As we reported earlier this month, MRI brain scans show that routine meditation builds brain matter.
And it builds brain matter in places linked to memory and learning, while shrinking a region linked to anxiety: see Meditation Builds Gray Matter
Likewise, a number of studies show that fish and or their omega-3s build brain matter in places linked to thinking and memory.
Now, a study from researchers at New York City's Columbia University adds fuel to the idea that brains benefit from diets rich in fish.
They examined brain changes produced by the Mediterranean diet, and found that a key component – fish – accounts for the biggest structural benefits.
The Mediterranean diet: An artificial but useful construct
The "Mediterranean” diet studied by scientists is based on the traditional diets of people living on Crete and other Aegean islands.
This idealized version of the Mediterranean diet is rich in vegetables, legumes (beans, peas and lentils), fruits, fish, extra virgin olive oil, small amounts of bread, pasta, and grains, and moderate amounts of red wine.
Unlike the standard American diet, meat plays a very minor role in the traditional Mediterranean eating pattern.
The advantages of the Mediterranean diet—and the benefits of its key components—have since been affirmed and detailed in many studies.
There's little doubt that the Mediterranean diet is a particularly healthful eating plan.
Its closest rival may be a hybrid of the Mediterranean diet and the low-sodium DASH diet, called the MIND diet.
Earlier this year, we reported the results of a study suggesting that close adherence to the MIND diet equaled or beat close adherence to either the Mediterranean or DASH diet for delaying the development of Alzheimer's.
Specifically, the brain-health benefit of following the MIND diet closely was equivalent to being 7.5 years younger than the one-third of the participants whose diets resembled the MIND diet least closely.
Mediterranean diet builds brains: Fish does the heaviest lifting
The study was led by Yian Gu, assistant professor of neuropsychology at Columbia University.
Professor Gu's team split 674 older adults – average age 80 – into two groups, based on how closely their diets aligned with the traditional Mediterranean pattern.
All the participants completed questionnaires about their food choices and eating patterns, and underwent MRI scans of their brains.
The Columbia researchers found that the brain volumes of those who followed a Mediterranean-style diet fairly closely were bigger than those who did not.
Differences in overall size were fairly significant, and meant that the brains of the participants in the Mediterranean diet group were about as large as the brains of people five years younger.
And their brains were larger than their peers in ways important for thinking and memory:
- Cortical thickness
- Total brain volume)
- Total gray matter volume
- Total white matter volume
Among the nine major food components of the Mediterranean diet, higher fish intake was associated with having more gray matter.
Conversely, similar brain benefits were associated with lower meat intake.
In other words, eating more fish and less meat was associated both with the best gains in brain volume, and with the least amount of brain shrinkage.
This outcome doesn't mean people should avoid meat entirely.
And fish isn't the only brain booster in the Mediterranean diet.
Results echo findings from earlier MRI study
This was not the first time Dr. Gu and her colleagues explored the brain and aging effects of diet.
Three years ago, an MRI study they conducted among 996 New Yorkers showed that those who adhered most closely to the Mediterranean diet had the least amount of "white matter hyperintensity volume” (Gardener H et al. 2012).
Hyperintensities or "bright signals” are simply bright areas on MRI brain scans … and you don't want to have too many.
Areas of white matter hyperintensity increase as a normal part of brain aging … but large amounts are closely associated with psychiatric illnesses, neurological disorders such as Parkinson's disease, and damage to small blood vessels in the brain.
Last year, Dr. Gu and her colleagues published a study that linked adherence to the Mediterranean diet to longer telomeres (Gu Y et al. 2015).
Telomeres are repetitive DNA sequences at the ends of chromosomes.
Like the cap on a shoelace, they wear out over time.
Shorter telomeres signal shorter life expectancy and greater risk of aging-related disease, while longer telomeres are linked to reduced disease risk and longer lives.
The take-away from these studies seems simple: follow a Mediterranean-style diet, and make sure it includes ample seafood.
