A new study provides more evidence that following a Mediterranean-type diet (MeDi) is good for the brain.
In a multiethnic cohort of elderly dementia-free adults, those more adherent to the MeDi had larger brain volume than their less adherent peers. And the difference between the groups is equal to about 5 years of aging.
“Our study adds to the existing literature showing that Mediterranean diet is a healthy diet,” Yian Gu, PhD, from Columbia University in New York City, and member of the American Academy of Neurology, told Medscape Medical News.
“These results are exciting, as they raise the possibility that people may potentially prevent brain shrinking and the effects of aging on the brain simply by following a healthy diet,” Dr Gu added in a news release.
The study was published online October 21 in Neurology.
The study involved 674 elderly individuals (mean age, 80.1 years) from the Washington Heights/Hamilton Inwood Columbia Aging Project (WHICAP). They completed food-frequency questionnaires regarding their diet over the past 12 months and underwent high-resolution structural MRI.
According to the diet history, 304 participants had “higher” adherence to the MeDi (they followed the MeDi principles in at least five food components, higher consumption of healthy foods, or lower consumption of unhealthy foods, achieving a MeDi score of 5 to 9) and 370 individuals had “lower” adherence to the MeDi principles (MeDi score, 0 to 4).
The MeDi includes high intake of vegetables, legumes, fruits, cereals, fish, and monounsaturated fatty acids, such as olive oil; low intake of saturated fatty acids, dairy products, meat, and poultry; and mild to moderate amounts of alcohol.
Individuals with higher adherence to the MeDi had total brain volume that was 13.11 mL greater (P = .007) than those with lower adherence. They also had more total gray matter volume (5.0 mL; P = .05) and total white matter volume (6.41 mL; P .05).
In particular, higher fish intake (P = .006) and lower meat intake (P = .002) correlated with greater total gray matter volume. Higher fish intake was also associated with 0.019-mm (P = .03) greater mean cortical thickness, the researchers report.
“The absolute effect of MeDi on brain measures were relatively small,” they note in their article. “However, the magnitude of the effect of consuming at least 5 recommended MeDi food components on TBV [total brain volume] is comparable to that of 5 years of increasing age. Similarly, having fish intake of 3–5 oz at least weekly, or keeping meat intake 100 g daily or less, may also provide a considerable protection against brain atrophy that is equivalent to about 3–4 years of aging,” they point out.
The observed relationships between the MeDi and brain MRI measures were not significantly modified by sex, ethnicity, or APOE ε4 status, they note. They say potential mechanisms include anti-inflammatory and/or antioxidative effects, as well as potential slowing of the accumulation of β-amyloid or phosphorylation and aggregation of tau.
“One More Check Mark” for MeDi
“Our study is an observational study. Although our findings are strong, it is still early to make recommendations based on this single [study]. However, our study provides a strong foundation and rationale for future longitudinal studies and intervention studies,” Dr Gu told Medscape Medical News.
This study is “one more check mark in the positive column for the Mediterranean diet,” Donn Dexter, MD, a neurologist at the Mayo Clinic, Mayo Clinic Health System, Eau Claire, Wisconsin, and member of the American Academy of Neurology, noted in an interview with Medscape Medical News.
“The Mediterranean diet,” he added, “would be a very reasonable thing to do if you are at risk or wanted to actively work on prevention. I encourage my patients to follow that advice. However, I still rank it significantly behind exercise, which has clearly been shown in many more studies to be more beneficial.”
“Overall, the check marks are really starting to add up for lifestyle intervention as being a positive step in prevention and maybe even treatment,” said Dr Dexter, who wasn’t involved in the study.
The study was supported by grants from the National Institutes of Health. Dr Gu has disclosed no relevant financial relationships. Several other authors made disclosure statements, which are listed the original article.
Neurology. Published online October 21, 2015. Abstract