Breast cancer risk reduced by Mediterranean diet

A study for the World Cancer Research Fund has suggested that the risk of contracting one of the worst types of breast cancer is reduced by 40 per cent by following a Mediterranean diet.

Published in the International Journal of Cancer, the study suggests that the diet could also significantly reduce the chances of women getting oestrogen-receptor-negative (ER-negative) breast cancer, a postmenopausal form of the disease that cannot be treated with hormone therapy.

The research studied 62,573 women aged 55 to 69 over two decades, starting in 1986. The trials analysed the different components of the Mediterranean diet individually. Of the participants, 3,354 contracted breast cancer, although 1,033 of the cases were not included in the analysis because the women had a history of breast cancer and/or had incomplete or inconsistent dietary data. Nut intake was most strongly inversely associated with ER-negative breast cancer, followed by fruit and fish.

A Mediterranean diet is traditionally rich in olive oil, fish, fruit, nuts, vegetables and wholegrains, and encourages a low intake of red meat, sweets and refined grains such as white bread or white rice. It maintains well-publicised health benefits, including reduced risk of stroke and heart disease.

The research concluded that if everyone ate the highest defined Mediterranean diet, approximately 32.4 per cent of ER-negative breast cancer cases and 2.3 per cent of all breast cancer cases could be avoided. Breast cancer is currently the most common cancer in women in the UK, with more than 53,000 new cases diagnosed each year.

Professor Piet van den Brandt, researcher from Maastricht University in the Netherlands, said: “Our research can help to shine a light on how dietary patterns can affect our cancer risk. We found a strong link between the Mediterranean diet and reduced oestrogen-receptor-negative breast cancer risk among postmenopausal women, even in a non-Mediterranean population. This type of breast cancer usually has a worse prognosis than other types of breast cancer.”

Dr Panagiota Mitrou, director of research funding at the World Cancer Research Fund, added: “With breast cancer being so common in the UK, prevention is key if we want to see a decrease in the number of women developing the disease,” he said. “We would welcome further research that helps us better understand the risk factors for the different breast cancer subtypes.”