So what is the real story behind the food-mood link? What kinds of foods affect the brain, and how? Sarah is one of my colleagues at the aptly-named Food and Mood Centre, where we study these very questions. Sarah's PhD focussed on the biological pathways between diet and depression, so she is the perfect person to tell us more about supporting mental health with food. Thanks, Sarah!
Whether we’re reading about it, shopping for it, preparing it or eating it, food is a big part of our day-to-day lives, and it provides the necessary fuel to keep us working and feeling our best. The idea of “food as thy medicine” has been around for hundreds of years. However, most of our understanding of the relationship between food and health has focused on physical health; adding an extra vegetable or two during flu season, or cutting down on treats in preparation for summer. But we have all sought comfort in our favourite indulgences after tough day, or celebrated success with a nice meal. We intuitively understand the connection between food and our mood; food matters to both our bodies and brains.
What do we know about the link between food and mood?
Interestingly, the scientific evidence on the food-mood connection has lagged somewhat behind conventional wisdom, and most has been produced within the last decade. Early research looked at relationships between individual nutrients (e.g. vitamin D, zinc, fish oils) and depression. While this research laid an important foundation in nutrition-mental health research, it does paint an unrealistic picture of how humans eat. Our food is filled with nutrients that interact with each other in different and complex ways – we eat food, meals and snacks, rather than single nutrients. Researchers have now moved towards studying dietary patterns as a whole, which gives a better snapshot of our overall dietary intakes.
There have now been many studies from around the world that have consistently shown what many of us suspected; diet is important to mental health. For example, studies from Spain, Norway, Australia and the US have all shown that following a healthy, ‘traditional’ dietary pattern, consisting of the foods we know to be good for us (colourful fruits and vegetables, whole grains, legumes and healthy fats) is protective of your mental health. The unfortunate, and perhaps unsurprising news is that the reverse appears to be true as well: unhealthy, processed ‘junk’ foods are not only bad news for our waistlines or hearts, but for our mental health too. While more research is required, the results of a recent study have shown that dietary improvement based on principles of the Mediterranean Diet may also be an effective strategy for treating depression.
…but how?
The question that now interests researchers is how exactly does diet exert its effects on mental health? The gut microbiome has been an area of great public and research interest, and we are learning a great deal about how it influences our overall health, as well as our mood. Diet has an important impact on the health and function of our gut. For example, whole, fibre-rich foods can promote a well-functioning gut microbiome, whereas highly processed foods may disrupt the balance of bacteria, or promote a ‘leaky gut’. There is emerging evidence that tells us that the gut and brain talk to each other. The idea that we may be able to improve mood via the gut microbiome is exciting, but this is a young field, and there is still a lot of research required to improve our understanding.
In the meantime, the diet-depression relationship is now clear: diet matters to mental health. While we’re still working to untangle the biological reasons that diet is important to our mood, the traditional advice on healthy eating remains true for the health of our brains; reaching for highly-processed foods can cause problems for our bodies, bellies and brains.
The burden of common mental disorders touches us all on some level; whether we are medical professionals, carers, relatives, or affected personally. While traditional treatments like medication or psychological therapy are life-changing for some who experience depression or anxiety, we are learning about new approaches to managing depression and promoting mental health. A good quality diet – filled with fruits, vegetables, nuts, legumes, fish, olive oil- for example, is an important and practical way to promote mental health. Not only is our diet something that is relatively within our control (unlike, say, our genetics), it’s something we’re already doing multiple times a day – eating! Now that the scientific evidence has ‘caught up’ in supporting the diet-mental health link, it’s time to prioritise a healthy, good quality diet as it is essential for good mental health.
Sarah Dash completed her PhD in Nutrition and Mental Health at the Food and Mood Centre at Deakin University in September 2017. (Here she is celebrating her thesis submission!). She is a Post-Doctoral Researcher at Baker IDI, and is interested in lifestyle medicine, prevention, and physical and mental health outcomes. When she’s not researching or writing, she can be found cooking, eating, or playing sports.
Image credits: The mouth-watering salad image by Kaboompics is licensed under CCO . Thanks to Sarah for her portrait.