Drinking milk may reduce the risk of colorectal cancer

Most of us know the saying, “An apple a day keeps the doctor away.” But could a glass of milk keep cancer away? According to a recent study — yes.

Researchers found that consuming an extra 300 mg of calcium daily — the amount in a large glass of milk — could be linked to a 17% reduction in the risk of colorectal cancer.

More than half a million women participated in the research led by the University of Oxford and published in Nature Communications. The study reviewed 16 years of medical data from each participant to identify any links between their dietary habits and colorectal cancer.

Mom’s always right

The study shows that your mother had good reason for telling you to drink your milk and eat your veggies. Milk is packed with calcium and other essential nutrients. And nondairy foods like leafy greens are also full of calcium, vitamins, fiber and antioxidants that could protect against colorectal cancer.

Taylor Dial, CNSC, a registered dietitian at Sharp Grossmont Hospital, says there are many ways to boost calcium intake besides milk. “Yogurt, cottage cheese and cheese are great options,” she says.

However, Dial cautions that cheese should be eaten in moderation due to its high saturated fat and sodium content, which can contribute to heart disease and high blood pressure.

She adds that leafy vegetables, like kale, spinach, Bok choy and collard greens, are also good sources. Additionally, almonds, chia seeds and sesame seeds can help.

The study also identified foods and drinks linked to a higher risk of colorectal cancer. The top offenders were alcohol and red and processed meats, like bacon, sausage, hot dogs and lunch meats. Specifically, drinking an additional 20g of alcohol daily — equivalent to a large glass of wine — was found to increase bowel cancer risk by up to 15%.

Calcium helps prevent colorectal cancer

Dial suggests that calcium may help reduce cancer risk by binding to bile and fatty acids in the colon, potentially neutralizing their cancer-causing effects. High levels of these acids in the body can be considered a risk factor for developing gastrointestinal cancers, particularly colon cancer.

“Calcium also strengthens the colonic barrier, which prevents harmful substances like toxins and bacteria from damaging the intestinal walls,” she explains. “Additionally, calcium supports normal cell development, helps prevent oxidative DNA damage, and may lower the chances of KRAS mutations, which can lead to uncontrolled cell growth and colorectal cancer.”

Does the study apply to men?

While the study focused on women, the effects of alcohol and red and processed meats on colorectal cancer risk are similar for both genders.

“Though the study didn’t include men, other large studies have shown similar trends,” says Dial. “It’s likely that the findings apply to both men and women.”

According to the American Cancer Society, colorectal cancer is the third-leading cause of cancer-related deaths in men and the fourth in women in the U.S. While the chance of developing colorectal cancer is about 1 in 24 for men and 1 in 26 for women, risk factors such as smoking, diet, physical activity, body weight and alcohol consumption can influence these odds.

The bottom line

A key takeaway from the study is the importance of getting enough calcium from dairy or plant sources to reduce the risk of colorectal cancer. Dial recommends aiming for five servings of fruits and vegetables daily for overall cancer prevention. “Eating a plant-based, fiber-rich diet lowers your risk and improves overall health,” she says.

A diet rich in colorful fruits and vegetables provides antioxidants, while whole grains like brown rice, quinoa, oats and whole wheat offer essential nutrients, Dial adds. Legumes and beans provide fiber and protein, and healthy fats from nuts, seeds and olive oil contribute to wellness.

“These habits not only reduce colorectal cancer risk,” Dial says, “but also aid digestion, boost the immune system, and lower the risk of other cancers.”

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