
What we eat affects more than our waistlines — it shapes how our brains work. British dietitian Kimberley Wilson highlights eight food groups that help keep your brain sharp and may slow cognitive decline.
Fermented Foods
These are products that undergo fermentation. This category includes pickled vegetables and fruits, kefir, blue cheese, live yogurt, and kombucha. They help increase the diversity of beneficial microbes in our gut, and their benefits extend beyond digestion.
Wilson says there’s still a lot to learn about how the gut microbiome affects the brain and mental health. But some recent studies show gut microbes can significantly influence cognition.

Tea, Coffee, and Dark Chocolate
These foods are rich in polyphenols, which improve blood-vessel elasticity. In the gut, polyphenols are converted into phenolic acids that have protective effects on brain cells.
Studies show tea can reduce anxiety and boost memory and attention. Caffeine raises levels of a brain enzyme linked to protection against dementia. There is also evidence that dark chocolate can increase blood flow to the brain and improve working memory and visual processing.
Leafy Greens
Swiss chard, kale, spinach, watercress, and arugula are packed with nutrients that support brain and nervous system function. These include beta-carotene, folate, vitamin K, and magnesium. Regularly eating leafy greens is associated with slower brain aging, better memory, and a lower risk of dementia.

Raw Unsalted Nuts
Almonds, hazelnuts, pistachios, walnuts, and Brazil nuts are good sources of polyphenols. When gut microbes break them down, they produce phenolic acids that help protect the brain.
Nuts also improve communication between existing brain cells and promote the formation of new ones. They are a solid source of vitamin E, which has been linked to better memory in older adults.
Berries
Wilson says berries boost production of compounds that support the survival of brain cells and produce cognitive benefits like improved attention and short-term memory, according to BBC Science Focus.

Beans and Whole Grains
These foods are high in fiber. When gut microbes break down fiber, they produce short-chain fatty acids (SCFAs). SCFAs help maintain the gut barrier and protect the brain from inflammation and oxidative stress. Recent studies find only 9 percent of British adults aged 19 to 64 consume enough fiber.
Seafood and Seaweed
Seafood and seaweed provide nutrients that support the brain’s antioxidant defenses. They also contain iodine, which is essential for fetal brain development during pregnancy.
Fatty Fish
Salmon, mackerel, anchovies, trout, herring, and sardines are rich in omega-3 fatty acids, which are essential for healthy brain structure and function.
Studies suggest omega-3s may help people with mild cognitive impairment and depression. To get enough omega-3s, eat one to two servings of fatty fish per week or take a supplement that contains these fatty acids.
