Omega-3 fatty acids (especially the type known as DHA) are essential for brain development and functioning, but most people eating a modern western diet consume low amounts of these compared to omega-6 fatty acids. Omega-3s are anti-inflammatory while omega-6s are pro-inflammatory. A large UK study published in the journal PLOS One in 2013 reported that healthy 7- to 9-year-olds with lower levels of omega-3 long-chain polyunsaturated fatty acids in their blood (including DHA, DPA, and EPA) had lower reading ability and working memory, and also had more behavior problems.
The oils in fish are the best source of omega-3 fatty acids, and most of the children with poor reading ability in the study fell short of the UK nutritional guideline that recommends eating two portions of fish per week.
Girls in the study had more dramatic deficits in omega-3 levels than boys. In adults, women tend to metabolize long chain polyunsaturated fatty acids more easily than men, but this difference is driven by hormones, and because the girls in the study had not yet reached child-bearing age, they did not reflect this benefit.
Omega-3 deficits in children have been connected with attention deficit hyperactivity disorder (ADHD), and supplementation with extra omega-3 fatty acids in the diet has led to improvements in ADHD.
Cultures where more omega-3 fatty acids (which have anti-inflammatory effects) and fewer omega-6 fatty acids (which have pro-inflammatory effects) are consumed have a lower incidence of depression and bipolar disorder. However, the exact role that each kind of fatty acid plays in the brain and whether dietary changes can improve mood disorders is still being investigated. A 2012 study in the Journal of Psychiatric Research examined the complete lipid profiles of participants with bipolar disorder to collect data on these questions.
The most significant results to come from the study were that levels of the long-chain omega-6 fatty acid dihomo-gamma-linolenic acid (DGLA) were positively correlated with neuroticism, depression severity, and decreased functioning. Depression severity was negatively correlated with the omega-6 fatty acid linolenic acid (LA) and the omega-3 fatty acid alpha-linolenic acid (ALA), and positively correlated with fatty acid desaturase 2 (FADS2), an enzyme that converts LA to the omega-6 fatty acid gamma-linolenic acid GLA.
The data suggest that particular omega-6 fatty acids and the enzymes that lead to their production may be used as biomarkers that can indicate depression.
Editor’s Note: Levels of specific omega-6 fatty acids and their related enzymes were found to correlate with depression severity in this study. Since omega-6 fatty acids are pro-inflammatory, diets higher in omega-6 fatty acids are associated with more cardiovascular problems, and a 2012 article by Chang et al. in the Journal of Psychiatric Research reported that completed suicides in bipolar patients with cardiovascular disorders were significantly higher than in those with bipolar disorder without cardiovascular illness, it seems a healthy diet can have multiple benefits, including potentially reducing depressive burden, cardiovascular risk, and suicide risk.
Several studies in adults and children suggest that omega-3 fatty acid supplementation may have antidepressant effects. At the 2013 meeting of the American Academy of Child and Adolescent Psychiatry in October, Melissa DelBello, a professor at the University of Cincinnati, reported on a new study of omega-3 fatty acids in depressed children who had a parent with bipolar disorder. The children taking omega-3 fatty acids were more likely to improve than those taking a placebo, but the findings were only of marginal significance.
Cold-water fish are a good source of omega-3 fatty acids, and DelBello said salmon is by far the best in this regard. People who live in countries where fish is consumed in greater quantities are less likely to suffer from depression. Other sources of omega-3 fatty acids include shellfish, plant and nut oils, English walnuts, flaxseed, algae oils, and fortified foods.
The omega-3 fatty acids from fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), while the omega-3 fatty acids from plants are alpha-linolenic acid (ALA), which breaks down into EPA and DHA. All of these are anti-inflammatory, though one must consume much greater quantities of ALA to match the benefits of EPA and DHA. In contrast, omega-6 fatty acids, which are much more common in the typical American diet, are pro-inflammatory.
In DelBello’s study of 56 depressed children of a parent with bipolar disorder, the participants were randomized to either 1.8 g of omega-3 fatty acids (1.2 g of EPA and 0.6 g of DHA) or placebo (olive oil). Those who received the omega-3 fatty acids had a 55.6% rate of remission versus 34.5% for those who received placebo, but while the odds ratio of 2.4 favored the omega-3 fatty acids, the difference in remission rates was not statistically significant, likely because of the small size of the study. However, improvement on the Children’s Depression Rating Scale was significantly different across the two groups, with children taking omega-3s improving more. Omega-3 fatty acids are known to have an anticoagulant effect (preventing the clotting of blood), and four children in the study did have prolonged clotting times (but no clinical problems with bleeding).
Editor’s Note: Given the existing literature on omega-3 fatty acids and the trend in this study, omega-3s are worthy of consideration for the treatment and potentially for the prevention of depression in children. This later possibility is further suggested by findings from Australia that, when compared to placebo, omega-3 fatty acids significantly reduced the rate of conversion from prodromal (preliminary) psychotic symptoms to a full-blown diagnosis of schizophrenia.
An article by Bloch & Qawasmi published in the Journal of the American Academy of Child and Adolescent Psychiatry last year suggested that omega-3 fatty acids could improve ADHD in children. The effects were milder than the standard pharmacological treatments for ADHD, but given that omega-3s have few side effects, there would be little risk to using them to supplement traditional treatments or in cases where traditional treatments cannot be used.
