1. Fatty fish
Fatty fish like sardines, mackerel, pilchards and salmon are packed with omega-3 fatty acids, especially DHA (docosahexaenoic acid), a critical polyunsaturated fatty acid. (Even tinned tuna contains omega-3s, though it’s not the richest source.) The brain uses these healthy fats to build brain and nerve cells vital for learning and memory. Omega-3s also help reduce inflammation (a major risk factor for many diseases) and lower the risk of cognitive decline, and a 2025 study1 in The Journal of Nutrition suggests fatty acids in fish may play a protective role in depression and anxiety.
Takeaway: “Aim to eat fish at least twice a week, choosing those with lower levels of mercury, such as sardines, pilchards, salmon, trout and tinned light tuna,” says Johannesburg-based registered dietitian Debby Watkins.
2. Berries
Blueberries are rich in antioxidant anthocyanins that give them their purple colour. Studies have shown2 they can delay brain ageing and help with learning and memory. Other berries, too, such as strawberries and raspberries, are high in antioxidants that are believed to protect cells in the brain from harmful free radicals, and contain chemicals that can change the way neurons communicate in the brain, improving its functioning. A 2024 study3 in The Journal of Berry Research found that including berries in your diet could be a useful way of “improving cognitive resilience and tackling neurological challenges”. Avocados are large berries, and an excellent source of vitamins your brain needs, such as C, E, K and the B complex vitamins.
Takeaway: Aim to have 150g (about a cup) of berries a day, and 50g of avocado (about a third of a medium-sized avocado, around 335kJ). “If you are trying to lose weight, reduce the portion of avo to a quarter,” says Watkins. “Avo is a very healthy fat, but fats are kilojoule-dense.”
3. Nuts
All nuts are full of protein, healthy fats, vitamins and minerals that benefit brain health, but walnuts are particularly potent. They are among the richest sources of alpha-linolenic acid (ALA), the plant form of omega-3 fatty acids, and among the best of the few foods containing serotonin, a chemical with a key role in regulating mood, sleep and appetite. A 2024 study4 in the journal Proceedings found the consumption of walnuts to be associated with improved mood and reduced stress. Another study5 in the journal Food & Function found a walnut-rich breakfast led to better reaction times and memory benefits.
Takeaway: Have 30g (about a handful) of nuts a day, raw and unsalted. “Watch the portion,” says Watkins.
4. Eggs
Versatile eggs are a rich source of protein (they contain all nine essential amino acids), B12, omega-3 fatty acids and choline, which your body uses to create acetylcholine – a neurotransmitter essential for regulating mood, memory and cognitive focus. They also contain tryptophan, which helps your body make mood-boosting serotonin. “Eggs once had a bad rap for containing cholesterol, but it’s now known that your brain needs cholesterol to function,” says Watkins. “And cholesterol from eggs has the least effect on your blood cholesterol.”
Takeaway: "Eating an egg a day, or three to seven eggs a week, is widely considered optimal for brain health, and safe for most people,” says Watkins. “They are also a very economical source of protein.”
5. Dark chocolate
Dark chocolate is high in brain-boosting compounds, including flavonoids, caffeine, antioxidants and tryptophan. These can improve blood flow to the brain and help with learning and memory, enhancing focus6, reducing mental fatigue and boosting overall mood. Dark chocolate also stimulates the brain to release endorphins, which act as natural mood boosters and pain relievers by binding to opiate receptors.
Takeaway: “Treating yourself to around 30g to 60g (two to four squares of a standard bar) of chocolate that is 70% cocoa solids or higher a few times a week as part of a healthy balanced diet is acceptable,” says Watkins.
References:
1. https://jn.nutrition.org/article/S0022-3166(25)00680-7/fulltext
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC7442370/
3. https://journals.sagepub.com/doi/10.1177/18785093241301881
4. https://www.mdpi.com/2504-3900/91/1/380
5. https://pubs.rsc.org/fo/article/16/5/1696/851336/The-impact-of-a-walnut-rich-breakfast-on-cognitive
6. https://www.sciencedirect.com/science/article/pii/S2405844024004614