Mediterranean diet may help boost longevity in cancer survivors

• The Mediterranean diet has been shown to help prevent heart disease and certain types of cancers, but less is known about how the diet affects adults who have already had a cancer diagnosis.
• Recent research suggests that adhering to a Mediterranean-style diet may significantly lower the risk of mortality, especially from cardiovascular diseases, among long-term cancer survivors.
• Experts say the Mediterranean diet may benefit people receiving treatment for cancer, but personalized nutrition advice from a dietitian is recommended for the best health outcomes.

A new study published in JACC CardioOncology suggests that a Mediterranean diet could support longevity and cardiovascular health in cancer survivors.

The Mediterranean diet is known for its emphasis on fruits, vegetables, legumes, extra-virgin olive oil , and other healthy plant-based foods, along with some fish and seafood. This diet pattern also generally limits meat, poultry, dairy, and heavily-processed food intake.

Although the Mediterranean diet has been widely studied for its potential cancer-preventive effects , less research has explored its impact on mortality among adults diagnosed with cancer.

To bridge this knowledge gap, Italian researchers investigated the relationship between the Mediterranean diet and mortality in 802 Italian adults with a history of cancer who took part in the Moli-sani Study .

They observed that, compared to those with low adherence, participants adhering more closely to a Mediterranean-style diet tended to live longer and had a reduced risk of cardiovascular mortality.

The researchers propose these results support a hypothesis that various chronic illnesses , including tumors and heart diseases, may share common molecular mechanisms. The Mediterranean diet appears to influence these mechanisms.

Simply put, what benefits your heart might also help prevent or manage cancer, and vice versa.

Mediterranean diet and death risk in cancer

Researchers aimed to understand how adherence to a traditional Mediterranean diet pattern could affect mortality risk among Italian long-term cancer survivors, using dietary data collected after cancer diagnosis.

The study analyzed data from the Moli-sani Study, a large population-based study conducted between 2005 and 2010. It involved 24,325 Italian adults aged 35 and older from a southern Italian region.

After excluding participants with missing data, the researchers studied 802 individuals with a documented history of cancer and cancer treatment information at the beginning of the Moli-sani Study. The average age of the included participants was 63, and nearly 60% were women.

In the Moli-sani Study, participants’ diets over the previous 12 months were self-reported using a food frequency questionnaire, which provides details on the frequency of consumption and portion size of a number of food items.

Using this dietary data, the present study measured adherence to a traditional Mediterranean diet using an established Mediterranean Diet Score . Participants’ adherence to the diet was categorized as poor (0–3), average (4–5), or high (6–9) on a 9-point scale.

Vegetables, legumes, fruits and nuts, cereal grains, and fish were among the diet’s beneficial components, while meat, poultry, and dairy products were considered detrimental.

The scoring also factored in daily ethanol (alcohol) intake and the ratio of monounsaturated to saturated fats in the diet.

Mortality was tracked using local death registers and validated through Italian death certificates, with causes reported, including cardiovascular disease and cancer, as part of the Moli-sani Study.

The results were adjusted for age, sex, calorie intake, and other factors and analyzed using hazard models to determine the association between Mediterranean-style diet adherence and risk of mortality.

Mediterranean diet tied to lower death risk in long-term cancer survivors

The study followed participants for nearly 13 years and recorded 248 deaths, with approximately 56% due to cancer and 24% from cardiovascular events. Among cardiovascular deaths, about 25% were caused by ischemic heart disease and another 24% by cerebrovascular diseases.

The study found that participants who adhered closely to a Mediterranean-style diet were generally more physically active and had better socioeconomic status than those with low adherence. The final analysis accounted for these disparities.

Importantly, high adherence to a Mediterranean-style diet pattern was linked with a 32% reduced risk of death from any cause and a 58% lower risk of cardiovascular mortality.

“The latter observation is relevant because patients with cancer are considered a high cardiovascular disease risk population because of shared modifiable risk factors and, potentially, molecular mechanisms of disease, as postulated by the ‘common soil” hypothesis’,” the study authors explained in the published paper.

Further analysis also indicated that each 2-point increase in the Mediterranean Diet Score correlated with a notable 16% lower risk of all-cause mortality and a 31% lower risk of cardiovascular death.

Surprisingly, though, there was no significant link between adherence to a Mediterranean-style diet and the risk of death from cancer.

The authors suggest this may be due to the different types of cancers included and the complex nature of cancer progression and recurrence.

Is there a ‘survival bias’?

“While the findings appear miraculous, the study has limitations to consider,” Kiran Campbell, RDN , a registered dietitian specializing in heart health, who was not involved in the study, commented for Medical News Today .

She explained that these include the study’s observational nature, which cannot establish cause and effect, the self-reported dietary intakes, which can be susceptible to misreporting, and flaws with the Mediterranean Diet Score, which broadly categorized food groups and level of diet adherence.

“In addition,” she said, “there is a concern for survival bias” because participants had already survived for an average of 9 years after their cancer diagnosis at the study’s start.

When asked if the findings are generalizable, Campbell pointed out that the study only included Italian long-term cancer survivors from a specific region. So, she said, “[w]e can only speculate on how the outcome would be for those of other populations.”

How Mediterranean diet may support longevity in cancer patients

Campbell highlighted that current American Cancer Society (ACS) guidelines for cancer prevention recommend a healthy eating pattern filled with “high-nutrient foods, including a variety of vegetables, fruits, and whole grains, while limiting the intake of red and processed meats, sugar-sweetened beverages, and highly processed foods and grain products.”

The ACS also recommends consuming a predominantly plant-based diet during and after cancer treatment “because it is lower in saturated fat and high in fiber, vitamins, and phytochemicals,” Campbell explained.

She noted that these recommendations closely mirror the Mediterranean diet pattern, which is rich in fruits, vegetables, and extra virgin olive oil and known for its high antioxidant content.

But why might this type of eating pattern specifically help reduce mortality risk in individuals diagnosed with cancer?

Although the exact mechanisms are unclear, diets rich in antioxidants help reduce oxidative stress and inflammation in the body, which are key factors in the development and progression of cancer and cardiovascular diseases.

Further research is needed, but other observational studies similarly suggest that a Mediterranean-style eating pattern may reduce the risk of cancer recurrence and mortality.

So, based on current knowledge, the Mediterranean diet may be a valuable consideration for cancer patients seeking dietary frameworks to support their health and recovery.

However, Campbell emphasized that dietary recommendations are not one-size-fits-all, especially for individuals managing chronic conditions like cancer.

Diet recommendations in cancer must be personalized

“More studies on a Mediterranean diet pattern in regards to specific types of cancer or tumor stages may help provide more knowledge in this area of research,” Campbell said.

In the meantime, she strongly advised individuals diagnosed with cancer to seek “individualized nutritional care from health professionals, including oncologists and registered dietitians specializing in cancer.”

Alexandra Filingeri, RDN, DCN , a registered dietitian and doctor of clinical nutrition who was not involved with the study, agreed that while a Mediterranean-style diet can be beneficial, individualized nutrition is essential for this population.

She emphasized that:

“There is no specific diet for patients with cancer diagnoses. Best practices include meeting a patient’s specific energy needs while providing a balanced variety of nutrients.”

However, she concluded that beyond essential nutrition, personalized dietary recommendations that consider a patient’s taste preferences, cultural background, and socioeconomic status are crucial for optimal health outcomes.