Colon cancer is one of the leading causes of death. According to the 2023 statistics on causes of death released by the National Statistical Office, 24.2% (85,271 people) of the total number of deaths (352,511 people) died of cancer. Deaths from colon cancer (9,348 people) ranked third after lung cancer (18,646 people) and liver cancer (10,136 people).
Globally, there is a sharp increase in the incidence of colon cancer among those under 50, up by 79% over the past 30 years. In South Korea, the situation is even more severe. From 2008 to 2011, the colorectal cancer incidence rate among Koreans aged 20 to 49 was 12.9 per 100,000, the highest in the world.
Colon cancer is known to be closely related to dietary intake. Recently, research has highlighted that calcium in food can reduce the risk of colon cancer. A research team from the University of Oxford published a study in the journal “Nature Communications,” reporting that drinking a glass of milk (about 300ml), containing 300mg of calcium, daily can reduce the risk of developing colon cancer by 17%.
The analysis of the diets of over 500,000 women over 16 years showed that calcium-rich foods like dark green leafy vegetables (spinach, broccoli, kale), and plant-based milk alternatives like soy milk, also have protective effects. Conversely, excessive consumption of alcohol and processed meats was found to increase the risk of colon cancer.
The study analyzed the impact of 97 dietary factors on colon cancer risk in 542,778 postmenopausal women who participated in the “Million Women Study.” During the research period, 12,251 were diagnosed with colon cancer. The analysis revealed that among the dietary factors, calcium and alcohol had the most significant impact on changes in colon cancer risk. Specifically, daily intake of 300mg of calcium was associated with a 17% reduction in colon cancer risk, whereas consuming 20g of alcohol daily increased the risk by 15%.
Dr. Keren Papier, the lead author from the University of Oxford, emphasized that the study underscores the potential protective role of dairy, mainly due to calcium, in the development of colon cancer. The explanation is that it’s not the milk itself but the calcium within that helps reduce cancer risk.
Consuming breakfast cereals, fruits, whole grains, carbohydrates, dietary fiber, and vitamin C also reduces colon cancer risk, though their effect is less pronounced.
It’s already well-known that processed meats (bacon, sausages, ham) and red meat (beef, pork) increase the risk of colon cancer, a fact confirmed by this study. Regular consumption of 20g of pure alcohol, equivalent to one glass of wine (200ml of 12% wine), one can of beer (500ml at 5%), or three shots of soju (17% alcohol), increases the risk of colon cancer by 15%. Adding approximately 28g of processed meat and red meat per day raises that risk by 8%.
So, what role does calcium play in cancer prevention? Calcium, essential for strengthening bones and maintaining healthy teeth, is increasingly recognized for its potential in preventing certain cancers. The research suggests that calcium can bind to bile and free fatty acids in the colon, reducing their potential carcinogenic effects and thus helping to prevent colon cancer.
Foods rich in calcium include dairy products like milk, yogurt, and cheese. ‘Lactose-free’ milk also contains calcium for those with lactose intolerance. Other calcium-rich foods include soybean and rice drinks, white bread, nuts, seeds, dried fruits like figs, green leafy vegetables like kale, and oily fish such as sardines. However, the study did not address whether calcium supplements offer the same protective effects.
Although this study focused on postmenopausal women, the researchers believe that the protective effects of calcium could also apply to men and younger individuals. As an observational study, it cannot definitively claim that calcium or other foods prevent or cause colon cancer. Nonetheless, the researchers are confident in their direction, describing it as the largest study on diet and colon cancer conducted to date.
Sophia Lowes, from Cancer Research UK, which funded the study, stated that maintaining a healthy weight, avoiding smoking, and following a balanced diet can reduce colon cancer risk. She recommended reducing alcohol, red meat, and processed meat consumption while increasing intake of fruits, vegetables, and whole grains.