♦ Mediterranean diet with more nuts and olive oil has been shown to improve heart and brain health
♦ The low fat diet also sees a drop in mental function.
A new study indicates that the Mediterranean diet could help improve mental health such as cognitive abilities and memory in older people when extra olive oil and nuts are added. The Mediterranean diet is one which contains plenty of vegetables with olive oil, whole grains, fish and low in red meats.
The American Medical Association’s publication, JAMA Internal Medicine, showed the supplemented Mediterranean diet was found to counter age-related cognitive decline. Most of the participants from Spain and Italy with an average age 67 and aged between 55 and 80, saw their mental abilities improve over the course of four years.
In this study, 447 volunteers considered at high risk of heart disease were assessed for the risk of dementia too because the two conditions are associated. They were already taking part in the Prevencion con Dieta Mediterranea (PREDIMED) study. None had dementia and all were considered as ‘brain healthy’ at the start of the study.
Three groups were created to study the extra additions. Two groups followed the Mediterranean diet, filled with vegetables and olive oil and low in meat and dairy. They were told to add either five tablespoons of extra virgin olive oil a day (about a litre per week), or a handful of mixed nuts (30g per day) including walnuts, hazelnuts and almonds.
The third group simply followed a low-fat diet.
Over the period of 4 years, all were examined for signs of cognitive decline using a range of tests to assess memory, and other cognitive functions such as working memory, attention span, and abstract thinking. The follow up study on 334 people showed 37 cases of mild cognitive impairment which is a more severe form of normal memory loss that comes with aging. Of these, 17 (13.4%) were in the Mediterranean diet plus olive oil group, whilst 8 (7.1 %) were in the Mediterranean diet plus nuts group. There was 12 (12.6%) in the low-fat control group.
There were no cases of dementia in the final study group.
The group that ate extra nuts performed better in terms of memory and the group given extra virgin olive oil performed better in tests that required quick thinking, according to the findings.
Dr Emilio Ros, the study lead at the Institut d’Investigacions Biomediques, August Pi Sunyer, at the Hospital Clinic in Barcelona wrote:-
“Our results suggest that in an older population a Mediterranean diet supplemented with olive oil or nuts may counteract age-related cognitive decline.
The lack of effective treatments for cognitive decline and dementia points to the need of preventive strategies to delay the onset and/or minimise the effects of these devastating conditions. The present results with the Mediterranean diet are encouraging but further investigation is warranted.”
NBC News reported that just over 13% amongst those who took extra olive oil were diagnosed with mild cognitive impairment, while 7% of those eating nuts were diagnosed with mild cognitive impairment. Around 13% of those who ate neither developed some form of memory loss.
The group who consumed olive oil also saw improved problem-solving and planning skills. Most participants in the low-fat-only group lost some memory and thinking skills, while those who ate extra nuts improved their memory skills on average.
Risk of heart disease and stroke was also lowered as was the risk of dying early, with the group who consumed the olive oil or nuts compared with those on the low-fat diet.
Commentators on the study such as Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, said:-
“The results of this trial appear to be encouraging but the effects seen were very subtle and as the researchers themselves point out, more work is needed to understand these findings fully. It’s important to note that the people in this study did not have dementia, and this trial does not tell us whether a Mediterranean diet could prevent the condition.
These findings suggest a need for much larger trials to understand better the effects of changes in diet on memory, thinking and dementia risk.
While there is currently no certain way to prevent dementia, evidence suggests the risk can be lowered with a healthy lifestyle including a balanced diet, regular exercise, not smoking, and keeping weight and blood pressure in check.”
Dr. Sam Gandy, the Director for the Center for Cognitive Health at Mount Sinai Hospital in New York City, said:-
“The general heart-healthy and brain-healthy effects of eating less beef and more chicken, fish, fruits and vegetables has been validated to the point that I now recommend this general Mediterranean diet to all my patients. Both olive oil and nuts have been associated with mental benefit in other studies, so, these findings are not so much a surprise as a reminder that there is more to the Mediterranean diet than meat, fruits and vegetables, and that calling out specific recommendations to include olive oil and nuts is probably worthwhile“.
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