Nutritional Supplements in Psychiatric Disorders – The Evidence
High fat and high sugar diets are unbalanced and nutrient-poor and these deficits can be a risk factor for not only cardiometabolic diseases and cancer but also mental health disorders.
Nutritional neuroscience is an emerging research field that investigates how nutrient supplementation can not only complement an inadequate diet but also provide added physiological benefits and act as adjuncts to pharmacotherapy. [Jacka 2017]; [Marx et al 2017]
Commonly cited nutrient supplements in the literature include the following [Firth et al 2019]:
- Vitamin B9 (folate) deficiency is linked to a number of psychiatric disorders including depression, dementia, and schizophrenia. In addition, vitamin D deficiency is linked not only to bone metabolism issues but also with cognitive impairment, dementia, psychosis, depression, and autism. [Maddock et al 2017]
- Deficiencies in trace minerals such as zinc and magnesium are associated with the underlying pathophysiology of depression and anxiety. [Młyniec K et al 2014; Młyniec K et al 2015]
- The growing interest in the gut microbiome and its role in the development of mental health disorders has resulted in the development of specific strains of gut bacteria that may be advantageous as well as investigations into probiotic nutrients that promote health-related microbiota.
Polyunsaturated fatty acids (PUFAs):
- PUFAs are essential fatty acids required for forming all membranes in the body and are especially necessary for the development, maintenance, and function of the brain. An imbalance in the types of fatty acids consumed is linked to mood disorders, psychosis, ADHD, and cognitive deficits. [Simopoulos et al 2008]
- N-acetylcysteine (NAC) is an acetylated derivative of the amino acid cysteine and a precursor to glutathione that has been clinically investigated as a potential disease modifier in mood disorders, schizophrenia, OCD, and addiction and substance use disorders. [Ooi et al 2018]
- Glycine is an important amino acid neurotransmitter that on the NMDA receptor and therefore may have a therapeutic effect in NMDA receptor hypofunction states associated with schizophrenia. [Javitt et al 2001]
Although there is very little evidence that wide-scale usage of multivitamin and mineral tablets reduces the incidence of disease, specific nutrients for specific populations (i.e. folic acid during pregnancy or omega-3 for patients with myocardial infarction) do have substantial supporting evidence.
A recent meta-review of RCTs analysed the literature to determine the possible causal relationship between nutrient supplements and the outcome on mental health illnesses for which a standardised mean difference (SMD) was used to measure effect size versus placebo. [Firth et al 2019]