Omega-3 protects our brains from normal ageing and dementia

normal vs Alzehimer's brain

Shereen Jegtvig reports for Reuters, Jan. 22, 2014, that a new study suggests that omega-3 fatty acids protect the brain from the loss of volume that happens with normal aging and which is seen more severely in people with dementia.

A team of researchers led by Professor James Pottala found that older women with higher levels of omega-3 fatty acids in their blood had slightly less brain shrinkage than women with low fatty acid levels.

Pottala, an assistant professor at the University of South Dakota Sanford School of Medicine in Sioux Falls and chief statistician for the Health Diagnostic Laboratory in Richmond, Virginia, said, “The brain gets smaller during the normal aging process – about 0.5% per year after age 70, but dementia is associated with an accelerated and localized process of brain shrinkage.” 

He and his colleagues analyzed data from the Women’s Health Initiative Memory Study to see whether omega-3s were associated with brain shrinkage in general, and in specific brain regions involved in memory and other cognitive processes.

The data covered 1,111 women who were, on average, 70 years old and had no signs of dementia at the beginning of the study. At that time, the amounts of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in their red blood cells were measured.

DHA accounts for 30% to 40% of the fatty acids found in brain cell membranes, and it’s especially concentrated near the synapses where the cells communicate with one another, Pottala and his colleagues note in their report, published in the journal Neurology.

Eight years after the women’s blood was tested, they underwent MRIs to measure the volume of gray matter and white matter in their brains. The researchers found that women with the highest EPA and DHA blood levels at the study’s outset:

  • had brains that were about two cubic centimeters larger overall than women with the lowest levels. 
  • had larger hippocampus, a brain region critical to forming and storing memories — 2.7% larger in women who had fatty acid levels twice as high as the average. Of 13 specific brain regions the researchers looked at, the hippocampus was the only one where they saw a significant difference.

The analysis adjusted for other factors that could influence the women’s brain size, including education, age, other health conditions, smoking and exercise.

The researchers didn’t measure cognitive function, only brain volume, so they cannot say whether the size differences they saw had any link with differences in memory or dementia risk.

Pottala says higher blood levels of omega-3 fatty acids can be achieved by dietary changes, such as eating oily fish twice a week or taking fish oil supplements.

Since the study does not prove that blood levels of omega-3s are the cause of the brain-size differences observed, or that those differences have any effect on cognitive function, the researchers caution that more research is needed to know whether raising omega-3 levels would make any difference to brain health.


Omega-3s are also good for heart health. The American Heart Association recommends that Americans eat two servings a week of fatty fish rich in omega-3 fatty acids, like sardine and wild salmon.

However, other research has raised questions about whether high levels of omega-3s may raise the risk of prostate cancer.


7 responses to “Omega-3 protects our brains from normal ageing and dementia

  1. How do we know what ocean Omega-3 oil comes from, that is, how can we be sure that it does not come from the Pacific Ocean?


  2. Chia seeds are the best for Omega 3 and I have a great pudding recipe that is made from them! We need to take in more Omega 3 also to offset all of the Omega 6 that we get under normal circumstances.


  3. My husband is a huge believer in this. A large percentage of his patients are on Fish Oil or Flaxseed Oil. We personally take prescription Lovaza, which is quite potent and better than some of the unknown brands of Fish Oil. For the past several years, my hairstylist comments on how she has never seen anyone’s hair grow as fast as mine–I guess a side-effect of the Fish Oil. We do freeze our capsules and take them frozen to prevent “fish burps”, which is a yucky side effect. Also, my husband has done a great deal of research on the link between dementia/Alzheimer’s and the Gluten-free diet. We have been on this for almost 2 years, and there are many other great advantages that we have noticed.


  4. Norway recently did a long term studiy of I believe 10,000 individuals on the effects of amounts of Omega-3 and it concluded there is a heightened risk of cancer, particularlly skin cancer and prostate cancer in patients who take fish oil suppliments. Those who received the omega-3 from the food they ate and didn’t take suppliments did much better.

    Persnally, I stay away from pills. I eat fish 1-2 times a week and I’ve always felt that only bad can come with packing your body with any suppliment where the levels rise higher than you can get from food alone.


  5. Thank you Dr. Eowyn for this interesting post. I will have to buy some fish oil.


  6. Just as brain doc & anti-aging specialist, Eric Braverman, says, “We shrink up, we dry up, & we rust up” & that it all begins from the brain downward, the “golden bowl” as King Solomon described our brains (Eccl. 12) & it’s downhill from there. Braverman is convinced it can all be postponed with the right brain nutrients (about 40 videos here of him discussing the brain over the years: )

    Now where’s that tuna I mentioned in another post… ehhh, forgettaboutit, fish oil softgels are cheaper… & great tip re freezing them first!


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