The notion that the food we eat can affect how sharp our mind is and how happy we feel is a relatively new concept with much scientific interest.Considering the stresses posed upon us through our modern lifestyle, work and study pressures, deadlines, the constant stream of easily accessible information from the internet, and the challenges posed by social media, how are we coping?Nearly 3 million Australians live with depression and anxiety, which can affect their wellbeing, personal relationships, career and productivity. One in 16 young Australians are currently experiencing depression and one in four have a mental health condition. Suicide is the biggest killer of young Australians and accounts for the death of more young people than car accidents. According to the World Health Organization, mental health problems are fast becoming the leading health issue this century.The body, including the brain, is made entirely of molecules derived from food, air and water. It would be foolish to believe our diet has no effect on our mental state. We need a new approach to mental wellbeing, integrated treatments with the inclusion of nutrition therapy, as well as more education around food and its therapeutic and preventative potential. Let's look at nutritional aspects of mental health and ways in which we can optimise brain performance.Although we can make energy from protein and fat, carbohydrates are the ideal brain fuel. For most otherwise healthy individuals, without metabolic or neurodegenerative conditions, moderate consumption of "slow-releasing" complex carbohydrates is optimal for the brain. Think natural, unrefined sources, wholegrains, vegetables, beans and lentils. Our brain thrives on a steady and gradual supply of energy, which these foods provide.On the other hand, regular consumption of refined carbohydrates such as white bread, white rice, white pasta and white sugar is a bit like putting rocket fuel in your car and crashing it with a bang. So rule number one for the dietary treatment of mental health issues or optimising brain performance is to quit refined sugar and cut right back on refined carbohydrates.Quality protein is also crucial for mental wellbeing, as almost all neurotransmitters, including mood-stabilising serotonin, are made from it. Scientific research indicates we can manipulate our diet in order to promote mental fitness. Specific nutrients can affect cognitive processes and emotions - they are the building blocks maintaining the structure and function of the neurons and brain centers. Sixty percent of the brain’s dry weight is fat and optimally 25% of that fat is docosahexaenoic acid (DHA), a long-chain Omega-3 fatty acid, which appears to be the preferred type of fat by the brain and nervous system. DHA is the critical nutrient for brain cell function, improving the fluidity of cell membranes. It supports the growth of the connective structures within the brain and improves the ability to release neuro-transmitters, as well as enhancing communication between neurons. One clever fat indeed! DHA is found in abundance in cold-water fatty fish, shellfish, cod liver oil, algae and in smaller amounts in plant based forms like walnuts or sunflower seeds.Another crucial nutrient is Vitamin B12, a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and the formation of blood. Vitamin B12 is a nutrient that helps keep the body's nerve and blood cells healthy and helps make DNA. B12 is a cofactor for methylation, which turns genes on and off. It impacts the metabolism of several different neurotransmitters and plays a major role in myelin production, the protective sheaths around nerves. If left untreated, vitamin B12 deficiency can lead to anaemia, as well as nerve and brain damage.A growing body of evidence shows our beneficial gut bacteria supports positive mood and emotional wellbeing through the microbiome-gut-brain axis, which in my view is the starting place in the treatment of mental disorders. We carry somewhere between 10-100 trillion microorganisms in our gut, many of them essential to human health. We see when our microbiome is disrupted in some way, disease may occur.The brain needs two things above all to function properly - oxygen and glucose (or alternatively ketones) as fuel, making iron another crucial nutrient. It is required for adequate oxygen delivery to the brain and its deficiency can have serious consequences, especially for women. Organ meats, red meat, oysters, clams are major sources of heme-based iron.Choline has been shown to improve cognitive performance, memory and even protect against neurotoxicity, which is why eggs were always my go-to food during exams when I was a student at Endeavour.It is also worth mentioning how helpful foods including vitamin D are to preserve cognitive function, particularly as we age. Curcumin, found in turmeric, protects the brain from oxidative stress and improves memory. It has strong anti-inflammatory benefits and protects against neurodegeneration.