Share on PinterestScientists have found a link between breast cancer risk and the Mediterranean diet. FOTOGRAFIA INC./Getty Images
- The Mediterranean diet, rich in fresh fruits and vegetables, olive oil, nuts, and seeds, and low in red meat and processed foods, is associated with several health benefits.
- These include a reduced risk of cardiovascular diseases, type 2 diabetes, certain cancers, and some mental health conditions.
- Now, a study suggests that following a Mediterranean diet may significantly reduce a person’s risk of breast cancer.
- The study found that women who followed a Mediterranean diet, particularly those who were postmenopausal, had a 13% reduced risk of breast cancer.
Breast cancer is the most common cancer in women in almost every country in the world. It can occur at any age after puberty, and about 1% of cases are diagnosed in men, but most breast cancers occur in women over the age of 50.
Although a person cannot change their age or genetics, they can help to reduce their risk of developing breast cancer by:
- Being physically active
- Checking with their doctor whether hormone replacement therapies or birth-control pills are right for them
- Not drinking excessive alcohol
- Breastfeeding their baby if able
- Maintaining a healthy weight.
Now, an analysis of 31 studies has found that following a Mediterranean diet may reduce a person’s risk of developing breast cancer by around 13%.
The study is published in Health Science Reports.
Kotryna Temcinaite, PhD, head of research communications and engagement at Breast Cancer Now, who was not involved in the study, commented:
“Studies like this, that observe people over time, can help us find links between certain activities, such as diet, and a certain disease, but they can’t prove if the diet directly impacted the development of the disease. For that we need experimental research that explains if, and more importantly how, a specific diet determines our health.”
“It’s also important to remember that there are many different factors that influence breast cancer risk — including genetics, lifestyle and environment — some of which you can change, but others are out of your control,” she told Medical News Today.
What is the Mediterranean diet?
The Mediterranean diet is based on the traditional eating pattern of countries around the Mediterranean region.
To follow it, a person should base their diet around:
- a wide variety of fresh fruits and vegetables
- whole grains, pulses and legumes
- healthy fats — olive oil, nuts, seeds, and oily fish
- moderate amounts of seafood
- limited quantities of dairy and red meat
- water, unsweetened beverages, and the occasional glass of red wine with food.
They should also keep their intake of refined, processed, and sweetened foods to an absolute minimum.
Breast cancer and the Mediterranean diet
The Mediterranean countries have a lower overall cancer rate than the United States, the United Kingdom, and Scandinavian countries, and studies suggest that this may be due, in part, to diet.
This new study analysed results from 31 observational studies (12 cohort and 19 case-control) that investigated whether there was any link between adherence to a Mediterranean diet and breast cancer risk. The women included in the studies ranged in age from 20 to 104 years.
The researchers investigated the effect of the diet on breast cancer risk in pre- and postmenopausal women, and by geographical region.
Overall, the Mediterranean diet reduced breast cancer risk by 13%. The effect was greatest in postmenopausal women and women in Asian regions.
“The findings are fascinating and an area of ongoing interest. It showed a 13% reduction in breast cancer risk with a more protective benefit found in postmenopausal women in Asian populations.”
— Connie Lee, MD, board certified breast surgical oncologist, MemorialCare Todd Cancer Institute at Long Beach Medical Center in Long Beach, CA.
Greater benefits in postmenopausal women
In premenopausal women in America, Europe, and Asia, the researchers found no significant reduction in breast cancer risk for those following the Mediterranean diet.
In postmenopausal women, the benefit was greater in case-control studies, which showed an 18% risk reduction, than in cohort studies, which showed a 9% reduction in breast cancer risk.
Lee explained why the benefits might be greater in postmenopausal women:
“The factors that are associated with increased risk in premenopausal women are multifactorial and genetics, I believe, play a stronger role in women diagnosed at an earlier age. After menopause, there is a hormonal shift where estrogen that was previously produced by the ovaries is now being driven by fat accumulation.”
“It has been established that the Mediterranean diet has a strong role in weight management and potentially fat reduction and this could be a possible explanation as to why a Mediterranean diet might impact the risk of a postmenopausal woman more significantly.”
— Connie Lee, MD
The authors suggest that their findings support the Mediterranean diet as a potential strategy for reducing breast cancer risk, but emphasise that further research is needed to verify their findings.
Why might the Mediterranean diet reduce cancer risk?
The findings of this study reinforce other studies that have associated reduced cancer risk with the Mediterranean diet. But why might it have this effect?
Components of the Mediterranean diet — fruits, vegetables, nuts, legumes, fish, whole grains, and extra-virgin olive oil —are high in many nutrients that are beneficial to health and may have anticancer properties.
“The Mediterranean diet is known to be rich in agents that function as antioxidants and [are] anti-inflammatory and these can contribute to its anti-cancer effect. It is also known to be an effective way of weight management, and obesity has long been associated with an increased risk for breast cancer.”
— Connie Lee, MD
The World Cancer Research Fund states that the combination of fibre, vitamins, minerals, and phytochemicals (naturally occurring plant chemicals) in fruits and vegetables may be responsible for their cancer-reducing potential.
Although the exact mechanism by which the Mediterranean diet may reduce cancer risk is unknown, studies suggest five possible beneficial effects:
- lowering lipid levels
- protecting against oxidative stress, inflammation, and platelet aggregation
- Modifying hormones and growth factors involved in the pathogenesis of cancer
- Inhibiting nutrient-sensing pathways by specific amino acid restriction
- Enhancing gut microbiota-mediated production of metabolites influencing metabolic health.
Any, or all, of these could contribute to the cancer-reducing potential of the diet.
“This study adds to interesting live discussions around how lifestyle factors might influence breast cancer. It shows that women who chose a Mediterranean diet had a reduced chance of getting breast cancer after the menopause. However, it doesn’t provide enough evidence to know if this diet or any specific food type helps to prevent breast cancer.”
— Kotryna Temcinaite, PhD
Megan Winter, health information manager at Cancer Research UK, advised:
“You don’t need to follow a set diet — simply aim to have plenty of fruit and veg, whole grains and healthy sources of protein like chicken, fish and pulses and cut down on processed and red meat, alcohol and foods high in fat, sugar and salt to reduce your cancer risk.”
And she added: “If you are worried about breast cancer in particular, there are proven steps you can take, such as keeping a healthy weight, drinking less alcohol, and stopping smoking.”
