You may know cow’s milk for its calcium content, but it has much more to offer. A single cup provides nearly all the nutrients your body needs. This complex and nutritious liquid offers a variety of health benefits.
Milk is a highly nutritious liquid formed in the mammary glands of mammals to sustain their newborns during their first months of life.
This article focuses on cow’s milk. Cow’s milk is used to make a wide variety of food products, such as cheese, cream, butter, and yogurt. These foods are referred to as dairy or milk products and are a major part of the modern diet.
Read on to learn what you need to know about cow’s milk.
The nutritional composition of milk is highly complex. It contains almost every single nutrient that your body needs.
One cup (249 grams) of whole cow’s milk with 3.25% fat
- Calories: 152
- Water: 88%
- Protein: 8.14 grams
- Carbs: 12 grams
- Sugar: 12 grams
- Fiber: 0 grams
- Fat: 8 grams
Milk proteins
Milk is a rich source of protein — providing approximately 1 gram of this nutrient in each fluid ounce (30 mL), or 8.14 grams in each cup (249 mL).
Proteins in milk can be divided into two groups based on their solubility in water:
- Insoluble milk proteins are called casein.
- Soluble milk proteins are known as whey proteins.
Both groups of milk proteins are considered to be of excellent quality, with a high proportion of essential amino acids and good digestibility.
Casein
Casein forms the majority — or 80% — of proteins in milk.
It’s really a family of different proteins, with alpha-casein being the most abundant.
One important property of casein is its ability to increase the absorption of minerals, such as calcium and phosphorus. It may also promote lower blood pressure.
Whey protein
Whey is another family of proteins, accounting for 20% of the protein content in milk. It’s particularly rich in branched-chain amino acids (BCAAs) — such as leucine, isoleucine, and valine.
Whey proteins have been linked to numerous beneficial health effects, including
Whey protein is excellent for
Milk fat
Whole milk straight from the cow is around 4% fat.
In many countries, the marketing of milk is mainly based on fat content. In the United States, whole milk is 3.25% fat, reduced-fat milk is 2%, and low fat milk is 1%. Milk fat is one of the most complex of all natural fats, containing about 400 different types of fatty acids.
Whole milk is very high in saturated fats, which make up about 70% of its fatty acid content. Polyunsaturated fats are present in small amounts, accounting for approximately 2.3% of the total fat content. Monounsaturated fats make up the rest — about 28% of the total fat content.
In addition, trans fats are naturally found in dairy products. In contrast to trans fats in processed foods, dairy trans fats — also called ruminant trans fats — are considered beneficial for health. Milk contains small amounts of trans fats, such as vaccenic acid and conjugated linoleic acid (CLA).
CLA has attracted considerable attention due to its potential for various health benefits — although the evidence is still limited. Some research suggests that CLA supplements may negatively affect metabolism.
Carbs
The carbohydrates in milk are mainly the simple sugar lactose, which makes up around 5% of milk.
In your digestive system, lactose breaks down into glucose and galactose. These are absorbed into your bloodstream, at which point your liver converts galactose into glucose.
Some people lack the enzyme required to break down lactose. This condition is known as lactose intolerance, which is discussed later.
Milk contains all the vitamins and minerals necessary to sustain growth and development in a young calf during its first months of life.
It also provides almost every single nutrient needed by humans — making it one of the most nutritious foods available.
The following vitamins and minerals are found in particularly large amounts in milk:
- Vitamin B12: Foods of animal origin are the only rich sources of this essential vitamin. Milk is very high in B12.
- Calcium: Milk is not only one of the best dietary sources of calcium, but the calcium found in milk is also easily absorbed.
- Riboflavin: Dairy products are the biggest source of riboflavin — also known as vitamin B2 — in the Western diet.
- Phosphorus: Dairy products are a good source of phosphorus, a mineral that plays an essential role in many biological processes.
Sometimes fortified with vitamin D
Fortification is the process of adding minerals or vitamins to food products. As a public health strategy, fortifying milk products with vitamin D is common and even mandatory in some countries. In the United States, 1 cup (240 mL) of vitamin-D-fortified milk may contain
More than 50 different hormones are naturally present in cow’s milk, which are important for the development of a newborn calf. With the exception of insulin-like growth factor-1 (IGF-1), cow milk hormones have no known effects in humans.
IGF-1 is also found in human breast milk and is the only hormone
Bovine growth hormone is another hormone naturally present in milk in small quantities. It’s only biologically active in cows and has no effect in people.
Milk is one of the most nutritious foods you can find. It has been widely studied and seems to have several important health benefits. In particular, cow’s milk may positively affect your bones and blood pressure.
Bone health and osteoporosis
Osteoporosis — a condition characterized by a decrease in bone density — is the main risk factor for bone fractures among older adults.
One function of cow’s milk is to promote bone growth and development in the young calf. Cow’s milk seems to have similar effects on people and has been associated with higher bone density. The high calcium and protein content of milk are the two main factors believed responsible for this effect.
