Calcium May Lower Risk of Colorectal Cancer in Women

A long-running study out of the United Kingdom is shining a light on an everyday nutrient that could play a powerful role in women’s health: calcium.

Researchers followed more than 540,000 women over 16 years, tracking their diets and monitoring cancer diagnoses. What they found was significant, for every 300 milligrams of calcium consumed per day (about the amount in one cup of milk), women saw a 17 percent lower risk of developing colorectal cancer.

Colorectal cancer is one of the most common cancers in women, yet it often develops quietly. Symptoms may not appear until the disease has progressed, which is why prevention and early detection are so important.

Calcium does more than strengthen bones. In the digestive tract, it binds to certain stomach and digestive acids, compounds that, in high amounts, can irritate the lining of the colon. By attaching to these substances, calcium helps neutralize their potential harmful effects and supports the body’s natural process of carrying waste and abnormal cells out through stool.

Researchers are careful to note that the protective effect depends on how much calcium is present in the gut, meaning consistent daily intake matters.

Many women fall short of the recommended daily calcium intake. Good sources include:

• Milk, yogurt and cheese
• Calcium-fortified plant-based milks
• Leafy greens like kale and collard greens
• Almonds
• Tofu
• Sardines and canned salmon (with bones)
• Fortified cereals and juices

Before starting supplements, it’s important to talk with your healthcare provider to determine what’s right for you.

While this study highlights a promising link between calcium and reduced colorectal cancer risk, diet alone is not a substitute for screening.

Because colorectal cancer often goes undiagnosed until symptoms develop, routine screening is the only way to catch it early, when it’s most treatable. For most adults at average risk, screening begins at age 45, though your provider may recommend starting earlier based on family history or other risk factors.

Small, consistent lifestyle choices like meeting your daily calcium needs, can make a meaningful difference in long-term health. Pairing those choices with regular screenings offers the strongest protection.