The strongest evidence for the use of nutritional supplements for mental health supports omega-3 as an add-on treatment for major depression, according to a new meta-review of 33 meta-analyses of randomized placebo-controlled trials.
“In this most recent research, we have brought together the data from dozens and dozens of clinical trials conducted all over the world, in over 10,000 individuals treated for mental illness,” said study lead author Joseph Firth, PhD, senior research fellow at Western Sydney University in Australia. “This mass of data has allowed us to investigate the benefits and safety of various different nutrients for mental health conditions—on a larger scale than what has ever been possible before.”
The review, published in World Psychiatry, showed strong evidence that certain nutritional supplements are effective adjunctive treatments for particular psychiatric disorders. However, the majority of supplements did not significantly improve mental health when used alone.
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According to the study, adjunctive treatment with omega-3 supplements reduced symptoms of major depression more than antidepressants alone.
Researchers also reported the following findings:
• Omega-3 supplements may offer small benefits for the treatment of attention-deficit/hyperactivity disorder, some evidence suggests.
• The amino acid N-acetylcysteine may be useful as an adjunctive treatment for mood disorders and schizophrenia, emerging evidence suggests.
• Special types of folate supplements may be effective as add-on treatments for major depression and schizophrenia. Folic acid, however, was ineffective.
Researchers found no strong evidence supporting omega-3 for schizophrenia or other mental health conditions, according to the study. Furthermore, they found little compelling evidence supporting the use of vitamins (such as E, C, or D) or minerals (zinc and magnesium) for any mental disorder.
Findings from the meta-review should be used to promote evidence-based use of nutritional supplements in mental health treatment, Dr. Firth advised.
“While there has been a longstanding interest in the use of nutrient supplements in the treatment of mental illness, the topic is often quite polarizing,” he said, “and surrounded by either overhyped claims or undue cynicism.”
Firth J, Teasdale SB, Allott K, et al. The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials. World Psychiatry. 2019;18(3):308-324.