The gut and the brain are in constant conversation through the vagus nerve, immune signalling, and a cast of trillions of microbes that manufacture neurotransmitters on your behalf. Roughly ninety percent of the body’s serotonin is produced in the digestive tract.
When the microbiome is diverse and well-fed, this conversation tends to be calm. When it is disrupted — by antibiotics, chronic stress, or a fibre-starved diet — the signals change, and research increasingly links that disruption to low mood, poor sleep, and brain fog.
Feeding the axis is straightforward: thirty different plant foods per week, fermented staples like curd and kanji, and restraint with emulsifier-heavy packaged foods. Think of it less as a diet and more as tending a garden that happens to live inside you.