A recent study published in the February 2012 issue of Neurology is now actually showing that people with a diet lacking in omega-3 fatty acids have lower brain volume and reduced brain function.1 We have known for some time that taking a fish oil supplement is good for your brain but now we are seeing that a lack of these fatty acids could actually cause brain dysfunction.

Using the participants of the Framingham Study, researchers recorded the red blood cell levels of DHA and EPA (omega-3 fatty acids) in 1,575 dementia-free people. MRI brain scans and cognitive evaluation that included a Logical Memory test, abstract reasoning skills, and attention and executive function abilities were also performed. Those participants with DHA levels in the bottom 25 percent were found to have the smallest brain volumes and scored the lowest in cognitive functions such as visual memory, executive function, and abstract thinking. Those participants with the highest levels of DHA within their red blood cells also had the largest brain volumes and the highest cognitive function. But that’s not all. Those with the highest DHA levels also had a 37 percent lower risk of Alzheimer disease and a 47 percent lower risk of all-cause dementia. That’s pretty substantial.

As well, the MRI findings in the lower brain volume participants represent a change equivalent to approximately 2 years of structural brain aging. So if you have low omega-3 DHA levels in your blood, expect that your brain is actually two years older than you are.

We know that higher dietary intake of omega-3 fatty acids in the form of fish oil supplements increases the amount of DHA omega-3 in red blood cells. Red blood cell membrane omega-3 levels represent averaged levels over the past 120 days.2 Levels of red blood cell DHA in the top quartile (the highest levels) may result in higher brain volume and improved cognitive function. This likely occurs by two main pathways: vascular and nonvascular.

Vascular Benefits:   Higher omega-3 levels improve the vasculature by reducing blood pressure, lowering risk of blood clots, reducing inflammation, and lowering blood triglyceride levels. Vascular risk factors, including cerebral atherosclerosis, have been associated with increased risk of dementia, as stated in the Neurology paper.

Nonvascular benefits of omega-3s, particularly DHA, are likely to occur in the brain, in which DHA is concentrated include:  Decrease in beta amyloid plaques, increase in brain derived neurotropic Factor (BDNF), synaptic protection with decreased free radicals and inflammation, and decrease in exitotoxic omega-6 arachidonic acid. The smaller brain volumes and greater white matter hyperintensity volumes found in people with lower DHA levels suggest DHA plays a major nonvascular role.

About two-thirds of brain matter is composed of fats. And the type of fats you eat will make a difference on your thought processes, mood and behavior, and memory.  If you eat nothing but saturated fat, expect that to go to your head as well. Make sure you take 1,000 mg of omega-3 supplement daily, and if anyone calls you a “fathead,” thank them and move on.


  1. Z.S. Tan, et al., “Red blood cell omega-3 fatty acid levels and markers of accelerated brain aging.” Neurology. 2012 Feb 28;78(9):658–64.
  2. L. Arab, “Biomarkers of fat and fatty acid intake.” J Nutr. 2003 Mar;133 Suppl 3:925S–932S.