Omega-3 fatty acids are a family of fats that occur naturally; three of them, in particular, are important components of the human diet. These are α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid (DHA). DHA is one of the more common omega-3 fatty acids and has been of great interest because of its potential ability to enhance biological processes that underlie learning in the brain.
Why are these fatty acids good for our brain and why do we need to get them from our diet? There are many reasons but one of the most obvious is that our brain cells, the neurons, use them extensively to build their cell walls and our body is terribly inefficient at making them on its own. Thus, we need to provide a daily source of omega-3 fatty acids, particularly DHA, in order to maintain good brain health.
In the near future, omega-3 fatty acids may also assist with the treatment of depression. When very low doses of an SSRI were combined with a combination of omega-3 fatty acids, the antidepressant drugs actually potentiated omega-3 antidepressant-like effects. This novel approach of combining a dietary nutrient with an ineffective dose of a common antidepressant might prove useful in treating patients whose depression has been resistant to conventional treatments. Even better, the need for lower doses of SSRIs would reduce the incidence of their unpleasant side-effects, such as sexual dysfunction and diminished libido, and consequently improve patient compliance.
How much omega-3 in the diet is enough? A few studies have tried to answer this question. The problem is that it is notoriously difficult to control the diet of human subjects. Also, making the analysis more difficult is that the results of most studies suggest that the components of our diets act in an additive fashion. Therefore, it's very difficult to point to just one nutrient and conclude that it is responsible for improved mental health. Thus, the best advice is to eat a highly varied diet with the caveat that people with depression should specifically include foods rich in omega-3 fatty acids, such as salmon, flax seeds, hemp seeds (yes, Cannabis sativa), kiwi fruit, walnuts and canola oil.
Finally, make these changes to your diet soon; a recently published study discovered that the effectiveness of omega-3 fatty acids may significantly decline with normal aging.
© Gary L. Wenk, Ph.D. Author of Your Brain on Food (oxford, 2010)