Omega-3s and Mental Health: A Report from ISSFAL 2010
By Joyce A. Nettleton, D.Sc.
Folklore has long held that fish is brain food … a belief increasingly bolstered by scientific evidence.
Three years ago, experts appointed by the American Psychiatric Association (APA) found the evidence that omega-3s support mental health quite compelling, albeit inconclusive. [Editor’s note: See “Top Psych Panel Says Omega-3s Deter Depression, Bipolar Disorder”.]
The APA’s expert panel concluded that abundant intake of omega-3s from seafood (DHA and EPA) helps support mental health ... and that the evidence warrants urgent research designed to better define omega-3s’ potential to prevent or treat specific mental problems.
Their positive position was based on what’s already known about key brain structures and functions – which rely heavily on omega-3 DHA – and an emerging body of evidence concerning omega-3s and mental conditions.
Our brains are mostly fat, and more than half of that heady stuff is omega-3 DHA.
We must have omega-3 DHA and EPA to survive or thrive, and can only obtain them in two ways:
Easily and abundantly from fish (especially fatty fish like sardines, tuna, and salmon).
Make small amount in our bodies from plant-form omega-3 ALA, in a very inefficient conversion process that’s hindered further by the flood of competing omega-6 fats, which Americans consume in unhealthful excess. (ALA is most abundant in walnuts, flax or hemp seed, leafy greens, beans, and grass-fed livestock.)
The APA panel also relied on the evidence existing then (in 2007). This included cell and animal studies, some preliminary clinical trials … and a larger number of epidemiological studies, in which scientists survey or follow groups of people, looking for any associations between health and diet.
Large, well-controlled clinical trials are the evidentiary gold standard, but because omega-3s are practically un-patentable products, therefore holding little profit potential, they rarely get funded by drug firms.
And costly clinical trials won’t get government funding without a persuasive body of lab and epidemiological evidence … a tipping point the APA panel thought we’d passed three years ago.
Here’s my summary of new and recent evidence concerning omega-3s and three major mental conditions (depression, suicide, and schizophrenia) … including papers presented at ISSFAL by the researchers themselves.
Depression
Some, but not all, studies have detected significant symptomatic improvements in people diagnosed with major depression who consumed modest amounts of omega-3s from fish (EPA and DHA) … with or without medication.
There is some evidence suggesting that omega-3 EPA may be more effective than omega-3 DHA or both together, but this possibility requires additional research.
Last summer, French researchers reported the results of a clinical trial involving 432 patients with depression, half of whom also had anxiety disorder.
[Editor’s note: We covered this report in a prior issue of Vital Choices; see “Fish Oil Rivals Antidepressants in Clinical Trial”.]
The patients were given about 1 gram per day of EPA or placebo for 8 weeks (St-André E et al., 2010; Lesperance F et al. 2010).
At the end of the treatment there were no differences in assessment scores between the two groups.
However, when the analysis excluded patients with anxiety disorder, EPA was associated with a significant improvement in depressive symptoms.
And in a study of pregnant women diagnosed with anxiety and depression, researchers observed that having higher levels of anxiety, but not depression, was associated with lower blood levels of omega-3 and omega-6 fatty acids (Bartke N et al. 2010).
Women with lower blood levels of omega-3 and omega-6 fatty acids and anxiety or depression also had shorter gestation times, attributable in part to their low omega-3 and omega-6 status.
Suicide
One of the most intriguing ISSFAL presentations noted that suicide deaths in the US military now outnumber the deaths from combat in current US engagements. The military suicide rate overall recently exceeded the civilian rate, for the first time since records have been kept.
A team of investigators that included renowned research psychiatrist Joseph Hibbeln, M.D., – from the National Institute on Alcohol Abuse and Alcoholism – proposed that low omega-3 status might increase the risk of depression and suicide in the US military. [Editor’s note: For more about Dr. Hibbeln’s work, see “‘Captain of the Happier Meal’ Gets a Salute”.]
To test this idea, they measured the long-chain omega-3s in the blood of 800 active duty suicide individuals and matched their leading characteristics to 800 controls (Hibbeln J et al., 2010).
The team’s analysis indicated that those with the highest levels of DHA were significantly less likely to die by suicide than those with the lowest levels.
An important contributing factor to suicide was the experience of seeing a soldier wounded or killed.
These observations suggest that low DHA status may be a risk factor for suicide, but might be overturned by dietary intervention … a possibility these investigators hope to test.
Schizophrenia
The ISSFAL presentations included a report of research in Tunisian schizophrenics, which supported the prior observation that individuals with schizophrenia have significantly lower levels of omega-6 ARA and omega-3 DHA in their red blood cells compared with non-schizophrenic individuals (Feki M et al. 2010).
Both of these fatty acids are essential to brain function, and blood levels fell as the severity of the symptoms increased … adding yet more evidence that deficits in long-chain omega-3 and omega-6 fatty acids occur in schizophrenic patients, and that disease severity increases as blood levels drop.
The Tunisian findings fit with a University of Cincinnati study, which showed that DHA levels in the orbito-frontal cortex brain region are lower in people with schizophrenia, compared with normal individuals (McNamara RK et al., 2007).
And evidence is growing that different psychiatric disorders may be related to DHA deficits in different regions of the brain.
For example, when researchers from the National Institute on Alcohol Abuse and Alcoholism measured omega-3 levels in the brain’s hippocampus region, they found no significant differences between mentally healthy people and patients with schizophrenia or bipolar disorder (Hamazaki H et al., 2010).
We may lack irrefutable proof that dietary omega-3s provide significant preventive or therapeutic benefits for the major mental health conditions.
But the scientists at ISSFAL certainly recommend urgent research into the effects of dietary fats on mental health … especially omega-3s and America’s badly skewed omega-3/omega-6 intake balance.
No comments:
Post a Comment