Key omega-3 fatty acids include eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), both found primarily in oily cold-water fish such as tuna, salmon, and mackerel.
DHA is a major structural component of the brain, the retina of the eye and the phosopholipid membranes around and within the nerve cells.
Why we need Omega-3 fatty acids
The brain needs Omega-3 fatty acids to function properly because they enhance the ability of brain-receptors to comprehend mood-related signals from other neurons in the brain. In other words, the omega-3s are believed to help keep the brain’s entire traffic pattern of thoughts, reactions and reflexes running smoothly and efficiently.
In a cross-national study published in Lancet, Hibbeln et al found that when fish consumption was high, there was a lower annual prevalence of major depression. In a later observational study, they observed that the likelihood of having depressive symptoms was significantly higher among infrequent fish consumers than among habitual fish eaters.
Hibbeln recently found a similar negative correlation between total seafood (including shellfish) consumption and the prevalence of post-partum depression in 22 countries. Higher concentrations of DHA in mother’s milk and greater seafood consumption both predicted lower prevalence of post-partum depression.
The most impressive clinical study to date on omega-3 fatty acids and unipolar depression was conducted by Peet and Horrobin. In this 12-week, double-blind, placebo-controlled study of 70 participants, patients receiving ethyl-EPA were divided into three dosage groups (1,2 or 4g daily). The participants had all experienced persistent depression despite taking standard antidepressants at adequate dosages. The patients receiving 1g EPA had the best outcome, with 53% achieving a 50-percent reduction on Hamilton depression scores. The 1g EPA dose led to improvements in sleep and libido and to decreased depression, anxiety, lassitude and suicidal ideation.
In another double-blind, placebo-controlled study of 22 participants, Nemets et al showed that the addition of 2g EPA to standard antidepressant medication enhanced the effectiveness of that medication, compared to the medication plus placebo, after three weeks of treatment.
The treatment of bipolar disorder was addressed in a well-designed four-month, double-blind, placebo-controlled study, conducted by Stoll et al. In this trial comprising 30 participants, non-placebo patients received 9.6g omega-3 fatty acids per day. Results showed that patients who had received the omega-3 fatty acids remained in remission significantly longer and showed a significant decrease in depressive symptoms.
Omega-3 fatty acids can also lessen depressive symptoms in women suffering from premenstrual syndrome (PMS). In a three month trial comprising 70 participants, patients took 2g of krill oil or fish oil daily for one month, then for eight days prior to and two days during menstruation for the following two months. Evaluations at 45 and 90 days revealed that patients taking krill oil showed a significant decease in the depressive symptoms of premenstrual syndrome.
How much Omega-3 should one take per day?
No clinically appropriate dose of Omega-3 fatty acids has been established yet for depression. To date, the bulk of clinical evidence suggests that it is the EPA component of fish oils which is most important for mood stability and that relatively low levels are required (1g daily) for successful outcomes.
The Food & Drug Administration (FDA) recommends a regular Omega-3 intake of 1g per day. This is equivalent to one of ReVite’s 1000 mg Double Strength Salmon Oil Concentrate capsules.
ReVite MD, André Niemann, points out that vegetarians can elect to use flaxseed oil capsules instead. Flaxseed contains alpha-linolenic acid (ALA) which is metabolised to become Omega-3 fatty acid in the body. Niemann cautions, however, that researchers still don’t know whether flaxseed oil is as effectively absorbed by the body as the Omega-3s (EPA and DHA) found in fatty fish oils.
1. Hibbeln JR. Fish consumption and major depression (letter). Lancet 1998; 351: 1213.
2. Tanskanen A, Hibbeln JR, Tuomilehto J, Uutela A, Haukkala A, Vilnamaki H, Lehtonen J, Vartiainen E. Fish consumption and depressive symptoms in the general population of Finland. Psychiatric Serv 2001: 52:529-31.
3. Hibbeln JR. Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: A cross-national, ecological analysis, Journal of Affective Disorders, accepted for publication.
4. Peet M, Horrobin DF. A dose-ranging study of the effects of ethyl-eicosapentaenoate in patients with ongoing depression despite apparently adequate treatment with standard drugs. Arch Gen Psychiatry 2002: 59: 913-919.
5. Nemets B, Stahl Z, Belmaker RH. Addition of omega-3 fatty acid to maintenance medication treatment for recurrent unipolar depressive disorder. Am J Psychiatry 2002: 159: 477-479.
6.Stol AL, Severus WE, Freeman MP, et al. Omega 3 fatty acids in bipolar disorder; a preliminary double-blind, placebo-controlled trial. Arch Gen Psychiatry 1999: 407-412.
7. Sampalis F, Bunea R, Pelland MF, et al. Evaluation of the effects of Neptune Krill Oil on the management of premenstrual syndrome and dysmenorrhea. Altern Med Rev 2003;8: 171-179.