Early psychosis is associated with deficiencies in vitamin B9 and vitamin D, new research from Australia has found.

Australian researchers have found a link between early psychosis and low levels of critical nutrients, particularly vitamin B9 (folate) and vitamin D.

The researchers who led the study, published in journal Schizophrenia Bulletin, say the findings could contribute to new non-pharmaceutical, nutritional-based interventions being added to standard treatment.

"Although just one of many factors, it is important to recognise that nutritional deficiencies could certainly be contributing to the poor physical and mental health outcomes often observed in young people with psychosis," said lead author Joseph Firth, a postdoctoral research fellow at the NICM Health Research Institute at Western Sydney University.

Researchers analysed 28 studies examining blood levels of six vitamins and 10 minerals in 2612 patients.

All participants were assessed either immediately after presenting with psychotic disorders - such as schizophrenia - for the first time, prior to antipsychotic treatment, or within the early stages of treatment.

The meta-analysis showed vitamin D and folate deficiencies, previously seen in long-term schizophrenia, existed right from the onset of illness and that is was associated with worse symptoms, said Mr Firth.

"Since both of these nutrients are vital for physical and psychological wellbeing, this finding emphasises the importance of promoting a healthy diet for young people with psychosis, and potentially suggests adding targeted nutritional supplementation to standard treatment could improve recovery," said Mr Firth.

This is yet to be tested and more research is needed to determine whether this is a by-product of the disorder, he noted.