Three portions of colourful fruit and vegetables a day can cut memory loss in old age by a fifth, a new study has found. When researchers at Harvard University followed 75,000 people in their late 40s and early 50s over a period of 20 years, they found that those with a diet rich in colourful foods were 20 per cent less likely to suffer cognitive decline.
Until now, you may have considered your waistline when making your dietary choices – but have you thought of your brain? Dr Lisa Mosconi, associate director of the Alzheimer's Prevention Clinic at Weill Cornell Medical College, suggests that of all the organs in the body, the brain is most easily damaged by a poor diet.
It's our most active organ, consuming 25 per cent of our energy and at times up to 50 per cent of our oxygen. And while there is no magic bullet when it comes to maintaining a healthy brain, eating enough certain nutrients has been proven to play an integral role in maintaining cognitive function and warding off dementia.
As a general rule, you should be aiming for a Mediterranean diet rich in fruit and vegetables, oily fish, wholegrains and the unsaturated fats found in olive oil, nuts and avocados. Lower your intake of foods with added sugars, saturated fat and processed meats.
Of course, you've heard this before – but science says it really does work. A study from the University of Edinburgh found that following the Mediterranean diet slows the shrinkage of the brain in old age. Another landmark study conducted at the University of California in 2016 showed on brain scans that a healthy lifestyle (including a Mediterranean diet and physical activity) reduces the build-up of proteins that lead to Alzheimer’s disease.
A varied diet is also key – 75 per cent of the processed foods that make up the majority of the average diet in the UK are based on just five animals and 12 products, as Professor James Goodwin, a director of the Brain Health Network, has told The Telegraph. This poses a problem for our health as getting stuck in a food rut can deprive the brain of key nutrients.
So, what should you have on your plate for a healthy brain?
Five nutrition rules for a better brain
1. Aim for three portions of colourful fruit and vegetables per day
The positive impact of a colourful diet on cognitive function is due to flavonoids, which can cut the risk of memory loss by a fifth and suppress neuroinflammation. Flavonoids are found in strawberries, oranges, grapefruit and blueberries, as well as other deeply coloured foods.
A study published in the Journal of Neuroscience found that, as well as improving memory, blueberries actively reversed memory loss and nerve cell damage in rats.
If their brain-boosting benefits weren’t enough, a 2019 study also found that a diet rich in flavonoids helps protect against cancer and heart disease.
2. Eat one portion of oily fish per week (at least)
The polyunsaturated fatty acids omega-3s are crucial for cognitive development at every stage of life, and aid learning and memory, so it may come as no surprise that one of the best things you can do for brain health is to eat at least one portion of oily fish per week (such as salmon, sardines, trout or mackerel).
Several studies have linked a low intake of omega-3 fatty acids with an increased risk of dementia. In one study, published in the Journal of the American Medical Association, participants who consumed fish once per week or more were found to have 60 per cent less risk of developing Alzheimer’s disease compared with those who rarely or never ate fish.
Salmon is also a good source of vitamin D, which is limited in food sources. A Cambridge University study found that people deficient in vitamin D performed worse in mental tests, and another from the University of Wisconsin-Madison showed that vitamin D helps preserve cognitive function in older adults.
3. Have eggs for breakfast
An egg or two for breakfast is one of the best things you can have on your plate for brain health. Egg yolks are a good source of choline, the nutrient that the body uses to produce neurotransmitter acetylcholine, which plays an integral role in regulating memory and mood. In one study published in the American Journal of Clinical Nutrition, a diet rich in choline was found to lower the risk of dementia by almost 30 per cent. Data from the US shows that most people consume less than the recommended intake of choline.
Eggs are also an excellent source of B vitamins, which have been shown to have a positive impact on cognitive function. A study published in the Journal of Nutrition found that folate, vitamin B-12 and vitamin B-6 supplementation had a positive effect on memory performance in a group of 211 women.
As psychologist Kimberly Wilson previously explained to The Telegraph, they are so crucial for a healthy brain that B vitamin deficiencies typically present with neurological symptoms such as memory loss and mood disturbance.
4. Snack on walnuts
Reach for walnuts as a brain-boosting snack – they are the highest in antioxidants of all nuts and are an excellent plant-based source of omega-3 fatty acids (in the form of alpha-linolenic acid). If that weren’t enough, they’re also a good source of vitamins and minerals including manganese, folic acid and vitamin E.
Research in the Journal of Nutrition, Health and Aging found that American adults who ate 13g of walnuts per day performed better on a range of cognitive tests, regardless of age and gender.
5. Drink tea
Pop the kettle on – a cup of tea could do your brain a favour. Tea is another source of the brain-boosting flavonoids found in colourful fruit and vegetables. Green tea also contains catechin, an antioxidant polyphenol that activates toxin-clearing enzymes.
The caffeine in tea (and coffee) also has short-term benefits for brain function: a study published in the Journal of Nutrition showed that participants with higher caffeine consumption scored better on tests of cognitive function, and other studies have positively linked caffeine with the ability to consolidate new memories.
However, hydration is of the utmost importance for brain health – even a small decrease in water intake can result in impaired cognitive function and brain fog. As caffeine has a dehydrating effect, bookend teas or coffees with plenty of water.