The Cancer Research
A growing number of studies link a Mediterranean pattern of eating with lower cancer risk. But it’s important to emphasize that this is compared to people with low scores for “Mediterranean” eating. That usually means compared to people who have eating habits that include more meat, refined grains and sweets. These studies do not establish Mediterranean diets as more protective than other healthy ways of eating.
Beyond meeting the recommendation for a plant-based diet, evidence is too limited to allow any conclusions about a Mediterranean diet specifically and cancer risk, concluded systematic reviews from AICR’s Third Expert Report and others.
However, there is probable evidence that a “Mediterranean-type” dietary pattern can reduce risk of weight gain, overweight and obesity. This is important, because there is strong evidence that excess body fat increases the risk of at least 12 different cancers. Mediterranean diets’ influence on weight and weight gain may stem from higher dietary fiber, amount and type of healthy fats, and overall “calorie density” that is lower than typical Western-style eating patterns. Lower calorie density means that calories are less concentrated, so you are able to eat larger, more satisfying amounts of food within the same amount of calories.
Interpreting the data
After a systematic review of the global scientific literature, AICR/WCRF analyzed how a variety of plant foods and their nutrients affect the risk of developing cancer.
- Evidence categorized as “probable” means there is strong research showing a causal relationship to cancer—either decreasing or increasing the risk. The research must include quality human studies that meet specific criteria and biological explanations for the findings.
- A probable judgement is strong enough to justify recommendations.
- Evidence categorized as “limited suggestive” means results are generally consistent in overall conclusions, but it’s rarely strong enough to justify recommendations to reduce risk of cancer.
Source: AICR/WCRF. Diet, Nutrition, Physical Activity and Cancer: A Global Perspective, 2018.
Ongoing Areas of Investigation
- More on Mediterranean Diet
Healthy fat, more than high-fat: Mediterranean cuisine is traditionally relatively high in fat, due to liberal use of olive oil. But research on this diet and health is based largely on scoring systems that include awarding points for more healthy types of fat, not for using more fat.
Wine in moderation is optional, not essential: Red wine in moderate amounts and with meals is a common part of the culture in many areas of the Mediterranean.
- One of the scoring systems used in Mediterranean diet studies awards one point for alcohol consumption within a range equivalent to 2 to 7 standard drinks/week for women or 5 to 12 for men. However, this is a minor element of the total Mediterranean diet score.
- Red wine contains a phytochemical called resveratrol that studies in isolated cells and animals link with effects that could decrease cancer development. However, there are far fewer human studies, most of which have investigated safety and absorption of different doses of isolated resveratrol, not the effectiveness of resveratrol against cancer.
- Human research does not support red wine as different from other alcoholic beverages as it increases cancer risk. For example, a pooled analysis of 20 studies following women from 6 to 16 years found that the increased risk of breast cancer associated with alcohol consumption was no different for wine than for beer or liquor.
- World Cancer Research Fund/American Institute of Cancer Research. Continuous Update Project Expert Report 2018. Diet, nutrition and physical activity: Energy balance and body fatness. Available at dietandcancerreport.org.
- Martínez-González MÁ, Hershey MS, Zazpe I, Trichopoulou A. Transferability of the Mediterranean Diet to Non-Mediterranean Countries. What Is and What Is Not the Mediterranean Diet. Nutrients. 2017;9(11):1226.
- Schwingshackl L, Schwedhelm C, Galbete C, Hoffmann G. Adherence to Mediterranean Diet and Risk of Cancer: An Updated Systematic Review and Meta-Analysis. Nutrients. 2017;9(10):1063.
- Liese AD, Krebs-Smith SM, Subar AF, et al. The Dietary Patterns Methods Project: Synthesis of Findings across Cohorts and Relevance to Dietary Guidance. J Nutr. 2015;145(3):393-402.
- World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Continuous Update Project Expert Report 2018. Available at dietandcancerreport.org.
- Dinu M, Pagliai G, Casini A, Sofi F. Mediterranean diet and multiple health outcomes: an umbrella review of meta-analyses of observational studies and randomised trials. Eur J Clin Nutr. 2018;72(1):30-43.
- Singh CK, Ndiaye MA, Ahmad N. Resveratrol and cancer: Challenges for clinical translation. Biochimica et Biophysica Acta (BBA) – Molecular Basis of Disease. 2015;1852(6):1178-1185.
- Shield KD, Soerjomataram I, Rehm J. Alcohol Use and Breast Cancer: A Critical Review. Alcohol Clin Exp Res. 2016;40(6):1166-1181.
- IARC Working Group on the Evaluation of Carcinogenic Risk to Humans. Personal Habits and Indoor Combustions. (IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 100E.) CONSUMPTION OF ALCOHOLIC BEVERAGES. Lyon (FR): International Agency for Research on Cancer;2012.
- Allen NE, Beral V, Casabonne D, et al. Moderate alcohol intake and cancer incidence in women. J Natl Cancer Inst. 2009;101(5):296-305.
- LoConte NK, Brewster AM, Kaur JS, Merrill JK, Alberg AJ. Alcohol and Cancer: A Statement of the American Society of Clinical Oncology. J Clin Oncol. 2018;36(1):83-93.
- Jung S, Wang M, Anderson K, et al. Alcohol consumption and breast cancer risk by estrogen receptor status: in a pooled analysis of 20 studies. Int J Epidemiol. 2016;45(3):916-928.