Mediterranean Diet Linked to Lower Mortality for Cancer Survivors, Study Finds

Researchers have found that adhering to the Mediterranean diet – known for being rich in vegetables and whole grains and low in sugar and salt – can reduce the risk of mortality for cancer survivors.

The study is published in JACC CardioOncology.

Health benefits of the Mediterranean diet

Many so-called “blue zones”, where people live to advanced ages, include areas in the Mediterranean like Greece and the Italian island of Sardinia. Here, people often live beyond the age of 80, with their long lifespans largely attributed to lifestyle factors such as a whole-food diet, physical activity and low stress.

The Mediterranean diet (MD) has been linked to many health benefits, including reduced all-cause mortality. The MD is rich in vegetables, whole grains, nuts and extra virgin olive oil, while limiting the intake of red meat, sweets and butter.

One study found that, for women, the MD was linked to a 23% reduction in all-cause mortality risk, while another found that adherence to the MD is associated with lower all-cause mortality, as well as cancer mortality.

However, there is limited data on the impact of the Mediterranean diet for cancer survivors. This is worth investigating, as the number of cancer survivors is expected to increase over the coming decades as treatment becomes more and more effective.

“The beneficial role of the Mediterranean diet in primary prevention of some tumors is well known in the literature,” explained Marialaura Bonaccio, first author of the study and postdoctoral researcher at IRCCS Neuromed. “However, little is known about the potential benefits that this dietary model can have for those who have already received a cancer diagnosis.”

MD associated with a lower mortality rate

Researchers in the new study investigated whether the traditional Mediterranean diet would impact mortality for cancer survivors, using data from the Italian Moli-sani study – one of the largest population cohorts in Europe.

They analyzed data from over 800 men and women who had already been diagnosed with cancer. The participants were followed for 13 years and provided detailed information on their food consumption in the year before they enrolled in the study. On average, diet was assessed 8.8 years after their cancer diagnosis.

The participants were given an MD score (MDS) based on their adherence to the MD, with 9 being the highest possible score and 4.4 being the average among participants. A higher MDS was associated with higher socio-economic status and physical activity.

A total of 248 all-cause deaths were reported during the study period – 59 attributed to cardiovascular disease and 140 to cancer. The researchers found that each increasing 2-point increment in MDS was associated with a 16% lower all-cause mortality rate. Higher adherence to traditional MD was independently associated with a “substantial reduction” in all-cause mortality rates among other cancer survivors.

“The results of our study indicate that people who had cancer and reported a high adherence to a Mediterranean way of eating had a 32% lower risk of mortality compared to participants who did not follow the Mediterranean diet,” explained Bonaccio. “The benefit was particularly evident for cardiovascular mortality, which was reduced by 60%.”

However, the nature of this observational study means that it cannot infer causality, it can only find an association. Additionally, a lack of repeated dietary assessments means that it could not account for changes in diet over time, and there is a possible survivor bias as participants had already survived for an average of 9 years at baseline.

“These data support an interesting hypothesis that different chronic diseases, such as tumors and heart diseases, actually share the same molecular mechanisms,” said Maria Benedetta Donati, principal investigator at IRCCS Neuromed. “This is known in the literature as 'common soil', namely a common ground from which these two groups of disorders originate."

Reference: Bonaccio M, Di Castelnuovo A, Costanzo S, et al. Mediterranean diet is associated with lower all-cause and cardiovascular mortality among long-term cancer survivors. JACC: CardioOncology. 2024. doi: 10.1016/j.jaccao.2024.05.012

This article is a rework of a press release issued by IRCCS Neuromed. Material has been edited for length and content.