Serotonin is the brains busiest neurotransmitter and responsible for our feelings of wellbeing; moderating our appetite, sleep, mood and pain. Predominantly produced in the gut and made from the amino acid tryptophan, serotonin regulates our mood by sending messages to the brain via the neural network we call the gut-brain axis. Tryptophan is found in high protein foods like milk, eggs, salmon, turkey, duck, beef, nuts, beans, seeds and oats. As well as making serotonin, tryptophan also makes its sibling substance melatonin, the hormone involved in the sleep-wake cycle. People with depression typically have low levels of serotonin; depression also being linked with gastrointestinal problems like IBS, appetite dis-regulation as well as poor sleep. A growing body of scientific evidence on gut microbiome research, indicates that the gut-brain axis, and specifically keystone species of bacteria of the bifidobacteria and lactobacillus genus, have a significant positive impact on mental health, via the biosynthesis of serotonin from food proteins. The production of serotonin in the gut is negatively impacted by poor diets, particularly those with low diversity of fibres, and high intakes processed carbohydrates, sugars and alcohol. Absorbed into the enteric nervous system (neural network) and transported to the brain, the bioprotein and neurotransmitter serotonin also connects to the old idea of “we are what we eat”. Who would have thought that our gut bugs – AKA these beneficial keystone species – were in a BIG way responsible for this? Amazing Science! It’s what I like to think of as the missing link. And so, not only is nutrition supportive for the tissues, fluids and organs of the body, we are starting to see that what we eat and it’s interaction with our gut bugs has an crucial role in modulating our mood, our emotions and supporting our mental wellbeing.