Marine
Omega-3 Fatty Acids for Treatment of Mental Depression
By
Morten Bryhn, MD, Ph D
8/1/2003
Mental depression is common affecting 8-10% of the population
at any time. Statistics show that the prevalence of major
depression has increased and the age of onset has decreased
in every decade during the 2000 century in the Western World.
As a result anti-depressive medication is on the top list
of social expenditure for drugs in many countries. But even
if these drugs have proven very effective there is a need
for the individual to take own responsibility for the disease,
especially in the prevention of relapse after having ended
the medical treatment. Prevention must be based on psychotherapy
to give the patient insight into which mechanisms that can
lead to new depressive attacks and to recognise early symptoms
of relapse. But there may also be complementary ways of
increasing the effects of non-pharmacological prevention,
like dietary measures.
Serotonin
regulates mode and awareness and malfunctions of the serotonergic
system are common in depression, but also other psychiatric
disorders. Drugs sustaining the function of serotonin in
the synapse or increasing the response at the receptor are
used for treatment of depression (Prosac is one example).
It seems that marine fatty acids increases the effects of
the serotonergic system and may be used therapeutically
as soft anti-depressive. Interestingly it seems that a lack
of polyunsaturated fatty acids in the diet may lead to depression.
A dietary
survey of 9 countries around the world clearly demonstrated
higher prevalence of mental depression in populations not
eating fish (1). In a recently published article US scientists
found low contents of omega-3 fatty acids in mothers milk
of women with depressive disease after delivery (2). Mothers
without depression had significantly different values. People
in Iceland do not have seasonal winter depression as the
inhabitants of Canada have, probably due to the very different
habits of seafood intake (3). People in Finland with a relatively
frequent intake of fish have less frequent depression and
significant lower risk of suicide compared to those not
eating fish (4). Patients with severe depression have in
general low levels of omega-3 fatty acids in the blood (5).
So there may be every reason to think that marine omega-3
fatty acids could be important for prevention and even treatment
of depression.
There
have been three controlled clinical studies on the effects
of treatment with marine omega-3 fatty acids on patients
with depressive diseases. One study in 30 manic depressive
patients from Boston clearly demonstrated that those given
omega-3 fatty acids stayed in remission better compared
to those given placebo (6). Positive effects were evident
also for manic symptoms. In a study from Israel on 20 patients
with major depressive disease, those given omega-3 fatty
acids improved their mental status while those given placebo
showed no effect (7). The two most common marine omega-3
fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA). In the studies mentioned either EPA alone or
the two fatty acids in combination were used. Recently there
where conducted a third study from Houston, where the anti-depressive
effect of DHA alone was examined in 35 depressive patients
(8). However, in this study the effect of DHA was not different
from the placebo treated group. So far it seems that either
EPA alone or the natural combination of EPA and DHA as found
in fish oil should be tried for anti-depressive effects.
The
brain contains high amounts of DHA but almost no EPA. It
would therefore seem logic to expect positive effects from
DHA supplementation rather that EPA. But these fatty acids
may have different actions in the brain. DHA may have important
effects in brain cell membranes providing mechanical and
functional properties. EPA on the other hand is an important
precursor for local acting hormones, the eikosanoids that
are known to have psychotropic effects. Results from ongoing
studies will probably shed light on which doses that are
effective and what type of omega-3 fatty acid combination
should be recommended. While waiting for these results marine
omega-3 fatty acids with EPA and DHA in the natural combination
should be tried as nutritional supplements for prevention
of depression and maintenance of good mental health.
REFERENCES:
1. Hibbeln
JR. Fish consumption and major depression. The Lancet 1998;
351:1213-1215
2. Hibbeln
JR. Seafood consumption, the DHA content of mother's milk
and prevalence rates of postpartum depression: a cross-national,
ecological analysis.
J Affective Disorders 2002; 69:15-29
3. Magnusson
A, et al. Lack of seasonal mood change in the Islandic population:
results of a cross-sectional study. Am J Psychiatry 2000;
157:234-238
4. Tanskanen
A,et al. Fish consumption and depressive symptoms in the
general population in Finland. Psychiatric Services 2001;
52:529-531
5. Maes
M, et al. Fatty acid composition in major depression. J
Affective Disorders 1996; 38:35-46
6. Stoll
AL, et al. Omega-3 fatty acids in bipolar disorder. Arch
Gen Psychiatry 1999; 56:407-412
7. Nemets
B, et al. Addition of omega-3 fatty acid to maintenance
medication treatment for recurrent unipolar depressive disorder.
Am J Psychiatry 2002; 159:477-479
8. Marangell
LB, et al. A double blind, placebo-controlled study of the
omega-3 fatty acid docosahexaenoic acid in the treatment
of major depression. Am J Psychiatry 2003; 160:996-998
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