Is milk bad for you? Health benefits and side effects

Milk contains essential vitamins and minerals and offers several health benefits as part of a nutritious diet. Humans have drunk cow’s milk throughout history, and studies trace its consumption back to the Middle Neolithic period, about 6,000 years ago. But drinking milk can also have harmful effects for some people.

Cow’s milk is not ideal for everyone. This article explains the pros and cons of dairy in your diet and who should opt for dairy-free alternatives.

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Milk Nutrition Facts

Milk is rich in protein and contains 18 of 22 essential nutrients, so it is often recommended as part of a balanced diet.

The nutrients of milk

According to the United States Department of Agriculture (USDA), an 8-ounce glass of low-fat (2%) milk contains:


The number of calories per serving of milk depends on its fat content. Eight ounces of whole milk have 146 calories compared to 83.6 calories for nonfat milk. Milk is a good source of energy.


The lactose in milk makes it a rich source of carbohydrates. The body breaks them down into glucose (blood sugar), which it converts into energy. Some dairy products have added sugars, which increases their carbohydrate content.


Milk also contains high levels of protein, making it a good source of this essential nutrient. About 20% of milk protein is whey, a soluble protein that the body digests faster. The remaining 80% is casein protein, an insoluble protein. Dairy protein contains all nine essential amino acids, which help with protein, neurotransmitters (brain chemicals), and hormone production.


Milk is classified by its fat content, so it’s easy to determine which type will have more or less of this nutrient. Whole milk contains 7.8 g per 8-ounce serving, while skim milk only has small amounts. About 70% is saturated fat (which can build up in the arteries when consumed in excess) and the rest is unsaturated.

Vitamins and minerals

Milk is an important source of several essential vitamins and minerals, including:

Benefits of milk

There’s a reason you might remember public health campaigns that encouraged people to drink milk. Researchers have discovered that consuming dairy products offers numerous health benefits.

Appetite control

Studies suggest that milk’s high protein, lactose and fat content keeps you fuller longer and may help control appetite. In a 2018 study of children with obesity, whole milk was found to suppress hunger for up to four hours.

bone development

Milk contains many vitamins and minerals necessary for bone formation and growth, including protein, calcium, phosphorus, magnesium, manganese, and zinc, as well as vitamins D and K. In children and adolescents, studies have linked the intake of dairy with healthier bone development.

High in protein

Milk is a rich source of protein and contains approximately 8 g per cup (8 ounce) serving. This results in several health benefits, including:

  • Bone density: Researchers found that the protein interacts with other minerals in milk to preserve bone density as adults age.
  • Healthy teeth: Casein, which makes up 80% of the protein content of dairy, can protect teeth and studies have associated milk consumption in children with fewer cavities.
  • Muscle development: Milk protein can also help build and maintain muscle; Researchers found that drinking milk after resistance training stimulates anabolism, the process of repairing and building muscle tissue.

Bone and dental health

There’s something about public health campaigns that link milk with strong teeth and bones. Research has found that nutrients in milk, including phosphorus, vitamin D, calcium, magnesium and protein, play a role in bone development in both children and adolescents. Some evidence also indicates that it helps adults in this regard as well.

milk and smiles

There is significant evidence that drinking milk promotes dental health. The calcium and phosphate content of milk helps teeth retain strength and protects them from cavities.

Heart health

The relationship between milk consumption and heart health is complicated and has positive and negative effects. Some studies have consistently linked low-fat, high-calcium dairy products to a reduction in blood pressure. This reduces the risk of hypertension (high blood pressure), protecting the body from heart problems and stroke (a dangerous interruption of blood flow to the brain).

Diabetes prevention and management

In several ways, drinking milk can help the body fight diabetes, a chronic inability to effectively metabolize sugar. Studies have found that high dairy consumption reduces the chances of developing childhood obesity (excess weight), a major risk factor for diabetes. Additionally, researchers have noted that consuming milk on a calorie-restricted diet can help facilitate weight loss, which helps control diabetes.

Negative side effects of milk

Although drinking milk can produce many positive health effects, it can also have potential disadvantages. Some people are allergic or intolerant to dairy. Dairy consumption has also been linked to certain conditions.


Acne (acne vulgaris) occurs when hair follicles become clogged with oil or dead skin, causing pimples or bumps on the skin. In a large review of data from more than 78,000 children and adults ages 7 to 30, dairy consumption (drinking milk and eating cheese) increased the chances of experiencing flare-ups. Researchers aren’t sure why this happens, but they think an inflammatory (immune) response to dairy may be to blame.

