Ask An Expert: How Your Gut Affects Your Mood

“There’s now a significant body of evidence suggesting that a healthy diet—one that is rich in vegetables, fruits, lean meats and healthy fats—can improve our mental health,” explains Dr Wolfgang Marx. A Postdoctoral Research Fellow and Head of the Nutraceutical Research stream at the Food & Mood Centre at Deakin University, he’s also an Accredited Practising Dietitian whose current research includes the role of polyphenols—compounds found abundantly in spices, fruits, and vegetables—in mental health and the gut microbiome.

Here, he breaks down why feeding your microbiome is so important and shares three easy ways to support your gut for the year ahead.

Why is the gut so important to our health?

“In recent years, there has been an explosion in research that suggests that the microorganisms within our gut may influence a wide range of important processes in our body. These include nutrient absorption, hormonal regulation, inflammation, the immune system. Because of these properties, we are now discovering that changes in our gut can positively and negatively influence our physical health including our risk of chronic diseases such as heart disease and also our brain health including our risk of mental illness and dementia. By looking after the health of our gut microbiota, we may improve our physical and mental wellbeing and reduce our risk of chronic diseases.”

What’s the link between mental health, diet and the microbiome?

“Growing evidence suggests that the beneficial effect of a healthy diet on our gut microbiota may be at least partly responsible for the effect of a healthy diet on our mental health. By feeding our microbiome a healthy diet, it may in turn help to protect our brain and mental health. The microbiome supports brain function through its interactions with inflammation and the immune system, by producing small molecules that talk to the brain, and through a network of communication with the stress-control system. In all of these ways, tiny microbes may be contributing to our mental health and brain function. So it’s important to feed them well!”

Which foods are best for boosting your mood and supporting a healthy gut?

“While a lot more research is needed, what we currently know is that eating a diverse range of plant foods—including fruits and vegetables but also spices, beans, teas, nuts and seeds—appears to be crucial to a healthy gut. This is because plant foods are a rich source of things like dietary fibre and polyphenols which act as prebiotics—compounds that provide fuel for, and promote the growth of, beneficial gut bugs. By consuming a diverse range of plant foods, you are also ensuring that you are consuming a diverse range of prebiotic compounds. Fermented foods such as yoghurt, sauerkraut and kefir may also be beneficial because they contain live bacteria that may promote a healthy gut microbiota.”

On the flip side, which foods are the most detrimental for mental and gut health?

“Highly processed foods appear to have a detrimental effect on the gut microbiota and our mental health. These foods are usually high in saturated and trans-fat, sugar and salt, all of which appear to have a negative effect on gut health. Highly processed foods are also low in the compounds that are good for the gut, particularly dietary fibre. Therefore, the more of these foods we eat, the more they displace the healthy foods that our gut loves.”

What are three simple things everyone can do to bring balance back to their gut after the festive season?

“First, eating a wide range of fruits and vegetables with a variety of colours each day. By doing this, you are ensuring that you are consuming a wide variety of prebiotic compounds to feed your gut.

Secondly, incorporate beans and lentils into your diet. Most Australians don’t regularly consume them, but they’re a rich source of prebiotics like dietary fibre and polyphenols as well as being an inexpensive source of protein, vitamins and minerals.

Thirdly, consume fermented foods. You don’t need to opt for any particular probiotic dietary supplement. Instead, foods such as yoghurt, kefir, sauerkraut and kimchi are great sources of probiotic bacteria and can also taste great.”

What are ‘psychobiotics’ and what is the Food & Mood Centre hoping to achieve with the Gut Feelings Study?

“The term psychobiotics refer to probiotics—foods or supplements that contain beneficial live bacteria—and prebiotics—things like dietary fibre and polyphenols—that beneficially affect mental and cognitive outcomes by improving the gut microbiota.

In the Gut Feelings Study, we are aiming to evaluate the effect of psychobiotics on low mood and the gut microbiome. We hope to be able to answer questions such as “Does the gut microbiome at baseline predict type or severity of low mood?” and “In what ways do psychobiotics affect the gut microbiome?”

Discover more about the microbiome on The Bio-Fermentary...