A Mediterranean diet - with added olive oil - can reduce the risk of breast cancer in women by two-thirds, a study has suggested.
The diet, which involves a combination of food groups from countries including Italy and Greece, typically advocates swapping butter for oils and reducing meat intake in favour of more fish. An increased amount of fruit and vegetables is also central to the diet.
Researchers compared two groups of women, with one group assigned to follow a Mediterranean diet with either extra olive oil or nuts and the other advised to follow a low-fat diet.
The study found that the women, aged between 60 and 80, who followed the Mediterranean diet with added extra virgin olive oil had a 68 per cent lower risk of malignant breast cancer than those following the low-fat diet.
Those following the Mediterranean diet with added nuts showed a “non-significant risk reduction”.
Of the 4,282 women in Spain surveyed between 2003 and 2009, there were 35 new cases of malignant breast cancer.
The average woman studied had an age of 67.7, a BMI of 30.4 and most had undergone menopause before the age of 55.
Lead author, Miguel A Martínez-González, said: “The results of the trial suggest a beneficial effect of a Mediterranean diet supplemented with extra virgin olive oil in the primary prevention of breast cancer.
"Nevertheless, these results need confirmation by long-term studies with a higher number of incident cases."
The authors also added that they could not establish whether the health benefits were due to the extra virgin olive oil alone “or to its consumption within the context of the Mediterranean diet".
However, Martínez-González advised that preventative strategies are “the most sensible approach against cancer”.
Mitchell H Katz, deputy editor of the JAMA Internal Medicine, where the study was published, said: “Of course, no study is perfect.
"This one has a small number of outcomes (only 35 incident cases of breast cancer)… and all [participants] were white, post-menopausal and at high risk for cardiovascular disease.
“Still, consumption of a Mediterranean diet, which is based on plant foods, fish and extra virgin olive oil, is known to reduce the risk of cardiovascular disease and is safe. It may also prevent breast cancer.”Reuse content