Colorectal cancer is one of the most common cancers in the world today. It affects the large intestine and rectum and can develop slowly over many years.
In 2022, nearly two million new cases were reported globally, making it the third most common cancer worldwide.
Although it has long been more common in high-income countries, rates are now rising in many other parts of the world. Experts believe that changes in diet and lifestyle are key reasons for this increase.
A major new study has taken a closer look at how everyday foods may influence the risk of developing colorectal cancer. The research was led by scientists at the University of Oxford’s Cancer Epidemiology Unit and was published in the journal Nature Communications. It is one of the largest and most detailed studies of its kind.
The researchers followed 542,778 women in the United Kingdom over an average period of 16.6 years. This long follow-up allowed them to see how diet over time was linked to cancer risk. The study used detailed food questionnaires to examine 97 different dietary factors. The team also used genetic data to better understand how certain foods may affect the body.
The findings showed clear links between some common foods and colorectal cancer risk. Alcohol was found to increase risk.
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 strong evidence from earlier studies that alcohol can harm the digestive system and raise cancer risk.
Red and processed meats were also linked to higher risk. Eating just 30 grams per day, which is about one slice of bacon, increased the risk by 8 percent.
Processed meats include foods like sausages, ham, and bacon, which are often preserved with salt or chemicals. These substances can form harmful compounds in the body that may damage cells over time.
On the other hand, the study found that several foods and nutrients may help protect against colorectal cancer. Calcium stood out as one of the most important protective factors. An increase of 300 milligrams of calcium per day, roughly the amount found 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. This is likely because they are rich in calcium. Scientists believe that calcium may help by binding to harmful substances in the gut, such as bile acids, which can damage the lining of the intestine.
Whole grains were another protective food group. Eating 20 grams of whole grains per day, which is about half a slice of whole wheat bread, reduced the risk by 10 percent. Whole grains contain fiber and other nutrients that support healthy digestion.
Breakfast cereal also showed a small benefit. A daily serving of 40 grams was linked to a 7 percent lower risk. Many cereals are made from whole grains and are often fortified with vitamins and minerals.
Fruits and vegetables also played an important role. Eating an apple a day, which provides about 5 grams of fiber, was linked to an 8 percent lower risk.
A cup of fruit, around 200 grams, reduced risk by 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, reducing risk by 10 percent when consumed in adequate amounts.
The researchers also used genetic information to support their findings. They found that people with genetic traits linked to higher milk consumption had a much lower risk of colorectal cancer. In fact, for every 200 grams of milk consumed daily, the risk was about 40 percent lower. This strengthens the idea that calcium plays a key role in protecting the gut.
Even though the study is very large and detailed, the researchers noted some limitations. People who eat healthier foods may also have other healthy habits, such as exercising more or not smoking. This makes it harder to know exactly how much of the benefit comes from diet alone.
The researchers also pointed out that while calcium appears helpful, more studies are needed to understand the long-term effects of high calcium intake and to make sure it is safe for everyone.
Overall, this study provides strong evidence that diet has a major impact on colorectal cancer risk. Small changes in daily eating habits may help reduce the risk over time. Cutting back on alcohol and processed meat, while eating more dairy, whole grains, fruits, and vegetables, could make a meaningful difference.
This research reminds us that what we eat every day can shape our long-term health. By making simple and balanced food choices, people may be able to lower their risk of serious diseases like colorectal cancer.
If you care about wellness, please read studies about how ultra-processed foods and red meat influence your longevity, and why seafood may boost healthy aging.
For more health information, please see recent studies that olive oil may help you live longer, and vitamin D could help lower the risk of autoimmune diseases.
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