Many studies have long suggested that a Mediterranean-style diet is beneficial for colorectal health, however, figuring out exactly which elements of a dietary pattern are the most important is a big challenge.
Researchers presenting at the recent ESMO 19th World Congress on Gastrointestinal Cancer aimed to do just that: finding three specific dietary shifts that are associated with a lower risk of colorectal cancer.
Led by Naomi Fliss Isakov fromTel-Aviv Medical Center, Israel, the team found that loading up on higher amounts of fish and fruit, and cutting back on soft drinks are the three most important things for colorectal health.
"We found that each one of these three choices was associated with a little more than 30% reduced odds of a person having an advanced, pre-cancerous colorectal lesion, compared to people who did not eat any of the MD components,” she said. “Among people who made all three healthy choices the benefit was compounded to almost 86% reduced odds.”
The team noted that colorectal cancers (CRC) develop from intestinal polyps which have been linked to a number of dietary risk factors including a low-fibre diet, heavy red meat intake, alcohol and high-calorie foods.
While a Mediterranean diet (MD) has been associated with lower rates of colorectal cancer, the definition of what elements in the diet are the most beneficial, has not always been clear, added Fliss Isakov and colleagues.
In the new study, the team used dietary questionnaires from 808 people who were undergoing screening or diagnostic colonoscopies to dig down to look at the fine details of their daily meals.
Adherence to the MD components was defined as consumption levels above the group median for fruits, vegetables and legumes, nuts and seeds, whole grains, fish and poultry and a high ratio of monounsaturated to saturated fatty acids, as well consumption below the median of red meat, alcohol, and soft drinks, the team explained.
Compared to subjects with clear colonoscopies, those who had advanced polyps reported fewer components of the Mediterranean diet (a mean of 1.9 versus 4.5 components).
However, the authors noted that even consumption of two to three components of the diet, compared to none, was associated with half the odds of advanced polyps.
Furthermore, odds were reduced in a dose response manner with additional MD components - meaning that the more MD components people adhered, the lower their odds of having advanced colorectal polyps.
After adjusting to account for other CRC risk factors, including other dietary components, the researchers narrowed in on high fish and fruit and low soft drinks as the best combination for reduced odds of advanced colorectal polyps.