A large new study from the University of Oxford has found strong links between what people eat and their risk of developing colorectal cancer.
This type of cancer affects the large intestine and rectum and is one of the most common cancers in the world. In 2022 alone, there were nearly 2 million new cases. While it is more common in richer countries, it is now rising in many parts of the world as diets and lifestyles change.
The research was carried out by scientists at the Cancer Epidemiology Unit at the University of Oxford and was published in the journal Nature Communications. It is one of the largest studies of its kind.
The team followed 542,778 women in the United Kingdom for an average of 16.6 years. This long follow-up period allowed researchers to observe how diet over time may affect cancer risk.
The study used detailed food questionnaires from participants in the well-known Million Women Study. Researchers examined 97 different dietary factors to understand how specific foods and nutrients might increase or lower the risk of colorectal cancer. They also used genetic data to better understand how certain foods may influence the body.
The findings clearly showed that some foods increase the risk of colorectal cancer. Alcohol was one of the strongest risk factors. For every 20 grams of alcohol consumed per day, which is about two standard drinks, the risk of colorectal cancer increased by 15 percent.
This adds to growing evidence that alcohol is harmful not only to the liver but also to many parts of the body, including the digestive system.
Red and processed meats were also linked to higher cancer risk. Eating just 30 grams per day, which is about one slice of bacon or a small portion of processed meat, increased the risk by 8 percent. These foods are already known to contain substances that can damage cells in the gut, especially when eaten regularly over many years.
At the same time, the study found that some foods and nutrients may help protect against colorectal cancer. One of the most important protective factors was calcium.
An increase of 300 milligrams per day, which is about the amount in one glass of milk, was linked to a 17 percent lower risk of cancer. Dairy products such as milk and yogurt were also associated with lower risk, likely because they are rich in calcium.
Whole grains also showed a protective effect. Eating 20 grams of whole grains per day, such as whole wheat bread or oats, reduced the risk by about 10 percent. Breakfast cereals, especially those high in fiber, were also linked to a lower risk.
Fruits and vegetables played an important role as well. Eating an apple a day, which provides about 5 grams of fiber, reduced the risk by 8 percent. A cup of fruit per day lowered the risk by about 10 percent.
Leafy green vegetables, which are rich in folate, were linked to a 12 percent lower risk. Vitamin C, found in foods like oranges, was also helpful and reduced risk by about 10 percent.
The study also included genetic analysis, which provided an interesting finding. People with certain genetic traits that made them more likely to drink milk had a 40 percent lower risk of colorectal cancer for every 200 grams of milk consumed daily.
This suggests that calcium may help protect the gut by binding harmful substances in the digestive system and reducing their ability to damage cells.
Even though the study provides strong evidence, the researchers noted some limitations. People who eat more fruits, vegetables, and whole grains often have other healthy habits as well, such as exercising more or smoking less.
This makes it harder to separate the exact effect of diet alone. In addition, while calcium appears to be protective, more research is needed to understand its long-term effects and whether very high intake is always safe.
Overall, the study highlights how important diet is in shaping cancer risk. While genetics and other factors cannot be changed, diet is something people can control. Small changes, such as reducing alcohol and processed meat and eating more whole foods, may make a meaningful difference over time.
These findings support the idea that everyday food choices can have a lasting impact on health. By choosing a balanced diet rich in fruits, vegetables, whole grains, and calcium-rich foods, people may be able to lower their risk of colorectal cancer and improve their overall well-being.
If you care about cancer, please read studies that a low-carb diet could increase overall cancer risk, and vitamin D supplements could strongly reduce cancer death.
For more information about health, please see recent studies about how drinking milk affects the risks of heart disease and cancer and results showing higher intake of dairy foods linked to higher prostate cancer risk.
Copyright © 2026 Knowridge Science Report. All rights reserved.
