A Mediterranean diet can reduce the risk of a deadly form of breast cancer by 40 per cent, a large study has found.
Scientists monitored more than 62,000 women over a period of 20 years to see how their breast cancer risk was affected by what they ate.
Those who adhered most closely to a Mediterranean diet rich in plant protein, fish and olive oil were 40 per cent less likely to develop ER-negative breast cancer than women who adopted the diet the least.
This form of the disease, which is not stimulated by the sex hormone oestrogen, is often harder to treat than hormone-sensitive cancer and more likely to prove fatal.
A typical Mediterranean diet includes high intakes of plant-based proteins such as nuts, lentils and beans, whole grains, fish and "healthy" monounsaturated fats such as olive oil.
Consumption of refined grain foods such as white bread or white rice, red meat and sweets is kept to a minimum.
Professor Piet van den Brandt, from Maastricht University in the Netherlands, who led the study published in the International Journal of Cancer, 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 post-menopausal women, even in a non-Mediterranean population."