It’s no secret that cancer is the disease of the century, but perhaps one of its most well-known and most worrisome varieties is breast cancer. Alarmingly, worldwide incidence of this cancer has increased by more than 20% since 2008 (1).
In most cases, breast cancer has a pretty high survival rate, but it also has a high rate of reoccurrence (2). That’s why researchers have been examining different variables in hopes of better preventing the disease.
At a recent international cancer conference hosted by the American Society of Clinical Oncology (ASCO), an Italian study was presented which found that eating a Mediterranean diet effectively prevented cancer reoccurrence in breast cancer survivors (3).
The study followed 307 women, 199 of whom followed the Mediterranean diet while 108 were asked to eat their normal diet, while being given advice on healthy food by a dietician.
After three years, none of the women following the Mediterranean diet suffered from cancer reoccurrence while 11 women in the control group were diagnosed with the disease.
The diet, which is rich in fruit, vegetables, fish and olive oil also focuses on reducing meat intake.
For the study, women following the diet were asked to eat four portions of vegetables, three pieces of fruit and one serving of grains a day. Their protein was limited to 4 or more servings of fish each week, a small quantity of red meat. They were encouraged to consume olive oil liberally and were allowed up to one alcoholic drink a day.
It’s believed that this diet is responsible for the low rates of large bowel, breast, endometrium, and prostate cancer among Mediterranean countries, as these cancers have all been linked to dietary factors (4).
“The preliminary results of this small study suggest that a Mediterranean diet could lower the risk of breast cancer returning, but we’d need much longer follow up than three years to confirm the diet’s impact,” said Prof Arnie Purushotham, Cancer Research UK’s senior clinical adviser. “Further studies with more women are needed to understand more about the impact that diet can have on breast cancer survival and the biological reasons behind this.”
The study has its limits, including the lack of information regarding the activity level of the patients studied. Since weight loss and being active improves cancer survivability and decreases reoccurrence rates, specialists suggests that although the study is promising, more research still needs to be done:
“The whole topic of lifestyle interventions for breast cancer survivors is a very important one…There is no information about the activity level or change in weight which for most of the lifestyle research one needs to be aware of,” said Dr Erica Mayer, an ASCO expert in breast cancer and assistant professor at Harvard Medical School. Mayer is also director of clinical research at the Dana-Farber Cancer Institute in the United States.
This isn’t the first study to examine the role of a Mediterranean diet on breast cancer incidence.
In late 2015, a Spanish study published in the JAMA Internal Medicine examined breast cancer development in 4282 women aged 60 to 80 years over the course of 4.8 years. The women, who were all at a high risk of developing heart disease, were randomly assigned one of 3 diets: the Mediterranean diet supplemented with extra-virgin olive oil, the diet supplemented with mixed nuts, or a control group given only advice to reduce dietary fat (5). This study, however, examined the women’s first experience with cancer, whereas the most recent study focuses on reoccurrence.
In the Spanish study, researcher identified 35 confirmed cases of breast cancer. Women in the olive oil group had a 68 percent lower risk of developing breast cancer whereas the nut group did not have a statistically significantly change in cancer risk when compared to the control group.
The researchers concluded: “Our results suggest a beneficial effect of a Mediterranean diet supplemented with extra-virgin olive oil in the primary prevention of breast cancer.”
The benefits of olive oil consumption are well known in the medical community, and many researchers, including Dr. Beth Overmoyer, a breast cancer specialist at the Harvard-affiliated Dana-Farber Cancer Institute, aren’t surprised (6). Olive oil, she insists, “seems to be beneficial across the board”