A lot has been written and discussed about the detrimental effects of excessive consumption of red meat, white bread and sugar-laden drinks. Pooled data from two new major health studies suggests that these foods increase inflammation in the body, which in turn is associated with a higher chance of developing colon cancer.
What makes for a healthy diet overall also appears to promote a cancer-free colon, according to senior researcher Dr Edward Giovannucci, a professor of nutrition and epidemiology at Harvard T H Chan School of Public Health in Boston, US. Previous studies have linked diet factors with colon cancer, but there’s been no clear explanation why that might be, he added. Giovannucci and his colleagues suspected that inflammation promoted by what a person eats could be at least one way in which diet could influence risk.
To test this possible connection, the researchers gathered data on more than 121,000 people from two studies ­– the Health Professionals Follow-up Study and the Nurses’ Health Study – in which people were followed for 25 years to track potential influences on their health.
Participants filled out food questionnaires every four years. Those questionnaires helped researchers determine a dietary inflammation “score” for each person. 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, the findings showed.
Processed meat, red meat, organ meat, refined flour and sugary drinks were among the foods linked most to cancer-related inflammation, Giovannucci said. 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, noted Dr Wafik El-Deiry, deputy director of Fox Chase Cancer Center in Philadelphia. Giovannucci said the study is best viewed as looking at a general pattern of healthy eating.
Marjorie McCullough, strategic director of nutritional epidemiology for the American Cancer Society, pointed out that it is important to focus on the overall pro-inflammatory diet, rather than on the specific foods contained in this diet pattern. “Also, 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,” McCullough added. “For example, certain spices and food preparation methods are not included, which may have strong effects on inflammation.”
Baxter noted that the people with the highest risk of colon cancer were the outliers in the study – the one-fifth of participants who were consistently eating a lot of foods that promote inflammation. Going by the study, published online last week in the journal JAMA Oncology, moderation is advised when adopting dietary habits.
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