Other skin conditions

High dairy consumption has also been associated with inflammatory skin conditions. In some people, dairy consumption can trigger attacks of eczema (itchy, peeling skin) and rosacea (red, red skin). Even in those without an outright allergy, researchers noted that consumption can trigger this response.


Researchers estimate that up to 3% of toddlers and children under 3 years old have some type of milk allergy. This decreases over time and 80% of children with milk allergies outgrow them by the age of 16. These allergies arise when dairy triggers inflammatory responses. An allergic reaction to consumption can cause:

  • Hives or bumps that develop on the skin.
  • Stomachache
  • Vomiting and nausea
  • bloody stools
  • Anaphylaxis (a rare, severe-onset systemic shock that causes breathing difficulties)

Lactose intolerance

Up to 68% of people have lactose malabsorption and lactose intolerance. These are problems digesting and breaking down lactose (milk sugar). Lactose intolerance can cause bloating, nausea, diarrhea, gas, abdominal pain, rumbling, and vomiting.

bone fractures

Although milk consumption has been linked to the development and maintenance of bones, it can also increase the risk of bone fractures. In a large study that evaluated data from more than 100,000 participants, researchers found that higher intake in women between 39 and 79 years old led to a higher incidence of bone fractures.


The evidence on milk consumption and cancer is mixed: some studies find that it protects against colorectal cancer. In several studies, dairy intake increased the risk of prostate cancer in men and ovarian cancer in women. Researchers have also linked dairy consumption to an increased risk of breast cancer, although more studies are still needed to confirm this.

heart disease

Although dairy intake has been associated with reducing high blood pressure and improving heart health, it can also cause negative side effects. Whole milk can cause spikes in low-density lipoprotein (LDL or “bad”) cholesterol, increasing the risk of heart disease. However, studies have yet to consistently link increased dairy consumption to this problem.

How much milk should you drink a day?

Barring a milk allergy or lactose intolerance, most nutritional guidelines recommend including dairy products regularly in your diet. It is an excellent source of animal fats, calcium and vitamin D, among other nutrients. According to the USDA, the recommended daily amounts are:

  • Three servings (3 cups milk or yogurt; 3 ounces cheese) for adults
  • Three servings for children from 9 to 18 years old
  • Up to 2.5 servings for toddlers and babies under 2 years old

However, all of this comes with some controversy. Citing possible links to disease and disproportionate lactose intolerance among non-white populations, the American Medical Association (AMA) urged the USDA to revise these guidelines and make dairy optional.

Who should avoid cow’s milk?

As much as dairy products can be part of a nutritious diet, they are not suitable for everyone. Those who have milk allergies or show symptoms of milk allergies, especially infants and young children, should avoid milk. Another reason to avoid dairy products is lactose intolerance. Compared to whites, this problem is more common among African Americans, Native Americans, Asian Americans, and Hispanic Americans.

Talk to a healthcare provider if you or your child experience digestive symptoms or hives after drinking milk. They can determine if you have lactose intolerance or a dairy allergy.

Alternatives to cow’s milk

If cow’s milk is not a good option for you, there are many plant-based alternatives. These come from four different sources:

  • Cereal milks such as oatmeal or rice milk
  • Legume milk, such as soy or pea milk.
  • Nut milks such as almond, cashew and coconut.
  • Seed-based milk, such as hemp or flax milk.

However, it is important to remember that the nutritional content of soy, almonds, oats and other dairy alternatives varies and may not match that of milk. Of all possible types of milk, only soy milk fortified with calcium, vitamin D, and vitamin A is considered comparable to cow’s milk in the USDA dietary guidelines.

When choosing alternatives to cow’s milk, check the milk’s Nutrition Facts label. Look for other options that are high in protein and low in saturated fat and have no added sugars or saturated fats. If you are on a diet, keep in mind that some plant milks have more calories than skimmed or low-fat milk.


Although it is not suitable for everyone, milk can be a healthy and nutritious part of your diet. Dairy products are rich in necessary vitamins and minerals and are good sources of protein and offer many health benefits. However, some people are allergic to milk or have lactose intolerance, and consuming milk can cause specific health problems. Plant-based alternatives, such as soy milk, may not have the same nutritional content as milk. Talk to a healthcare provider about whether you should include milk in your diet.

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