January 4, 2017

expert reaction to study looking at Mediterranean diet and brain volume

The association between Mediterranean-type diet and change in brain size across a 3-year period in older age (73-76 years) is assessed in new research publishing in the journal Neurology.

Prof. Derek Hill, Professor of Medical Imaging Science, UCL, and CEO of IXICO, said:

“This is high quality research from a good team, using one of the leading UK-based epidemiological cohorts.

“Measuring change in brain volume from MRI brain scans is a well-established technique.  We know that brain shrinkage (also called atrophy) is a natural result of ageing, and also that this rate of shrinkage accelerates when someone has Alzheimer’s disease, with the brains of those who die after years with dementia being dramatically smaller than healthy people’s.  This well designed study looks at whether diet can impact the rate at which brain shrinks, using a very well characterized group of people all born in 1936, and who have been carefully studied for decades (the Lothian birth cohort).

“This exciting study finds that a Mediterranean diet is associated with significantly slower brain shrinkage in people in their 70s, and suggests this link might be causal.  This provides some evidence that a Mediterranean diet may improve brain health in old age.  Further work, however, will be needed to find out whether it protects people from getting dementia.”

Prof. Peter Passmore, Professor of Ageing and Geriatric Medicine, Queen’s University Belfast, said:

“There is a lot of interest in the role of diet in brain health.  This study backs up some of the evidence that better adherence to Mediterranean diet is good for brain health and preserves brain volume.  The study is from a reputable group and involves the Lothian cohort which is a good resource.  The design, analysis and conclusions are sound and the relevant confounders have been addressed, particularly in relation to more educated and intelligent individuals.  While it would seem that the loss of brain volume over time is not what anyone would want to see and therefore that preservation of volume should be a good thing in terms of cognitive ability, it is still not fully clear exactly what this could mean in terms of memory and dementia.  The authors do point out that further research is needed.”

Dr Sujoy Mukherjee, Consultant Psychiatrist, West London Mental Health NHS Trust, said:

“It is a well-designed study in a relatively large number of healthy elderly to show that Mediterranean diet may protect from subsequent brain atrophy.  This adds to the growing body of evidence highlighting the importance of proper diet on our brain health.  However, this study refers to nonspecific brain atrophy rather than specific brain changes that are common in conditions like Alzheimer’s disease, hence the implication of such diet in prevention of a degenerative brain disease remains unclear.  Also, this study does not take into account lifelong eating habits, hence its findings may have limited impact in relation to public health advice.”

Dr David Reynolds, Chief Scientific Officer, Alzheimer’s Research UK, said:

“A Mediterranean-style diet that is low in meat and dairy but rich in fresh fruit and vegetables, cereals, beans, nuts and ‘healthy’ fats like olive oil, has been linked to a range of health benefits.  This study adds to previous research highlighting the importance of this kind of well-balanced diet in maintaining a healthy brain as we age.  While the study points to diet having a small effect on changes in brain size, it didn’t look at the effect on risk of dementia.  We would need to see follow-up studies in order to investigate any potential protective effects against problems with memory and thinking.

“The brain, just like other parts of the body, can be affected by the way we live our lives.  While a balanced diet is one way we can help to maintain a healthy brain, the best current evidence points to a number of other lifestyle factors that can also play a role.  These include not smoking, staying mentally and physically active, only drinking in moderation and keeping blood pressure and cholesterol in check.”

* ‘Mediterranean-type diet and brain structural change from 73 to 76 years in a Scottish cohort’ by Michelle Luciano et al. published in Neurology at 21:00 UK time on Wednesday 4 January 2017.

Declared interests

Prof. Derek Hill: “Derek Hill is a founder and chief executive of IXICO plc, a company that provides image analysis capabilities to pharmaceutical companies testing drugs on patients with neurodegenerative diseases.  IXICO has no involvement in this research.”

Prof. Peter Passmore: “I would point out that I have received funding from Nutricia in relation to Souvenaid.”

Dr Sujoy Mukherjee: “None.”

Dr David Reynolds: “No relevant interests to declare.”