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Fish Changes Brains for the Better
Mediterranean-style diets rich in fish linked to beneficial changes in brain structure

10/23/2015 By Craig Weatherby
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.

For more on that, see Omega-3s May Expand, Sharpen Brains, Omega-3s May Slow Brain Shrinkage, and their links to related reports.

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. 

Ironically, the so-called "Mediterranean diet” is fast disappearing around this legendary sea … see Mediterranean Region's Diets Differ from Ideal.

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.

For more on that study, see MIND Diet May Cut Alzheimer's Risk.

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.

Instead, as in the idealized Mediterranean diet, we should eat substantially more fish than meat … and favor leaner, naturally raised meats such as organic, grass fed beef and heritage chicken.

And fish isn't the only brain booster in the Mediterranean diet.

There's growing evidence that extra virgin olive oil plays a substantial role: see Brain Benefits from Olive Oil?.

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.

Their findings linking the Mediterranean diet to longer telomeres echo those of a study reported on last year: see Mediterranean Diet: Women's Anti-Aging Ally?.

The take-away from these studies seems simple: follow a Mediterranean-style diet, and make sure it includes ample seafood.


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