate found in milk.
In the digestive system, it is broken down into its subunits, glucose and galactose.
However, this does not happen in all people.
An enzyme called lactase is necessary for the decomposition of lactose. Some people lose the ability to digest lactose after childhood.
This inability to digest lactose is called lactose intolerance.
It has been estimated that around 75% of the world population has lactose intolerance (26). However, the proportion of lactose intolerant people varies greatly depending on the genetic makeup.
This photo shows the frequency of lactose intolerance in various parts of the world: