A review of 12 studies has concluded that the Mediterranean diet has a positive impact on cognitive function, lowering the risk of dementia and Alzheimer’s disease.
The Mediterranean style of eating is one that focuses on higher intakes of unsaturated olive oil, fruits and vegetables, whole grains, beans, nuts, seeds, and fish. Red meat and poultry are eaten very rarely, and dairy foods are also limited. Other positive factors surrounding the Mediterranean diet is the focus on family meals and the encouragement for daily activity.
Overall, the more one complies with the tenets of the Mediterranean diet, the better their cognitive function, lower the rate of cognitive decline, and a reduced risk of developing Alzheimer’s disease.
So how does the Mediterranean diet protect the brain? Several ways, in fact.
• Unsaturated fats – When a high fat, high saturated fat diet is consumed, the risk of high cholesterol and heart disease. When blood vessels become clogged, they can reduce blood flow to the brain, causing tissue damage that can lead to memory loss. High cholesterol levels also raise risk independently, especially in those genetically at risk for Alzheimer’s.
• Omega-3 fatty acids – also reduces the risk of atherosclerosis, thrombosis (blood clots that lead to strokes) and inflammation. In addition, they may help reduce the accumulation of beta-amyloid plaques, characteristic of Alzheimer’s.
• Folate – reduces the risk of circulating homocysteine levels, a marker of poor cardiovascular health as well as a risk factor for cognitive impairment.
• Vitamin E – an antioxidant, reducing the damage caused by oxidative stress
• Polyphenol intake – Fruits, vegetables and whole grains are rich in polyphenols which are plant nutrients thought to delay the onset of Alzheimer’s disease.
• Less meat intake – methionine from meat may increase Alzheimer’s risk. Another study suggests high iron accumulation (found in red meat) may also contribute to dementia risk.
• Exercise – those who are more physically active have a reduced risk of developing Alzheimer’s.
• Social – having more social connections with family and friends reduces the risk of cognitive impairment.
NIHR PenCLAHRC researcher Iliana Lourida said: "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."
Ilianna Lourida, Maya Soni, Joanna Thompson-Coon, Nitin Purandare, Iain A. Lang, Obioha C. Ukoumunne, David J. Llewellyn. Mediterranean Diet, Cognitive Function, and Dementia. Epidemiology, 2013; 24 (4): 479 DOI:10.1097/EDE.0b013e3182944410