If you’ve ever found yourself absentmindedly digging into a tub of ice cream after a bad day, you’re already aware that there’s some kind of link between food and mood.

Beyond that cinematic moment, we now know there is indeed a relationship between what we eat and how we feel.

This gut-brain connection starts with serotonin — a neurotransmitter that helps regulate sleep, appetite, mood, and also plays a role in pain inhibition. Around 95% of the body’s serotonin is produced in the digestive tract, which is lined with millions of nerve cells, or neurons.

The function of these neurons, as well as the production of neurotransmitters, is influenced by the trillions of bacteria that make up the gut microbiome. These bacteria are crucial for our health — they protect the intestinal wall, reduce inflammation, improve nutrient absorption, and activate neural pathways that connect directly with the brain.

What we eat directly affects the composition and function of the bacteria living in our gut. A healthy diet has a positive impact on the gut microbiota.

Eating well helps us feel better. There is clear evidence of a relationship between a healthy dietary pattern — such as the Mediterranean diet — and a reduced risk of depression.