What the Evidence Says About the Mediterranean Diet for Patients With Cancer
By Jyothirmai Gubili (https://voice.ons.org/author/jyothirmai-gubili), MS, Alyona Weinstein, MSN, FNP-BC, and Yen Nien (Jason) Hou, PharmD, Dipl OM, LAc
Inspired by cultures around the Mediterranean Sea, the Mediterranean diet emphasizes (https://doi.org/10.3390%2Fnu14142956) whole, minimally processed, seasonal foods. It is rich in fruits, vegetables, grains, nuts, legumes, and olive oil with moderate amounts of red wine and smaller portions of dairy, poultry, and seafood. Considered more of a lifestyle than a diet, a key element (https://doi.org/10.3390%2Fnu14142956) is sharing and enjoying food with family and friends, encouraging social exchange and communication.
Researchers have consistently linked the Mediterranean diet with reductions in cardiovascular disease, cancer, and overall mortality because of its variety of included nutrients. For example, higher consumption of dietary fiber has been associated (https://doi.org/10.3390/nu9101063) with reduced risk of cancer mortality, and high intake of polyphenols from flavanols, lignans, and hydroxybenzoic acids may be associated (https://doi.org/10.1016/j.numecd.2013.12.014) with reduced risk of cardiovascular disease. Extra virgin olive oil, which contains vitamin E and phenolic compounds, also has antiatherogenic properties that improve endothelial function (https://doi.org/10.1016/j.atherosclerosis.2014.05.954), lipid profiles, glycemic control, insulin sensitivity, and blood pressure levels (https://doi.org/10.1161/hypertensionaha.113.03353).
What the Research Tells Us
A large systematic review and meta-analysis of 83 studies with 2,130,753 participants reported an inverse association (https://doi.org/10.3390/nu9101063) between adherence to the Mediterranean diet and cancer mortality (14% lower risk) for several cancer types, including colorectal, breast, gastric, and prostate.
Another meta-analysis of 20 prospective cohort studies involving 682,149 individuals revealed an association between Mediterranean diet and a 17% and 14% lower risk (https://doi.org/10.1007/s10654-019-00504-7) of hemorrhagic and ischemic stroke, respectively, in Mediterranean and non-Mediterranean populations.
Both alone and when combined with leisure-time physical activity, the Mediterranean diet was correlated (https://doi.org/10.1007/s00394-018-1689-y) with lower all-cause mortality in older adults. Notably, adhering to the Mediterranean diet, engaging in physical activity, abstaining from smoking, and avoiding sedentary behavior decreased all-cause mortality (https://doi.org/10.1111/jgs.17521) in adults, regardless of age or medication burden.
The Mediterranean diet may also have positive impact on cognitive health. In an analysis of multiple studies involving 8,358 participants researchers associated (https://doi.org/10.1001/jamapsychiatry.2023.0800) adherence to the Mediterranean–Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay diet with a 17% lower risk of incident dementia in middle-aged and older adults.
What Oncology Nurses Need to Know
As an essential member of the interprofessional cancer team, oncology nurses should be prepared to discuss the potential benefits and indications for Mediterranean diet based on the latest scientific discoveries and clinical trial findings. Nurses should also educate patients about the risk of alcohol consumption in any amount and advise them to consult a dietitian before adopting any new diets because disease states and treatments can affect nutritional status.
Although the Mediterranean diet’s benefits are compelling, it might not be suitable for individuals with multiple food intolerances or allergies, patients recovering from recent colorectal surgery, or those who have digestive conditions such as chemotherapy-induced diarrhea, nausea, gas, and abdominal bloating or colitis triggered by immunotherapy. Incorporating a dedicated dietitian in interprofessional discussions can help the oncology care team establish a dietary regimen tailored to each patient’s medical history and current clinical needs.