By Jason Feirman, published on March 1, 2005 - last reviewed on February 13, 2007
If you walked into your therapist's office and he told you to stop taking Prozac and start eating more fish, you'd probably think he was crazy. But a study has found that a combination of common food components might be as effective in treating depression as traditional drugs.
Scientists at Harvard-affiliated McLean Hospital looked at how uridine and omega-3 fatty acids could prevent depressive-like symptoms in laboratory rats. They found that each substance has antidepressant-like effects but together they are more effective than either is alone. It's a case of one plus one equals three.
Despite their powerful therapeutic effects, both uridine and omega-3 fatty acids are naturally occurring ingredients found in ordinary foods. Cold-water fish such as salmon and sardines are rich in omega-3 fatty acids, as are walnuts. Molasses and sugarbeets are good sources of uridine.
Researchers tested the two agents on rats that were forced to swim, a situation from which it was impossible to escape. It creates severe stress that induces a depression-like state of inaction and immobility. The stress, mediated by hormones, activates genes in key brain regions known to influence activity levels and mood.
When fed alone to rats, uridine had an immediate effect in relieving depression; the rats became less immobile in the forced swim test. Omega-3 fatty acids also reduced indicators of immobility, but it took a solid month of steady consumption of dietary supplements containing omega-3 fatty acids for the animals to show signs of improved mood.
Researchers then performed another experiment in which they fed the rats normally ineffective amounts of uridine with supplements containing omega-3 fatty acids. After ten days of treatment, rats showed signs of reduced immobility, increased swimming and increased climbing.
No one is sure why the combination of uridine and omega-3 fatty acids is so effective at relieving depression, but the researchers have some theories. Uridine affects the synthesis of nerve cell membranes and their fluidity, which in turn has an impact on all transactions that must take place.
In addition, uridine influences the levels of neurotransmitters such as dopamine and norphinephrine. Both are important brain chemicals that effect mood, mobility and general arousal.
Omega-3 fatty acids are also known to affect the fluidity of nerve cell membranes. They may be affecting the ability of serotonin to dock at the cell membrane, the first step before it unloads its cargo. Serotonin is a neurotransmitter which plays an important role in depression, bipolar disorder and anxiety.
Indeed, it is possible that uridine and omega-3 fatty acids act like a good song and dance act. Uridine may rev up membrane synthesis and then the omega-3s are on hand to slip smoothly into the nerve cell membranes. There they can facilitate a whole range of processes, including improving the action of serotonin.
Membrane fluidity may be especially important for mitochondria, the little energy factories found inside all cells of the body, including nerve cells. Omega-3 acids seem to boost the flexibility of mitochondrial membranes while uridine delivers raw material for the mitochondrial furnace.