Could something as simple as milk be linked with a lower risk of bowel cancer? A large 2025 study from researchers at the University of Oxford found that higher calcium intake was associated with a lower risk of colorectal cancer.
But the finding is more nuanced than the headline “milk cuts bowel cancer risk by 5%” suggests. The study did not prove that drinking milk prevents cancer, and it did not recommend that everyone start drinking more milk.
What Did the Study Find?
Researchers analyzed dietary information from 542,778 women participating in the UK Million Women Study and followed their health outcomes for an average of 16.6 years.
During that period, 12,251 participants developed colorectal cancer.
The researchers examined 97 dietary factors and found that calcium had one of the strongest inverse associations with colorectal cancer risk.
An additional 300 milligrams of calcium per day was associated with a 17% lower risk of colorectal cancer.
For context, 300 milligrams is roughly the amount of calcium found in a large glass of milk.
However, this does not mean that one glass of milk directly reduces an individual's cancer risk by 17%. The researchers studied dietary patterns and health outcomes, so the findings show an association rather than proof of cause and effect.
Why Is Calcium Important?
Calcium is best known for supporting healthy bones and teeth, but researchers are also studying its possible role in the digestive tract.
One proposed explanation is that calcium may bind with certain bile acids and fatty acids in the intestine. This could potentially reduce their contact with the lining of the bowel.
Researchers are still investigating exactly how calcium may influence colorectal cancer development.
The 2025 study found similar associations for calcium from both dairy and non-dairy sources, which suggests that calcium itself may be an important part of the relationship.
Is Milk the Reason for the Lower Risk?
Not necessarily.
Milk and yogurt were among the calcium-rich foods associated with a lower risk of bowel cancer. But the researchers also found similar associations with some non-dairy calcium sources.
That is one reason it would be inaccurate to describe milk as a cancer-prevention treatment.
Instead, milk can be considered one possible source of calcium within an overall balanced diet.
For people who do not consume dairy, calcium-fortified alternatives and other calcium-containing foods can also contribute to calcium intake.
What About Yogurt and Other Dairy Foods?
The study found associations between several dairy-related foods and lower colorectal cancer risk.
This is consistent with other evidence suggesting that dairy products can be part of a diet associated with a lower risk of bowel cancer.
However, not every dairy product has the same nutritional profile.
For example, some products can contain significant amounts of added sugar or saturated fat. Choosing options that fit your overall nutritional needs is more important than relying on one food as a protective “superfood.”
Cancer Research UK notes that milk and other dairy products can be part of a healthy, balanced diet and that there is good evidence linking dairy consumption with a lower risk of bowel cancer.
What Should You Eat for Better Bowel Health?
There is no single food that guarantees protection from bowel cancer.
A healthier overall eating pattern can include:
- Milk or unsweetened dairy alternatives that provide calcium
- Yogurt with little or no added sugar
- Vegetables and fruit
- Whole grains and other high-fiber foods
- Beans and other pulses
- Fish and other nutritious protein sources
It is also important to limit factors associated with higher bowel cancer risk.
Cancer Research UK notes that eating too little fiber, consuming alcohol, and eating large amounts of red and processed meat are among factors associated with bowel cancer risk.
Do You Need to Drink Milk Every Day?
No.
The study does not establish that everyone needs to drink milk every day to prevent bowel cancer.
If you enjoy milk and tolerate dairy well, it can be a convenient source of calcium and protein. But people who avoid dairy can obtain calcium from other foods and fortified alternatives.
People with lactose intolerance, milk allergy, dietary restrictions, or other health considerations should choose foods that work for their individual needs.
What About Calcium Supplements?
This is an important distinction.
The 2025 study examined dietary intake but could not determine whether calcium supplements would provide the same potential benefit.
Cancer Research UK also notes that more research is needed to determine whether calcium supplements can reduce bowel cancer risk.
Therefore, you should not start taking calcium supplements specifically to prevent bowel cancer without discussing your individual needs with a healthcare professional.
The Bigger Picture
The strongest lesson from this research is not that milk is a miracle food.
Instead, it adds to evidence suggesting that adequate calcium intake and a balanced diet may be relevant to bowel health.
The study was large and followed participants for many years, but it was still an observational analysis. Observational research can identify relationships between diet and disease, but it cannot prove that a particular food directly prevents cancer.
More research is needed to understand whether these findings apply equally to different populations and whether increasing calcium intake would actually prevent colorectal cancer.
Bottom Line
Milk can be a nutritious source of calcium, and a large 2025 study found that higher calcium intake was associated with a lower risk of colorectal cancer.
But the research does not prove that drinking milk prevents bowel cancer or that one glass of milk reduces your individual risk by a specific percentage.
The best approach is to focus on an overall balanced eating pattern, adequate fiber and calcium, healthy lifestyle habits, and appropriate medical screening.
If you have symptoms such as persistent changes in bowel habits, blood in the stool, unexplained weight loss, or ongoing abdominal discomfort, speak with a healthcare professional rather than trying to manage the problem through diet alone.
Medical Disclaimer
This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Research findings describe population-level associations and may not apply to every individual. If you have concerns about bowel cancer, calcium intake, digestive symptoms, or your personal cancer risk, speak with a qualified healthcare professional.
Sources
- University of Oxford, Cancer Epidemiology Unit — research summary on calcium, dairy intake, and bowel cancer.
- Nature Communications — Diet-wide analyses for risk of colorectal cancer: prospective study of 12,251 incident cases among 542,778 women in the UK.
- Cancer Research UK — analysis of the 2025 calcium and bowel cancer research.
- Cancer Research UK — information on milk, dairy, and cancer risk.
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