A new study published in the journal JAMA Oncology has suggested that chowing down on red meat, white bread and sugar-laden drinks might increase the long-term risk of colon cancer. These foods all increase inflammation in the body and the inflammation they cause is associated with a higher chance of developing colon cancer.

Previous studies have linked diet factors with colon cancer, but there has been no clear explanation why that might be. The researchers suspected that inflammation promoted by what a person eats could be at least one way in which diet could influence risk.

The chronic inflammation has a lot of negative effects on people, and not just on cancer. It is not a natural state. It is not natural for us to have ongoing inflammation. To test the possible connection, the researchers gathered data on more than 121,000 people from two studies.

One is Health Professionals Follow-up Study and another is the Nurses' Health Study, in which people were followed for a quarter of a century to track potential influences on their health. Participants filled out food questionnaires every four years.

There were 2,699 cases of colorectal cancer that occurred during follow-up. The investigators compared the foods these people ate against the diet of people who didn't develop colon or rectal cancer. People who ate the most inflammatory foods were 37% more likely to develop colon cancer and 70% more likely to develop rectal cancer, compared with those who had the lowest inflammation diet score.

Processed meat, red meat, organ meat, refined flour and sugary drinks were among the foods linked most to cancer-related inflammation. On the other hand, green leafy vegetables, dark yellow vegetables, whole grains, coffee and fruit juice appeared to reduce inflammation.

A person appeared to achieve the greatest anti-inflammatory effect from their healthy diet if they also refrained from alcohol. There were some odd findings, as well. For example, a pizza was said to reduce inflammation even though it is made up of individual items known to increase inflammation; at the same time, tomatoes cropped up as a cause of inflammation.

Since there are multiple factors, a single one by itself is not overall that important, but they contribute. If people do everything in the right direction, then they will have a significant impact.

It is important to focus on the overall pro-inflammatory diet, rather than on the specific foods contained in this diet pattern.  The impact is likely to be even greater, as the foods in this pattern capture only some of the foods that are likely to influence inflammation in the body.

The people with the highest risk of colon cancer were the outliers in the study. Approximately one-fifth of participants who were consistently eating a lot of foods that promote inflammation. These are people who do not have a typical diet, the researchers reported.