The University of Navarra has led a large-scale study on how the Mediterranean diet reduces the risk of developing breast cancer by up to two thirds. The work, which for the first time offers quantifiable results, was carried out on a sample of about 4,300 women.

A new research, coordinated by the University of Navarra and the Center for Biomedical Research in Network-Physiopathology of Obesity and Nutrition (CIBERobn), reveals that the Mediterranean diet substantially reduces the risk of developing breast cancer - up to 66% less. The work, within the framework of the PREDIMED multicenter study and published in the journal JAMA Internal Medicine, is the first article to demonstrate, with a randomized trial, the preventive value of the Mediterranean diet against this type of tumor.

The pattern rich in virgin olive oil largely explains the protection 

“The studies done so far have been based on observation. This is the first research that offers results of a high scientific level after a mean follow-up of 4.8 years in a sample of 4,282 women,” says Miguel Ángel Martínez-González, coordinator of the study and scientist at the Navarra Health Research Institute (IDISNA).

The participants, from all over Spain, followed three types of diet: Mediterranean rich in extra virgin olive oil, Mediterranean supplemented with nuts, and a low-fat diet recommendation for the control group. In the first two cases, the data confirm that a lower incidence of the disease is obtained, which is almost a third of that in the control group.

According to the authors of the study, the assignment of the participants to the Mediterranean diet pattern rich in virgin olive oil - where it accounts for at least 15% of the energy ingested - largely explains the protection achieved against breast cancer

 “All this despite the fact that the control group, or the group with which the comparison was established, also followed an already healthy diet, which suggests that the results could have been even more significant if it had been compared with a standard of diet like the one that is followed in non-Mediterranean western countries”, clarifies Martínez-González.

These figures are consistent with those obtained in observational studies, some of them conducted in Spain. However, the conclusions suggest the need for further analysis with larger samples to confirm these data

Healthy diet against breast cancer

Of the total sample, there were only 35 diagnosed cases of the disease. "Taking into account that breast cancer is the disease that takes the most years of life for women in Spain - one in thirteen women will develop this tumor sometime in their life - the results of the study represent a great step forward in the field prevention”, underlines Estefanía Toledo, researcher at the University of Navarra and first author of the article.

Of the total sample, there were only 35 diagnosed cases

In his opinion, preventive strategies are the most effective tool to fight this invasive tumor. "Dietary intervention can be especially valuable because it can be applied from primary care centers and, in the case of the Mediterranean diet, it can provide other proven benefits, such as the prevention of type 2 diabetes, cardiovascular diseases and obesity", concludes Toledo.

There was a time when protein shakes would have 50 to 100 grams of protein per shake. It wasn’t until this study came out that it was determined that per meal we can only ingest 20g to 30g of protein every 3 to 4 hours. Every person varies on timing and needs. Instead of having 2 chicken breast per meal (which has approximately 62 grams of protein), have 1 chicken breast per meal (31 grams).

Exipure