The Mediterranean diet may significantly reduce the risk of one of the worst forms of breast cancer, according to a study published in the International Journal of Cancer.
The Mediterranean diet — which consists of mostly healthy fats, nuts, olive oil, fruits, fish, vegetables and whole grains — has many known health benefits such as reducing the risk of heart disease and may even slow down the aging of the brain.
Now researchers are adding one more health benefit to the list — it may also reduce the risk of oestrogen-receptor-negative (ER-negative) breast cancer, a postmenopausal form of cancer that cannot be treated with hormone therapy.
“Our research can help to shine a light on how dietary patterns can affect our cancer risk,” said the study’s lead researcher, Professor Piet van den Brandt of Maastricht University in the Netherlands.
Over the course of 20 years, scientists monitored the diets of more than 62,000 women between the ages of 55 to 69. They specifically studied how the women’s breast cancer risk was impacted by their diet. The researchers found that the women who mostly ate a Mediterranean diet full of plant protein and olive oil were 40 percent less likely to develop ER-negative breast cancer than the other women.
“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,” Professor Piet van den Brandt said.
Out of all the women who participated in the study, 3,354 were diagnosed with breast cancer. However, there were 1,033 additional cases not included in the analysis because those women had a family history of breast cancer or did not follow the Mediterranean diet consistently.
The study excluded alcohol, which is typically a small part of the Mediterranean diet, because of its known links to breast cancer.
The researchers examined the different components of the Mediterranean diet to determine what exactly about the diet proved to be so beneficial for staving off breast cancer. They concluded that nuts, fruit and fish were most strongly inversely associated with ER-negative breast cancer.
“This important study showed that following a dietary pattern like the Mediterranean diet, could help reduce breast cancer risk – particularly the subtype with a poorer prognosis,” said Dr. Panagiota Mitrou, Director of Research Funding at the charity World Cancer Research Fund, which funded the new research.
The American Breast Cancer Society estimates that in 2017 alone there will be 255,180 new cases of breast cancer, and over 41,000 people will die from the disease.