Recent studies suggest benefits of omega-3 fats for the ageing brain

Previously on this site, for example here, I have written about the evidence which supports the idea that fish is what might be regarded as ‘brain food’. The study highlighted in that particular blog showed that high levels of DHA (docosahexaenoic acid – a so-called omega-3 fat found in certain species of fish) were associated with a substantially reduced risk of dementia and Alzheimer’s disease in the elderly. This sort of study cannot be used to prove that it is DHA that is the critical factor. However, it is known that DHA makes up a significant proportion of the fat found in the nerve cell membranes in the brain. With this in mind, it’s not too difficult to imagine that ensuring good levels of DHA in the body and brain might be important to brain function.

The link between fish and omega-3 levels and brain function have recently been re-examined again in two studies that appear in this month’s edition of the American Journal of Clinical Nutrition. In one of these studies, the relationship between fish intake and brain function (as measured by a battery of tests) was assessed in a group of more than 2000 Norwegians aged 70-74 [1]. The researchers found that eating an average of 10 g or more of fish a day, compared to eating less fish than this, was associated with better brain function and lower risk of being rated with ‘poor cognitive performance’.

One thing that strengthens the idea that it’s something in the fish that doing good here is the fact that there was what is known as a ‘dose-response’ relationship between fish intake and brain function: In other words, the more fish that was eaten, the better the brain function. This relationship held up to an intake of 75 g a day, after which there appeared to be no additional benefit.

In the second study, researchers measured blood levels of omega-3 fats in more than 800 men and women aged 50-70, and compared these to brain function (again, measured with a battery of tests) [2]. The participants of this study were assessed over a 3-year period. Over time, individuals with higher body levels of omega-3 fats were found to be significantly less prone to decline in two tests of cognitive performance (sensorimotor speed and complex speed). However, there was no relationship found between omega-3 levels and other tests of brain function including memory and word-fluency.

The authors of this second study call for potential for omega-3 fats to preserve or enhance brain function to be assessed with randomised controlled trials. This means treating a population with omega-3 fats, and comparing the effects of this over time with placebo (inactive agent). Such research, if properly conducted, would help settle one and for all whether omega-3 fats can help preserve brain function as we age.

While randomised controlled trials in this area have yet to be published, there is however a fair volume of work which has assessed the affects of omega-3 supplementation on depression and even bipolar disorder (once known as manic depression). A recent analysis of 10 relevant studies found that, compared to placebo, omega-3 fats were found to have significant antidepressant effect [3]. Taken as a whole, I believe the bulk of the evidence suggests that omega-3 fats have genuine benefits for the brain. And let’s not forget that these fats appear to have considerable ability to ward of physical ailments too ” particularly with regard to cardiovascular disease. Good sources of omega-3 fats include salmon, trout, mackerel, herring and sardine. For a guide to the most sustainable fish in our seas, see


1. Nurk E, et al. Cognitive performance among the elderly and dietary fish intake: the Hordaland Health Study. Am J Clin Nutr. 2007;86(5):1470-8.

2. Dullemeijer C, et al. n 3 Fatty acid proportions in plasma and cognitive performance in older adults. Am J Clin Nutr. 2007;86(5):1479-85.

3. Lin PY, et al. A meta-analytic review of double-blind, placebo-controlled trials of
antidepressant efficacy of omega-3 fatty acids. J Clin Psychiatry. 2007;68(7):1056-61.

11 Responses to Recent studies suggest benefits of omega-3 fats for the ageing brain

  1. Sue 16 November 2007 at 3:41 am #

    Has anyone read “The Brain Trust Program” written by a neurosurgeon – Larry McCleary, M.D.? I’ve just started reading it. He talks about the best nutritients required for the brain and how to slow down/stop alzheimers, enhance memory, alleviate migraine and hormonal problems.

    High insulin levels play havoc with the brain.

  2. Paul 16 November 2007 at 4:05 pm #

    Does the Omega 3 have to come from fish? My local Waitrose sells a Hemp Seed Oil which claims to be high in Omega 3 and other ‘good’ fats (can’t remember which ones at the moment). Do all omega 3 oils have the same beneficial effects irrespective of their source? If so wouldn’t it be better to eat non-fish sources because of diminishing fish stocks and pollution risks?

