Taking fish oil or vitamin D supplements can boost the effectiveness of anti-depressants for those suffering from depression.
That's the finding from an evidence review conducted by a team from Melbourne University and Harvard Medical School, assessing 40 clinical studies worldwide.
Researchers found that certain nutrient or plant-based supplements had a positive effect on enhancing mood when taken with anti-depressants.
It's welcome news for sufferers who see little improvement from taking anti-depressants alone.
"This is an exciting finding because here we have a safe, evidence-based approach that could be considered a mainstream treatment," research leader Dr Jerome Sarris said.
"Millions of people in Australia currently take anti-depressants. There's real potential here to improve the mental health of people who have an inadequate response to them."
He said the studies backed omega 3 fish oil for boosting treatment, while vitamin D, methylfolate (an active form of folic acid), and S-adenosylmethionine (sometimes used to treat osteoarthritis) were also proven to lift mood levels.
"We've realised previously that omega 3 is good for the brain health ... and omega 3 was shown to be more beneficial than a placebo when combined with anti-depressants in improving depression treatment."
However, experts don't know the extent of the correlation between the supplement and the anti-depressant - whether it's the interaction of the two substances that can help lift someone's mood, or if just taking the supplement itself helps.
"Is it working together synergistically to improve the activity of it (the anti-depressant) or is it working on different chemical pathways? My understanding is that it could be a combination of both," Dr Sarris said.
While the results are encouraging, he warned patients to run any additions to their treatment by their doctors first.
"We're not telling people to rush out and buy buckets of supplements. Always speak to your medical professional before changing or initiating a treatment," he said.
