If you’ve suffered from depression, you know that it’s a serious and often debilitating illness. Treating it often involves psychotherapy or medication, or both.
It’s difficult to pinpoint the causes of depression, but it’s probably due to a combination of factors, including genes, environment, and psychology, according to the National Institutes of Mental Health. But two recent studies on depression treatment methods suggest that increased inflammation in the brain increases the risk of depression, and researchers propose that if inflammation could be decreased—by exercise and/or fish oil supplements—then the onset of depression could perhaps be delayed or prevented.
Exercise and Depression
A study in the journal Cell looked at the effects of physical activity on depression. When you exercise, there’s an increase in the skeletal muscle [muscle attached to the skeleton] of a particular protein called PGC-1a1. "During exercise, the muscle cells have more of this protein, and it may prevent inflammation in the brain," says Alan Manevitz, MD, a psychiatrist at Lenox Hill Hospital in New York City. "Well-trained muscles (muscles that we exercise) may help our bodies metabolize [physically process] the byproducts of stress that may lead to depression."
The study, from the Karolinska Institutet in Stockholm, looked at both normal mice and genetically modified mice with elevated PGC-1a1 levels. Both groups of mice were exposed to loud noises, flashing lights, and other stressors. After five weeks, the normal mice displayed depressive symptoms, but the genetically modified mice did not.
"Our initial research hypothesis was that trained muscles would produce a substance with beneficial effects on the brain," said Jorge Ruas, principal investigator at the Institutet's Department of Physiology and Pharmacology, according to a Institutet press release. "We actually found the opposite: well-trained muscle produces an enzyme that purges the body of harmful substances. So in this context the muscle's function is reminiscent of that of the kidney or liver." That is, well-trained muscles don’t seem to produce any health-promoting substances; instead they flush out inflammation-causing ones.
So how much exercise would you need in order to stave off depression? "Twenty minutes of exercise a day is fabulous," says Los Angeles-based Susan Lindau, MSW, LCSW. She recommends walking because it doesn't require any special tools or equipment—just a pair of properly fitted walking shoes. You can walk alone or with a buddy, even a non-human one. If you live with a Fido or Rover, "I suggest walking with the dog," Lindau says.
Exercising reduces the body's level of cortisol, a stress hormone, and raises the levels of the feel-good hormones called endorphins, Lindau adds.
Omega-3 Fatty Acids and Depression
The other study looked at the relationship between depression and omega-3 fatty acids. Omega-3 fatty acids, commonly found in fatty fish and fish oils, have anti-inflammatory properties; they’re used to treat conditions like rheumatoid arthritis, for example. In a study of 152 people, researchers found that "even a short course (two weeks) of a nutritional supplement containing one such omega-3 polyunsaturated fatty acid (eicosapentaenoic acid, or EPA), reduced the rates of new-onset depression to 10%," according to Carmine Pariante, MD, FRCPsych, PhD, a professor at the Institute of Psychiatry, Psychology, and Neuroscience at King's College, London, in a press release.
But fish oil alone may not be enough to stave off depressive symptoms, though it’s an excellent addition to other depression treatments, says Amelia Villagomez, MD, clinical assistant professor in the Department of Psychiatry at the University of Arizona Medical School in Tucson. "Most studies that have looked at fish oil have looked at it as an augmentation [addition to other forms] of treatment," she says. "I don't prescribe fish oil alone because its effects are modest."
To treat depression with fish oil, look for a product with a ratio of 3:2 of EPA to DHA (docosahexaenoic acid, another omega-3 commonly found in fish oil supplements), Villagomez advises. And while there is no official recommended daily amount of fish oil, she feels that 1 to 2 grams per day is ideal. (Fish oil capsules are usually labeled in milligrams, or mg; 1,000 mg equals 1 gram). Be sure to take the fish oil with a meal since it is more readily absorbed this way, Villagomez says. You may buy either the liquid formula or capsules, she adds. And since fish oil can thin the blood, individuals should consult with their physician before taking blood thinners.
Alan Manevitz, MD, reviewed this article.
Sources
Alan Manevitz, MD.
"Some Forms of Depression May Be Prevented by Omega-3 Fatty Acids." Medical News Today. October 3, 2014.
Su, Kuan-Pin, Hsueh-Chou Lai, Hui-Ting Yang, Wen-Pang Su, Cheng-Yuan Peng, Jane Pei-Chen Chang, Hui-Chih Chang, and Carmine M. Pariante. "Omega-3 Fatty Acids in the Prevention of Interferon-Alpha-Induced Depression: Results from a Randomized, Controlled Trial." Biological Psychiatry 2014 76(7): 559-66.
"Exercise Protects Against Depression–But How?" Medical News Today. September 26, 2014.
Jorge L. Ruas, et al. "Skeletal Muscle PGC-1a1 Modulates Kynurenine Metabolism and Mediates Resilience to Stress-Induced Depression." Cell. Published online 25 September 2014.
"How Physical Exercise Protects the Brain Against Stress-Induced Depression." Karolinska Institutet. Accessed 25 September 2014 via AlphaGalileo.
Calder, Philip C. "n-3 Polyunsaturated Fatty Acids, Inflammation, and Inflammatory Diseases." American Journal of Clinical Nutrition 2006 vol. 83 no. 6: S1505-1519S
"Fish Oil." MedlinePlus. Last reviewed August 21, 2014.
"What Is Depression?" National Institute of Mental Health. Page accessed November 27, 2014.
