Glass of milk a day keeps colorectal cancer away, massive study reveals

LONDON — What if reducing your cancer risk was as simple as adding a glass of milk to your daily diet? A study of over half a million women concludes that dairy products, particularly those rich in calcium, may help protect against colorectal cancer, while alcohol and processed meats continue to pose significant risks. The massive research project tracked the eating habits and health outcomes of 542,778 British women for over 16 years, identifying key foods and nutrients that could help prevent one of the world’s most common cancers.

Colorectal cancer shows striking differences between regions, with higher rates in wealthy nations like the United States, European countries, and Japan, compared to lower rates in much of Africa and South Asia. However, when people move to countries with higher rates, their risk begins matching that of their new home within about a decade, suggesting that lifestyle factors, particularly diet, play a crucial role.

The international research team analyzed 97 different dietary components, from specific foods to nutrients. During the study period, 12,251 women developed colorectal cancer, allowing scientists to identify clear patterns between eating habits and cancer risk.

Among the strongest protective factors was calcium intake. Women who consumed more calcium-rich foods showed a significantly lower risk of developing colorectal cancer. The benefit appeared consistent whether the calcium came from dairy products or other sources.

Dairy milk emerged as another powerful player in cancer prevention. Regular milk drinkers showed notably lower cancer risk, and other dairy products like yogurt demonstrated similar protective effects. Several nutrients commonly found in dairy — including riboflavin, magnesium, phosphorus, and potassium — also showed benefits.

On the flip side, alcohol consumption stood out as the strongest risk factor. Having about two standard drinks more per day was linked to a 15% higher risk of developing colorectal cancer. The risk appeared particularly pronounced for rectal cancer compared to colon cancer.

Red and processed meats maintained their concerning reputation. Each additional daily serving about the size of a slice of ham was associated with an 8% higher risk. This finding supports previous research that led international health organizations to classify processed meat as cancer-causing and red meat as probably cancer-causing in humans.

The researchers took an innovative approach to confirm dairy’s protective effects by examining genetic differences that affect how well people can digest milk products. This analysis provided additional evidence that dairy foods help protect against colorectal cancer, as people who were genetically better able to digest dairy had lower cancer rates.

While breakfast cereals, fruits, whole grains, and high-fiber foods showed some protective effects, these benefits became less pronounced when researchers accounted for overall lifestyle habits. This suggests that people who eat these foods might have generally healthier lifestyles that contribute to lower cancer risk.

Scientists believe calcium helps prevent cancer in several ways: by binding to harmful substances in the digestive system, promoting healthy cell development in the colon, and reducing inflammation. While dairy products aren’t suitable for everyone, particularly those with lactose intolerance or milk allergies, the research suggests that for many people, including more dairy in their diet might help reduce their cancer risk.

These findings provide compelling evidence that simple dietary changes, like having more dairy products while limiting alcohol and processed meats, could help reduce the risk of developing one of the world’s most common cancers. However, no single food acts as a magic bullet: it’s the overall pattern of dietary choices that matters most for cancer prevention.