Impact of Mediterranean Diet on Cancer: Focused Literature Review

Background: Cancer is a major public health problem worldwide, and the number of incident cases increases every year expected to reach 17.1 million a year by 2020. There is evidence that people who adhere to the Mediterranean Diet (MediD) have lower incidence of cancer. However, cancers' location and culture studies seem to affect the MediD impact. We aimed to review these discrepant findings. Materials and Methods: A critical review from a focused literature search was conducted. A literature search of controlled trials from: EMBASE (1970-), MEDLINE (1950-) and PsycINFO (1960-) was undertaken. Two authors (DF and YB) independently extracted the data. Results: Out of 785 abstracts identified only 583 publications focused solely on MediD and cancer. Of these, 46 were clinical trials published since 2007. Twenty-eight trials with a total of 570,262 participants are included in accordance with inclusion criteria. Only four reported the MediD does not reduce the risk of cancer. Of the negative studies, three were undertaken in non-Mediterranean populations. Cancers of the digestive tract were studied in 11 studies. Except for pancreatic cancer, all other sites along the digestive tract demonstrated significantly reduced rate with the MediD. Conclusion: The MediD is associated with reduction in overall cancer rates as well as significantly lower rates of digestive tract cancers. These effects may be accentuated in the Mediterranean countries themselves. Further studies are needed to support or refute the effects of the MediD on other cancer types.