Is adherence to a Mediterranean diet associated with cognitive function and dementia?

This review was led by the Evidence Synthesis Team.

Background

Relationships between diet and physical health are well recognized as are the protective effects of the Mediterranean diet on the risk of various chronic diseases and longevity. Dietary patterns, as opposed to individual nutrients or foods, are an emerging area of research in recent years. It is believed that dietary patterns can reflect dietary behaviours of individuals more spherically, as they combine foods which in turn may have synergistic or antagonistic effects on health.

The traditional Mediterranean diet refers to an eating behaviour characterised by:

  • High intake of fruits
  • Vegetables
  • Cereals
  • Legumes
  • Low consumption of saturated fats with olive oil as the main source of fat
  • Moderate consumption of fish
  • Low to moderate intake of dairy products (in the form of yogurt and cheese)
  • Low consumption of red meat and meat products
  • Moderate amount of alcohol, especially wine, usually consumed during meals.

    • Such a multi-nutrient approach includes most of the components studied in relation to cognitive decline and incident dementia. Thus, it is reasonable to believe that adherence to a Mediterranean diet may be protective against cognitive decline and dementia, while it may also prove useful in the management of malnutrition and vitamin deficiencies often observed in dementia patients and elderly people.

    Project aims

    This systematic review aimed to investigate and determine the potential association between adherence to a Mediterranean diet and cognitive function and dementia.

    Method

    We conducted a systematic review of 11 electronic databases (including Medline) of published articles up to January 2012. Reference lists, selected journal contents, and relevant websites were also searched. Study selection, data extraction, and quality assessment were performed independently by two reviewers using predefined criteria. Studies were included if they examined the association between a Mediterranean diet adherence score and cognitive function or dementia.

    Findings

    Published studies suggest that greater adherence to Mediterranean diet is associated with slower cognitive decline and lower risk of developing Alzheimer disease. Further studies would be useful to clarify the association with mild cognitive impairment and vascular dementia. Long-term randomized controlled trials promoting a Mediterranean diet may help establish whether improved adherence helps to prevent or delay the onset of Alzheimer disease and dementia.

    Further information

    For more information view the protocol and read the published findings of this review.

    Collaborators

    • Dr David Llewellyn