Can nutraceuticals help mental illness? Research into the role of nutrition in mental health has shown that a healthy diet can potentially play a significant role in the prevention and management of mental illness. A related question that researchers are trying to answer is what happens when we give specific nutrients, rather than a whole diet, to people experiencing mental illness? There is some research in this area that allows us to get an idea of the effect of specific nutrients, in the form of nutraceuticals, for mental health. What is a nutraceutical? In a nutshell, a nutraceutical is any preparation (e.g. a capsule, powder, liquid) that contains either singular or multiple nutrients, and has been created with the aim to improve health. The term nutraceutical is sometimes used interchangeably with the term “dietary supplement” but generally, nutraceuticals refer to a dietary supplement that is being investigated as part of a laboratory or clinical trial. How could nutraceuticals help treat mental illness? Nutrients such as fish oil, B vitamins, and vitamin D have all been shown to interact with multiple pathways in our body that are can affect mental illness. These include pathways such as inflammation, an imbalanced gut microbiome (learn more about the gut here), a reduction in the growth of brain cells (also called neurogenesis), and the production of free-radicals. Furthermore, some people might be more susceptible to mental illness because they have in-born errors in some of these pathways which could result in an increased need of certain nutrients in order to prevent malabsorption and/or deficiencies A quick primer on randomised controlled trials and meta analyses One of the best ways that we can determine if therapies such as nutraceuticals are effective is by running randomised controlled trials. A randomised controlled trial is considered one of the strongest forms of evidence that something does or does not work because it removes many of the potential factors that could confuse our interpretation of a study’s results. To go one step further, sometimes researchers will conduct a systematic review and meta-analysis of randomized controlled trials, these are studies that pool the results of randomized controlled trials in order to see what the overall evidence says instead of relying on the individual results of only a few studies. These are a particularly strong form of evidence. What does the evidence say? Supplements in nutrition interventions have often been used to avoid the difficulties of addressing dietary intakes, however it needs to be stressed that diet and nutritional supplements are not equivalent and data supporting the utility of such supplementation in mental illness are still somewhat limited so far. However, there have been several systematic reviews that have investigated the effectiveness of a broad range of nutraceuticals and provide support for the use nutraceuticals for certain people experiencing mental illness or related issues. Omega-3 fatty acid supplements (such as fish oil) have the strongest and most extensive evidence base in psychiatry. The systematic review evidence particularly supports the use of supplements containing a higher proportion of EPA compared to DHA, both of which are dietary fats with an array of health benefits, and as an adjunctive treatment (this means a treatment in addition to other forms of treatment) for unipolar and bipolar depression. Another recent systematic review, which included a meta-analysis, aimed to assess whether a broad range of nutraceuticals could be effective when combined with conventional antidepressant medications for people diagnosed with depression. The study reviewed 40 clinical trials and found that the pooled results of multiple studies that had investigated nutraceuticals such as S-adenosylmethionine (SAMe), methylfolate, omega-3, and vitamin D had a significant positive effect on depression. Furthermore, some nutraceuticals including creatine, folinic acid, and an amino acid combination, had only been investigated by single studies but all of these nutraceuticals had a significant benefit on depression as well. Zinc, folic acid, vitamin C, inositol, and tryptophan were also investigated but the meta-analysis found mixed or non-significant results for these interventions. Another recent systematic review and meta-analysis examined the literature on the short and long term impact of Vitamin B12 and folate as a treatment for depression. The results suggested that that the evidence did not support these B-group vitamins as being useful as a short-term treatment for depression, but that they might offer some preventive potential over the longer term. Another research paper systematically reviewed studies that investigated the use of nutraceuticals in combination, as opposed to being studied individually. The review found some limited support for micronutrient combinations for stress, antisocial behaviours, and depressed mood in healthy people. The review also found preliminary evidence to suggest that nutraceutical combinations might be of some benefit for ADHD and autism. However, there were few studies to report on and most of the studies in this review were conducted in people who were not clinically diagnosed with a mental illness. More research in people currently experiencing mental illness is needed. Other nutraceuticals with methods of action focused on addressing the biological pathways that influence many psychiatric disorders have shown early promise. For example, N-acetyl cysteine (NAC) – a bioavailable amino acid – appears to be helpful in relieving symptoms in schizophrenia, depression, and bipolar depression. In summary, while the results of these studies paint a promising picture of the state of nutraceutical interventions for helping to treat mental illness, this area is still in its infancy and many more high quality trials are needed to improve the state of the evidence. Until then, the research shows that it is important to ensure that we are eating a healthy diet in order to get sufficient amounts of a wide-range of nutrients and for some individuals, nutraceuticals may provide a significant benefit to mental health. However, if you are interested in taking a nutraceutical, it is always wise to discuss this with your doctor as some of these, particularly St John’s Wort, may interact with other medications.