  3. Janet Alton MNIMH 16 November 2007 at 5:20 pm #

    Hemp seed oil does have quite high levels of Omega 3 as plants go (18%), but there’s far more Omega 6 in it (55%), including some GLA (3%). Flax seed oil is another good source of basic Omega-3 (53%). However, the kind of Omega 3 that occurs in plants is simpler than that found in fish. It takes the form of a short chain. In order to make it into DHA, the longest-chain Omega-3, a conversion process has to take place, either in a fish’s body or in your body, essentially bolting carbon atoms on to make a longer chain. Eating fish gives you DHA (and EPA, the next longest Omega-3) which can be incorporated into cell membranes straight away. Some people’s bodies don’t manage this conversion very well, especially those who suffer from allergies, and even the best converters only turn about 15% of the original plant oils into DHA. So eating fish really is the best option. However, there are ethical and other reasons for not wanting to do this. There’s a product called Water4Life (see their website) which is an EPA/DHA supplement made from sustainable algae stocks (fish get some of their Omega-3 by eating algae).

  4. Dr John Briffa 16 November 2007 at 5:24 pm #

    Work in this area has focused on DHA and EPA which are found in fish oil but not flaxseed oil (which is rich in another omega-3 fat – alpha-linolenic acid). If you decide you’re going to go for DHA/EPA and are looking for a non-fish source, you might like to look at this link:

  5. James H 16 November 2007 at 8:41 pm #

    I use the algae derived supplement mentioned by Dr Briffa. The site you buy it from says the process actually has a negative carbon impact so is good environmentally and is free from contaminants. But then you get it shipped to you in a padded envelope all the way from switzerland!

    There have been some studies that have suggested algae produced DHA can be more affective than the fish derived, see PMID 15812447. So don’t think you are getting second best going for the algae option. I would have thought it is very likely that our ancestors in the past eat algae from ponds and lakes etc so hopefully given the thumbs up for that reason too ?

  6. Neil 16 November 2007 at 9:10 pm #

    And ther’s also plankton derived oil (the plankton are called krill, hence krill oil) Supposed to be sustainable source.
    Never had it myself, and seems expensive in the UK compared with bog standard CLO, but its another alternative

  7. Vivienne 16 November 2007 at 11:47 pm #

    Not only for the brain and the joints but also for the eyes! I have the beginning stages of both Macular Degeneration and Cataracts and have been strongly advised to take Omega3. My big problem is, all the versions of the capsules and tablets, whose ingedients I study, contain Soya.

    I was a patient in your clinic in 2004 when we discussed my food intolerances: wheat, yeast and soya. The flaxseed oil has wheat. I wonder whether the hemp oil has either or both.
    (I do eat fish once or twice a week.)
    As with many other supplements, there are problems. Even Biocare DigestAid has started including Soya.


  8. helen 18 November 2007 at 9:23 pm #

    funny how saturated fat from fish is better than saturated fat from other animals! oh yes but we can give it a groovy name like omega 3 fatty acids!! Plant sources are not as good as animal sources of these essential fatty acids as the body has to convert it into the sort our animal bodies can use. Soy is one of the worst anti nutriants known to man & causes all manner of hormonal imbalances for more information on this product that even the AHA 8 year study into soy being good for the heart found it to be usless & infact possibly dangerous although they really didn’t seem to want to believe the results of their own study – funny how it didn’t make it into the mainstream media! Oh well you can find it on their web site if you really want to or go to & check out the entire history of soy! it is pretty scary how gullible we are when it comes to corporate advertising.

  9. Vivienne 19 November 2007 at 10:45 pm #

    As a user of Thyroxine, I would never have been advised to use SoyA, which conflicts with Thyroxine, even if my food intolerances had never been diagnosed.

  10. Hilda 26 November 2007 at 8:15 am #

    Helen : omega 3 is not saturated.

  11. Jason 30 November 2007 at 9:44 pm #

    Correct, Hilda. Omega-3 fatty acids are highly unsaturated. And the saturated fats in animal foods like fish, pork, and others, are not harmful to human health as commonly reported; Just the opposite, they are excellent for human health and vitality. A high fat, moderate protein, and low-carbohydrate diet is optimal for human health. In my opinion, obtaining the omega-3 fatty acids EPA and DHA from animal foods is optimal. I’ve always said, let the animal do the work accumulating high levels of DHA and then reap the benefits by eating IT. I’m pretty sure our ancestors probably weren’t going around scraping out algae out of bodies of water and scarfing it down — yuk. It seems logical to think that they most likely fished; Take the native americans for example, and the Inuit… They fished a lot and consumed the eyes, heads, brains, and other organ meats of the animals. These were the valuable components that provided vibrant health.

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