Diet and Mental Health
Most people are well aware of the impact that diet has on their physical health. However there is good evidence to show that nutrition and diet are also critical to our mental health and well-being.
The foods we eat impact our energy levels, mood and cognitive ability, as well as supporting a healthy gut microbiome. There are many studies which clearly show the role that diet plays in depression and other mental illnesses at a macro and micronutrient level(1). For example, dietary proteins and amino acids are the building blocks of many of the neurotransmitters responsible for mental function, including serotonin and dopamine.
What is serotonin?
Serotonin is a neurotransmitter which regulates mood, appetite and sleep as well as playing an important role in digestion. Up to 90% of serotonin is actually found in the gut, and is synthesized from its precursor tryptophan, an essential amino acid. Tryptophan is found in a wide variety of whole foods including meats, dairy, fruit, nuts and seeds(2) so most people should be able to get sufficient tryptophan from their diet. However, there are a number of studies showing that poor gut health may have an impact on our ability to convert this into serotonin(3) (4). Supplementing with 5HTP (5-Hydroxytryptophan) is useful for some people as 5HTP is able to cross the blood brain barrier, providing a more direct way for your body to bio-synthesize serotonin.
What is dopamine?
Dopamine also functions as a neurotransmitter in the brain, and plays a key role in our motivation and reward systems. Dopamine is linked with attention, memory and learning, as well as balance and movement(5). Along with serotonin, dopamine is one of the most extensively researched neurotransmitters because of its importance to human behaviour and the brain’s reward system(6). Outside of the central nervous system dopamine helps to regulate the release of insulin in your pancreas.
The gut-brain axis
The gut-brain axis is a very complex bi-directional communication system between the brain and your resident gut flora. There is a growing body of evidence showing that a healthy gut plays a critical role in mental health via the gut-brain axis, which has been described as a ‘paradigm shift in neuroscience’(7).
One recent study has helped to explain the link between gut bacteria and anxiety, where scientists found that “tiny molecules in the brain may help gut bacteria hijack people’s emotions”. There are other studies which show that specific gut flora can activate neural pathways, linking the microbiome with depression and other mental health issues(8). This has given rise to the new field of “psychobiotics” - the use of probiotics and prebiotics to hack your microbiome and improve your mental health(9).
Look out for our next post on the three steps you can take to improve your mental health through better nutrition and gut health.