There may be a beneficial effect of a Mediterranean diet supplemented with extra-virgin olive oil in the primary prevention of invasive breast cancer among women at high cardiovascular risk, a new study published online ahead of print in JAMA Internal Medicine has shown.1
Because the incidence of breast cancer has increased by more than 20% worldwide since 2008, and is the leading cause of female cancer burden, researchers sought to evaluate whether the Mediterranean diet reduces the risk of breast cancer.
For the study, researchers enrolled 4,282 women age 60 to 80 with high cardiovascular disease risk and randomly assigned them 1:1:1 to a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet that included reduced dietary fats.
Results showed that after a median follow-up of 4.8 years, there were 35 confirmed incident cases of breast cancer. Compared with the control group, patients who completed the Mediterranean diet with extra-virgin olive oil were 68% less likely to develop breast cancer (HR = 0.32; 95% CI: 0.13-0.79).
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Patients in the Mediterranean diet and mixed nuts group were 41% less likely to develop breast cancer than the control group.
The authors note that these findings need to be confirmed in longer-term and larger studies.
- Toledo E, Salas-Salvadó J, Donat-Vargas C, et al. Mediterranean diet and invasive breast cancer risk among women at high cardiovascular risk in the PREDIMED trial [published online ahead of print September 14, 2015]. JAMA Intern Med. doi: 10.1001/jamainternmed.2015.4838.