Mediterranean Diet: Which Elements Prevent Colon Cancer?

Many studies have shown that Mediterranean diets (MD) help prevent the colorectal lesions that lead to cancer, but which elements of the diet offer the most protection? A new study from Israel’s Tel-Aviv Medical Center offers some answers.

Researchers found that a diet rich in fish and fruit and miserly on soft drinks are the three most important components.

“We found that each one of these three choices was associated with a little more than 30 percent reduced odds of a person having an advanced, pre-cancerous colorectal lesion, compared to people who did not eat any of the MD components,” said Naomi Fliss Isakov, Ph.D.

“Among people who made all three healthy choices the benefit was compounded to almost 86 percent reduced odds,” Isakov said.

Colorectal cancer (CRC) develops from intestinal polyps and has been linked to diets low in fiber and high on red meat, alcohol and high-calorie foods, said Isakov.

And while the Mediterranean diet has been associated with lower rates of colorectal cancer, the elements of the diet that are the most beneficial haven’t been clear.

Researchers used dietary questionnaires from 808 people who were undergoing screening or diagnostic colonoscopies. Subjects were between 40 and 70 years old, without high risk of CRC.

A Mediterranean diet includes consumption of high amounts fruits, vegetables and legumes, nuts and seeds, whole grains, fish and poultry along with a high ratio of monounsaturated to saturated fatty acids, as well consumption below the median of red meat, alcohol, and soft drinks.

The investigators found that 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). Yet even consumption of two to three components of the diet, compared to none, was associated with half the odds of advanced polyps.

The more components of the Mediterranean diet people included in their diets, the lower their odds of having advanced colorectal polyps.

Benefits of the diet keep mounting. A recent study from the University of Edinburgh found that Mediterranean diets keep brains from shrinking in old age. Volunteers were given MRIs to measure brain volume at age 73, and again at age 76. Those who closely followed a Mediterranean diet had half the brain loss of those who didn’t follow the diet.

A 2015 study published in Gut found that eating a typical Mediterranean diet increased the amount of short-chain fatty acids in the gut. SCFAs have been linked to many health benefits, including a reduced risk of inflammatory diseases, diabetes, and cardiovascular disease.