The Role of the Gut Microbiome and Diet in Depression – Prof Michael Berk

Posted on: July 2, 2019
Last Updated: December 1, 2023

Prof Michael Berk is the Alfred Deakin Chair of Psychiatry at Deakin University. He is a past President of the International Society of Bipolar Disorders and the Australasian Society of Bipolar and Depressive Disorders. In addition, he holds several honorary professorial research fellowships. Prof Berk has published over 800 papers and has received several national and international awards, including the Brain and Behaviour Foundation Colvin prize. 

Author Quotes  

A very important question is, ‘does reverse causality explain the relationship between diet and depression?’. And the answer appears to be ‘no’.

We are now beginning to understand that one of the important mediators of the relationship between diet quality and the brain is the microbiome, and the gut is now a critical area of feverish interest in the whole field.

The most important factor influencing the gut microbiome is diet.

Summary and slides  

Professor Berk begins this segment by stating that most longitudinal studies appear to show diet quality predicts mental health outcomes. However, mental health at baseline does not have a predictive capacity in terms of subsequent diet.  

The link between diet and inflammation is described; increasing diet quality proportionally decreased levels of C-reactive protein. The opposite effect was seen with worsening diet quality. 

The effect of diet quality on brain structure over time is then described, with age-related progressive brain changes being ameliorated to an extent by a good quality diet. 

The microbiome as a ‘hot topic’ area of research into depression is then discussed. 

He then talks about the importance of gut microbiota on metabolism, body weight, the immune system, and mood and behaviour. 

Professor Berk then describes the link between biological systems that are dysregulated in depression and gut microbiota, highlighting that diet is the most important factor which influences gut microbiota. 

Finally, he talks about up-coming trials that will investigate the effect of faecal microbial transplants in treating depression. 

Take-home Points  

  • Depression is an inflammatory disease, and inflammation is significantly impacted by diet. 
  • Diet is the single most important factor that influences the gut microbiome. 
  • Trials investigating the impact of altering the microbiome in depression are ongoing.


Learn more

  1. Effect of the Mediterranean Diet On Depression By Prof Michael Berk
  2. Early Life Nutrition and Neurodevelopment by Prof Michael Berk
  3. Healthy Diet vs Nutraceuticals in Depression by Prof Michael Berk
  4. Effect of Diet and Lifestyle Changes in Depression by Prof Michael Berk
  5. Applications of N-Acetylcysteine (NAC) – From Addiction to Autism By Prof Berk
  6. N-Acetylcysteine (NAC) in Schizophrenia and Bipolar Disorder- Prof Michael Berk
  7. Glutathione, Oxidative Stress and N-Acetylcysteine (NAC) in Psychiatric Disorders – Prof Michael Berk
  8. Oxidative and Inflammatory Biomarkers as Targets for Novel Therapies – Prof Michael Berk
  9. The Simplified Guide to the Gut-Brain Axis – How the Gut and The Brain Talk to Each Other