While it is the case that DHA is important structurally in the brain, a consensus has emerged in the scientific and medical community that it is EPA which is the more beneficial of the omega-3 fatty acids for optimal neurological function. More and more supplement companies are acknowledging this body of evidence and are gradually increasing the ratio of EPA to DHA to the extent that some forward-thinking companies, like ourselves, remove the DHA completely through molecular distillation. This oxygen-free process extracts the EPA, which is left “ultra-pure” and is most bio-available to the body.
The primary reason why our oil only contains ultra-pure EPA and absolutely no DHA is due to the fact that clinical trials show that as the ratio of EPA to DHA increases in a supplement, so does its effectiveness. In addition, some leading experts believe that DHA (docosahexaenoic acid) may inhibit the beneficial actions of EPA (eicosapentaenoic acid). Indeed, recent research has confimed that pure EPA derived from fish oil is as effective as fluoxetine for the treatment of clinical depression (i).
Professor Puri, Consultant at Hammersmith Hospital and Imperial College London, is the author of over 100 scientific papers and more than 20 books He explains: “In general it has been found that as the ratio of EPA to DHA rises in the supplement used in clinical trials of certain conditions, such as depression and attention-deficit hyperactivity disorder (ADHD), the ability of the supplement to improve the condition also rises.”
We are not negating the use of DHA in all circumstances; its importance for the developing foetus, for example, cannot be over-emphasised. DHA also has properties which make it beneficial for cardiovascular and joint health. What should be recognised, however, is that these fatty acids have very distinct roles for health, particularly the role of EPA in brain function and mood disorders, for which DHA has little benefit. Studies have shown that for these conditions EPA alone is far more effective than in combination with DHA, which can inhibit the beneficial actions of EPA.
With the necessary co-factors the body can convert EPA into DHA as and when it needs it, preventing the unnecessary build-up which results from taking DHA in supplement form, thus avoiding any concerns about its high rate of oxidation.
(i) Jazayeri S, Tehrani-Doost M, Keshavarz SA, Hosseini M, Djazayery A, Amini H, Jalali M, Peet M. Comparison of therapeutic effects of omega-3 fatty acid eicosapentaenoic acid and fluoxetine, separately and in combination, in major depressive disorder. Aust N Z J Psychiatry. 2008 42:192-8.
This is what Minami Nutrition scientific board has to say about the EPA/ DHA debate.
“For children under 5, a direct supply of DHA is helpful as this is an essential component of the actual structure of the brain and nervous system. (For this reason, pregnant mothers should also ensure a good intake of DHA – along with other essential nutrients – to support the developing baby`s brain growth without putting their own supplies at risk of depletion. There is evidence that a low intake of omega-3 may increase the risk of maternal depression, for example.)
For older children, a greater emphasis should probably be placed on EPA, as this plays a more `functional` role.* Considerable research – including our own – now supports the view that EPA is likely to be more helpful than DHA in reducing difficulties in behaviour, learning and mood. Thus although both are important, a high-EPA formulation may be more suitable for children beyond the age of 5, and also for adults.
EPA is used to make other substances in the brain and body that regulate hormone balance, immune function and blood flow – and the ones made from EPA are essential to counterbalance others made from the omega-6 fatty acid, AA. The latter is plentiful in modern diets (mainly from meat and dairy produce), but its derivatives promote inflammation and blood clotting, while EPA`s derivatives are anti-inflammatory and improve blood flow. “ Dr Barry Sears is a leading expert in Omega 3 fatty acids this week he has said that the key to the mental health benefits to be
obtained from fatty fish or fish oil supplements are not down to DHA but to EPA.
“Expectant mothers have always been told that fish is brain food not
only for the developing child, but for the mother as well,” said Dr. Sears in a
statement. “New research data questions that ancient wisdom, or does it?”
“To understand this seeming paradox requires a detailed knowledge of
fish oils and omega 3 fatty acid metabolism that is not available to most
medical journalists” he said.
Now we have been hearing a lot of press that women who eat a lot of Omega 3 fatty acids are less likely to develop post natal depression and their children are likely to be smarter. However, most fish oil supplements on the market contain both EPA and DHA.
Dr Sears explains that the brain contains relatively low amounts of EPA so many have mistakenly assumed that DHA must be the fatty acid responsible for the benefits to be gained from fish oil, which is why it is added to baby milk formulas. No one ever really tested that hypothesis until now says Dr Sears.
He pointed out that the October issue of the Journal of the American Medical Association carried an article about fish oil supplements high in DHA and low in EPA and therefore researchers saw no real benefit from supplementing with fish oil.
The answer according to Dr Sears “is that benefits of fish consumption
or fish oil supplementation are due to the EPA, not the DHA.”
EPA is rapidly used up says Dr Sears whereas DHA is stored, which is why there is so little EPA compared to DHA in the brain.
EPA has a powerful anti inflammatory action and “it is this anti-inflammatory action that is responsible for the neurological benefits. This is confirmed by numerous studies in which DHA has little, if any benefits, in treating depression or attention deficit hyperactivity disorder, whereas fish oils rich in EPA do have remarkable benefits” said Dr Sears.