Several large population studies have linked low levels of omega-3 fatty acids – or high levels of omega-6 fatty acids – with risk of depression.
Unfortunately, this generally unhealthful “omega imbalance” typifies the average American’s diet and blood fat profile.
The results of clinical trials testing omega-3s against depression have been mixed, possibly because different trials have used different kinds of omega-3s at different doses, in patients with varying degrees of depression.
And it goes without saying that a person’s individual genetics may also influence the effects that a nutrient or drug exerts (or doesn’t) on their mood health.
Overall, as a panel appointed by the American Psychiatric Association concluded in 2006, the evidence seems encouraging … see “Top Psych Panel Says Omega-3s Deter Depression, Bipolar Disorder.”
But what about omega-3s’ potential to ease the related mood disorder called anxiety?
Omega-3s and anxiety: Prior evidence points to potential benefits
America’s growing anxiety epidemic has led to a steep rise in prescriptions for “anxiolytic” drugs … a trend with a definite downside: see “Abuse of Xanax Leads a Clinic to Halt Supply”).
Five years ago, we reported the results of studies that found potential anti-anxiety benefits from omega-3s and showed how they might help … see “Feeling Anxious? Fish and Fish Oil May Help.”
And four years back, we reported on several studies indicating that omega-3s improve impulse control and anger in substance abusers … see “Feel-Good Findings” and “Can Fish Oil Keep Cain from Killing Abel?”
More recently, a Spanish study found that the participants reporting the highest omega-3 intake were least likely to show signs of depression, anxiety, or stress … see “Omega-3 Mood Benefits Get More Backing.”
Now, researchers from Ohio State University report the positive outcomes of a clinical trial testing the potential calming effects of omega-3 fish oil in people who were not diagnosed with anxiety.
In brief, the results showed that a daily dose of 2.5 grams (2,500mg) of fish-source omega-3s may reduce symptoms of anxiety by about 20 percent (one-fifth).
Ohio State study sees reduced anxiety in med students
An Ohio State research team recruited medical students to participate in a small but rigorous – randomized, placebo-controlled, double-blind – pilot clinical trial funded by the National Institutes of Health (Kiecolt-Glaser JK et al. 2011).
The 68 prospective physicians took either placebo capsules or fish oil capsules containing 2,085 mg of omega-3 EPA and 348 mg of omega-3 DHA, for three months.
They provided blood samples and completed a battery of mental tests designed to measure stress, anxiety, and depression, at the outset of the trial and every two weeks.
The researchers expected to detect significant signs of anxiety, due to the tough medical school curriculum … but unplanned changes made the students’ schedules less stressful than expected.
As lead author Janice Kiecolt-Glaser, Ph.D., told a reporter for Psych Central, “These students weren’t really stressed. They were actually sleeping well throughout this period, so we didn’t get the stress effect we had expected” (PC 2011).
Nonetheless, the psychological tests still detected substantial reductions in anxiety among the students.
Compared with the placebo group, the fish oil group showed two major benefits:
A 20 percent reduction in anxiety symptoms.
A significant reduction in key blood markers for inflammation.
Importantly, as the authors wrote, “The reduction in anxiety symptoms associated with omega-3 supplementation provides the first evidence that omega-3s may have potential [anti-anxiety] benefits for individuals without an anxiety disorder diagnosis … [and] can reduce inflammation and anxiety even among healthy young adults.” (Kiecolt-Glaser JK et al. 2011)
A reduction in chronic inflammation is highly desirable, since it is a major causative or exacerbating factor in most major degenerative conditions – from cardiovascular disease to dementia – and is also linked to anxiety.
The study authors explained the link between anxiety and inflammation: “Pro-inflammatory cytokines promote secretion of corticotropin-releasing hormone (CRH), a primary gateway to hormonal stress responses; CRH also stimulates the amygdala, a key brain region for fear and anxiety. Accordingly, alterations [increases] in inflammation could also influence anxiety.” (Kiecolt-Glaser JK et al. 2011)
Their blood analyses showed a significant, 14 percent drop in blood levels of a pro-inflammatory cytokine (messenger protein) called IL-6 in the omega-3 group, compared to the placebo group.
And, the fish oil group developed lower omega-6/omega-3 ratios over the course of the study, which correlated with their reducing anxiety scores and with drops in production of another pro-inflammatory cytokine, called TNF-alpha.
We should note that the mental tests showed no effect on symptoms of depression … which is unsurprising since the students did not suffer from depression.
In contrast, folks in high-pressure environments like medical school will periodically experience more worry than normal … which means that an efficacious drug or nutrient could reduce anxiety signs, even in people who do not have a diagnosed anxiety disorder.
The Ohio trial’s findings do not prove that fish oil capsules are potent, fast-acting “chill pills” that can treat serious anxiety … though hope and more research are clearly warranted by the positive indications of this and prior studies.
That said, the new results suggest that supplemental omega-3s – or fish-rich diets – may help us all feel a bit calmer overall.
Buydens L, Branchey M, Roy A. N-3 Polyunsaturated Fatty Acids Decrease Feelings of Anger in a Population of Substance Abusers. Neuropsychopharmacology. , 2005;30(1):S87-S88.
