Mediterranean diet is healthy for the mind, according to a new study conducted by researchers from the University of Exeter's Medical School.

Researchers found that large quantities of fresh fruits and vegetables, nuts, fish and olive oil lessen the risk of age-related diseases such as dementia.

This study is considered to be the first systematic review of the diet's benefits to the brain. The findings are published in Epidemiology.

The team, supported by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care in the South West Peninsula, studied 12 eligible pieces of research, 11 observational studies and one randomised control trial.

Researchers claim that nine of the 12 studies showed following a strict Mediterranean diet lead to superior cognitive function, lower rates of cognitive decline and a reduced risk of Alzheimer's disease.

 "Mediterranean food is both delicious and nutritious, and our systematic review shows it may help to protect the ageing brain by reducing the risk of dementia," Lead researcher Iliana Lourida said.

"While the link between adherence to a Mediterranean diet and dementia risk is not new, ours is the first study to systematically analyse all existing evidence."

"Our review also highlights inconsistencies in the literature and the need for further research. In particular research is needed to clarify the association with mild cognitive impairment and vascular dementia."

"It is also important to note that while observational studies provide suggestive evidence we now need randomised, controlled trials to confirm whether or not adherence to a Mediterranean diet protects against dementia."