Fish Consumption and Brain Health

Bill Yates
Brain Posts

Posted 24th February 2014

I have previously examined outcomes for MRI changes known as brain white matter hyper intensities (WMHI).

WMHIs are noted in a minority of adults and are not completely understood. The changes are considered subclinical in nature, meaning  they do not reach a threshold for medical significance.

However, these subclinical WMHI are linked to higher rates of premature cognitive decline. Absence of WMHI is seen by some as one marker of brain health.

Jyrki Virtanen and colleagues from Finland recently examined the relationship between WMHI and other subclinical brain abnormalities in 3660 adults 65 years of age and older. A subset of subjects had a repeat MRI 5 years later.

MRI scans for this cohort were examined for several subclinical brain abnormalites including white matter grade, brain atrophy, ventricular size and sulcal size.

Subjects also completed blood levels of omega-3 polyunsaturated fatty acids (PUFA). Omega-3 PUFAs are markers of dietary intake for fish and fish oils and higher levels have been linked to improved brain health.

Subjects were grouped into quartiles of omega-3 level from highest to lowest.

The main findings from the study included:

• High quartile omega-3 subjects had lower rates of subclinical brain infarct (odds ratio 0.60)
• Higher levels of long-chain omega-3 PUFAs were associated with high brain white matter grade
• Omega-3 PUFA levels were not associated with other subclinical brain abnormalities (sulcal size, ventricular size or brain atrophy grades)

The authors concluded "among older men and women, plasma phospholipid long-chain omega-3 PUFAs, and in particular DHA, were associated with specific findings consistent with better brain health, including lower risk of prevalent subclinical (lacunar) infarcts, better white matter grade, and lower risk of worsening white matter".

The authors note that dietary omega-3 PUFA is found in tuna and other fatty fishes but not in fried fish sources such as fish sticks.

They also note that the omega-3 PUFA docosahexanoic acid or DHA may "be most relevant for brain health".

Correlational studies always need to be interpreted carefully as correlation does not equal causation.

Nevertheless, this study adds to growing evidence of the value of regular tuna, sardines and salmon in a healthy diet.

Readers with more interest in this study can access the free full-text manuscript by clicking on the PMID link below.

Photo of great blue heron with fish is from the author's files.

Follow the author on Twitter WRY999.

Virtanen JK, Siscovick DS, Lemaitre RN, Longstreth WT, Spiegelman D, Rimm EB, King IB, & Mozaffarian D (2013). Circulating omega-3 polyunsaturated fatty acids and subclinical brain abnormalities on MRI in older adults: the Cardiovascular Health Study. Journal of the American Heart Association, 2 (5) PMID: 24113325

See the original article:

Fish Consumption and Brain Health

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