Take-Home Messages:

• There is great interest in small vessel damage in the brain and growing evidence suggests better dietary habits may reduce such damage.
• Greater adherence to a Mediterranean-style of eating reduces cognitive decline and may reduce risk of Alzheimer’s.
• Measurable effects on the brain’s white matter supports this association between a better diet and cognitive effects.

In regards to cardiovascular disease, public attention remains more focused on the “cardio” than overall “vascular” issues, even though it’s clear that peripheral vascular disease, for example, can wreak havoc in multiple vascular beds. In terms of the most distal vasculature, the legs and feet get a lot of attention but, at the other end, little north of the carotids get much notice unless there is a stroke.

Given the diminishing returns as arteries clog, what about the cognitive effects of vascular disease?

Think About It

Studies have suggested that consumption of a Mediterranean-style diet is associated with a reduced risk of the metabolic syndrome, coronary heart disease, stroke, and cognitive disorders. (This way of eating emphasizes a high consumption of olive oil, plant proteins, whole grain, and fish; a moderate consumption of alcohol; and a low consumption of red meat, refined grains, and sweets.)

In one prospective cohort study, adherence to a Mediterranean diet was associated with slower cognitive decline but not for risk of incident dementia.¹ However, in a similarly-sized study (both about 1,400 individuals) by Sacco and colleagues, higher adherence to a Mediterranean diet was associated with a trend for reduced risk of developing mild cognitive impairment and with reduced risk of mild cognitive impairment (MCI) conversion to Alzheimer’s disease (p = 0.02 for trend).²

Very recently, Sacco et al. reported taking a deeper look beyond standard cognitive testing using brain MRI to evaluate white matter hyperintensity volume (WMHV).³ Previously, associations were observed between two components of a Mediterranean-style daily diet – moderate alcohol use and fish consumption – and white matter abnormalities.^4-6

WMHV is a marker of small vessel damage in the brain, and their finding of a lower WMHV burden among those with greater consumption of a Mediterranean diet are consistent with previous studies demonstrating inverse associations between dietary adherence and variables such as improved endothelial function and lower levels of inflammatory markers, including CRP and interleukin 6. Such associations may offer possible mechanisms for the previous cognitive findings and indicate that the overall daily dietary pattern, rather than any of the individual components, may be more etiologically relevant in relation to WMHV.

In neurology, Sacco and colleagues note great interest in small vessel damage as it relates to mild cognitive impairment, dementia, and Alzheimer’s disease. Although replication of their findings in other cohorts is necessary, as well as prospective imaging studies, their brain imaging work adds to the literature suggesting that a Mediterranean diet may be protective against subclinical vascular damage.

References

1. Féart C, Samieri C, Rondeau V, et al. Adherence to a Mediterranean diet, cognitive decline, and risk of dementia. JAMA 2009;302:638-48.
2. Scarmeas N, Stern Y, Mayeux R, et al. Mediterranean diet and mild cognitive impairment. Arch Neurol 2009;66:216-25.
3. Gardener H, Scarmeas N, Gu Y, et al. Mediterranean diet and white matter hyperintensity volume in the northern Manhattan study. Arch Neurol 2012;69:251-6.
4. Virtanen JK, Siscovick DS, Longstreth WT Jr., et al. Fish consumption and risk of subclinical brain abnormalities on MRI in older adults. Neurology 2008;71:439-46.
5. Mukamal KJ. Alcohol consumption and abnormalities of brain structure and vasculature. Am J Geriatr Cardiol. 2004;13:22-28.
6. Mukamal KJ, Longstreth WT Jr., et al. Alcohol consumption and subclinical findings on magnetic resonance imaging of the brain in older adults: the Cardiovascular Health Study. Stroke 2001;32:1939-46.

 

Keywords: Stroke, Dementia, Interleukin-6, Coronary Disease, Cognition Disorders, Diet, Mediterranean, Brain

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