Many of us have felt the gut-brain connection before we ever heard the term. We get “butterflies” in our stomach when we are nervous. We may lose our appetite during grief, feel nauseous when anxious, or crave sweet and salty foods when stress is high.
These are everyday examples of a powerful truth: the gut and brain are constantly talking to each other.
This two-way communication is called the gut-brain axis. The brain sends signals to the gut through nerves, hormones, and stress chemicals. When we are under stress, the body releases hormones like cortisol and adrenaline. These can change digestion, slow or speed bowel movements, increase stomach sensitivity, and affect appetite. This is why stress can trigger stomach pain, bloating, diarrhea, constipation, or cravings.
The gut also talks back to the brain. Inside our intestines are trillions of bacteria called the gut microbiome. Healthy bacteria help digest food, protect the gut lining, support the immune system, and produce helpful compounds. These compounds can send messages through the bloodstream, immune system, and nervous system, including the vagus nerve, which connects the gut and brain.
A well-nourished gut supports healthy bacteria growth, helping the body feel steadier and more resilient. An irritated or poorly nourished gut may contribute to digestive stress, fatigue, brain fog, anxiety, low mood, or poor sleep. Our daily food choices can affect not only our stomach, but also how we feel, think, and handle stress.
So, what feeds a healthier gut-brain connection? Fiber is one of the most important nutrients, as it feeds beneficial gut bacteria and help them produce short-chain fatty acids, which support the gut lining and may help calm inflammation. Good choices include kalo, poi, ʻuala, ʻulu, oats, tofu, mung beans, lentils, vegetables, and fruits.
Fermented foods, such as sour poi, yogurt, kimchi, natto, miso, and tempeh, also support healthy gut bacteria growth. Avocado, banana, nuts, seeds, and green leafy vegetables provide minerals like magnesium that support the nervous system.
Natural plant compounds, such as carotenoids and polyphenols, act as antioxidants that lower inflammation, supporting the health of the gut lining and brain cells.
Carotenoids include papaya, mango, kabocha, orange ʻuala, watercress, spinach, moringa, sweet potato leaves, and cooked lūʻau leaf. Polyphenols are found in purple ʻuala and eggplant, berries, ginger, turmeric, and garlic. Fish rich in omega-3 fatty acids, such as ʻōpelu, akule, sardines, salmon, and other fatty fish, also support brain health and inflammation balance.
Diets high in sugary drinks (juice, soda, energy drinks, specialty coffee drinks) and foods, fried foods, processed meats (Vienna sausage, hot dog, spam, deli meats), and packaged snacks support unhealthy bacteria growth and inflammation.
When these foods become the norm, this pattern may gradually make the body less resilient to stress and may contribute to fatigue, brain fog, irritability, low mood, anxiety, or difficulty coping with everyday stress.
Our kūpuna may not have used the word “microbiome,” but they understood that food, ʻāina, body, and spirit are connected.
