October 11, 2005
Fish In Diet Slows Rate Of Cognitive Decline

Here is more evidence for the benefit of fish for reducing the rate of brain aging.

CHICAGO – Consuming fish at least once a week was associated with a 10 percent per year slower rate of cognitive decline in elderly people, according to a new study posted online today from Archives of Neurology, one of the JAMA/Archives journals. The study will be published in the December print edition of the journal.

Martha Clare Morris, ScD, of Rush University Medical Center, and colleagues analyzed six years of data from an ongoing study of Chicago residents, 65 years and older, first interviewed between 1993 and 1997 and every three years in two follow-up interviews. Interviews included four standardized cognitive tests and dietary questions on the frequency of consumption of 139 different foods, as well as questions of daily activities, exercise levels, alcohol consumption and medical history.

Morris found dietary intake of fish was inversely associated with cognitive decline over six years in this older, biracial community study. "The rate of decline was reduced by 10 percent to 13 percent per year among persons who consumed one or more fish meals per week compared with those with less than weekly consumption. The rate reduction is the equivalent of being three to four years younger in age," she said.

The benefit might not be from omega 3 fatty acids.

Although fish is a direct source of omega-3 fatty acids, which have been shown to protect against Alzheimer's disease and stroke, the dietary intake of omega-3 fatty acids was not associated with cognitive change in this study.

In addition, neither consumption of fruit and vegetables nor overall cardiovascular health appeared to account for the study findings, the researchers said.

However, see below for another report that demonstrates a mechanism by which omega 3 fatty acid DHA reduces inflammation and protects brain cells from damage and cell death.

Morris has previously reported that consumption of foods high in vitamin E reduces the incidence of Alzheimer's Diseaes.

Louisiana State University researcher Nicolas G. Bazan has just recently discovered a mechanism by which omega 3 fatty acid DHA protects the brain from neurotoxins and prevents cell death.

Their study shows that docosahexaenoic acid (DHA), an omega-3 fatty acid found in coldwater fish such as mackerel, sardines and salmon, reduces levels of a protein known to cause damaging plaques in the brains of Alzheimer's patients.

What's more, the researchers discovered that a derivative of DHA, which they dubbed "neuroprotectin D1" (NPD1), is made in the human brain. That natural substance plays a key role, too, in protecting the brain from cell death, the study showed.

Here is Bazan's paper.

A time-dependent release of endogenous free DHA followed by NPD1 formation occurs, suggesting that a phospholipase A2 releases the mediator’s precursor. When NPD1 is infused during ischemia-reperfusion or added to RPE cells during oxidative stress, apoptotic DNA damage is down-regulated. NPD1 also up-regulates the anti-apoptotic Bcl-2 proteins Bcl-2 and BclxL and decreases pro-apoptotic Bax and Bad expression. Moreover, NPD1 inhibits oxidative stress-induced caspase-3 activation. NPD1 also inhibits IL-1 -stimulated expression of COX-2. Overall, NPD1 protects cells from oxidative stress-induced apoptosis.

I just decided to have salmon for lunch.

Share |      Randall Parker, 2005 October 11 09:49 AM  Aging Diet Brain Studies

Stuart said at October 11, 2005 10:54 AM:

A company called Martek with the symbol MATK manufactures DHA and adds it to baby formulas, there are rumors that they are cutting a deal with General Mills to add it to cereal, but that is a rumor.

Full disclosure: I don't own the stock but am following it with the intent to purchase if it looks good. Searching for the company will give you info on DHA.


Randall Parker said at October 11, 2005 11:22 AM:


Martek grows algae and extracts the DHA from the algae. That's where fish get the DHA too.

In the long run crops will be genetically engineered to make DHA and EPA. That'll lower costs.

Ivan Kirigin said at October 11, 2005 12:53 PM:

Randall, you seem to be in a pretty good position to aggregate a bit of information.

While in the long-term, these supplements are important for slowing decline, I'm sure many people are very interested in optimal performance today.

Could you give a listing of some candidates for "boosters" of intelligence, with possible side effects, and potential benefits? How about an external resource you know of which you would recommend?


Engineer-Poet said at October 11, 2005 7:40 PM:

Between that and the effect of chilis on sleep, I decided to have Thai catfish (with extra cayenne) for dinner.

One more reason to become a capsaicin junkie!

Stuart said at October 12, 2005 8:20 AM:

Thanks for the response.
Have any companies made any progress in GMO crops with DHA and/or EPA yet?
Would it be something in a corn, soybean, rice or other terrestial plant or is there something about DHA that it would have to be an aquatic plant?

Rob said at October 12, 2005 12:41 PM:

Ivan, yeah I've been wanting to see brain boosters here or at gnxp for awhile
Here are a couple
creatine (demonstrated for vegetarians)
iron (for women after a month) improves memory

I'd love to have a good list, I especially need to boost visuospatial ability.

C'mon Randall

Randall Parker said at October 12, 2005 12:53 PM:

Check out my Brain Enhancement category archive. I've done a few applicable posts for your interests.

My take on brain enhancement is that there is a large overlap between what slows brain aging and what makes your brain work better in the short term. First eat an ideal diet to slow brain aging. That'll help.

But I do not think we can accomplish all that much with what dietary and drug stuff that is available now. Though you can accomplish more if you currently eat a bad diet.

My own personal experience is that Total cereal works to give me somewhat of a mental boost. Also, popcorn helps.

Ned said at October 13, 2005 7:03 AM:

A recent post on this board talked about the risks of mercury poisoning through the consumption of fish. See http://www.epa.gov/waterscience/fishadvice/advice.html#isthere. Actually, salmon seems pretty safe, but fishies farther up the food chain, such as shark and swordfish, are pretty high in mercury. So the same fish that prevents cognative decline may also be damaging your brain through mercury poisoning. Like everything else in life, this seems to be a trade-off.

Roger Kalla said at October 18, 2005 6:40 AM:

GM plants that produce DHA have been engineered by several groups worldwide. The first ones to do it were Calgene Pacific. CP was bought up by Monsanto. On a Monsanto web site that explains the technology and its benefits the company claims it is aiming for commercialising the GM crop with DHA within the next 5 years. Another promising approach has been taken by some colleagues closer to home (in my case Melbourne , Australia). The Australian Federal reserach agency CSIRO is working on developing GM cereals with DHA(see www.csiro.au/index.asp?type=faq&id=omegathree&stylesheet=divisionFaq). They are also probably 5- 6 years away from any commercial product. Meanwhile Clover Corporation here in Australia is using microencapsulation technology to stabilise the fish oils and make it available in a powder that doesn't smell or taste fishy and that can easily be added to processed food products. This is the main source of DHA you find in fortified foods at present. Hope this answers some of the questions. Please feel free to contact me if you need any more info.

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