Saturday, March 3, 2012

Brain Aging and Omega 3

Framingham, Massachusetts, founded in 1700, is a manufacturing area somewhat to the north of where I live.  Most folks interested in the medical sciences have heard of Framingham because it houses the subjects of one of the longest-running and famous studies of all time, the Framingham Heart Study.  Begun in 1948, scientists have followed several generations of residents assessing diet, heart health, and other markers of disease.

In this new paper, the second Framingham study generation (average age 67) was observed for a relationship between red blood cell omega 3 (specifically DHA) levels, scores on cognitive testing, and MRIs.  It's a snapshot, just some interesting info, but let's see what we find.

Many studies measure levels of omega 3 in the body.  Plasma levels (from the blood) reflect dietary intake over a few days.  Red blood cells live about 120 days, so RBC membranes have omega 3 levels that correlate to dietary intake over the same amount of time.  These levels also correlate with fatty acid concentrations in other tissues, like the heart.  

First off, the MRIs.  The images were studied to look for measures of brain aging, such as lower brain volume, hippocampal volume, and white matter hyperintensity volume.   Gray matter is the cell bodies, white matter is the wiring (more or less), and "white matter hyperintensity" can indicate scarring or other damage.  The Framingham participants in the lowest quartile of RBC DHA amount had the oldest-looking brains, with lower total volumes and more white matter hyperintensity.  Once you got past the lowest quartile, however, there was no further relationship between the DHA levels and these brain findings.  So it appears there is a threshold where you need enough omega 3, and beyond that more omega 3 is not helpful (if we assume causation, that lower dietary omega 3 will cause problems and higher is protective).

The cognitive testing was fairly basic, but given over 1500 participants in the study, that is not surprising.  Delayed verbal memory, visuospatial memory, similarities testing, and a trails test were done.  In general these tests can give a rough picture of how good your memory, reasoning, attention, and executive functioning are.  RBC DHA levels were continuously and positively associated with 3 of the 4 tests (only verbal memory had no association).  

We know from other observational studies that regular fish consumption is (for the most part) associated with a lower risk of cardiovascular disease and dementia.  It seems that the ability to make DHA and EPA from the shorter ALA decreases as we age, so the older we are, the more important it is to get long chain omega 3s in the diet.  As I have reviewed in past blog posts, controlled trials supplementing with DHA, EPA, or both seem to have no effect in advanced dementia, but do seem to have a positive effect in mild cognitive impairment (a very early form of dementia that can progress further) and very mild Alzheimer's dementia.

Alzheimer's dementia and vascular dementia (dementia caused by the cumulative damage of strokes) are the most common forms of dementia, and having sufficient long chain omega 3s could protect us from both.  DHA and EPA seem to lower blood pressure, vascular inflammation, and reduce blood clotting.  These long chain omega 3s are also vital constituents of the "lipid rafts" and therefore cell membrane function.  As I've reviewed in the past, good levels of DHA in the brain seem to reduce neuroinflammation and the creation of amyloid beta plaques (associated with Alzheimer's).

Since long chain omega 3 fatty acids duke it out with the omega 6s for a spot on the plasma membrane of cells, it seems plausible that you don't need to eat fish three times a week if you keep your omega 6 intake low.  If you listen to this guy, your omega 6 intake will be high.  If you avoid processed foods, peanut and seed oils, and large quantities of most nuts and poultry and conventional eggs and lard… well, omega 6 will be less.  Your brain can tell the difference!


3 comments:

  1. This is in response to your Lithium and Inflammation post. I couldn't post a comment there for some reason.

    ""After going on the drug, she gained 30 lbs"" quoted from the comment above.

    It's quite plausible for someone to gain 20 or even 30 lbs while on Lithium treatment.

    What's important to note is Lithium's role with inhibiting the enzyme GSK-3B and thus inhibiting one's *metabolism*. This means you have a slower metabolism (that you're obviously not aware of), continue to eat the same food and do the same exercise for a number of days, and BAM you've gained 30 lbs doing "nothing wrong". This can be a very disheartening moment for the patient, and may very well cause a lot of disdain towards Lithium. I'm surprised that more Doctors don't properly prepare their patients, informing them that their metabolisms may very well drop, and considerably too. A timely adjustment could spell a 10 lb weight gain, instead of a 30 lb gain.

    Perhaps a comprehensive study should be undertaken regarding Lithium and the direct influence on one's metabolism.

    Are you of the opinion that it's perfectly acceptable for a male's metabolism to be reduced from 2500 calories a day, down to 1800 calories a day for the "break even point", and thus gain 20-30 lbs easily in the process?

    This then happens with it being virtually impossible to lose the weight while remaining on Lithium. This is acceptable to you?

    Also as the man gets older, the extra 30 lbs could mean higher blood pressure, being at a increased risk for diabetes, heart trouble, etc. Are we setting up a patient to potentially face considerable health problems in the future, just to "solve" his problem in the present?

    Perhaps you could make a blog post with any information you have regarding Lithium and it's influence over GSK-3B and thus over one's metabolism (by inhibiting it and considerably lowering the amount of calories/day for break even point).

    There's a very easy way to measure one's resting metabolic rate now. You just breathe into an apparatus for about 10 minutes. So I imagine the Lithium + Metabolism study wouldn't cost too much either.

    Thanks for reading this and responding if you have the time. I apologize if I asked too many questions as well. Btw, you have a terrific blog.

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  2. Hi Emily

    This is interesting (the fish omega 3's not the Lithium comment/questions above - although that isn't uninteresting!) when you consider the theory that humans evolved larger brains and higher functions during a period where they are believed to have been coastal dwellers due to the encroachment of ice. If the bottleneck theory is correct, and that modern humans did indeed flow from a small number who made it 'through' by dwelling on the coastlines it would seem to follow why our brains are demonstrably 'happier' with some minimum requirement for marine nutrition.

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  3. I wonder what you think about researcher Ray Peat who says that rancid n-3 fatty acids are common in the brains of those with AD. In other words, he thinks EFAs are not essential.

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