Buydens-Branchey L, Branchey M, Hibbeln JR. Associations between increases in plasma n-3 polyunsaturated fatty acids following supplementation and decreases in anger and anxiety in substance abusers. Prog Neuropsychopharmacol Biol Psychiatry. 2008 Feb 15;32(2):568-75. Epub 2007 Nov 1.
Buydens-Branchey L, Branchey M, McMakin DL, Hibbeln JR. Polyunsaturated fatty acid status and aggression in cocaine addicts. Drug Alcohol Depend. 2003 Sep 10;71(3):319-23.
Colin A, Reggers J, Castronovo V, Ansseau M. [Lipids, depression and suicide] Encephale. 2003 Jan-Feb;29(1):49-58. Review. French.
Cott J, Hibbeln JR. Lack of seasonal mood change in Icelanders. Am J Psychiatry. 2001 Feb;158(2):328.
Gesch CB, Hammond SM, Hampson SE, Eves A, Crowder MJ. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. Randomised, placebo-controlled trial. Br J Psychiatry. 2002 Jul;181:22-8.
Hamazaki T, Sawazaki S, Itomura M, Asaoka E, Nagao Y, Nishimura N, Yazawa K, Kuwamori T, Kobayashi M: The effect of docosahexaenoic acid on aggression in young adults. A placebo-controlled double-blind study. J Clin Invest 1996; 97: 1129-1133.
Hibbeln JR, Linnoila M, Umhau JC, Rawlings R, George DT, Salem N Jr. Essential fatty acids predict metabolites of serotonin and dopamine in cerebrospinal fluid among healthy control subjects, and early- and late-onset alcoholics. Biol Psychiatry 1998; 44: 235-242.
Hibbeln JR, Nieminen LR, Lands WE. Increasing homicide rates and linoleic acid consumption among five Western countries, 1961-2000. Lipids. 2004 Dec;39(12):1207-13.
Hibbeln JR, Salem N Jr. Dietary polyunsaturated fatty acids and depression: when cholesterol does not satisfy. Am J Clinical Nutr 1995; 62: 1-9.
Hibbeln JR, Salem N Jr. Risks of cholesterol-lowering therapies. Biological Psychiatry 1996; 40: 7: 686-687.
Hibbeln JR, Umhau JC, George DT, Salem N Jr. Do Plasma Polyunsaturates predict Hostility and Violence? World Rev Nutr Diet 1996; 82: 175-186.
Hibbeln JR, Umhau JC, Linnoila M, George DT, Ragan PW, Shoaf SE, Vaughan MR, Rawlings R, Salem N Jr. A replication study of violent and nonviolent subjects: cerebrospinal fluid metabolites of serotonin and dopamine are predicted by plasma essential fatty acids. Biol Psychiatry. 1998 Aug 15;44(4):243-9.
Hibbeln JR. Seafood consumption and homicide mortality. A cross-national ecological analysis. World Rev Nutr Diet. 2001;88:41-6.
Iribarren C, Markovitz JH, Jacobs DR, Schreiner PJ, Daviglus M, Hibbeln JR. Dietary intake of n-3, n-6 fatty acids and fish: Relationship with hostility in young adults-the CARDIA study. Eur J Clin Nutr. 2004 Jan; 58(1): 24-31.
Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Omega-3 supplementation lowers inflammation and anxiety in medical students: A randomized controlled trial. Brain Behav Immun. 2011 Jul 19. [Epub ahead of print]
Mihm S. “Does Eating Salmon Lower the Murder Rate?” The New York Times, April 16, 2006. Accessed April 22, 2006 at http://select.nytimes.com/search/restricted/article?res=F3071EFB35540C758DDDAD0894DE404482
Tanskanen A, Hibbeln JR, Hintikka J, Haatainen K, Honkalampi K, Viinamaki H. Fish consumption, depression, and suicidality in a general population. Arch Gen Psychiatry. 2001 May;58(5):512-3. No abstract available.
Tanskanen A, Hibbeln JR, Tuomilehto J, Uutela A, Haukkala A, Viinamaki H, Lehtonen J, Vartiainen E. Fish consumption and depressive symptoms in the general population in Finland. Psychiatr Serv. 2001 Apr;52(4):529-31.
Virkkunen M, Rawlings R, Tokola R, Poland RE, Guidotti A, Nemeroff C, Bissette G, Kalogeras K, Karonen SL, Linnoila M. CSF biochemistries, glucose metabolism, and diurnal activity rhythms in alcoholic, violent offenders, fire setters, and healthy volunteers. Arch Gen Psychiatry. 1994 Jan;51(1):20-7.
Virkkunen ME, Horroboin DF, Jenkins DK, Manku MS: Plasma phospholipid essential fatty acids and prostaglandins in alcoholic, habitually violent and impulsive offenders. Biol Psychiatry 1987; 22: 1087-1096.
Weidner G, Connor SL, Hollis JF, Connor WE: Improvements in hostility and depression in relation to dietary change and cholesterol lowering. Ann Int Med 1992; 117: 820-823.
- Weidner G, Connor SL, Hollis JF, Connor WE: Improvements in hostility and depression in relation to dietary change and cholesterol lowering. Ann Int Med 1992; 117: 820-823.