Fish Oils and Mood Disorder Prevention

From the March 2006 edition of Dr. Fuhrman's Healthy Times:

In addition to adequate micronutrient intake, fatty acid balance also plays a critical role in mental health. Low fish consumption has been found in multiple studies to be a statistically significant finding in those with depression. For example, this study showed that rates of depression increased more than twofold in women who were rare fish consumers compared with regular fish eaters.1 Research scientists consistently found a reduced level of omega-3 fatty acids in patients with mood disorders and mental illness. There is overwhelming evidence that omega-3 fatty acids are important to mental health.

The two main omega-3 fatty acids in fish oil, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), have important biological functions in the brain. DHA is a major structural component of neuronal membranes, and changing the fatty acid composition of neuronal membranes leads to functional changes in the activity of receptors and other proteins embedded in the membrane phospholipid. EPA has important physiological functions that can affect neuronal activity. Clinical trials have suggested benefits from DHA and EPA treatments in borderline personality disorder, bipolar or manic-depressives, schizophrenia, and attention deficit hyperactivity disorder.

Our bodies have the ability to make these important fats from the short chain omega-3 fats found in leafy greens, walnuts, flax, and hemp, but some people do not fabricate sufficient DHA from the shorter length precursors as well as other people do, predisposing them to neurological problems. These individuals have a greater need to supplement their diets, especially since fish today is so polluted, and farm-raised fish is no longer a dependable source of DHA and EPA. Using a DHA supplement or a purified fish oil is cleaner and more dependable.

Documented benefits
The following interesting observations are found in the scientific literature:
1. Both lower DHA content in mothers’ milk and lower seafood consumption were associated with higher rates of postpartum depression.2

2. Depressed patients have lower levels of DHA in their fatty tissues compared to normals.3

3. Multiple studies indicate that in depression and schizophrenia, one gram a day of the EPA component is more effective than DHA, and a higher dose does not add additional efficacy.4
Depression is related to low levels of these long chain omega-3 fats in the brain, and it is apparent that supplementation with DHA and EPA have beneficial results in patients with mood disorders. Since studies have shown that EPA is even more effective than DHA for alleviating depression in the short run, and DHA is more important for structural normalcy to maintain long-lasting results, I recommend real fish oil containing both EPA and DHA for those with depression and related mood disorders. About two grams of fish oil usually contains about one gram of active ingredient (EPA + DHA) appropriate for those with mild mood disorders. With major depression, use about 3 grams to achieve the one gram of EPA that has documented clinical efficacy for depression. Look for an oil that gives the most active ingredients (EPA + DHA) per gram of oil. At my office, we have highly purified and concentrated fish oil in stock.

Other natural remedies for depression have only minor value.
DHEA—DHEA is a hormone in the steroid family produced by the adrenal glands. It has been shown in scientific protocols to have value in aiding mildly depressed elderly patients, since a fall in DHEA later in life may contribute to the development of depression.5 It is not without side effects or risks.


St. John’s Wort—Some studies show slight benefit; others show none.6 I do not recommend St. John’s Wort for major depression.

SAMe—SAMe is a methyl donor involved in the synthesis of various neurotransmitters in the brain. A small number of clinical trials have shown that, at doses of 200-1600 mg/d, SAMe is superior to placebo in alleviating depression.7 Most individuals require dosages of 600-1200 per day. I do not recommend it often as it is expensive and only mildly effective.

Tryptophan—A comprehensive metanalysis of all studies on 5- hydroxytryptophan (5-HTP) and tryptophan showed 108 trials, but of all these studies, only two trials, involving a total of 64 patients, were of sufficient quality to meet inclusion criteria. The evidence suggests these substances were better than placebo at alleviating depression; however, the evidence was of insufficient quality to be conclusive.8 The bottom line is that very few studies of quality exist, but it is likely to have mild beneficial effects.

1. Timonen M, Horrobin D, Jokelainen J, et al. Fish consumption and depression: the Northern Finland 1966 birth cohort study. J Affect Disord. 2004;82(3):447-52.

2. Hibbeln JR. Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. J Affect Disord. 2002;69(1-3):15-29.

3. Mamalakis G, Tornaritis M, Kafatos A. Depression and adipose essential polyunsaturated fatty acids. Prostaglandins Leukot Essent Fatty Acids. 2002;67(5):311-8.

4. Murck H, Song C, Horrobin DF, Uhr M. Ethyleicosapentaenoate and dexamethasone resistance in therapy-refractory depression. Int J Neuropsychopharmacol. 2004;7(3):341-9. Peet M. Eicosapentaenoic acid in the treatment of schizophrenia and depression: rationale and preliminary double-blind clinical trial results. Prostaglandins Leukot Essent Fatty Acids. 2003;69(6): 477-85. Peet M, Stokes C. Omega-3 fatty acids in the treatment of psychiatric disorders. Drugs. 2005;65(8):1051-9. Frangou S, Lewis M, McCrone P, et al. Efficacy of ethyl eicosapentaenoic acid in bipolar depression: randomized double-blind placebo-controlled study. Br J Psychiatry. 2006;188:46-50.

5. Schmidt PJ, Daly RC, Bloch M, et al. Dehydroepiandrosterone Monotherapy in Midlife- Onset Major and Minor Depression. Arch Gen Psychiatry. 2005;62:154-162.

6. Shelton RC, Keller MB, Gelenberg A, et al. Effectiveness of St. John’s wort in major depression: a randomized controlled trial. JAMA. 2001;285 (15):1978-86.

7. Röder C, Schaefer M, Leucht S. Metanalysis of effectiveness and tolerability of treatment of mild to moderate depression with St. John’s Wort. Fortschr Neurol Psychiatr. 2004;72(6):330-43. Mischoulon D, Fava M. Role of S-adenosyl-L-methionine in the treatment of depression: a review of the evidence. Am J Clin Nutr. 2002;76(5): 1158S-61S. Williams AL, Girard C, Jui D, Sabina A, Katz DL. S-adenosylmethionine (SAMe) as treatment for depression: a systematic review. Clin Invest Med. 2005;28(3):132-9.

8. Shaw K, Turner J; Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev. 2002;(1):CD003198.
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Magnus - October 17, 2006 5:02 AM

Are there any studies made on the w-6 content of people with low levels of DHA/EPA? As I understand too much w-6 will impair the bodys ability to transform short chained w-3 to EPA/DHA. Wouldn't it in that case be better to try to lower the w-6 before taking fish oil (that might have unwanted substances in it)?

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