A new study suggests that a Mediterranean diet could protect against certain changes to the brain in older age.
The "traditional" Mediterranean diet - consisting of large amounts of fruits and vegetables, whole grains, olive oil, a moderate amount of fish, dairy, and wine, as well as a limited intake of red meat - has been shown to improve cardiometabolic health.
Research ranging from observational studies to randomized trials has shown the diet to reduce the risk of type 2 diabetes and obesity, aid weight loss, and contribute to the prevention of cardiovascular disease.
Other studies have suggested that the diet helps to keep mental and physical health well into old age and can reduce the risk of premature death.
New research published in Neurology, the medical journal of the American Academy of Neurology, looks specifically at the benefits of the Mediterranean diet on brain health in elderly adults.
Examining link between diet and brain volume in elderly people
Researchers led by Michelle Luciano, Ph.D. - from the University of Edinburgh in Scotland - looked at the effects of the Mediterranean diet (MeDi) on total brain volume, gray matter volume, and the thickness of the cortex.
The authors explain that, with age, the human brain shrinks, and more and more of its cells die. This may cause problems with learning and memory.
The study followed 967 people aged between 73 and 76 years, who lived in Scotland and who did not have dementia, over a period of 3 years.
The 967 participants were asked to complete food questionnaires when they were 70 years old - 3 years prior to collecting data on their brain volume.
Then, 562 of these people had a magnetic resonance imaging brain scan at the age of 73, in order to measure total brain volume, gray matter volume, and cortical thickness. Of these, 401 people had a second brain scan at age 76.
People's dietary habits were calculated using a food frequency questionnaire. The brain measurements were compared with how well the participants adhered to the MeDi during the 3-year period.
Mediterranean diet accounts for 0.5 percent of total brain volume change
The scientists found an association between MeDi adherence and brain volume.
Participants who did not follow the diet closely were likely to develop brain atrophy over the 3-year interval.
More specifically, poor adherence to the diet was associated with a 0.5 percent greater reduction in total brain volume than those who had followed the diet closely.
A 0.5 percent decrease in brain volume is half the size of what is considered a normal decrease due to the natural aging process.
The study found no association between the diet and gray matter volume or thickness of the cortex.
Contrary to previous studies, this research did not find a relationship between fish and meat consumption and changes in brain volume. This suggests that other individual components of the diet - or all of its components taken in combination - might be responsible for the association.
Additionally, unlike previous research - which measured the brain at one point in time - this study examined changes in brain volume over time.
"In our study, eating habits were measured before brain volume was, which suggests that the diet may be able to provide long-term protection to the brain. Still, larger studies are needed to confirm these results."
Michelle Luciano, Ph.D.