Considered one of the world’s healthiest dietary patterns, and certainly the most well- researched, the Mediterranean diet is linked to a host of positive health benefits. The Mediterranean diet is abundant in fruits, vegetables, wholegrains, legumes and olive oil. It features fish and poultry and is low in red meat. Red wine is also an enjoyed, but not over-consumed, feature of the diet.

With so much research into the Mediterranean diet, what has been lacking until now is a comprehensive collation of the wide spectrum of health outcomes associated with the diet. Italian researchers undertook an umbrella review of the evidence. An umbrella review allows the findings of reviews relevant to the question at hand to be compared. For the Mediterranean diet, there is already an abundance of meta-analyses of observational studies and randomised clinical trials.

What the study found

The review brought together 13 meta-analyses of observational studies and 16 meta-analyses of randomised-controlled trials. Studies investigated the association between adherence to a Mediterranean-style diet and 37 different health outcomes. Over 12 million people were part of the collective studies.

Convincing evidence was seen for longevity, cardiovascular diseases, coronary heart disease, heart attack, overall cancer incidence, neurodegenerative diseases, Alzheimer’s disease, dementia and diabetes.

For most specific types of cancers, aside from breast cancer, the evidence was only suggestive of a benefit or overall quite weak. A benefit on body weight, blood pressure and total cholesterol was also considered weak.

The umbrella review is not without its limitations. Several of the health outcomes investigated only had a few studies to inform them, making definitive conclusions difficult. Many of the research studies were observational studies, which cannot prove a direct benefit, only an association. The quality of the research was mixed and the researchers did find an indication of potential bias in the research field.

Implications

Dietary trends come and go, but there is a good reason why the traditional Mediterranean-style dietary pattern consistently receives endorsement from health groups and research teams. There is no one best way to eat but we can certainly take some cues from the messages it gives about what sort of choices to make for a healthier diet.

 

Last Reviewed: 14/02/2019

© Norman Swan Medical Communications.


References

Dinu M et al. Mediterranean diet and multiple health outcomes: an umbrella review of meta-analyses of observational studies and randomised trials European Journal of Clinical Nutrition Epub online May 10, 2017. doi: 10.1038/ejcn.2017.58