A new large-scale study suggests that a Mediterranean diet, rich in fish, vegetables, olive oil, fruits, nuts, and whole grains, could significantly reduce risk of oestrogen-receptor-negative (ER-negative) breast cancer. This would add to a substantial list of health benefits associated with the diet, including reduced risk of both stroke and heart disease. The new research, led by Professor Piet van den Brandt of Maastricht University, has now suggested it can also reduce the risk of one of the more dangerous forms of breast cancer.
ER-negative breast cancer is a postmenopausal form of breast cancer which cannot be treated with the hormone therapy often used to treat other forms of the disease.
According Professor Van den Brandt:
“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.”
The research tracked diets over two decades, of 62,573 women aged 55 to 69, all of whom were participants in the Netherlands Cohort Study on cancer and diet, which began in 1986. The research tracked to what extent the women followed a Mediterranean diet, with minimal intake of white bread, white rice, sugar, and red meat.
While the traditional Mediterranean diet includes a degree of alcohol consumption, alcohol was excluded from the study since past research has suggested it contributes to cancer risk. One study suggested 12,000 instances of breast cancer in the UK would be prevented if alcohol were not consumed.
A total of 3,354 women in the study developed breast cancer, though 1,033 were excluded from the study due to having a history of breast cancer or unreliable dietary data. With this data, the study examined elements of the Mediterranean diet separately, noting that nut consumption, followed by fruit and fish, had the strongest inverse link to the occurrence of ER-negative breast cancer.
Ultimately, the research concluded that, given an assumption of causality, if everyone began following the Mediterranean diet as closely as possible, it would avoid 32.4 percent of ER-negative breast cancer and 2.3 percent of all breast cancer cases. The researchers said their findings had been confirmed by a meta-analysis of cohort studies.
The results are “intriguing” according to clinical director at Breast Cancer Care, Emma Pennery. She added:
“We know how devastating a diagnosis is and this study adds to evidence that a healthy diet, full of ‘good’ low-saturated fats, plays a part in lowering risk of the disease. However, it’s important to remember while lifestyle choices like eating a well-balanced diet and taking regular exercise can help reduce the risk of cancer, they don’t guarantee prevention. So it’s crucial women know the signs and symptoms of breast cancer, and contact their GP with any concerns.”