A Mediterranean diet is high in vegetables, fruits, whole grains, and olive oil and low in meat, sweets, and saturated fat. It is linked to lower risks of cancer and relief of some symptoms and imbalances common among people with cancer.

How can a Mediterranean diet help me? What the research says

We summarize the clinical evidence for each medical benefit here. We begin with our assessment of the strength of evidence within each category, followed by a brief summary of individual studies or reviews of several studies. In assessing the strength of evidence, we consider the study design, number of participants, and the size of the treatment effect (how much outcomes changed with treatment).

Learn more about how we research and rate therapies.

Due to the nature of studies of lifestyle interventions, several risks of bias exist within the studies about the Mediterranean diet that are nearly impossible to avoid, even within a very well designed study. For example, it is not possible to blind participants to the intervention they are receiving, study groups will likely need to be treated differently beyond just the intervention (they will have to have food prepared for them or be trained in preparing Mediterranean meals), and the sample population will likely be biased towards only people who are already interested in lifestyle interventions. Several researchers have gone to great lengths to minimize these risks of bias but the risk will always be there to some degree. Due to these inherent risks, we consider the highest quality any individual RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects can achieve is “moderate.”

Treating cancer

Is a Mediterranean diet linked to improved survival? Is it linked to less cancer growth or metastasis? Does it enhance the anticancer action of other treatments or therapies? We present the evidence.

Cancer as a whole

Insufficient evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently) of increased survival among people with cancer with the highest adherence to a Mediterranean diet

Prostate cancer

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of Gleason grade group progression among men with prostate cancer with each 1-unit increase in adherence to a Mediterranean diet

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on prostate cancer mortality among people with prostate cancer with the highest adherence to a Mediterranean diet in a large study

Optimizing your body terrain

Does a Mediterranean diet promote an environment within your body that is less supportive of cancer development, growth, or spread? We present the evidence.

Blood sugar and insulin resistance

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of better markers of glycemic control among people with type 2 diabetes or other diagnoses following a Mediterranean diet

Good evidence of lower fasting insulin and homeostatic model assessment of insulin resistance (HOMA-IR) but not HbA1C among people following a Mediterranean diet

Insufficientpreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently) and conflicting evidence of an effect on fasting glucose among people following a Mediterranean diet

Body weight

Good evidence of lower BMI, waist circumference, and/or body weight among people adhering to a Mediterranean diet

Hormone imbalance

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on daily cortisol patterns among healthy people eating a standardized Mediterranean meal as their first meal of the day in a small study

Immune function

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of better immune function among people following a Mediterranean diet for several years

Inflammation

Good evidence of lower markers of inflammation such as C-reactive protein (CRP), high sensitivity CRP (hs-CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) among people following a Mediterranean diet

Oxidation

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of reduced oxidative stress among people following a Mediterranean diet

Your microbiome

Strong evidenceconsistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results (this is the CancerChoices definition; other researchers and studies may define this differently) of an alteration of gut microbiotathe collection of microbes living on and within your body to a status associated with less inflammation, reduced risks of disease, and eubiosisdominance of microbial taxa associated with lower risk of disease in general among people following a Mediterranean diet

Managing side effects and promoting wellness

Is a Mediterranean diet linked to fewer or less severe side effects or symptoms? Is it linked to less toxicity from cancer treatment? Does it support your quality of life or promote general well-being? We present the evidence.

Anxiety

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of lower anxiety among people with breast cancer achieving a higher adherence to the Mediterranean diet

Fatigue

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) of less cancer-related fatigue during androgen deprivation therapy (ADT) among people with prostate cancer eating a Mediterranean diet

Quality of life and function

Preliminary evidence of better quality of life scores during androgen deprivation therapy (ADT) among people with prostate cancer eating a Mediterranean diet

Symptoms not specific to cancer

Preliminary evidence of lower anxiety scores among people diagnosed with depression receiving training in and adhering to a Mediterranean diet

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of better cognitive scores among people following a modified Mediterranean diet

Modest evidence of less depression or better mood among people following a Mediterranean diet

Modest evidence of improved quality of life and function among people following a Mediterranean diet at midlife or later

Preliminary evidence of less pain among people with stable rheumatoid arthritis eating a Mediterranean diet for 12 weeks

Mediterranean diet as part of a combination therapy

Preliminary evidence of greater reduction in depression scores among people achieving higher MedDiet scores and taking fish oil supplements

Reducing cancer risk

Is a Mediterranean diet linked to lower risks of developing cancer or of recurrence? We present the evidence.