- Alcalay RN, Gu Y, Mejia-Santana H, Cote L, Marder KS, Scarmeas N. The association between Mediterranean diet adherence and Parkinson's disease. Mov Disord. 2012 May;27(6):771-4. doi: 10.1002/mds.24918. Epub 2012 Feb 7.
- Gardener H, Rundek T, Wright CB, Gu Y, Scarmeas N, Homma S, Russo C, Elkind MS, Sacco RL, Di Tullio MR. A Mediterranean-style diet and left ventricular mass (from the Northern Manhattan Study). Am J Cardiol. 2015 Feb 15;115(4):510-4. doi: 10.1016/j.amjcard.2014.11.038. Epub 2014 Nov 29
- Gardener H, Scarmeas N, Gu Y, Boden-Albala B, Elkind MS, Sacco RL, DeCarli C, Wright CB. Mediterranean diet and white matter hyperintensity volume in the Northern Manhattan Study. Arch Neurol. 2012 Feb;69(2):251-6. doi: 10.1001/archneurol.2011.548.
- Gardener S, Gu Y, Rainey-Smith SR, Keogh JB, Clifton PM, Mathieson SL, Taddei K, Mondal A, Ward VK, Scarmeas N, Barnes M, Ellis KA, Head R, Masters CL, Ames D, Macaulay SL, Rowe CC, Szoeke C, Martins RN; AIBL Research Group. Adherence to a Mediterranean diet and Alzheimer's disease risk in an Australian population. Transl Psychiatry. 2012 Oct 2;2:e164. doi: 10.1038/tp.2012.91.
- Gu Y et al. Mediterranean-type diet and brain volumes in an elderly population (S36.008). Neurology April 6, 2015 vol. 84 no. 14 Supplement S36.008
- Gu Y, Honig LS, Schupf N, Lee JH, Luchsinger JA, Stern Y, Scarmeas N. Mediterranean diet and leukocyte telomere length in a multi-ethnic elderly population. Age (Dordr). 2015 Apr;37(2):24. doi: 10.1007/s11357-015-9758-0. Epub 2015 Mar 8.
- Lehert P, Villaseca P, Hogervorst E, Maki PM, Henderson VW. Individually modifiable risk factors to ameliorate cognitive aging: a systematic review and meta-analysis. Climacteric. 2015 Oct;18(5):678-89. doi: 10.3109/13697137.2015.1078106. Epub 2015 Sep 11.
- Scarmeas N, Luchsinger JA, Mayeux R, Stern Y. Mediterranean diet and Alzheimer disease mortality. Neurology. 2007 Sep 11;69(11):1084-93.
- Scarmeas N, Luchsinger JA, Stern Y, Gu Y, He J, DeCarli C, Brown T, Brickman AM. Mediterranean diet and magnetic resonance imaging-assessed cerebrovascular disease. Ann Neurol. 2011 Feb;69(2):257-68. doi: 10.1002/ana.22317.
- Scarmeas N, Stern Y, Tang MX, Mayeux R, Luchsinger JA. Mediterranean diet and risk for Alzheimer's disease. Ann Neurol. 2006 Jun;59(6):912-21.
- Singh B, Parsaik AK, Mielke MM, Erwin PJ, Knopman DS, Petersen RC, Roberts RO. Association of mediterranean diet with mild cognitive impairment and Alzheimer's disease: a systematic review and meta-analysis. J Alzheimers Dis. 2014;39(2):271-82. doi: 10.3233/JAD-130830. Review.
- Smyth A, Dehghan M, O'Donnell M, Anderson C, Teo K, Gao P, Sleight P, Dagenais G, Probstfield JL, Mente A, Yusuf S; ONTARGET and TRANSCEND Investigators. Healthy eating and reduced risk of cognitive decline: A cohort from 40 countries. Neurology. 2015 Jun 2;84(22):2258-65. doi: 10.1212/WNL.0000000000001638. Epub 2015 May 6.