However, more recent evidence is conflicting. Some studies have
Blood pressure
Abnormally high blood pressure is a major risk factor for heart disease. Dairy products have been linked to a reduced risk of high blood pressure. It’s thought that the unique combination of calcium, potassium, and magnesium in milk are responsible for this effect.
Other factors, such as peptides formed during the digestion of casein, may also play a part.
The health effects of milk are complex — some components in milk are quite beneficial, while others may have adverse effects.
Lactose intolerance
Lactose, or milk sugar, is the main carbohydrate found in milk. It’s broken down into its subunits — glucose and galactose — in your digestive system. However, some people lose the ability to fully digest lactose after childhood — a condition known as lactose intolerance.
An estimated 65% of the world’s population has lactose intolerance, though the proportion of lactose-intolerant people varies greatly depending on genetic makeup. Lactose intolerance is most prominent in parts of Asia, Africa, and South America, where it’s estimated to affect 70–100% of the population.
In people with lactose intolerance, lactose is not fully absorbed, and some or most of it passes down to the colon, where the resident – bacteria normally in the gut – bacteria start fermenting it. This fermentation process leads to the formation of short-chain fatty acids (SCFAs) and gas, including methane and carbon dioxide.
Lactose intolerance is associated with many unpleasant symptoms, including gas, bloating, abdominal cramps, diarrhea, nausea, and vomiting.
Milk allergy
Milk allergy is rare in adults but more frequent in young children. Most often, allergic symptoms are caused by whey proteins called alpha-lactoglobulin and beta-lactoglobulin, but they can also be due to caseins.
The main
- skin rash
- swelling
- breathing problems
- vomiting
- diarrhea
- blood in stools
Acne
Milk consumption has been associated with acne — a common skin condition characterized by pimples, especially on the face, chest, and back. High milk consumption is associated with increased levels of insulin-like growth factor-1 (IGF-1), a hormone believed to be involved in the development of acne.
Milk and cancer
Numerous observational studies have examined the relationship between milk consumption and cancer risk. Overall, the evidence is mixed, and very few conclusions can be drawn from the data.
However, several studies indicate that dairy consumption may increase the risk of prostate cancer in men. Conversely, numerous studies have found a link between dairy consumption and a lower risk of colorectal cancer.
As a general recommendation, excessive consumption of milk should be avoided. Moderation is key.
Virtually all milk sold for human consumption is processed in some way. This is done to increase the safety and shelf life of milk products.
Pasteurization
Pasteurization is the process of heating milk to destroy potentially harmful bacteria that are occasionally found in raw milk. The heat eliminates beneficial and harmful bacteria, yeasts, and molds.
However, pasteurization does not make milk sterile. Therefore, it needs to be quickly cooled down after heating to keep any surviving bacteria from multiplying.
Pasteurization results in a slight loss of vitamins due to their sensitivity to heat but doesn’t have a substantial effect on milk’s nutritional value.
Homogenization
Milk fat is made up of countless particles, or globules, of different sizes. In raw milk, these fat globules tend to stick together and rise to the surface.
The purpose of homogenization is to increase the shelf life of milk and to give it a richer taste and whiter color.
Most milk products are produced from homogenized milk. Cheese is one exception; it is usually produced from unhomogenized milk. Homogenization does not have any adverse effects on nutritional quality.
Raw milk is a term used for milk that has not been pasteurized or homogenized. Pasteurization is the process of heating milk to increase shelf life and minimize the risk of illness from harmful microorganisms that may be present in raw milk.
Heating results in a slight decrease in several vitamins, but this loss is not significant from a health perspective. Homogenization — the process of breaking the fat globules in milk into smaller units — has
Drinking raw milk is associated with a reduced risk of childhood asthma, eczema, and allergies. The reason for this association remains unclear. Although raw milk is more natural than processed milk, its consumption carries a higher risk.
Most of these bacteria are not harmful — and many may even be beneficial — but occasionally, milk gets contaminated with bacteria that have the potential to cause disease.
Although the risk of getting ill from drinking raw milk is small, a single milk-borne infection may have serious consequences.
Risks of consuming raw milk
According to the
- Campylobacter
- Cryptosporidium
- E. coli
- Listeria
- Brucella
- Salmonella
Some groups, such as children under 5, adults over 65, pregnant individuals, and people with weakened immune systems, are at a higher risk of serious illness from these germs.
People are usually quick to recover, but those with weak immune systems — such as older adults or very young children — are more susceptible to severe illness.
Most public health advocates agree that any potential health benefits of drinking raw milk are outweighed by possible health risks resulting from contamination with harmful bacteria.
Milk is one of the most nutritious drinks in the world. It’s not only rich in high quality protein but also an excellent source of vitamins and minerals, such as calcium, vitamin B12, and riboflavin. It may cut your risk of osteoporosis and reduce blood pressure.
Still, some people are allergic to milk proteins or intolerant to milk sugar (lactose). Milk has also been linked to acne and an increased risk of prostate cancer.
Talk with a healthcare professional or nutritionist to determine if milk intake would be beneficial for you.
At the end of the day, moderate consumption of cow’s milk is healthy for most people — but you should avoid drinking it in excess.