Young woman had brain fog but all her neurology tests were normal: Was her diet slowing her brain?

What many do not know is that the cause of muddled thinking may not be in the brain but way down in the stomach. New research indicates that an imbalance of the gut microbiome could very well play a key role in causing brain fog symptoms. And the easiest way to reset the gut is to change what you eat. We changed her platter to include fibre-rich foods, complex carbs, probiotics, legumes, fruits and vegetables. We threw out processed foods, caffeine and even tea. We increased her fluid uptake in the form of fruit-infused water. Simultaneously we worked on reducing her stress levels and encouraging sleep hygiene that improved her sleep pattern from five hours to seven hours.

Her symptoms began to ease within weeks. Over time, her energy levels and mental clarity improved significantly, underscoring how restoring gut balance can directly influence brain function.

How the gut triggers brain fog

Our gut is home to trillions of microbes — bacteria, viruses, fungi — which together make up the gut microbiome. When this system is in good health, it functions synergistically with the body’s immune, endocrine and nervous systems. But when it gets out of balance (a condition referred to as “dysbiosis”), it can set off downstream consequences that affect brain activity.

The gut-brain relationship is facilitated by the so-called “gut-brain axis” — the two-way communication pathway consisting of nerves (specifically the vagus nerve), immune signalling, bacterial metabolites (small molecules produced by bacteria) and hormonal messages. When harmful bacteria outnumber the good ones, then they damage the intestinal lining, known as “leaky gut,” permitting microbial fragments or toxins to pass into the bloodstream. This leads to systemic inflammation and can extend to the brain, impacting its functions.

Beneficial gut microbes release short-chain fatty acids (SCFAs) such as butyrate that nurture the gut-brain axis. An imbalance diminishes these healthy signals, which can cause mental slowness.

The gut microbiome plays a role in the production of major neurotransmitters (e.g., serotonin, GABA) and modulates the immune system. An imbalance can thus disrupt mood, concentration, memory and lucidity — all traits of brain fog. The idea is to reduce inflammation, feed the beneficial microbes and stabilise gut-brain signaling. That begins with the diet.

The diet changes we should make

1. Food diversity: A high-fibre, plant-based diet encourages microbial diversity. So exclude high-processed sugar and saturated fat that imbalance the good and bad bacteria.

2. Probiotic and prebiotic supplementation: Although the area is developing, research suggests some probiotics can restore balance to the microbiome and perhaps alleviate brain-fog symptoms.

3. What to throw out: Refined sugar, processed snacks, fried and packaged foods and foods high in saturated fats — all of which promote inflammation and harm the gut microbiome. Limit alcohol and artificial sweeteners as they disturb microbial balance.

4. What to include: Fresh vegetables, whole fruits, legumes, whole grains, fermented foods (such as curd, kefir, kimchi), nuts, seeds, and adequate hydration. Fibre-rich foods and natural probiotics feed the “good” bacteria that support brain health.

What’s a sample gut reset meal plan?

• Breakfast: Oats or millet porridge with flaxseeds, fresh fruit, and a serving of curd or kefir.

• Lunch: Brown rice or quinoa with mixed lentils, steamed vegetables and a bowl of curd or buttermilk.

• Dinner: Grilled or sautéed vegetables with a light protein such as tofu, paneer or fish, and a portion of fermented salad (like beetroot or cucumber with apple cider vinegar).

• Hydration tip: Start your day with warm water and lemon; include herbal teas like chamomile or peppermint for gut comfort.

The gut and brain work as one ecosystem — when we nourish one, the other heals too.

(Dr Praveen Gupta, chairman, Marengo Asia International Institute of Neuro & Spine (MAIINS), Marengo Asia Hospitals, Gurugram)