Editors note: It would also be worth seeing if omega-3s helped mood symptoms too. A meta-analysis we wrote about here suggests that the omega-3 fatty acid EPA or the combination of EPA plus DHA has positive effects on depression in adults.
An article in Time Healthland last year reported that preliminary research shows that women who took fish oil during pregnancy experienced fewer symptoms of post-partum depression than women who did not take fish oil supplements.
This data has not yet been replicated, but since there are few side effects to taking fish oil supplements, which are high in omega-3 fatty acids, the risk-to-benefits ratio suggests that there is no reason pregnant women shouldn’t take fish oil supplements to decrease the likelihood of depression after delivery.
We have written before about the possible benefits of omega-3 fatty acids.
Iris Manor reported at the 57th Annual Meeting of the American Academy of Child and Adolescent Psychiatry (AACAP) in October 2010 that phosphatidylserine (a phospholipid component) containing omega-3 fatty acids had significant positive effects in children with ADHD. These findings were notable because Manor and other investigators had previously found that omega-3 fatty acids themselves were not effective in ADHD, raising the possibility that the phosphatidylserine component offers unique therapeutic advantages. This compound is currently available in Israel and may become available in the US in the next year.
We’ve been posting recently about diet and about treatments that are weight-neutral. There is evidence that diet, inflammation and depression are all linked. Epidemiological studies by Joe Hiblen have shown that in countries whose populations eat more fish and thus have high levels of omega-3 fatty acids in their diet, there is lower incidence of depression, suicide, and cardiovascular disease such as heart attacks and strokes. This may be because the major omega-3 fatty acids, EPA and DHA, are anti-inflammatory, and inflammation has been linked to depression. EPA inhibits the enzymes phospholipase A2 and cyclo-oxygenase-2 (COX-2), and their subsequent inflammatory effects on cytokines. DHA inhibits the pro-inflammatory cytokine IL6.
Researcher John Davis recently reviewed relevant literature and found that diets high in anti-inflammatory omega-3 fatty acids are associated with lower incidence of depression, cardiovascular disease, and markers of inflammatory processes. Conversely, diets high in fat and in inflammatory omega-6 fatty acids are associated with obesity, depression, and cardiovascular disease.
Various studies have shown the links between inflammation and depression. For example, when patients are given alpha-interferon to treat viral hepatitis, there is a subsequent increase in inflammatory cytokines IL-1 and IL-6, and depression often follows. Also, depressed patients have an increased ratio of pro-inflammatory to anti-inflammatory cytokines in their blood.
Another sign of a link between bipolar illness and inflammation can be seen in biochemical analysis of brain specimens obtained at autopsy. Researcher Rapaka Rao in the laboratory of Stanley Rapoport at the National Institute on Aging at the National Institutes of Health in Bethesda, Maryland, has reported that increased markers of neuronal inflammation and excitotoxicity were found in the brains of people who had had bipolar disorder. Phospholipase A2 and COX-2 were significantly elevated in the brains of those with bipolar illness and those with schizophrenia compared with controls. Pro-inflammatory interleukin I was also significantly increased in the brains of those who had had either illness. Read more
Omega-3 fatty acids are important for brain development and function and are essential to the human diet since they cannot be synthesized by the body. Omega-3 fatty acids are derived from canola oil, walnuts, flax seed oil, leafy vegetables, and especially fish. The main omega-3 fatty acids include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). They have anti-inflammatory effects, unlike omega-6 fatty acids, which are pro-inflammatory. The omega-6 fatty acids come from soy, peanuts, corn oil, and meats, and are associated with increases in obesity, myocardial infarction, and stroke.
In a recent review of the literature, John Davis and Joe Hiblen found that diets that include high levels of omega-3 fatty acids are associated with decreased incidence of depression, suicide, and cardiovascular disease. The researchers performed a meta-analysis of all the prospective depression treatment studies of omega-3 fatty acids compared to placebo. They found that EPA had antidepressant effects in humans, with moderate effect size and a high degree of statistical significance. DHA, however, did not appear to have an antidepressant effect, and pure DHA was even associated with some worsening of depression.
Editor’s note: This meta-analysis helps clarify some of the ambiguities in the literature about the antidepressant efficacy of the omega-3 fatty acids, clarifying that EPA alone is an effective antidepressant. The one study that did not find antidepressant effects with EPA was carried out by the Bipolar Collaborative Network, in which I am an investigator. Our study, published in an article by Keck et al., showed that 6g of EPA was not significantly more effective than placebo in bipolar depression or in rapid cyclers. However, there is some indication that 6g may be too high a dose of EPA, and most of the recommendations now suggest using 1-2g of either EPA or an EPA/DHA combination. Read more
EDITOR’S NOTE: Dr. Gagin Joshi of Massachusetts General Hospital, who presented the work on carbamazepine and lamotrigine on page 1 provided us with his own general treatment algorithm for youngsters with bipolar disorder.
Joshi typically starts with 0.5 to 2 gms of omega-3 fatty acids because of their benign side-effects profile, the many studies suggesting they are effective in adult mood disorders, and a recent article indicating that they were effective in preventing the conversion of prodromal schizophrenia into full-blown illness in a randomized double-blind controlled study in Australia.
After the omega-3 fatty acids, Joshi’s second choice is typically the atypical antipsychotic aripiprazole (Abilify) because of its lesser degree of weight gain compared to atypicals quetiapine (Seroquel) or risperidone (Risperidol). Risperidone can be a third option if aripiprazole is not effective or tolerated.