The Mediterranean diet is based on the diets of people who live in the Mediterranean part of the world. It contains high levels of omega-3 fatty acids, fruits, vegetables, nuts and whole grains and low levels of meats and saturated fats. A recent study suggests that eating a Mediterranean diet may be associated with a lower risk of developing breast cancer.
The researchers examined data from the PREDIMED trial, which included 4,282 women between the ages of 60 and 80 who were at a high risk of cardiovascular disease. They had an average BMI of 30.4, most of them went through menopause before 55, and less than 3% had used hormone therapy. The study took place from 2003 to 2009.
The women were instructed to follow the Mediterranean diet supplemented with extra virgin olive oil (EVOO), the Mediterranean diet supplement with nuts, or a control diet that included advice to lower their dietary intake of fats.
The study had a follow up period of approximately five years, during which time 35 new cases of malignant breast cancer occurred.
The researchers found that women who followed the Mediterranean diet supplemented with EVOO had a 68% lower risk of malignant breast cancer than those who followed the control diet. They also noted that the women following the Mediterranean diet supplemented with nuts had a non-significant risk reduction when compared with the control group.
Limitations on the study included the fact that breast cancer was not the primary end point for the trial, the number of breast cancer cases was low, the authors did not have information about mammograms, and the study could not establish whether the noted beneficial effect was due to the EVOO or to its consumption in conjunction with the Mediterranean diet.
Researchers from the University of Navarra in Pamplona and the CIBEROBN in Madrid conducted the study. It was published on September 14, 2015, in JAMA Internal Medicine.
Previous research has shown that the Mediterranean diet may improve heart health, lower the risk of diabetes and asthma, lower rates of obesity and possibly decrease the overall risk of mortality.
The key components of the Mediterranean diet are eating primarily plant-based foods, replacing butter with olive oil, using herbs and spices instead of salt, eating red meat no more than a few times a month, eating fish and poultry at least twice a week.