Milk has long been considered a healthy drink. Many people grow up being told that drinking milk helps build strong bones and supports overall health. Milk contains several important nutrients that the body needs to function well.
These include calcium, phosphorus, B vitamins, potassium, vitamin D, and high‑quality protein. Because of these nutrients, milk is often recommended to help maintain bone strength and support muscle health, especially as people grow older.
However, milk is not always perfect for everyone. Some people experience problems when they drink it. A small number of children, about two percent, have an allergy to the protein found in cow’s milk. This can cause symptoms such as rashes, stomach pain, or breathing problems.
In addition, many adults around the world have lactose intolerance. Lactose is the natural sugar in milk, and people who cannot digest it properly may develop bloating, stomach cramps, or diarrhea after drinking milk.
Because milk has both benefits and possible drawbacks, scientists have long debated whether it helps or harms long‑term health. In particular, researchers have tried to understand how milk consumption affects the risk of major diseases such as heart disease and cancer.
Some studies have suggested milk is protective, while others have suggested it may increase certain health risks. These mixed results have made the topic difficult to understand.
To explore this question further, scientists from Sun Yat-sen University conducted a large study examining how milk drinking relates to the risk of death from heart disease and cancer. The research focused on older adults living in Guangzhou, China, where people traditionally drink much less milk than populations in many Western countries.
The researchers used data from the Guangzhou Biobank Cohort Study, a long‑term project that follows the health of thousands of adults as they age.
For this analysis, the team looked at information from 18,214 participants who were aged 50 years or older. At the beginning of the study, which took place between 2003 and 2006, none of the participants had cardiovascular disease.
The participants were grouped according to how much milk they reported drinking. A large portion of the group, about 69.6 percent, said they did not drink milk at all. Another 14.7 percent drank milk in moderate amounts, defined as one to three servings per week.
In this study, one serving was equal to about 250 milliliters, roughly the amount in a typical glass of milk. The remaining 15.8 percent of participants reported drinking milk more frequently, which the researchers classified as high consumption, meaning more than three servings each week.
The researchers then followed the participants for an average of 11.5 years to observe their health outcomes. During this time, 2,697 participants died. Among these deaths, 917 were related to heart disease and 1,029 were caused by cancer.
When the researchers compared the groups, they found an interesting pattern. Participants who drank milk moderately appeared to have a lower risk of dying from several causes. In particular, moderate milk drinkers had lower risks of death from heart disease, stroke, and overall mortality compared with people who did not drink milk at all.
However, the results were different for people who drank milk more frequently. Participants with higher milk consumption showed an increased risk of death from cancer overall. The strongest link was seen with deaths from esophageal cancer.
At the same time, the researchers did not find evidence that higher milk consumption increased the risk of death from several other types of cancer. These included lung cancer, liver cancer, gastrointestinal cancer, and colorectal or anal cancers. This suggests that the possible risk linked with high milk intake may affect only certain types of cancer rather than all cancers.
Based on their findings, the scientists suggested that the effects of milk may depend on how much people drink. In populations where milk consumption is generally low, drinking moderate amounts may help protect heart health. However, drinking larger amounts might be linked to a higher risk of cancer death.
The researchers also emphasized that more studies are needed to fully understand these relationships. Diet, lifestyle, genetics, and other health factors may all influence how milk affects the body. Because of this complexity, scientists believe further research is necessary before clear recommendations can be made for all populations.
This research was conducted by Xiang Jun Wang and colleagues from Sun Yat-sen University and was published in the journal Clinical Nutrition. Their work adds new evidence to the ongoing discussion about how dairy consumption affects long‑term health.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
For more health information, please see recent studies that apple juice could benefit your heart health, and results showing yogurt may help lower the death risks in heart disease.
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