Cancer as a whole

Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of cancer or mortality among people without cancer at baseline with higher adherence to a Mediterranean diet

Bladder cancer

Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of bladder cancer among people with the highest adherence to the Mediterranean diet

Breast cancer

Good evidence of lower risk of breast cancer among people with the highest adherence to a Mediterranean diet, although the effect may vary with the specific types of breast cancer

Colorectal cancer

Modest evidence of lower risk of colorectal cancer among people with the highest adherence to a Mediterranean diet

Gastrointestinal cancer

Modest evidence of lower risk of upper gastrointestinal cancers as a whole

No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on risk of esophageal cancer among people with the highest adherence to a Mediterranean diet in a combined analysis of studies

Modest evidence of lower risk of liver cancer among people with the highest adherence to a Mediterranean diet

Gynecological cancer

No evidence of an effect on risk of endometrial cancer among people with the highest adherence to a Mediterranean diet in a combined analysis of studies

Head and neck cancer

Modest evidence of lower risk of head and neck cancers among people with the highest adherence to a Mediterranean diet

Leukemia

No evidence of an effect on the risk of chronic lymphocytic leukemia (CLL) among people with the highest adherence to the Mediterranean diet in a large study

Lung cancer

Good evidence of lower risk of lung cancer, stronger among people who smoke heavily and perhaps stronger among men, among people with the highest adherence to a Mediterranean diet

Ovarian cancer

No evidence of an effect on risk of ovarian cancer among people with the highest adherence to a Mediterranean diet in a large study

Pancreatic cancer

Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of pancreatic cancer among those with the highest adherence to a Mediterranean diet

Prostate cancer

Insufficient evidencepreclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example) (this is the CancerChoices definition; other researchers and studies may define this differently) of lower risk of prostate cancer among people with the highest adherence to the Mediterranean diet

Keep reading about Mediterranean diet

Authors

Andrew Jackson, ND

Research Associate
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Andrew Jackson, ND, serves as a CancerChoices research associate. As a naturopathic physician practicing in Kirkland, Washington, he teaches critical evaluation of the medical literture at Bastyr University in Kenmore, Washington. His great appreciation of scientific inquiry and the scientific process has led him to view research with a critical eye.

Andrew Jackson, ND Research Associate

Nancy Hepp, MS

Lead Researcher and Program Manager
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Ms. Hepp is a researcher and communicator who has been writing and editing educational content on varied health topics for more than 20 years. She serves as lead researcher, program manager, and writer for CancerChoices. Her graduate work in research and cognitive psychology, her master’s degree in instructional design, and her certificate in web design have all guided her in writing and presenting information for a wide variety of audiences and uses. Nancy’s service as faculty development coordinator in the Department of Family Medicine at Wright State University also provided experience in medical research, plus insights into medical education and medical care from the professional’s perspective.

Nancy Hepp, MS Lead Researcher and Program Manager

Curator and reviewer

Laura Pole, RN, MSN, OCNS

Senior Clinical Consultant
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Laura Pole is senior clinical consultant for CancerChoices. Laura is an oncology clinical nurse specialist who has been providing integrative oncology clinical care, navigation, consultation, and education services for over 40 years. She is the co-creator and co-coordinator of the Integrative Oncology Navigation Training at Smith Center for Healing and the Arts in Washington, DC. Laura also manages the “Media Watch Cancer News That You Can Use” listserv for Smith Center/Commonweal. In her role as a palliative care educator and consultant, Laura has served as statewide Respecting Choices Faculty for the Virginia POST (Physician Orders for Scope of Treatment) Collaborative as well as provided statewide professional education on palliative and end-of-life care for the Virginia Association for Hospices and Palliative Care.

For CancerChoices, Laura curates content and research, networks with clinical and organizational partners, brings awareness and education of integrative oncology at professional and patient conferences and programs, and translates research into information relevant to the patient experience as well as clinical practice.

Laura sees her work with CancerChoices as a perfect alignment of all her passions, knowledge and skills in integrative oncology care. She is honored to serve you.

Laura Pole, RN, MSN, OCNS Senior Clinical Consultant

Last update: June 28, 2022

CancerChoices provides information about integrativein cancer care, a patient-centered approach combining the best of conventional care, self care and evidence-informed complementary care in an integrated plan cancer care. We review complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocial therapy, and acupuncture therapies and self-care lifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress practices to help patients and professionals explore and integrate the best combination of conventionalthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy and complementary therapies and practices for each person.

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