Dec. 21 (UPI) — Taking dietary supplements containing omega-3 fatty acids will not prevent depression or improve mood, a study published Tuesday by JAMA found.
Participants who consumed 1 gram, or a little over one-quarter of an ounce, of the popular supplement had a 13% higher risk for developing depression than those who took a placebo, or sham treatment that offers no clinical benefit, the data showed.
Those using the supplement also reported no significant improvement in their overall mood, the researchers said.
The findings do not support the use of omega-3 supplements to prevent depression, they said.
“Treatment with omega-3 supplements compared with placebo yielded mixed results,” the researchers wrote.
There was “a small but statistically significant increase in risk of depression or clinically relevant depressive symptoms but no difference in mood scores,” they said.
Omega-3 fatty acids are found in foods such as fish and flaxseed, and in dietary supplements, such as fish oil, according to the National Institutes of Health.
The three main omega-3 fatty acids are alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid, and alpha-linolenic acid found mainly in plant oils such as flaxseed, soybean and canola oils, while the others are found in fish and other seafood, the agency says.
The agency recommends men consume 1.6 grams, about half an ounce, of omega-3s daily and that women take in 1.1 grams per day, as the nutrient has been linked with reduced risk for heart disease, rheumatoid arthritis and other chronic diseases.
Earlier studies have also indicated that omega-3s have positive effects on the brain, hence the interest in exploring its use in the prevention of depression, which affects up to 20 million people in the United States, according to the National Institute of Mental Health.
For this study, the researchers from Massachusetts General Hospital and Harvard Medical School in Boston assessed the effects of omega-3 fatty acid supplement use on depression risk in more than 18,000 adults age 50 and older over a five-year period.
About half of the study participants took omega-3 supplements daily over the study period, while the other half were given a placebo, the researchers said.
Over the five-year period, 651, or 7%, of the participants in the omega-3 group developed depression compared with 583, or 6%, of those in the placebo group, the data showed.
Participants had similar results on assessments designed to measure mood and the presence of depression symptoms, the researchers said.
Similar percentages of participants in both groups reported side effects from study treatments, with about 3% reporting heart-related complications, they said.
This is significant, given that taking too much omega-3 has been linked with heart ailments, according to the researchers.
“Although results from this study contrast some evidence in support of omega-3 as adjunctive treatment … among high-risk persons with an established history of mood disorders, they are consistent with results from shorter-term and smaller-sample [studies],” the researchers wrote.
“Also, evidence for omega-3 as a treatment augmentation for adults with major depressive disorder is modest and has not uniformly shown benefit,” they said.