Serkan Ozturk

Women who eat a Mediterranean diet supplemented with extra-virgin olive oil are at reduced risk of developing breast cancer, according to a major study.

The Spanish research involved more than 4000 women aged between 60 and 80 who were at high risk of cardiovascular disease.

They were allocated to one of 3 groups, consuming either a Mediterranean diet supplemented with extra-virgin olive, a Mediterranean diet with a daily serving of mixed nuts, or a low-fat diet. They were followed up at around 5 years.

Results show the risk of breast cancer was cut by 68% in those who ate a Mediterranean diet supplemented with extra-virgin olive compared with those who stuck to a low-fat diet.

Meanwhile, those in the Mediterranean diet and nut-eating group saw a reduction in breast cancer risk compared with the low-fat control group, but it wasn't statistically significant.

The Mediterranean diet is characterised by its focus on plant foods such as nuts, seeds and beans, and fish, and olive oil.

The authors said this was the first trial to find a long-term dietary intervention which had an effect on reducing breast cancer.

“Our results suggest a beneficial effect of a Mediterranean diet supplemented with extra virgin-olive oil in the primary prevention of breast cancer.”

Four of the study’s authors declared links to the nut industry, including to groups like the International Nut and Dried Fruit Foundation and the California Walnut Commission.

Last Reviewed: 18/09/2015



Toledo E, et al. Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial. JAMA Internal Medicine 2015; online.