Actually, any oily fish offers benefits – so that includes mackerel, trout and fresh tuna, too. They're rich in omega-3 fatty acids – chiefly DHA and EPA – which play a key role in healthy brain function. DHA provides the building blocks of the brain and nervous system, and has been associated with improved learning ability. A healthy diet should include at least one portion (around 140g) oily fish each week. However, most of us don't manage this, says Public Health England.
omega 3 alternatives
Don't fancy fish? Walnuts are a good vegetarian source of omega-3s. Various studies have associated walnut consumption with better memory scores and cognitive function. And recent research, published in the Journal of Alzheimer's Disease, found that a walnut-rich diet may help reduce the risk, delay the onset and slow the progression of Alzheimer's. Eat half a handful as a snack, or add them to salads.
10 reasons to eat more nuts
Eat nutrient-rich leafy green vegetables such as spinach or kale every day – and you could stave off mental decline. That's according to a recent study from Rush University Medical Center in the US, which tracked the diets and cognitive powers of 950 people for an average of five years. On average, those who ate one or two servings of greens daily displayed the cognitive ability of someone 11 years younger who ate none.
While we're on the subject of veggies, broccoli is thought to be an effective brain-booster, too. Like spinach and kale, it's rich in vitamin K, which has been associated with improved memory and cognitive function. Add it to stir-fries, salads, curries and soups.
In order to function effectively, your brain needs a slow, steady supply of energy - which comes in the form of glucose. So opting for plenty of wholegrains – including granary bread, bran and brown pasta – will ensure your brain gets all the energy it needs.
6. Olive oil
Olive oil is rich in monounsaturated fats, which appear to slow the rate at which the brain ages. One study, published in the Annals of Neurology, looked at the diets of older women over five years. At the end of this period, those who'd consumed the most monounsaturated fat had the best cognitive functioning scores. Use olive oil in cooking and to dress salads.
Find out more about the health-boosting properties of oils
A diet rich in strawberries and blueberries can delay memory decline by up to two-and-a-half years, according to a Harvard study on older women. The reason? Berries boast high levels of antioxidant flavonoids called anthocyanidins, which protect the hippocampus – the area of the brain associated with memory and learning. Add fresh berries to your breakfast or eat them with yoghurt for dessert.
Yes, it can temporarily turn your teeth purple – but surely that's a small price to pay for boosting your brain power. A daily dose of beetroot juice can increase blood flow to the brain in older adults, say researchers at Wake Forest University in the US. The effect is thought to be due to the high concentration of nitrates found in beetroot. Nitrates are converted into nitrites, which in turn open up the blood vessels and increase blood flow and oxygen to the areas of the body that are most in need.
Adults who consume milk or other dairy products daily perform better in brain function tests than those who rarely or never touch dairy, scientists from the University of South Australia and University of Maine have found. The researchers suggest the effect may stem from the particular mix of nutrients found in dairy. This includes calcium, whey protein, vitamin D and magnesium. One word of warning, though: dairy produce is also high in unhealthy saturated fats. Always opt for skimmed or semi-skimmed milk.
10. Dark chocolate
Fancy a little treat? Choose a couple of chunks of high-quality dark chocolate – one that contains at least 70 per cent cocoa. Cocoa is rich in antioxidants called flavanols, which have been shown to boost brain health. One recent study from Columbia University in the US, for example, found that dietary cocoa flavanols may reverse age-related memory decline in healthy older adults.
Find out more about the health benefits of chocolate